Safety Standards for Scaffolds Used in the Construction Industry

SUMMARY: The Occupational Safety and Health Administration (OSHA)

hereby revises the construction industry safety standards which

regulate the design, construction, and use of scaffolds. The final rule

updates the existing scaffold standards and sets performance-oriented

criteria, where possible, to protect employees from scaffold-related

hazards such as falls, falling objects, structural instability,

electrocution and overloading.

In particular, the final rule has been updated to address types of

scaffolds--such as catenary scaffolds, step and trestle ladder

scaffolds, and multi-level suspended scaffolds--not covered by OSHA's

existing scaffold standards. In addition, the final rule allows

employers greater flexibility in the use of fall protection systems to

protect employees working on scaffolds and extends fall protection to

erectors and dismantlers of scaffolds to the extent feasible. Another

area that the final rule strengthens is training for workers using

scaffolds; the conditions under which such employees must be retrained

are also specified in the final rule. Finally, the language of the rule

has been simplified, duplicative and outdated provisions have been

eliminated, overlapping requirements have been consolidated, and the

performance orientation of the rule has been enhanced to allow

employers as much flexibility in compliance as is consistent with

employee protection.

DATES: Effective dates. This standard will become effective on November

29, 1996, except for Sec. 1926.453(a)(2), which will not become

effective until an Office of Management and Budget (OMB) Control number

is received and displayed for this ``collection of information'' in

accordance with the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et

seq.). OSHA will publish a document in the Federal Register announcing

the effective date of Sec. 1926.453(a)(2).

Incorporation by reference. The incorporations by reference of

certain publications listed in this final rule are approved by the

Director of the Federal Register as of November 29, 1996.

Compliance date: Employers are required to comply with the

provisions of paragraphs (e)(9) and (g)(2) of Sec. 1926.451, which

address safe access and fall protection, respectively, for employees

erecting and dismantling supported scaffolds starting on September 2,

1997.

Comments. Written comments on the paperwork requirements of this

final rule must be submitted on or before October 29, 1996.

ADDRESSES: In compliance with 28 U.S.C. 2112(a), the Agency designates

for receipt of petitions for review of the standard, the Associate

Solicitor for Occupational Safety and Health, Office of the Solicitor,

Room S-4004, U.S. Department of Labor, 200 Constitution Avenue, N.W.,

Washington, D.C. 20210.

Suggestions and information regarding the drafting of non-mandatory

Appendix B, ``Criteria for Determining the Feasibility of Providing

Fall Protection and Safe Access for Workers Erecting or Dismantling

Supported Scaffolds'' should be submitted to the Docket Officer, Docket

S-205, U.S. Department of Labor, Room N-2625, 200 Constitution Avenue,

NW., Washington, D.C. 20210.

FOR FURTHER INFORMATION CONTACT: Ms. Anne C. Cyr, Occupational Safety

and Health Administration, Office of Information and Public Affairs,

Room N-3647, U.S. Department of Labor, 200 Constitution Avenue, N.W.,

Washington, D.C. 20210, Telephone: (202) 219-8148.

SUPPLEMENTARY INFORMATION:

I. Background

Congress amended the Contract Work Hours Standards Act (40 U.S.C.

327 et seq.) in 1969 by adding a new section 107 (40 U.S.C. 333) to

provide employees in the construction industry with a safer work

environment and to reduce the frequency and severity of construction

accidents and injuries. The amendment, commonly known as the

Construction Safety Act (CSA), significantly strengthened employee

protection by authorizing the promulgation of construction safety and

health standards for employees of the building trades and construction

industry working on federal and federally-financed or federally-

assisted construction projects. Accordingly, the Secretary of Labor

issued Safety and Health Regulations for Construction in 29 CFR part

1518 (36 FR 7340, April 17, 1971).

The Occupational Safety and Health Act of 1970 (the OSH Act) (29

U.S.C. 651 et seq.) authorized the Secretary of Labor to adopt

established federal standards issued under other statutes, including

the CSA, as occupational safety and health standards. Accordingly, the

Secretary of Labor adopted the Construction Standards, which had been

issued under the CSA, as OSHA standards (36 FR 10466, May 29, 1971).

The Safety and Health Regulations for Construction were subsequently

redesignated as 29 CFR part 1926 (36 FR 25232, December 30, 1971).

Standards addressing scaffolds, Secs. 1926.451 and 1926.452, were

adopted in subpart L of part 1926 as OSHA standards as part of this

process.

Various amendments were made to subpart L during the first two

years of the OSH Act. The amendments revised scaffold provisions that

addressed planking grades, wood pole scaffold construction, overhead

protection, bracket scaffold loading, and plank spans. Also,

substantive provisions concerning pump jack scaffolds, height of catch

platforms, and guardrails were added (37 FR 25712, December 2, 1972).

Based on concerns regarding the effectiveness of the existing

scaffold standards, OSHA began a complete review of subpart L in 1977.

The Agency consulted the Advisory Committee on Construction Safety and

Health (ACCSH) several times regarding draft revisions to subpart L.

The transcripts of these meetings are part of the public record for

this rulemaking (Ex. 3-4). OSHA addresses specific recommendations from

the ACCSH, as well as those submitted by other rulemaking participants,

in the Summary and Explanation section, below.

On November 25, 1986, OSHA issued a notice of proposed rulemaking

(NPRM) on scaffolds used in construction (51 FR 42680). The proposal

set a period, ending February 23, 1987, during which interested parties

could submit written comments or request a hearing. The Agency twice

granted requests for more time to submit comments and hearing requests.

OSHA first extended the comment and hearing request period to June 1,

1987 (52 FR 5790, February 26, 1987) and then extended that period to

August 14, 1987 (52 FR 20616, June 2, 1987). OSHA received 602 comments

on the proposal, along with several hearing requests.

On January 26, 1988, OSHA announced that it would convene an

informal public hearing on March 22, 1988 to elicit additional

information on

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specific issues related to scaffolds, fall protection and stairways and

ladders (53 FR 2048). The informal public hearing was held on March 22-

23, 1988, with Administrative Law Judge Joel Williams presiding. At the

close of the hearing, Judge Williams set a period, ending May 9, 1988,

for the submission of additional comments and information. OSHA

received 31 submissions, including testimony and documentary evidence,

in response to the hearing notice. On August 11, 1988, Judge Williams

certified the rulemaking record, including the hearing transcript and

all written submissions to the docket, thereby closing the record for

this proceeding.

In 1988, the American National Standards Institute (ANSI), an

organization which sets voluntary consensus standards, approved a

revision of ANSI A10.8-1977, Scaffolding, updating its safety

requirements for the use of scaffolds in construction and demolition

operations. Section 6(b)(8) of the OSH Act requires that when an OSHA

standard differs substantially from an existing national consensus

standard, the Secretary must publish ``a statement of the reasons why

the rule as adopted will better effectuate the purposes of the Act than

the national consensus standard.'' In compliance with that requirement,

OSHA has reviewed the requirements of this final rule with reference to

the corresponding provisions of ANSI A10.8-1988. The Agency discusses

the relationship between the provisions of subpart L and corresponding

provisions of ANSI A10.8-1988 in the Summary and Explanation, below.

On March 29, 1993, OSHA reopened the rulemaking record for subpart

L (58 FR 16509) to obtain additional comments and information regarding

fall protection and safe means of access for employees erecting and

dismantling scaffolds; the use of crossbraces in scaffold systems; and

the use of repair bracket scaffolds. The comment period was scheduled

to end on May 28, 1993. On May 26, 1993, the Agency extended the

comment period (58 FR 30131) to June 29, 1993, in response to a request

for additional time to submit comments. OSHA received 46 comments in

response to the March 29 notice. Those comments are discussed below in

relation to the pertinent provisions of the final rule.

On February 1, 1994, OSHA again reopened the rulemaking record (59

FR 4615) to obtain comments and information regarding scaffold

stairways; repair bracket scaffolds; tank builder scaffolds; a NIOSH

study of workplace fatalities; and scaffold-related material

incorporated from the proposed part 1910, subpart D rulemaking. The

comment period, which ended on March 18, 1994, elicited 46 comments.

Those comments are also discussed below in relation to the pertinent

provisions of the final rule.

A wide range of employers, businesses, labor unions, trade

associations, state governments, and other interested parties

contributed to the development of this record. OSHA appreciates these

efforts to help develop a rulemaking record that provides a sound basis

for the promulgation of revised subpart L.

Based on its review of existing subpart L, OSHA believes that

certain provisions in the existing standards are outdated, redundant,

or ambiguous. In addition, some types of scaffolds used in construction

(e.g., catenary scaffolds) are not clearly addressed by the existing

standards, and some provisions cover only certain types of scaffolds

when they should apply to all. The final rule eliminates those

unnecessary, outdated and redundant provisions (e.g., revised subpart L

states the requirement for guardrails once, rather than 19 separate

times as in the existing standard).

OSHA is coordinating the revision of part 1926, subpart L, with the

ongoing rulemakings initiated to revise the General Industry (part

1910, subpart D) and Shipyard (part 1915, subpart N) scaffold

standards, so that those standards will be consistent, where

appropriate.

II. Hazards Involved

Scaffold-related incidents resulting in injuries and fatalities

continue to occur despite the fact that OSHA has had a scaffold

standard (existing subpart L) in place since 1971 (Exs. 1, 2, 3, 42,

43, 44 and 45). However, the Agency believes that compliance with the

standard being published today will be better than it has been in the

past because this standard has been simplified, brought up to date, and

strengthened to provide additional protection.

Although specific accident ratios cannot be projected for the

estimated 3.6 million construction workers currently covered by subpart

L, the Economic Analysis that accompanies this final rule estimates

that, of the 510,500 injuries and illnesses that occur in the

construction industry annually, 9,750 are related to scaffolds. In

addition, of the estimated 924 occupational fatalities occurring

annually, at least 79 are associated with work on scaffolds.

OSHA prepared the following statistical estimates (based on 4.5

million construction workers then covered by subpart L) to support the

1986 proposal for subpart L, based on a review of accident data

prepared by the Bureau of Labor Statistics (BLS) (Ex. 3-1). The revised

scaffold standards contain a number of provisions designed specifically

to address the findings of this analysis.

a. Seventy-two percent of the workers injured in scaffold accidents

covered by the BLS study attributed the accident either to the planking

or support giving way, or to the employee slipping, or being struck by

a falling object. Plank slippage was the most commonly cited cause.

b. About 70 percent of the workers learned of the safety

requirements for installing work platforms, assembling scaffolds, and

inspecting scaffolds through on-the-job training. Approximately 25

percent had no training in these areas.

c. Only 33 percent of scaffolds were equipped with a guardrail.

The following are recent examples, from the OSHA Integrated

Management Information System (IMIS) data, of the types of accidents

that continue to injure and kill employees working on scaffolds.

In July, 1991, two employees were working on a pump jack

scaffold doing roofing work. The scaffold became overloaded and broke.

The employees fell 12 feet to the ground, resulting in one fatality and

one serious injury.

In August, 1992, two workers were erecting an aluminum

pump jack scaffold. As they were raising the second aluminum pole, the

pole apparently contacted an overhead power line. The pole being raised

was 29 feet 10 inches long and the line was 28 feet 10 inches high. The

line was approximately 11 feet from the house. One employee died and

the other suffered severe burns and was hospitalized. The surviving

employee noted that he thought they had enough room to work around the

power lines, which were not de-energized or shielded.

In July, 1993, a foreman climbed up the frame of a 45 foot

high tubular welded frame scaffold to check on an employee who was

sandblasting inside a stack at a steam plant. The scaffold was not

equipped with guardrails and there was no access ladder. After talking

to the employee, the foreman either fell from the unguarded platform or

fell while climbing down the scaffold end frame, resulting in his

death. There were no witnesses to the fall.

Based on its analysis of the available data and its field

experience in enforcing construction standards, the Agency has

determined that employees using scaffolds are exposed to a

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significant risk of harm. Specifically, scaffold related fatalities

still account for approximately 9% of all fatalities in the

construction workplace. In addition, the above data indicate that the

revised final standard would have prevented many of these accidents

more effectively than compliance with the existing scaffold standards.

Consequently, OSHA finds that the revision of its scaffold standards

for construction is necessary to improve employee protection. OSHA has

determined that, as revised, the standard clearly states employers'

duties and the appropriate compliance measures.

For additional discussion of incidence rates, significance of risk,

and the protectiveness of the final rule, see Section IV, Summary of

the Final Economic Analysis.

III. Summary and Explanation of the Final Rule

The following discussion explains how the final rule corresponds to

or differs from the proposed scaffold standard and the existing

standard, and how the comments and testimony presented on each

provision influenced the drafting of the final rule. Except where

otherwise indicated, proposed provisions which did not elicit comment

have been promulgated as proposed, for reasons stated in the preamble

to the proposed rule which is hereby incorporated by reference (51 FR

42680).

Subpart L--Scaffolds. The title of subpart L of OSHA's Construction

standards has been changed from ``Scaffolding'' to ``Scaffolds'', as

proposed. The word ``scaffold'' is used in the title and throughout the

final rule in lieu of the longer word ``scaffolding.'' This change does

not affect the scope of subpart L. OSHA did not receive any comments

concerning the title of the subpart.

Section 1926.450 Scope, application and definitions applicable to

this subpart. Paragraph (a) of Sec. 1926.450 states the scope and

application of subpart L. The final rule will apply to all scaffolds

used in construction, alteration, repair (including painting and

decorating), and demolition operations covered under 29 CFR part 1926,

except that crane or derrick suspended personnel platforms will

continue to be regulated under Sec. 1926.550(g). Language explicitly

excluding these platforms has been added to the final rule. The

relationship between Sec. 1926.550(g), which covers these platforms,

and subpart L is discussed further in relation to Sec. 1926.451(c)(2)

and NPRM Issue 3, below. In addition, aerial lifts are covered

exclusively in Sec. 1926.453, as noted in paragraph (a) of

Sec. 1926.450. Proposed paragraph (a) covered all scaffolds.

A commenter (Ex. 2-38) recommended that OSHA explicitly exempt

personnel platforms suspended by cranes or derricks from this final

rule. The commenter stated ``[t]his would avoid confusion, both for the

Compliance Officer and the employer.'' As noted above, the Agency

recognizes the need for an exemption and has revised paragraph (a)

accordingly.

Another commenter (Ex. 2-18), representing the elevator industry,

suggested that OSHA revise the scope of proposed subpart L to exclude

``False cars used in elevator construction that are equipped with

independent safeties that operate on the guardrails * * *'' The

commenter supported the suggestion as follows: ``An elevator false car

operates on fixed guiderails * * * equipped with safeties that ride on

the guiderails * * * and are operated automatically by the slackening

of the hoisting rope. Past OSHRC (Occupational Safety and Health Review

Commission) decisions have recognized that a false car is a unique tool

and is not a scaffold.'' The commenter did not cite any specific OSHRC

decisions to support its assertion.

OSHA disagrees with this commenter on this point, because the

findings in two enforcement cases involving the Otis Elevator Company

(12 OSHRC 1470 and 12 OSHRC 1513 (1985)) clearly indicate that the

scaffold standards of subpart L cover false cars. In Otis Elevator

Company, 12 OSHRC 1513 (1985), the final order stated:

The evidence in this case showed that the false cars were used

as elevated working space from which employees installed permanent

elevator rails. The ability to raise and lower the false cars by

means of cables from overhead supports does not remove false cars

from the applicability of the scaffold standard, and a false car is

found to be a scaffold within the meaning of 29 CFR 1926.452(b)(27).

The Agency notes that elevator false cars fit the definition of a

``scaffold'' in final rule Sec. 1926.450(b) in that they are temporary

elevated work platforms used for supporting employees. Accordingly,

there are no apparent grounds for disputing that elevator false cars

are properly regulated under part 1926, subpart L. Therefore, OSHA will

continue to regulate temporary elevated work platforms, such as false

cars and go-devils used in elevator shaft construction, as scaffolds.

The Scaffolding, Shoring and Forming Institute (SSFI) (Ex. 2-367)

recommended that OSHA include ``Window cleaning'' within the scope of

subpart L, because ``[w]indow cleaning is a common activity that, for

the overwhelming majority of instances, uses transportable suspended

scaffolds.'' In addition, the Scaffold Industry Association (SIA) (Ex.

2-368) suggested that OSHA add ``scheduled and unscheduled maintenance

(including but not limited to painting and decorating, tuck pointing,

sand blasting, water proofing and window cleaning)'' to the scope of

subpart L, because maintenance is a type of work ``regularly performed

on scaffolds addressed in this subpart and, therefore, should be

included in the scope.''

Another commenter (Ex. 2-462) stated that expanding the scope of

subpart L to include maintenance would create confusion and ``would

greatly reduce the safety standard already in place for Powered

platforms for exterior building maintenance'' (29 CFR 1910.66).

The Agency is not expanding the scope to include building

maintenance because building maintenance (such as window cleaning) is a

general industry activity, addressed under the appropriate scaffold and

powered platform standards of 29 CFR part 1910.

OSHA received a general comment (Ex. 2-29) which noted that

Sec. 1910.66 addressed powered platforms used for exterior building

maintenance in general industry and urged OSHA to ensure that the

corresponding regulatory language in the construction standard for

scaffolds was consistent. As discussed above, the Agency agrees, and is

coordinating its General Industry, Shipyard and Construction rulemaking

activity so that employers in those industries have consistent

regulation, to the extent that workplace conditions permit.

Paragraph (b) of Sec. 1926.450 lists and defines all major terms

used in subpart L. Proposed terms and definitions which elicited no

comments and which have been promulgated unchanged or with only minor

editorial revisions are not addressed below. Those terms include

``adjustable suspension scaffold'', ``boatswains' chair'', ``body

belt'', ``body harness'', `` brace'', ``cleat'', ``coupler'',

``crawling board'', ``double pole scaffold'', ``exposed power lines'',

``fabricated decking and planking'', ``float (ship) scaffold'', ``form

scaffold'', ``hoist'', ``interior hung scaffold'', ``ladder stand'',

``lean-to scaffold'', ``lower level'', ``mobile scaffold'', ``multi-

level suspension scaffold'', ``multi-point adjustable scaffold'',

``open sides and edges'', ``overhand bricklaying'', ``platform'',

``pole scaffold'', ``pump jack scaffolds'', ``roof bracket scaffold'',

``runner'', ``self-

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contained adjustable scaffold'', ``shore scaffold'', ``single-point

adjustable suspension scaffold'', ``single pole scaffold'', ``step

platform and trestle ladder scaffold'', ``stone setter multi-point

adjustable suspension scaffold'', ``supported scaffold'', ``suspension

scaffold'', ``tube and coupler scaffolds'', ``tubular welded frame

scaffold'', ``two-point suspension scaffold'', ``unstable objects'',

``vertical pickup'', ``walkway'', and ``window jack scaffold''.

As proposed, OSHA is revising its definitions for particular types

of scaffolds by specifying whether a particular type of scaffold is a

``supported'' or a ``suspension scaffold.'' OSHA believes that adding

this information will make it easier for employers to identify the

appropriate general requirements in final rule Sec. 1926.451.

In addition, the Agency has revised subpart L definitions by

deleting language that limits the use of a particular type of scaffold.

Such substantive limitations are more appropriately placed in

regulatory text. Accordingly, for example, OSHA has revised the

definition for ``bricklayers' square scaffolds'' (a scaffold composed

of framed wood squares which support a platform, limited to light and

medium duty) by deleting the words ``limited to light and medium

duty''. Similarly, OSHA has revised the definition for ``coupler'' to

be ``a device for locking together the component tubes of a tube and

coupler scaffold'', deleting language addressing the material used for

the coupler because such requirements are more properly located in

Secs. 1926.451 or 1926.452.

The following discussion covers the terms for which definitions are

being added or revised in this final rule and those proposed terms

which elicited comments.

``Bearer (Putlog).'' This definition is the same as the definition

proposed except that the word ``Putlog,'' an industry-used term, has

been added to the definition. A commenter (Ex. 2-29) suggested putlog

should be included in the proposed definition ``to show a close or

synonymous relationship to the term `bearer' '' and because ``it is a

widely used and understood term.'' The Agency agrees with the commenter

and has revised the proposed definition accordingly.

``Bricklayers' Square Scaffold'' is defined in existing

Sec. 1926.452(b) and the proposed definition is substantively unchanged

in the final rule. The definition deletes the existing Sec. 1926.452(b)

requirements that bricklayers' square scaffolds be constructed of

``wood'' and that the platform capacity be limited to ``light and

medium duty.'' The revised definition recognizes that bricklayers'

square scaffolds can be constructed of materials other than ``wood''

and that their capacity is not limited to ``light and medium duty'' as

long as they can meet the capacity requirements set forth in final rule

Sec. 1926.451(a)(1).

A commenter (Ex. 2-23) suggested that OSHA adopt the ANSI A10.8-

1977 definition for Bricklayers' Square Scaffold which specifies the

use of ``wood'' and the ability to sustain light to medium loads. As

stated above, OSHA believes it would be inappropriate to limit

technological advances that would provide for the use of other

materials with greater capacities. Therefore, the Agency has not made

the suggested revision.

``Carpenters' bracket scaffold.'' This term means a supported

scaffold consisting of a platform supported by brackets attached to

building or structural walls. The final rule is identical to the

proposal. The SIA (Ex. 2-368) suggested that because different trades

(i.e., cement finishers) use this type scaffold, the term be renamed

``bracket scaffold'' exclusively. OSHA recognizes that this type of

scaffold is used by several trade groups. However, OSHA believes that

it is widely recognized in the construction industry that ``carpenters'

bracket scaffolds'' are not used only by carpenters. Therefore, the

Agency is not making the suggested revision.

``Catenary scaffold.'' This type of scaffold is not specifically

addressed in OSHA's existing rule but is covered in final rule

Sec. 1926.452(r). This term refers to a suspension scaffold consisting

of a platform supported by two essentially horizontal and parallel

ropes which are secured to structural members and may be supported by

vertical pickups. The proposed definition has been changed to replace

the language ``fastened to'' with ``supported by'' and a phrase has

been added explaining that horizontal ropes ``may be supported by

vertical pickups.''

One commenter (Ex. 2-23) suggested that OSHA insert the word

``wire'' between the words ``parallel'' and ``rope.''

However, OSHA does not intend to restrict the type of material used

for suspension scaffold rope as long as it is ``capable of supporting

without failure six times the maximum intended load'' as set forth in

final rule Sec. 1926.451(a)(3).

Two commenters (Exs. 2-23 and 2-368) suggested OSHA replace the

words ``fastened to'' with ``supported by'' in this definition. OSHA

agrees that the suggested words more accurately describe the function

of the horizontal ropes with relation to the platform and is revising

the proposed definition accordingly.

In addition, the SIA (Ex. 2-368) suggested that OSHA add the phrase

``and may be supported by vertical pickups''. OSHA agrees with the

commenter. Vertical pick-ups can act as supports for sagging horizontal

ropes. Also, because final rule Sec. 1926.452(r)(1) refers to vertical

pickups, OSHA believes that it is appropriate to include this phrase in

the definitions.

``Chimney hoist.'' This term is being added to recognize a specific

type of multi-point adjustable suspension scaffold used to gain access

to worksites inside chimneys.

``Competent person.'' This term is being added to the final rule as

a matter of convenience for users. The definition is identical to that

found in Sec. 1926.32.

``Continuous run scaffold (run scaffold)'' means a two-point or

multi-point adjustable suspension scaffold constructed using a series

of interconnected braced scaffold members or supporting structures

erected to form a continuous scaffold. This term is being added to

recognize this type of system. The Agency notes that the key element

here is that the scaffold members must be interconnected so that the

erected scaffold acts as a single unit. This would preclude planking

across two independent scaffolds without joining them so the resulting

scaffold acts as one unit. This system allows erecting a lengthy

scaffold without requiring a continuous planked platform, as long as

the smaller platform is properly guarded.

``Deceleration device.'' This term means any mechanism, such as a

rope grab, rip stitch lanyard, specially-woven lanyard, tearing or

deforming lanyard, automatic self-retracting lifelines/lanyard, which

serves to dissipate a substantial amount of energy during a fall

arrest, or otherwise limits the energy imposed on an employee during

fall arrest. The proposed definition, which was effectively identical,

has been editorially revised for the sake of clarity.

Three commenters (Exs. 2-13, 2-368 and 2-516) suggested that rope

grabs and some self-retracting lifelines are not ``deceleration

devices'' but are actually fall arrest devices. OSHA notes, however,

that it is difficult to differentiate clearly between system

components, as suggested, because fall arrest (stopping) and energy

absorption (braking) are closely related. The Agency also observes that

the performance criteria for personal fall arrest equipment address the

entire system, not just ``fall arresters'' or

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``energy absorbers''. Accordingly, OSHA has not made the suggested

change.

``Equivalent.'' This term is used in the final rule to allow

alternative means of complying with the standard. The definition

provides that the employer must be able to demonstrate that the

alternative means of compliance will provide an equal or greater degree

of safety than that attained by using the method or item specified in

the standard. The final definition is identical to the proposed

definition, except that minor editorial changes have been made for the

sake of clarity. The final rule definition is consistent with the

corresponding definitions in Sec. 1910.66 and in part 1926, subparts M

and X.

The SIA (Ex. 2-368) suggested that OSHA not require the employer to

``demonstrate whether or not the scaffold is of `equal or greater

degree of safety' because the employer is too many steps removed from

the manufacturer'' and because requiring the employer to test for

equivalency would create a significant danger that failure would occur.

However, the proposed language reflects the Agency's longstanding

position that employers who choose to deviate from criteria set in OSHA

standards must be able to demonstrate that employee protection has not

been adversely affected. The employer has the flexibility to establish

equivalence by any effective means, including information available

from equipment suppliers and taking into account the specific

circumstances of the work to be done.

``Eye'' or ``eye splice'' means a loop with or without a thimble at

the end of a wire rope. This term is being added to the final rule to

clarify the Agency's intent that this type of connection is an

acceptable way to connect wire ropes without significantly affecting

their strength or capacities. The term is used in final rule

Sec. 1926.451(d) (8) and (9).

``Fabricated frame scaffold'' means a supported or suspended frame

scaffold consisting of platform(s) supported on fabricated end frames

with integral posts, horizontal bearers, and intermediate members. This

is the term for the type of scaffold presently identified as ``tubular

welded frame scaffold.'' OSHA has determined that the current term is

too restrictive because the words ``tubular'' means round and

``welded'' means that metal components are involved. The provisions of

final rule Sec. 1926.452(c), Fabricated frame scaffolds, are not

subject to such limitations. They address fabricated frames and related

scaffold components whether the component parts are square or round, or

made of metal, plastic, wood, or some other material. The final rule

definition is identical to that in the proposed rule.

Two commenters (Exs. 2-13 and 2-320) suggested using the existing

term ``tubular welded frame'' and one commenter (Ex. 2-23) suggested

using the term ``Fabricated tubular frame (Tubular welded frame

scaffold)'' instead of the proposed term. However, as explained above,

OSHA does not intend to restrict this term to ``tubular'' or ``welded''

components.

``Failure.'' This term is used in performance-oriented paragraphs

such as Secs. 1926.451 (a)(1) and (a)(3), which address scaffold

capacity. Because the word might otherwise be interpreted to mean only

breakage or a physical separation of scaffold components, the final

rule definition clearly indicates that load refusal (the point where

the ultimate strength of a component is exceeded) is also considered to

be failure. This is the point where structural members lose their

ability to carry loads although they have not broken or separated. The

term is the same as the term defined in Subpart X of Part 1926, Ladders

and Stairways. The definition for ``failure'' in the final rule is the

same as proposed.

One commenter (Ex. 2-40) suggested that the term ``ultimate

strength'' was not clearly defined. Another commenter (Ex. 2-38)

suggested deleting the last sentence of the proposed definition (Load

refusal is the point where the ultimate strength is exceeded) to avoid

confusion between ``ultimate strength'' and ``overloading without

breaking.'' As OSHA stated above, ``ultimate strength'' may be exceeded

without component parts breaking or separating. Therefore, the Agency

believes the suggested changes are unnecessary.

``Guardrail system.'' This term refers to perimeter protection

composed of vertical barriers which are erected to prevent employees

from falling. The final rule definition is essentially identical to the

proposed definition. This term replaces the definition of ``guardrail''

in the existing rule, which appeared at Sec. 1926.452(b)(10). The old

definition was rail secured to uprights and erected along the exposed

sides and ends of platforms. OSHA believes that this definition did not

adequately reflect the manner in which toprails, midrails and other

intermediate members, and toeboards combine to provide effective fall

protection. The final rule definition of guardrail clearly indicates

that the entire system, including toprail, midrail (or other

intermediate protection), and uprights, is covered when guardrails are

addressed in final rule Sec. 1926.451(e). The definition of guardrail

system used in the proposed rule stated that a guardrail system was ``a

vertical barrier erected to prevent employees from falling from an open

side or edge of a scaffold platform or walkway''. The proposed

definition also distinguished between ``Type I guardrails'', which were

capable of providing fall protection without the use of personal fall

arrest systems, and ``Type II guardrails'', which would need to be

supplemented by personal fall arrest systems (as explained below, OSHA

has not maintained this distinction in the final rule).

The SIA (Ex. 2-368) suggested replacing the word ``prevent'' with

the word ``protect'' in the proposed definition of ``guardrail

system''. According to standard dictionary meanings of both words,

``prevent'' more accurately describes the function of the guardrail

system, which is to keep the employee from going past the perimeter of

the scaffold in the first place. Therefore, the Agency is not making

the suggested change.

Three commenters (Exs. 2-13, 2-53 and 2-370) recommended that OSHA

retain the guardrail rules in the existing scaffold standard and

eliminate the concept of ``Type I'' and ``Type II'' from the proposed

definition of guardrail systems. The commenters suggested that the old

rule's definition of guardrail protection would provide more fall

protection than the definition used in the proposed rule. For reasons

discussed further below, OSHA finds that the final rule's requirements

for guardrail systems, which are essentially identical to those in the

proposed rule, provide more protection than the requirements in the

existing rule. However, OSHA has deleted the discussion of ``Type I''

and ``Type II'' guardrails from the final rule for the sake of clarity

and has added specific criteria for guardrails to final rule

Sec. 1926.451(g).

``Horse scaffold'' means a supported scaffold consisting of a

platform supported by construction horses. Horse scaffolds made of

metal are sometimes known as trestle scaffolds. The proposed definition

was similar except that it did not include the term ``trestle

scaffold.'' The SIA (Ex. 2-368) suggested revising the definition to

specify that horse scaffolds ``may be constructed of wood, metal, or a

combination of both. The metal horses may be referred to as `trestle

horses'.'' Under OSHA's performance-oriented approach to subpart L, an

employer may use any construction materials (e.g., wood or metal) that

enable the scaffold to comply with the capacity requirement set forth

in Sec. 1926.451(a)(1). However,

[[Page 46031]]

the Agency agrees that it would be useful to indicate that some horse

scaffolds constructed of metal are known as trestle scaffolds. OSHA has

revised the definition accordingly.

``Ladder jack scaffold.'' The final rule definition, which is

identical to that in the proposed rule, states that this type of

scaffold is a supported scaffold consisting of a platform supported by

brackets attached to ladders.

A commenter (Ex. 2-23) stated that the capacity of this type of

scaffold should be limited to ``light duty'' and that the words ``light

duty'' should be included in this definition. As discussed above, OSHA

believes it is inappropriate for definitions to include substantive

requirements. In any event, the Agency has determined that a ladder

jack scaffold which complies with the capacity criteria of

Sec. 1926.451(a)(1) and the other pertinent subpart L requirements will

be considered acceptable. Accordingly, OSHA has not made the suggested

change.

``Landing.'' This new term, which has been added to ensure that the

requirements of final rule Sec. 1926.451(e)(4) are clearly understood,

refers to a platform at the end of a flight of stairs.

``Large area scaffold'' means a pole scaffold, tube and coupler

scaffold, systems scaffold, or fabricated frame scaffold erected over

substantially the entire work area, for example; A scaffold erected

over the entire floor area of a room. The Agency has added this term

and definition, along with final rule Sec. 1926.452(d), to provide a

reference point in the standard for this widely used type of scaffold.

``Lifeline'' means a component consisting of a flexible line for

connection to an anchorage at one end to hang vertically (vertical

lifeline) or for connection to anchorages at both ends to stretch

horizontally (horizontal lifeline), and which serves as a means for

connecting other components of a personal fall arrest system to the

anchorage. A vertical lifeline is sometimes known as a dropline. A

horizontal lifeline is sometimes known as a trolley line. This

definition, which was not part of the proposed rule, has been added for

the sake of clarity. The definition in part 1926, subpart M, Fall

Protection, is consistent with the definition in final subpart L. The

proposed terms ``dropline'' and ``trolley line'', along with their

definitions, have been deleted as separate definitions and have been

incorporated into this final rule definition.

One commenter (Ex. 2-57) stated that a ``trolley line'' was a

``horizontal lifeline'' and suggested that OSHA set ``strength

requirements.'' While final rule subpart L does not set numerical load

requirements for ``horizontal lifelines'', criteria for such equipment

are provided in Sec. 1926.502(d), subpart M, as referenced by a note to

final rule Sec. 1926.451(g)(3).

``Masons' adjustable supported scaffold.'' OSHA proposed this term,

which was not defined in existing subpart L, so employers who used

``self-contained adjustable scaffolds'' in masonry operations would

have a clear reference point in revised subpart L. The final rule is

identical to the proposed rule definition.

One commenter (Ex. 2-23) suggested replacing the parenthetical

reference to self contained adjustable scaffolds with the definition

for such scaffolds in ANSI A10.8-1977. However, to limit redundancy and

confusion, OSHA does not believe that this term should be defined by

the format suggested by the commenter.

``Masons' multi-point adjustable suspension scaffold.'' This term

replaces the term ``Masons' adjustable multiple-point suspension

scaffold'' in the existing standard. The term means a two-point or

multi-point adjustable suspension scaffold designed and used for

masonry operations. The final rule definition is the same as that

proposed.

One commenter (Ex. 2-23) suggested OSHA adopt the definition for

this term from ANSI A10.8-1977, which contains the language

``continuous platform.'' However, it is not OSHA's intent to limit this

type of scaffold to a single ``continuous platform.'' All types of

multi-point suspension scaffolds covered by subpart L may consist of

more than one platform. Multi-point scaffolds are not limited by the

number of suspension wires, platforms, or the location of attachment of

the suspension wires to the platform or platforms (Example: A multi-

point scaffold may consist of one platform suspended by four wires or

it may consist of two platforms suspended by four wires). Additionally

the definition suggested by the commenter did not include the words

``masonry operations.'' OSHA is including the words ``masonry

operations'' in this definition so it applies specifically to such

scaffolds used in the masonry trade.

``Maximum intended load'' means the total load of all persons,

equipment, tools, materials, transmitted loads, and other loads

reasonably anticipated to be applied to a scaffold or scaffold

component at any one time. This term replaces the existing terms

``maximum rated load'' and ``workload''. The term addresses the types

of loads which are to be included when determining the maximum load.

OSHA has been concerned that the word ``rated'' in the existing term

``maximum rated load'' does not clearly express how the safety factor

of four (existing rule paragraph 1926.451(a)(7)) or six (existing rule

paragraph 1926.451(a)(2)) is to be incorporated into the determination

of the maximum load. The final rule definition and final rule

Sec. 1926.451(a)(1) clearly indicate that the maximum intended load is

determined without regard to safety factors. Once the maximum intended

load is determined, the employer then applies the pertinent safety

factor to determine the requisite strength for the system in question.

The final rule definition is the same as in the proposed rule

except the word ``employees'' has been replaced with the word

``persons''. The SIA (Ex. 2-368) suggested this change because

``[p]ersons other than employees might be on a scaffold thus

overloading it.'' OSHA agrees that the weight of all ``persons'' needs

to be considered when calculating the maximum intended load.

One commenter (Ex. 2-23) suggested that OSHA add the closely

related term ``scaffold load rating'' which includes definitions for

the words ``heavy-duty loading,'' ``medium-duty loading,'' ``light-duty

loading'' and ``special loading.'' The Agency provides examples of

appropriate measures for ``heavy-duty,'' ``medium-duty'' and ``light-

duty'' scaffold in non-mandatory Appendix A of final rule subpart L.

Accordingly, the Agency believes the appropriate information is

available and no further changes are necessary.

Two comments (Exs. 2-13 and 2-320) suggested replacing the proposed

term and definition of maximum intended load with the term ``Maximum

Rated Load.'' The commenters suggested that the term ``Maximum Rated

Load'' takes into account safety factors established by the designer or

manufacturer.

OSHA agrees that the term ``Maximum Rated Load'' does include

built-in safety factors. As stated above, by not including the words

``safety factor'' in this definition or replacing the proposed term

with ``Maximum Rated Load,'' which implies built-in safety factors,

OSHA clearly indicates that the minimum safety factor of 4:1 as set

forth in final rule Sec. 1926.451(a)(1) applies. The Agency believes it

is appropriate to take into account the ``expected'' burden as well as

the burden a scaffold ``can'' support without failure.

``Needle beam scaffold'' means a suspension scaffold supported by

needle beams. The final rule definition is the same as the proposed

definition. One commenter (Ex. 2-23) suggested

[[Page 46032]]

that OSHA limit the use of this type of scaffold to ``light-duty''.

However, as discussed earlier, the Agency does not intend to limit the

capacity of a scaffold as long as it meets the pertinent requirements

of Sec. 1926.451(a). OSHA has provided examples of measures that would

enable a scaffold to comply with these requirements in non-mandatory

Appendix A.

``Outrigger.'' This term means the structural member of a supported

scaffold used to increase the base width of a scaffold in order to

provide support and stability for the scaffold. The terms, ``outrigger

beam'' and ``outrigger scaffold'' are new definitions provided to

explain the difference between these three similar terms. The final

rule differs from the proposal, which defined outrigger as ``the

structural member of a supported scaffold used to increase the base

width of a scaffold in order to provide greater stability for the

scaffold.'' The wording change was made in response to a comment from

the SIA (Ex. 2-368), suggesting that OSHA replace the word ``greater''

with the words ``support and increased.'' OSHA agrees that the

suggested wording more accurately expresses the Agency's intent.

``Personal fall arrest system.'' This term, which replaces the

proposed term ``body belt/harness system'', refers to a system used to

arrest the fall of an employee from a working level. It consists of an

anchorage, connectors, and a body belt or body harness and may include

a lanyard, deceleration device, lifeline, or suitable combinations of

these. The final rules on fall protection (part 1926, subpart M) and

powered platforms (Sec. 1910.66) also define ``personal fall arrest

system'' in this manner. The final rule definition is essentially the

same as that proposed for ``body belt/harness systems'', and the phrase

``personal fall arrest systems'' appears in the final rule wherever the

phase ``body belt/harness systems'' was used in the proposed rule. A

commenter (Ex. 2-13) suggested that the definition be reworded to

indicate clearly that lifelines and deceleration devices are not always

included as a part of a body belt/harness system. OSHA agrees and has

clarified this point in the revised definition.

OSHA has deleted the proposed term ``platform unit'' and has

incorporated the proposed definition language into final rule

Sec. 1926.451(b)(1)(i), which addresses the construction of scaffold

platforms.

``Power operated hoists.'' This new term refers to hoists which are

powered by other than human energy. The final rule language differs

from the proposed language, which used the term ``mechanically-powered

hoists''. OSHA has revised the terms ``mechanically powered'' and

``manually powered'' hoists to read ``power operated hoists and

manually operated hoists'', because the Agency has determined that the

language should be consistent with ANSI A10.8-1988, paragraph 6.

``Qualified.'' This term is being added to the final rule as a

matter of convenience for users. The definition is identical to that

found in Sec. 1926.32.

``Rated load.'' This new term addresses the maximum load that a

hoist is allowed to lift. The discussion of final rule

Sec. 1926.451(a)(1), below, addresses the use of this term.

``Repair bracket scaffold.'' This new term has been added to

address the type of scaffold addressed by final rule Sec. 1926.452(x).

This term is discussed below in conjunction with the discussion of that

paragraph.

``Scaffold.'' This term refers to a temporary elevated platform

(supported or suspended) and its supporting structure, including points

of anchorage, used for supporting employees or materials or both. The

definition also clearly indicates that crane or derrick suspended

personnel platforms are not scaffolds. The Agency has added the phrase

``including points of anchorage'' to the definition of scaffold in the

final rule to indicate clearly that points of anchorage are considered

to be part of a scaffold.

``Stair tower (Scaffold stairway/tower).'' This new term has been

added to describe the means of access addressed by final rule

Sec. 1926.451(e)(4). This term is addressed in relation to that

provision below.

``Stall load.'' This new term has been added to identify the

maximum load that a hoist can lift without stalling or shutting down.

The use of this term is discussed in relation to final rule

Sec. 1926.451(a)(2), below.

``Stilts'' mean a pair of poles or similar supports with raised

footrests, used to permit walking above the ground or working surface.

This term and definition has been added to recognize this type of

scaffold, which is used by many trades in the construction industry to

allow employees to walk elevated above the ground or working surface.

Final rule paragraph Sec. 1926.452(y) addresses the safe use of this

type of scaffold both as a scaffold itself, and on other types of

scaffolds (large area scaffolds).

``System scaffold'' means a scaffold consisting of posts with fixed

connection points that accept runners, bearers, and diagonals that can

be interconnected at predetermined levels. This new term has been added

to the final rule to recognize the existence and acceptance of this

type of scaffold. The definition is identical to the definition for the

same term found in ANSI A10.8-1988.

``Tank builders' scaffold'' means a supported scaffold consisting

of a platform supported by brackets that are either directly attached

to a cylindrical tank or are attached to devices that are attached to

such a tank. In the February 1, 1994 notice of record reopening (59 FR

4618), OSHA suggested a definition of ``tank builders' scaffold'' for

consideration. That definition was very similar to the final rule

definition except that the reopening notice definition did not

specifically refer to cylindrical tanks and did specify that the

platform was welded to the steel plates of the tank.

The commenters (Exs. 43-19, 43-23, 43-33, 43-34, 43-35, 43-39, 43-

40, 43-42, and 43-43) who responded to the proposed definition for tank

builders' scaffold stated:

A ``tank'' is not necessarily a cylinder. The scaffold is used

on structures that can be cylindrical, rectangular, conical,

spherical, spheroidal, or elliptical. Also, ``tanks'' are

constructed of material other than metal; e.g., fiberglass, wood,

etc. Some tanks have vertical walls that are so thin that a bracket

could not be welded to it; rather, the bracket would have to be

bolted. We would further comment that the bracket is often inserted

into a device which is welded to the steel plate. So we would

suggest not referencing the bracket being attached to the structure,

but rather the bracket being attached to a device that is affixed to

the structure.

In addition, eleven commenters (Exs. 43-19, 43-21, 43-23, 43-27,

43-33, 43-34, 43-35, 43-39, 43-40, 43-42, and 43-43) stated that the

criteria of an April 4, 1975 variance (40 FR 15139), which addressed

tank builder scaffolds, would be adequately addressed by general

provisions of the final rule and the definition of ``tank builders'

scaffold''.

The 1975 variance order stated:

The applicants' business, which is part of the tank building

industry, involves the erection of relatively large steel plate

segments of circumferential rings. Due to the unique nature of the

construction involved, special procedures, including special

scaffolding, have been developed. For example, as opposed to more

conventional scaffolds, tank scaffolds must be highly portable and

have a relatively low density of occupancy by [workers]. These

scaffolds are raised up the shell of the tank as new rings of steel

are added and work is completed at the level below.

Most plate structures are fabricated from standard length plates

* * * each approximately 31.416 feet (9.42 m.) long, [with] brackets

[normally] welded to them while they are on the ground prior to

being

[[Page 46033]]

placed into position on the tank wall. Scaffolding and guardrail

supports are then attached to these brackets. If the applicants were

to comply with [requirements] that [the maximum spacing for supports

be no more than 8 feet (2.4 m.) for guardrails or 10 feet (3.0 m.)

for planking], they assert it would be necessary to lay out each

steel plate into sections with the brackets located approximately

7.854 feet (2.36 m.) apart. Instead, the applicants wish to lay out

the plates into three equal sections with brackets located

approximately 10' 6'' (3.15 m.) apart.

* * * Because the contour of the steel plates of the tank face

is curved and the adjacent edge of the scaffold platform is

straight, there is an open space between them. As a result,

applicants have installed taut wire rope on the scaffold brackets

that extends midway between the innermost edge of the scaffold

platform and the curved plate structure of the tank face to serve as

a safety line in lieu of an inner guardrail assembly.

Since the information submitted to OSHA in relation to the variance

addressed scaffolds used on cylindrical steel tanks, the Agency is

applying the criteria of the variance only to structures that are

approximately cylindrical. The Agency believes that non-cylindrical

structures should be addressed on a case-by-case basis under the

general provisions of the final rule. OSHA notes that 9 of the 11

commenters (Exs. 43-19, 43-23, 43-33, 43-34, 43-35, 43-39, 43-40, 43-

42, and 43-43) mentioned above also stated ``[t]ank builders place the

scaffold inside of a cylinder, traditionally, to erect the tank.''

However, the Agency believes that the requirements of the variance, as

modified in Appendix A of the final rule, can reasonably be applied to

cylindrical tanks that are constructed of materials other than steel.

The final rule definition for ``tank builders' scaffold'' has been

worded accordingly.

OSHA has not promulgated specific requirements for tank builders'

scaffolds in the final rule because the Agency believes that the

requirements for those scaffolds are adequately addressed in the

general provisions of the final rule. The Agency notes that it has

placed several provisions (some of which have been editorially

modified) of the variance in Appendix A for the benefit of employers

who use tank builders' scaffolds, and that the introductory text to the

Appendix clearly indicates that following the Appendix will be

considered to constitute compliance with the requirements of this

standard with regard to scaffolds used in the construction of

cylindrical tanks. However, employers choosing not to follow the

Appendix must still comply with the applicable requirements of

Sec. 1926.451, particularly paragraphs (a) and (f).

``Top plate bracket scaffold.'' This term is being added to the

final rule to recognize a type of scaffold which is similar to

carpenters' bracket scaffolds and form scaffolds. This type of scaffold

consists of a platform supported by brackets that hook over or are

attached to the top plate of a wall. Such scaffolds are used in

residential construction when employees are setting roof trusses.

OSHA has deleted the following terms, which are defined in the old

scaffold standard, from the definition section of the final rule,

because those terms are now defined in other subparts or because the

final rule no longer uses the terms in question: ``heavy duty

scaffold,'' ``light duty scaffold,'' ``medium duty scaffold,''

``midrail,'' ``toeboard,'' and ``working load.'' In addition, the

proposed definitions for ``drop lines'', and ``trolley line'' have been

deleted from this final rule, since they have been incorporated into

the definition of ``lifeline''.

Under Issue L-12 in the preamble of the proposed rule, OSHA

solicited testimony and related information on a suggestion by the

ACCSH (Tr. 206, 6-9-87) that definitions for ``ramp'' and ``runway'' be

added to the standard. The ACCSH indicated that the added definitions

would facilitate clear understanding of the requirements in proposed

Sec. 1926.451(c)(4) (final rule Sec. 1926.451(e)(4)). As noted under

the discussion of the Issue, a member of the ACCSH recommended that the

Agency use the definition of ramp developed by the National Safety

Council.

The one comment (Ex. 2-593) OSHA received addressing the Issue

supported defining the two terms. The commenter did not provide any

suggested wording but indicated that the definitions should be ``clear

and consistent with existing OSHA and ANSI definitions.''

In the final rule, OSHA has replaced the proposed term ``runway''

with the term ``walkway'', to indicate the Agency's regulatory intent

clearly . However, the Agency believes that ``ramp'' is a commonly

understood term and does not require a specific OSHA definition.

Accordingly, OSHA has not added a definition for ``ramp'' to the final

rule.

Paragraph 1926.451(a) Capacity

Final rule paragraph (a) sets the minimum strength criteria for all

scaffold components and connections. The final rule sets scaffold

capacity requirements that are substantively the same as those in

existing subpart L, while eliminating ambiguities and apparent

inconsistencies. The introductory text of the proposed paragraph, which

stated that ``the following requirements applied to all types of

scaffolds except as indicated:'', has been deleted in the final rule

because the Agency has determined that it is too similar to the

introductory text of paragraph (a)(1) and, therefore, is unnecessary.

Paragraph (a)(1) requires that each scaffold and scaffold component

be capable of supporting, without failure, its own weight and at least

4 times the maximum intended load applied or transmitted to it.

Paragraphs (a)(2), (a)(3), (a)(4), (a)(5) and (g) of Sec. 1926.451

provide exceptions to this general rule, and are discussed below. This

provision is based on existing Sec. 1926.451(a)(7), which requires that

scaffolds and scaffold components ``be capable of supporting without

failure at least four times the maximum intended load''.

The final rule clearly provides that the 4 to 1 factor for a

component applies only to the load which is actually applied or

transmitted to that component, and not to the total load placed on the

scaffold. Existing Sec. 1926.451(a)(7), taken literally, could be read

to require that each separate scaffold component be able to support

four times the maximum intended load (MIL) of the entire scaffold. For

example, the existing provision could be interpreted to require that a

crossbrace on a supported scaffold be capable of supporting the same

load as a scaffold leg, that is, be sized to support four times the

entire MIL regardless of where the load is placed on the scaffold and

regardless of the fact that the function of a brace is to prevent sway

and not directly to support the MIL. Such an approach was not OSHA's

intent. The Agency intended that each component be adequate to meet the

4 to 1 factor, but only for the portion of the MIL applied or

transmitted to that component. The MIL for each component depends on

the type and configuration of the scaffold system. Final rule paragraph

(a)(1), which is effectively identical to the corresponding language in

proposed paragraph (a)(1), clearly expresses the Agency's intent. The

proposed provision has been editorially revised and reorganized for the

sake of clarity. In particular, the exceptions to proposed paragraph

(a)(1), which provide different coverage for suspension scaffolds, have

been clearly delineated as separate paragraphs (a)(2) through (a)(6) in

the final rule.

Paragraph (a)(2) of the final rule requires that direct connections

to roofs and floors and counterweights used to balance adjustable

suspension scaffolds be capable of resisting at least 4 times the

tipping moment imposed by the scaffold operating at either the rated

[[Page 46034]]

load of the hoist or at 1.5 (minimum) times the tipping moment imposed

by the scaffold operating at the stall load of the hoist, whichever is

greater. Proposed paragraph (a)(2) simply required that direct

connections to roofs and floors, and counterweights used to support

suspension scaffolds, be capable of providing a resisting moment of at

least four times the tipping moment. The proposed provision was

intended to clarify that the safety factor of four to one also applies

to direct connections to floors and roofs and to counterweight systems.

These areas are as integral to the scaffold system as the scaffold

platform itself. OSHA has revised the proposed provision to account for

the need to base the factor of safety for adjustable suspension

scaffolds on the rated load of the hoist and the stall load of the

hoist.

Several commenters (Exs. 2-8, 2-28, 2-64, 2-367, and 2-516)

indicated that the factors of safety for adjustable suspension

scaffolds should be based on the rated load of the hoist. Four of those

commenters (Exs. 2-28, 2-64, 2-367 and 2-516) and the SIA (Ex. 2-368)

recommended that the stall capacity of the hoist be considered in the

factors of safety.

One of these commenters (Ex. 2-28) stated that many suspended

scaffolds are rigged by inexperienced persons who do not realize that

if the scaffold catches on an obstruction, the maximum lifting power

(stall load) of the hoist can be developed and transmitted to the

counterweights and anchorages. This commenter suggested adding one of

the following requirements to proposed Sec. 1926.451(a)(2) as an

alternative to four times the tipping moment: (1) or 4,000 pounds,

whichever is greater; (2) or 150 % of the maximum pulling power of the

hoist, whichever is greater; or 4 times the rated load of the hoist,

whichever is greater. The SIA (Ex. 2-368) recommended changing the

resisting moment of proposed Sec. 1926.451(a)(2) to ``at least 1.5

times the stall capacity of the hoist or four times the maximum

intended load, whichever is greater.''

Three commenters (Exs. 2-8, 2-28, and 2-516) indicated that

Underwriters Laboratories (U.L.) standard 1323 (Standard for Scaffold

Hoists) limits the maximum output of a scaffold hoist to 3 times the

rated working load of the hoist. One commenter (Ex. 2-64) recommended

that OSHA limit the stall load of a hoist to no more than three times

the rated load of the hoist. Another commenter (Ex. 2-8) stated that if

the safety factor for suspended scaffolds is not based upon the highest

rated working load of any component, normally the hoist, failure can

occur.

Two commenters (Exs. 2-8 and 2-516) presented examples of the

relationship between the stall load of a hoist and the rated load of

the same hoist. One commenter (Ex. 2-8) provided the following example:

A typical hoist with a ``rated working load'' of 1000 lbs. can

exert a pulling force of 3000 lbs. if an obstruction is encountered

such as a window ledge or air conditioner while ascending. If one

designs for a maximum intended load of only 500 lbs. because of a

short light scaffold platform or a work cage and the counterweight

or suspension system is designed for 4:1 MIL then the ultimate load

that the suspension can support is 4 x 500 lbs. MIL or 2000 lbs. A

3000 lb. hoist pull can cause failure or even wire rope failure if 6

x MIL is used. No one intends to stall a hoist on an obstruction

but it does occur. Therefore, a suspended scaffold should be

designed for safety factors based upon MIL or rated working load of

the hoist whichever is greater.

OSHA agrees that the safety factors for the counterweights,

riggings, direct connections to roofs and floors, and suspension ropes

of adjustable suspension scaffolds should be related to the rated load

of the hoist and the stall load of the hoist, and not be based on the

maximum intended load. OSHA agrees with the commenters who stated that

failure can result if the factors of safety are based on the maximum

intended load. Furthermore, the Agency also agrees with the commenters

(Exs. 2-28 and 2-368) who indicated that these factors of safety should

be based on 1.5 times the stall load of the hoist.

The Agency notes that the stall load of a hoist is equal to three

times the rated load of that hoist. When one applies the 4 to 1 safety

factor required (4 x rated load = 4/3 x stall load) the result

would be 1.33 times the stall load. However, while using 1.33 times the

stall load would provide the required safety factor, OSHA is using 1.5

times the stall load based on the above comments. The Agency believes

that such a requirement reduces the possibility of failure due to

improperly installed equipment as well as the dynamic loads that can be

developed when an obstruction is encountered. Accordingly, the Agency

has changed the final rule language so that it requires a factor of

safety of four times the maximum rated load of the hoist or 1.5 times

the stall load of the hoist, whichever is greater.

Paragraph (a)(3) of the final rule provides that ``[e]ach

suspension rope, including its connecting hardware, used on non-

adjustable suspension scaffolds shall be capable of supporting, without

failure, at least 6 times the maximum intended load applied or

transmitted to that rope.'' This is the same requirement as the

proposed rule except that final rule paragraph (a)(3) applies only to

non-adjustable suspension scaffolds, while the requirements for

adjustable suspension scaffolds have been placed in final rule

paragraph (a)(4), below. The proposed rule did not distinguish between

these two types of scaffolds. Proposed paragraph (a)(4)(i) has been

redesignated to Sec. 1926.451(f)(11) of the final rule, to consolidate

all requirements for wire rope used with suspension scaffolds. In

addition, proposed paragraphs (a)(4)(ii) and (iii) have been moved to

non-mandatory Appendix A, so that examples of measures that would

comply with final paragraph (a) are consolidated in one place.

Paragraph (a)(4) of the final rule provides that ``[e]ach

suspension rope, including connecting hardware, used on adjustable

suspension scaffolds shall be capable of supporting, without failure,

at least 6 times the maximum intended load applied or transmitted to

that rope with the scaffold operating at either (a) The rated load of

the hoist, or (b) 2 (minimum) times the stall load of the hoist,

whichever is greater''.

This provision addresses adjustable suspended scaffolds and is

similar to proposed paragraph (a)(3) except that the proposed paragraph

contained the language ``maximum intended load applied or transmitted

to the rope'' instead of ``rated load of the hoist (or at least 2 times

the stall load of the hoist, whichever is greater)''. The proposed rule

was based on existing Sec. 1926.451(a)(19).

Three commenters (Exs. 2-8, 2-64, and 2-516) recommended that OSHA

use ``rated capacity of the hoist'' instead of ``maximum intended

load.'' This recommendation was based on the belief that the safety

factor for adjustable suspended scaffolds should be based on the

highest rated work load of any component, normally the hoist. The

Agency agrees and has modified the proposed rule accordingly. In

addition, the Agency has included language that accounts for the stall

load of the hoist in the factor of safety for the same reasons that

were discussed in regard to final rule Sec. 1926.451(a)(2), except that

the factor to be applied to the stall load has been increased from 1.5

to 2 in order to account for the 6:1 factor of safety applied to

suspension ropes. This factor of safety does not include an added

margin as does the factor of safety in paragraph (a)(2). One commenter

(Ex. 2-516) recommended an 8:1 factor of safety for suspension ropes on

adjustable suspension scaffolds. This recommendation was based on

several factors that can reduce the effective

[[Page 46035]]

strength of a rope: (1) A termination rating of 80% of the wire rope

design strength; (2) time-use of the rope; (3) energy applied to the

system when the overspeed brake is actuated; and (4) failure of the

brake to set or the loss of one end of the platform rigging. The

commenter concluded that these factors can reduce the factor of safety

from 6:1 to 1.15:1, with failure occurring if anything else goes wrong

such as the free end of the platform swinging through its arc.

OSHA notes that this commenter addresses a worst case scenario

which would involve violations of other provisions of the final rule.

The Agency believes that each of the elements of the scenario will be

prevented by compliance with the final rule. For example, final rule

Sec. 1926.451(d)(6) requires winding drum hoists to contain not less

than four wraps of the suspension rope at the lowest point of scaffold

travel, thereby reducing the force applied to the termination at the

winding drum. In addition, final rule Sec. 1926.451(d)(12)(v) prohibits

the use of U-bolt clips at the point of suspension for any scaffold

hoist. Also, final rule Sec. 1926.451(a)(3) requires that suspension

rope connections be considered part of the rope and that they be taken

into account when determining whether a rope is capable of withstanding

without failure at least six times the loads imposed upon it.

Further, final rule Sec. 1926.451(d)(10) requires that a competent

person inspect suspension ropes prior to each workshift or after any

occurrence which could affect a rope's structural integrity. Paragraph

1926.451(d)(10) also requires that defective or damaged ropes be

removed from service. For these reasons, OSHA believes that the final

rule adequately addresses the commenter's concerns.

The third commenter (Ex. 2-29) recommended that OSHA include the

weight of the scaffold and all its components in calculating maximum

intended load. The Agency believes the above described changes made to

proposed paragraph (a) resolve the concerns raised by this comment.

Paragraph (a)(5) of the final rule, which was not part of the

proposed rule, requires that the stall load of any scaffold hoist not

exceed 3 times its rated load. OSHA finds that this requirement is

reasonably necessary to prevent accidental overloading of suspension

scaffold support systems. OSHA notes that U.L. standard 1323 limits the

output force of a scaffold hoist to three times the rated load of the

hoist. As far as OSHA has been able to determine, the other

laboratories which test and list scaffold hoists adhere to the

requirements of U.L. 1323.

A commenter (Ex. 2-64) recommended that OSHA limit the stall load

of scaffold hoists to three times the rated load of the hoist. The

Agency agrees that it is appropriate to add the suggested provision,

for the reasons described above.

Final rule paragraph (a)(6) requires that scaffolds be designed by

a qualified person and constructed and loaded in accordance with that

design. The provision also indicates that non-mandatory Appendix A

provides examples of criteria, including design specifications, that

will enable the employer to comply with paragraph (a) of this section.

Proposed paragraph (a)(1), which focused on supported scaffolds, also

referenced Appendix A for acceptable criteria.

Non-mandatory Appendix A provides examples of design and

construction measures that employers can use to comply with final rule

Sec. 1926.451(a). This Appendix is based on the requirements set by

existing Secs. 1926.451(c)(1)-(4) and by Tables L-3 through L-19. OSHA

has recognized that employers can design and construct scaffolds which

satisfy the performance requirements of the final rule without

following the specifications set by the existing rule, and drafted both

the proposed and final rule Sec. 1926.451(a) accordingly. The Agency

believes that the above-cited specifications could assist an employer

in complying with the capacity requirements of the final rule, so OSHA

has relocated that language to non-mandatory Appendix A.

In Issue 5 of the preamble to the NPRM, OSHA requested comment on

whether or not all scaffold units (such as planks and decks) should

have their capabilities or grades marked on them. Some commenters (Exs.

2-41, 2-46, 2-51, 2-54, 2-73, 2-367, 2-495, 2-512, 2-516, and 2-534)

indicated they favored the requirements for such markings. Two

commenters (Exs. 2-495 and 2-534) stated ``very few people would know

which grade for any species of wood qualifies that plank as scaffold

grade.'' Those commenters recognized that there was a lack of consensus

concerning the maximum safe loads on certain plank spans, stating that

``[a]t the same time, we believe it may be premature to require that

all planks be so marked since agreement on methodology of determining

load displacement has not been reached by the engineering profession.''

Another commenter (Ex. 2-54) indicated that marks would not wear

off platform units because ``[i]n most instances, planks are placed and

not moved [and are] generally not rubbed against each other

constantly.'' Another commenter (Ex. 2-516) stated ``[i]f it is so worn

that the mark is lost, it probably needs retesting anyway.''

One commenter (Ex. 2-51) stated that while grade marks would wear

off, it seems unlikely ``that every plank on an entire job would

simultaneously suffer such a fate. We believe that invariably, there

would be some plank where grade stamping was legible if grade stamping

ever existed.''

Another commenter (Ex. 2-41) stated ``[k]nowledge of the capacity

of each [piece of] equipment is basic to implementation of this

proposal.''

In addition, the SSFI (Ex. 2-367) pointed out that fabricated plank

stages and platforms are currently marked as to their capacity. They

stated that this ``practice should be continued for fabricated planks,

stages, and platforms, as these are designed for unique applications.''

The commenter also stated ``there is no common practice within the

industry to have solid sawn lumber marked as to their load capacity.''

The SSFI recommended ``that the solid sawn lumber or laminated veneer

be repeatedly and continuously grade[-]stamped along the side edge of

the material at the time the plank is initially purchased.''

Another commenter (Ex. 2-51) stated that ``[s]ince 1980, Timber

Products Inspection has been involved in five cases where plank failure

has resulted in injury and litigation. In all five cases the planks

that failed were purchased as rough Canadian Spruce #1 and better or #2

and better. None of the planks were grade-stamped and one plank was

identified as Lodge pole pine instead of spruce.''

Another commenter (Ex. 2-35) recommended that OSHA adopt the

language of the ANSI A10.8 draft scaffold standard that requires

``solid sawn scaffold plank to bear the grade stamp of a grading agency

approved by the American Lumber Standards Committee.'' The commenter

also stated ``it is essential to assure use of scaffold members of

adequate strength and stiffness.''

In addition, a commenter (Ex. 2-534) stated:

We are strong advocates of requiring that all plank to be used

as scaffold plank be required to be stamped or embossed as

``SCAFFOLD PLANK''. To most people, all planks look alike. Very few

people would know which grade for any species of wood qualifies that

plank as scaffold grade unless the grade stamp is explicit for

flatwise use as ``Scaffold Plank''.

* * * There is everything to gain, and nothing to lose, by

requiring marks that

[[Page 46036]]

communicate to answer the bottom line question, ``Is this plank OK

as a scaffold plank?''

In addressing Issue 5, the ACCSH recommended (Tr. 6/9/87, pp. 64-

65) that all planking and decks, etc., be properly marked as scaffold

materials. The Advisory Committee indicated that a performance

standard, which would allow employers to determine how they wanted to

mark these materials, would be appropriate. Among the options

envisioned by the ACCSH to distinguish the materials intended solely

for scaffold system use were color-coding systems, stamping, and

tagging.

On the other hand, some commenters expressed the view that a

marking requirement would be impractical (Exs. 2-15, 2-20, 2-22, 2-368,

and 2-390). In addition, commenters (Exs. 2-20, 2-53, 2-55, and 2-390)

stated that the requisite costs would be burdensome, and others (Exs.

2-13, 2-15, 2-69, and 2-368) stated that, while manufactured or

fabricated planks or platforms were often or usually marked, carrying

this over to wooden components was inadvisable, citing anticipated

problems with the volume of planks to be marked and the marks wearing

off. Several commenters (Exs. 2-20, 2-55, 2-70, and 2-390) pointed out

the marks would lend a possibly false sense of security or safety, and

some (Exs. 2-20, 2-55, 2-69, and 2-390) added that maintaining the

marks would be neither feasible nor economical. One commenter (Ex. 2-

70) stated ``The user of platform units can calculate the maximum load

that can be placed on a scaffold and it is up to management personnel

to ensure that the scaffolding is not overloaded. I feel that the

marking of platform units does not, in itself, insure a safe

scaffolding.''

After careful evaluation of the above comments, the Agency has

decided not to require marking of platform units. OSHA has determined

that, while markings can increase confidence in and use of appropriate

platform units, they do not add to the inherent safety of the scaffold.

Furthermore, the absence of markings does not establish a lack of

quality.

In addition, materials quality is only one of several factors which

must be considered when erecting a scaffold platform. Other significant

elements include unit size, span, and load applied. A platform unit,

whether wood or metal, solid sawn or prefabricated, which is marked as

appropriate for use as a plank, may be appropriate for use in one set

of conditions but not in another (i.e., longer span or higher load).

Similarly, a platform unit which does not have the quality

characteristics to allow its use in one situation may be acceptable for

use in another (i.e., shorter span or lighter load) whether or not it

is marked. The important consideration in all situations is that the

platform be capable of supporting the load with a design factor of

four.

OSHA believes the grading rules of recognized independent

inspection agencies, such as the American Lumber Standards Committee

(ALSC), provide useful information about wood plank selection and use.

Planks that are marked and used in accordance with pertinent grading

rules of the ALSC or other recognized independent inspection agency

will be deemed to meet the four-to-one requirement. Therefore, given

the extent to which the private sector has voluntarily adopted plank

grading and marking programs, the Agency has concluded that any benefit

resulting from the addition of marking requirements would be minimal.

Wood products such as Canadian spruce, which are alleged to be

unacceptably inferior in some applications, could have standards

developed for their use by a recognized grading agency. OSHA believes

there are combinations of thickness, quality, span, loads, and other

factors that can be established for all species of wood used for

platforms.

Issue 17 of the preamble to the NPRM asked whether the Agency

should specify a minimum slippage capacity of 4,000 pounds and a

minimum breakage capacity of 16,000 pounds for couplers used on tube

and coupler type scaffolds. The SSFI and SIA (Exs. 2-367 and 2-368)

opposed such a requirement, stating that ``the entire scaffold

structure should be required to withstand the specified design loads.''

They also noted that this special component requirement was unlike

other OSHA requirements. The SIA (Ex. 2-368) also stated:

It is redundant and unnecessary to specify a quantitative value

for clamp strength since the required safety factors already in

existence provide the proper strength for the intended load. There

may be cases where the clamps should be of higher value or lower

value, depending on usage. Consequently, requiring a numerical value

may produce the catastrophe which the proposed rule is trying to

avoid in the first place. Existing rules require design by competent

individuals, which provides the proper safeguards against abuse and

eliminates the need for the proposed rule.

Also, a commenter (Ex. 2-15) indicated that a British standard (BS

1129) recognizing 2800 lb. has been in place for 20 years ``with

satisfactory results.'' The commenter stated that most American clamps

are built to BS1129, and went on to indicate that the same 2800 lb.

figure is generally sufficient, except for possible heavy-duty

applications in a specific configuration. The commenter further felt

that specifying a 4,000 lb. minimum slippage capacity would ``outlaw''

many clamps.

One commenter (Ex. 2-22) stated that both slippage and minimum

breakage capacities ``should be equivalent to that required on the

other parts of the scaffold.''

Another commenter (Ex. 2-128) stated ``couplers for tube and clamp

[scaffolds] should be rated by the manufacturer in accordance with a

recognized testing standard [and] certified by an engineer.'' In

addition, a commenter (Ex. 2-13) expounded on the relationship between

the torque applied to tighten a coupler and the slippage capacity, and

noted that proper torque values needed to be determined by tests or

calculations.

The ACCSH (Tr. 6/9/87, pp. 138-147) recommended that OSHA specify

both minimum slippage and breakage capacities and should require

employers to obtain manufacturer's specifications and/or certifications

that a scaffold meets minimum standards. However, the ACCSH did not

endorse the suggested 4000 and 16,000 pound limits and did not propose

any other limits.

After a careful review of the above comments, OSHA has determined

that the capacity provisions set out in final rule Sec. 1926.451(a)

will appropriately address the concerns regarding scaffold strength and

that additional specifications would be redundant.

Issue 21 of the preamble to the NPRM requested public comment on

appropriate field test procedures or certifications for determining the

capacity of scaffolds and scaffold components such as planks and ropes.

As noted above, existing Sec. 1926.451(a)(7) and proposed

Sec. 1926.451(a)(1) require scaffolds to be capable of supporting,

without failure, at least four times the maximum intended load. OSHA

has recognized, however, that field testing of scaffolds and scaffold

components with loads four times greater than the maximum intended load

could cause damage that would render the scaffold and scaffold

components unusable.

One commenter (Ex. 2-54) mentioned reliance on testing laboratories

to ensure that rope and planks meet industry standards. Another

commenter (Ex. 2-64) stated that scaffolds' and support systems' rated

capacities should be marked when manufactured and that any field

testing beyond that set forth in a manufacturer's instructions would be

superfluous and could conflict with those instructions.

[[Page 46037]]

The SSFI (Ex. 2-367) and the SIA (Ex. 2-368) both stated that field

testing of supported scaffolds would permanently damage equipment or

render it useless, and that a visual check of the scaffolding before

use should ensure safety ``as the manufacturer already warrants the

appropriate safety factors.'' The SIA also stated that current testing

methods ``are not suitable for checking the ultimate capacity of

scaffold components.'' The SIA further stated that for metal

components, visual inspection is the only practical method available.

For wooden components, the SIA stated that inherent material variables

make obtaining repeatable results from a suitable bending test

impossible. On the other hand, the SIA recommended that suspension

scaffolds be field tested with the intended load.

Two other commenters (Ex. 2-495 and 2-534) agreed with the SIA that

it is impossible to obtain repeatable results from a bending test.

However, they stated that a minimum threshold design value for flat-

wise bending of planks could be derived from available information for

flat-wise bending for any specie of plank. Those commenters also stated

that field testing would not necessarily permanently damage or render a

plank useless. They stated that strength testing of used planks could

be accomplished by combining visual inspections with deflection testing

using a safe load and deflection testing machines that are currently

available.

One commenter (Ex. 2-516) indicated that a reasonable level of load

testing for scaffold machinery might be found ``somewhere near 1.25

times [the] rated load'' and that ``any field tests should be a ratio

of rated load, not failure load.'' The commenter assumed different

safety factors for moving equipment, suspended scaffold hoists, and

fixed structures. The commenter also questioned whether the safety

factor referred to in Issue 21 was for static, dynamic, or shock loads,

and noted that 4 to 1 is not an engineering safety factor but a gross

factor. In addition, the commenter stated:

Any device or mechanism designed for a structural safety factor

of four-to-one certainly can be tested at some level less than four-

to-one without structural failure. * * * It is difficult to

comprehend the rationale of prohibiting testing of a structure using

1\1/2\ times rated load for fear it will collapse, when the

structure must not collapse at 4 times rated load. There would then

be doubt in my mind as to its ability to meet that 4-to-1 criterion.

Also, the commenter (Ex. 2-516) pointed out that any test of wood

components should consider the effects of aging material, and he listed

a number of variables for which some testing adjustments would be

required. These variables included ``fatigue, finish,'' and ``material

test scales.''

Two commenters (Exs. 2-13 and 2-69) indicated there would be no

need for field testing since scaffolds should be designed for their

intended load with an added safety factor. In particular, one of those

commenters (Ex. 2-13) stated ``[t]here are no appropriate field tests

for such items as planks and ropes. A simple visual inspection is all

that is required by a competent person.''

The ACCSH (Tr. pp. 163-174, 6-9-87) recommended that the

manufacturer's design specifications be recognized as sufficient for

manufactured scaffolds. The ACCSH also recommended that specifications

or testing procedures be specified for job-made scaffolds.

After carefully considering the above comments, OSHA has decided

not to require field testing of scaffolds. Based on the comments

received, the Agency has determined that such testing is not needed and

that, given the inspection and capacity requirements, it would be

difficult or impossible to implement effectively for the range of

materials in question.

Issue 23 of the preamble to the NPRM solicited comments on whether

or not the Agency should revise paragraph 1.(b) of proposed non-

mandatory Appendix A, which provides for selection of wood scaffold

planks according to the grading rules established by a recognized

independent inspection agency. In particular, OSHA asked if the

language should be more specific and, if so, what that language should

be.

Four commenters (Exs. 2-13, 2-22, 2-29, and 2-53) responded that

the proposed Appendix A language was adequate. One commenter (Ex. 2-13)

added ``it should be mandatory that the employer visually check all

scaffold planks before they are used.'' Another commenter (Ex. 2-54)

stated that scaffold planks ``should have identification'' to indicate

that they are scaffold grade.

However, a commenter (Ex. 2-534) noted that ``it may be premature

to require that all planks be so marked since agreement on methodology

of determining load displacement has not been reached by the

engineering profession.''

The SSFI (Ex. 2-367) recommended that scaffold planks be marked,

and noted that the most plank failures are inspection related. The SIA

(Ex. 2-368) recommended that OSHA revise paragraph (b) of proposed

Appendix A to read, in part, as follows:

All solid sawn planking shall be `SCAFFOLD GRADE' plank and

grade stamped as appropriate per the published grading rules of the

recognized independent inspection agency and as approved by the

Board of Review of the American Lumber Standards Committee. The

maximum permissible spans for 2 x 10 inch (nominal 1\1/2\'' x

9\1/4\'' minimum dressed (S4S), 1\5/8\'' x 9\1/2\'' minimum rough

or 2'' x 10'' minimum rough, solid sawn wood planks shall be as

shown in the following table.

Paragraph 1(b) of Appendix A should be expanded and clarified to

eliminate the confusion that exists over the use of nominal

thickness scaffold grade planks on 10 ft. spans for light trades.

This could be achieved by defining a scaffold grade plank in the

manner done in Cal-OSHA standards.

Cal-OSHA Section 1637(e) requires what it calls a ``structural

plank'' for scaffold platforms as follows:

``Except as specified in certain other Orders, all planking

shall be 2-inch (nominal) material selected for scaffold grade plank

as defined in Section 1504 under the heading Lumber--`Structural

Plank'.''

The ACCSH, in its June 9, 1987 (Tr. pp. 175-180), meeting,

recommended that a competent person be responsible for the selection

and use of scaffold materials, where scaffolding materials are not

certified by the manufacturer.

After carefully considering the above comments, OSHA has decided to

modify paragraph 1.(b) of non-mandatory Appendix A to the final rule to

provide for identification of scaffold planks by the grade stamp of the

recognized lumber grading association or independent lumber grading

inspection agency under whose grading rules the planks were selected.

OSHA is also modifying proposed Appendix A to provide that the

association or agency under which the wood is graded should be

certified by the Board of Review, American Lumber Standard Committee as

set forth in the American Softwood Lumber Standard of the U.S.

Department of Commerce. This added language clearly indicates what

constitutes a ``recognized'' inspection agency.

As a separate matter, OSHA is modifying Appendix A to the final

rule to provide that allowable spans of scaffold planks, other than 2 x

10 inch (nominal) or 2 x 9 inch (rough) solid sawn planks which are

addressed in the table in paragraph 1 (b), shall be determined in

accordance with the National Design Specification For Wood Construction

published by the National Forest Products Association or with ANSI

A10.8-1988, paragraph 5. OSHA notes that Appendix A is intended to help

the employer comply with the scaffolding rules. The Agency believes

that the above modifications will facilitate compliance with those

rules.

[[Page 46038]]

Paragraph (a)(6) of the final rule, which was not part of the

proposed rule, requires that scaffolds be designed by a qualified

person and must be constructed and loaded in accordance with that

design. OSHA believes that a ``qualified'' person can design a scaffold

which satisfies the criteria of Sec. 1926.451(a). This provision also

notes that non-mandatory Appendix A contains examples of criteria that

will enable employers to comply with paragraph (a) of this section.

Issue 24 of the preamble of the NPRM noted that existing

Secs. 1926.451(b)(16), (c)(4), (c)(5), (d)(9) and (g)(3) and proposed

Sec. 1926.451(b)(18)(i) and Secs. 1926.452(a)(10), (b)(10), (c)(6) and

(i)(8) require that an engineer design specified scaffold types and/or

components that are not built or loaded in accordance with Tables L-4

through L-13 of existing Sec. 1926.451 or proposed Sec. 1926.451

Appendix A, respectively. OSHA asked for comments regarding the extent

to which the services of an engineer or of a qualified person would be

needed to design scaffolds in accordance with the provisions of

Appendix A or to design scaffolds that, while not in accordance with

Appendix A, would comply with Sec. 1926.451(a).

Two commenters (Exs. 2-69 and 2-437) responded that employers

should be allowed to assess whether individual employees with several

years of hands-on experience are capable of designing and modifying

scaffolds or an engineer's services are required. Also, a commenter

(Ex. 2-22) expressed the view that there was no need for further

licensing and determinations because employers are responsible for

ensuring that scaffolds meet regulations for capacity and that

alterations of scaffold designs are made by qualified individuals. The

AGC commenters (Exs. 2-20, 2-55, and 2-390) stated ``there are many

individuals in the construction industry with many years of experience

who are quite capable of scaffold design and modification. Employers

should be permitted the flexibility to determine if such individuals

are capable or if they should seek the services of an engineer.''

Another commenter (Ex. 2-54) noted that not all engineers are

capable of designing scaffolds and that a good many people who work

with scaffolds do not know all the scaffold limits or strengths. The

commenter acknowledged that complicated scaffold designs require the

skills of an engineer familiar with the equipment available. However,

the commenter added that a competent worker who has followed an

engineer's drawings to erect a scaffold can at times recall and use

that experience in another situation requiring a complicated scaffold

structure.

In addition, a commenter (Ex. 2-21) stated that no additional

specification requiring the use of engineering services was warranted.

The commenter explained that ``[c]onditions on most construction jobs

change daily and can best be handled by qualified foremen or

supervisors on the job.'' Also, a commenter (Ex. 2-31), addressing

pumpjack scaffolds specifically, responded that although he was not an

engineer himself, he knew at least as much as anyone else about

pumpjack scaffolds. He felt that an engineer could be supplanted by

someone with recognized expertise but added that he did not believe a

specific definition of someone qualified to design a scaffold system

could be made.

Both the SSFI (Ex. 2-367) and the SIA (Ex. 2-368) recommended that

a ``qualified person,'' as defined in proposed ANSI A10.8, be allowed

to design those scaffolds that would not require the services of a

registered engineer. They quoted the proposed ANSI definition as

follows:

A term describing one who, by possession of a recognized degree,

certificate, or professional standing, or who by extensive

knowledge, training, and experience, has successfully demonstrated

the ability to solve or resolve problems relating to the subject

matter, the work, or the project.

The suggested definition is identical to the definition of

``qualified'' in Sec. 1926.32(l).

Two Saf-t-Green commenters (Exs. 2-14 and 2-15) stated that people

other than engineers were capable of designing scaffolds. In

particular, one commenter (Ex. 2-15) stated ``There are many good,

practical scaffold designers who are not engineers. They should not be

excluded.''

On the other hand, some responses to Issue 24 stated that the

services of a registered or professional engineer were needed (Exs. 2-

3, 2-9, 2-13, 2-70, 2-128, and 2-516). One such commenter (Ex. 2-13)

stated that he backed using registered professional engineers ``with

the knowledge and training required for [designing] a life support

system'' and queried where ``an equivalent qualified responsible person

could be found?'' One commenter (Ex. 2-70) offered a brief response,

``when in doubt, consult an engineer.'' Another commenter (Ex. 2-516)

responded:

I would rather take my chances with the engineer [-designed

scaffold system]. At least he knows some limits. Any other

definition lets anyone determine by themselves that they are

eminently qualified. All it then takes to be qualified is a big ego,

a little knowledge, and a pile of frame scaffold.

A comment from Aluma-Systems, Incorporated (Ex. 2-128) expressed

the belief that an engineer's services should be required for all but

the simplest of scaffold structures. The commenter indicated that the

Province of Ontario requires that a professional engineer design any

scaffold which exceeds 15 meters in height (approximately 50 feet), any

suspension scaffold where the scaffold consists of more than one

platform, or any suspension scaffold where the weight of the platform

and its components exceed 363 kg.

In addition, two commenters (Exs. 2-12 and 2-53) responded that the

existing regulations were sufficient or adequate. One of the two (Ex.

2-12) stated that there was already sufficient regulation and

questioned whether rules could be made to cover all situations.

In its June 9, 1987, meeting, the ACCSH (Tr. pp. 180-183)

recommended that OSHA authorize a competent person, rather than a

qualified person, to follow Appendix A for scaffold design, but that a

registered professional engineer be required to design scaffolds where

conditions are not covered by Appendix A. The Agency notes that a

competent person, as defined in Sec. 1926.32(f) and in the final rule

for subpart L, is able to detect hazards and has the authority to have

hazards corrected. On the other hand, ``qualified'', as defined in

Sec. 1926.32(m) and in the final rule for subpart L, refers to a person

who has the ability to solve or resolve safety and health problems.

After carefully considering the above comments, OSHA believes that

the proposed rule adequately addressed the conditions under which a

scaffold must be designed by an engineer. Accordingly, the above-listed

proposed requirements (Sec. 1926.451(b)(18)(i) [now final rule

Sec. 1926.451(d)(3)(i)] and Secs. 1926.452(a)(10), (b)(10), (c)(6), and

(i)(8)) have been promulgated in the final rule. As discussed below,

proposed rules Sec. 1926.452(a)(10) and (b)(10) have been revised to

distinguish more clearly between those circumstances where the employer

would need the services of a registered professional engineer and those

situations where the services of a qualified person, who could refer to

non-mandatory Appendix A, would be sufficient.

The Agency believes that there are qualified persons who can

properly design scaffolds without reference to Appendix A. The Agency

also believes that there will be circumstances where the ``qualified

person'' retained to comply with paragraph (a)(6) will need to be a

registered professional engineer.

[[Page 46039]]

Paragraph 1926.451(b) Scaffold Platform Construction

Paragraph 1926.451(b) of this final rule provides criteria for the

construction of scaffolds. Paragraph (b)(1) requires all platforms,

except walkways and those platforms used by employees performing

scaffold erection and dismantling operations, to be fully decked or

planked. In addition, paragraph (b)(1)(i) requires that platform units

be placed so that spaces between units do not exceed 1-inch, except

where employers establish that more space is needed. For example, this

would be necessary to fit around uprights when using side brackets to

extend platform width. Paragraph (b)(1)(ii) provides that, where the

exception created by paragraph (b)(1)(i) applies, employers shall place

platform units as close together as possible, with the space between

the platform and uprights not to exceed 9\1/2\ inches. OSHA set 9\1/2\

inches as the maximum space allowed, because the minimum width for

scaffold units that could be expected to sustain a working load is just

over 9\1/2\ inches. This provision, which is effectively identical to

the provision in the proposed rule, codifies the Agency's longstanding

interpretation of existing Sec. 1926.451(a)(4), which addresses

guardrails on scaffolds, to require that guardrails be erected as close

as possible to the platform planking. Because guardrails normally can

be conveniently attached only at the scaffold uprights, OSHA has

required the platforms to be sized such that there is no gap between

the outermost plank edge and the guardrail. However, most prefabricated

end frames do not have a lateral spacing between uprights which can

accommodate an integral number of commercially-available planks. In

order to comply with the existing rule, some employers have modified

the last plank (notched, slanted, or cut it to size). This can lead to

a significant reduction in plank strength, and possibly cause tipping

of the plank (sideways) if eccentrically loaded. Therefore, to deal

with this problem, proposed and final rule paragraph (b)(1) have

modified the corresponding requirement of the existing standard by

requiring the span between uprights to be planked or decked as fully as

possible, but allowing up to 9\1/2\ inches between the planking or

decking and the guardrail supports. As explained above, 9\1/2\ inches

is the maximum allowable open space.

One commenter (Ex. 2-29) stated that the 1-inch opening allowed by

proposed paragraph (b)(1)(i) would be large enough to ``allow many

tools and small materials to fall through'', and recommended a maximum

space of \1/4\ inch between units. OSHA, however, finds that such a

small maximum space would pose unreasonable compliance burdens, and is

retaining the 1-inch maximum.

The SSFI and the SIA (Exs. 2-367 and 2-368) stated that compliance

with proposed paragraph (b)(1) would be impossible when erecting or

dismantling scaffolds. In particular, the SIA (Ex. 2-368) stated:

For example: On a multi-level supported scaffold where

construction work is to be performed only at the top level, lower

levels would not be planked. Erectors would only use sufficient

planks required to construct the scaffold.

Load requirements limit the number of levels that can be planked

on many installations. The additional cost in labor and material

would be staggering. In addition, the fatigue factor created by

installing full planking from one level to the next would create a

greater hazard to the erectors.

The Agency agrees with the SIA comments and acknowledges that a

requirement to fully plank under these conditions would unreasonably

interfere with the erection and dismantling process. The Agency also

agrees that a requirement to fully plank every intermediate platform

level, where no work other than scaffold erection or dismantling

operations will occur, is overly burdensome. Therefore, OSHA has

revised proposed paragraph (b)(1), which already excepted walkways from

the requirement for full planking or decking, to add an exception to

the final rule to the planking requirements for erection or dismantling

operations. In a situation where no work, other than erecting or

dismantling the scaffold, is being done at intermediate levels, the

final rule requires only that the planking established by the employer

as necessary to provide safe working conditions for employees erecting

or dismantling the scaffold be used. On the other hand, if scaffold

erection or dismantling is being performed from an intermediate level

platform that is being or will be used as a work area, that platform

must be fully planked in accordance with paragraph (b)(1).

Paragraph (b)(2) of the final rule requires that all scaffold

platforms and walkways be at least 18 inches (46 cm) wide, with lesser

widths allowed for ladder jack scaffolds, top plate bracket scaffolds,

pump jack scaffolds, roof bracket scaffolds, and boatswains' chairs,

and for scaffolds in areas shown to be too narrow to accommodate an 18-

inch wide surface. Proposed paragraph (b)(2) also required a minimum

18-inch width, with exceptions for ladder jack scaffolds (12 inches)

and boatswains' chairs (any width). The rationale for setting a 12-inch

minimum width for ladder jack scaffolds, as discussed in the preamble

of the proposal (51 FR 42684-85), was the difficulty of handling one

18-inch wide plank or two 9-inch planks on a ladder, which the Agency

considered more hazardous than working on a 12-inch wide plank. In the

final rule, OSHA has also included pump jack scaffolds in the exception

to paragraph (b)(2) for which a minimum platform width of 12 inches is

permitted, based on a commenter's statement (Ex. 2-31) that OSHA's

performance criteria for pump jack scaffolds enable employees to work

safely on platforms that are 12 inches or 14 inches wide. The commenter

also indicated that requiring pump jack scaffold platforms to be at

least 18 inches, instead of 12 inches, wide would create ``an economic

hardship * * * for this very prevalent size aluminum platform.'' OSHA

agrees that pump jack scaffolds with platforms as narrow as 12 inches

can satisfy the performance criteria of the final rule and has revised

paragraph (b)(2) accordingly.

In addition, the Agency is recognizing top plate bracket scaffolds

and adding them to the list of scaffolds which are permitted to have

platforms not less than 12 inches in width. As discussed above in the

definition section, these are supported scaffolds, similar to

carpenters' bracket scaffolds and form scaffolds, which consist of a

platform supported by brackets that hook over or are attached to the

top plate of a wall. These scaffolds are used in residential

construction for setting trusses, usually for high ceiling situations

(e.g., cathedral ceilings, atria). The Agency has determined that use

of this type of scaffold, even with a 12-inch wide platform, provides

greater protection for employees setting trusses than the use of

ladders, makeshift scaffolds or walking the top plate. OSHA concludes

that it would be less safe to require wider platforms for top plate

scaffolds because setting up this type of scaffold would then require

handling and positioning an 18-inch wide platform or two nine-inch wide

platforms, and handling and positioning larger, heavier brackets, which

is usually done from ladders. OSHA finds that this would be more

hazardous than working on one 12-inch wide platform equipped with fall

protection.

As proposed, OSHA is deleting the requirement that appeared in the

existing scaffold rule at Sec. 1926.451(l)(1), which sets the minimum

dimensions of

[[Page 46040]]

a boatswains' chair at 12 inches by 24 inches, because, with the advent

of slings and molded seats, the Agency believes that setting minimum

dimensions is overly restrictive. This performance-oriented approach is

reflected by the inclusion of language in paragraph (b)(2)(i) which

specifically exempts boatswains' chairs from any width requirements.

The SIA (Ex. 2-368) suggested that platforms as narrow as 12 inches

wide be allowed in areas where entryways are restricted. Another

commenter (Ex. 2-64) suggested that suspension scaffolds designed for

special applications (e.g., to fit through manholes) be permitted to be

as narrow as 12 inches. OSHA realizes that there may be instances where

the nature of the work being performed makes it impossible to make

platforms and walkways at least 18 inches wide. Where the employer can

establish that such a situation exists, the Agency will accept

platforms and walkways that are less than 18 inches wide, provided both

that such platforms and walkways are as wide as is feasible and that

employees are adequately protected from fall hazards by the use of

guardrails and/or personal fall arrest systems, as required by

paragraph (g).

Final rule paragraph (b)(3) (proposed as paragraph (b)(4)) sets the

requirements for the space between the front edge of a platform and the

face of the structure where the scaffold is being used. Paragraph

(b)(3) requires that, except as provided in paragraphs (b)(3)(i) and

(b)(3)(ii), the front edge of all platforms must be no more than 14

inches from the face of the structure, unless the employer implements

guardrail systems or personal fall arrest systems that comply with

paragraph (g) of the final rule to protect employees from falling

between the platform and the structure. Final rule paragraph (b)(3)(i)

requires that the front edges of outrigger scaffolds be no more than

three inches from the face of the structure, as is required by

Sec. 1926.451(g)(4) of OSHA's existing standard. Final rule paragraph

(b)(3)(ii) requires that the front edges of scaffolds used for

plastering and lathing operations be no more than 18 inches from the

face of the structure.

The 18-inch dimension was developed from data collected by Wang

Associates (Ex. 5) which show that a shorter distance between the

scaffold platform and the wall is not feasible for the operators of

plastering and lathing equipment because of interference with the tools

used during such operations. However, these same operations cause the

employee to stand back from the edge and the hazard of falling is

correspondingly reduced. The SIA (Ex. 2-368) supported the 18-inch

provision as being necessary for the types of work covered, while

acknowledging that in some cases 14 inches would be adequate.

Final rule paragraph (b)(3) is effectively identical to proposed

paragraph (b)(4), except that the proposed provision specified ``Type

I'' guardrails instead of requiring compliance with paragraph (g). OSHA

has deleted the designations ``Type I'' and ``Type II'' from the final

rule for subpart L, as discussed above in relation to the definition of

``Guardrail system''.

Existing Sec. 1926.451(a)(4) requires guardrails on all open sides

and ends of a scaffold platform, but does not specify how far away a

scaffold platform may be from a building before the side facing the

building is considered to be an ``open side.'' OSHA's existing scaffold

rule has often been interpreted to mean that no open space is allowed.

However, zero clearance during all phases of construction is not

feasible. The 14-inch limit in proposed paragraph (b)(4) recognized

that during construction the face of the wall being built often moves

out toward the scaffolds. There must be sufficient space at the

beginning of work to allow for the installation of insulation, lathing,

plaster, masonry units, ledges, facings and other architectural or

structural additions. The spacing must be allowed for from the start,

because it is not practical to move large scaffolds away from the wall

as wall construction progresses outward. When the initial set back

distance must be more than 14 inches, the platform can often still be

kept within 14 inches of the building by the use of side brackets or

extensions on supported scaffolds, and by angulated roping, static

lines, or equivalent means on suspension scaffolds.

Two commenters (Exs. 2-41 and 2-465) questioned the use of 14

inches in this provision, suggesting that a maximum of 12 inches be

allowed. While OSHA recognizes that the suggested 12-inch spacing could

be marginally more protective, the Agency also recognizes that, as

discussed above, in many cases an unobstructed working space of at

least 14 inches is necessary. OSHA also notes that ANSI A10.8-1988,

paragraph 4.5.9, allows up to a 16-inch space for supported scaffolds

and a 12-inch space for suspended scaffolds. In support of OSHA's

position, the SIA (Ex. 2-368) endorsed the proposed language as the

proper solution to the problem, while noting that it would prefer 18

inches. The Agency believes that the 14-inch space appropriately

addresses both the safety concerns and the need to allow necessary room

for many of the jobs normally performed from scaffolds.

Final rule paragraph (b)(4) requires each end of a platform unit,

unless cleated or otherwise restrained by hooks or equivalent means, to

extend over the center line of its support at least six inches (15 cm).

This provision is virtually identical to proposed paragraph (b)(5),

which was based on existing Sec. 1926.451(a)(14). The use of cleats,

hooks, and similar securing devices would also be allowed as

alternatives to the six inch extension in the proposed and final rules,

because of their ability to restrain movement of platform units.

OSHA received one comment (Ex. 2-40) on this provision, which

stressed the importance of securing platform units against movement.

Final rule paragraph (b)(5) (proposed paragraph (b)(6)) addresses

the maximum distance platform units may extend over their supports. In

particular, paragraph (b)(5)(i) provides that each end of a platform

unit 10 feet (3 m) or less in length shall not extend over its support

more than 12 inches (30 cm) unless the unit is designed, and installed

so that the cantilevered portion of the unit is able to support

employees or material without tipping or has guardrails which prevent

employee access to the cantilevered end. In addition, paragraph

(b)(5)(ii) provides that each platform unit greater than 10 feet in

length shall not extend over its support more than 18 inches (46 cm),

unless the unit is designed and installed so that the cantilevered

portion of the unit is able to support employees without tipping, or

that the unit has guardrails which block employee access to the

cantilevered end.

OSHA proposed to change the maximum overhang allowed by existing

Sec. 1926.451(a)(14) from 12 inches to 18 inches because many planks in

use are 10 feet long, and are used to span eight foot distances. OSHA

also notes that ANSI A10.8-1988, paragraph 4.17, limits planks from

extending more than 18 inches over their supports, without regard to

the length of the plank.

OSHA's thinking at the time of the proposal was that the existing

requirement was unnecessarily restrictive, and that strict adherence to

the existing maximum overhang limit would require platform units to be

cut if they extended beyond the 12-inch limit.

Although no comments were received on this provision, OSHA has

concluded, upon further consideration of this matter, that the maximum

overhang allowed, unless the above specified

[[Page 46041]]

measures have been taken, should be limited to 12 inches for planks 10

feet or less in length, and 18 inches for planks greater than 10 feet

in length. The Agency concludes that allowing an 18-inch overhang as a

matter of course would be unsafe, because the weight of an employee on

an 18-inch overhang could easily tip a 10-foot plank. However, an 18-

inch overhang on a plank that is longer than 10 feet would be

permissible because the additional weight of the longer platform would

offset the weight of the employee on the overhang. In addition, an

employer who seeks to use platform units that overhang the supports

more than the prescribed distance would be required to satisfy the

performance criteria of paragraph (b)(5) of the final rule.

Under final rule paragraph (b)(6), where platform units are abutted

to create a long platform, each abutted end shall rest on a separate

support surface. Abutted platform units do not rest one on another, but

instead are end-to-end. Consequently, one unit does not support the

other, and proper support can only be provided by separate support

surfaces. This provision is virtually identical to proposed paragraph

(b)(7), except that the final rule has deleted the words ``butt plate

or equivalent means of support'', because those words add nothing to

the requirement for ``separate support.'' This provision is based on

existing Sec. 1926.451(b)(12), which currently applies only to wood

pole scaffolds. OSHA has determined that all scaffolds need proper

platform support and, accordingly, has promulgated this provision.

The Agency has also added a note to this provision stating that

common support members such as ``T'' sections or hook-on platforms

designed to rest on common supports are not prohibited by this

provision. The Agency is doing this to prevent confusion since these

commonly used support members might be considered not to meet the

requirements of this provision.

Final rule paragraph (b)(7) provides that where platforms are

overlapped to create a long platform, the overlap shall occur only over

supports, and shall not be less than 12 inches (30 cm) unless the

platforms are nailed together or otherwise restrained to prevent

movement. This provision is virtually identical to proposed paragraph

(b)(8) which was based on existing Sec. 1926.451(a)(12).

Final rule paragraph (b)(8) requires that at all points of a

scaffold where the platform changes direction, such as turning a

corner, any platform that rests on a bearer at an angle other than a

right angle shall be laid first and platforms which rest at right

angles over the same bearer shall be laid second, on top of the first

platform. This provision is virtually identical to proposed paragraph

(b)(9), which was based on existing Sec. 1926.451(b)(13). While this

provision in OSHA's existing standard addresses only wood pole

scaffolds, OSHA has determined, as with final rule paragraph (b)(6),

that the existing requirement is appropriately applied to the

construction of all scaffold platforms.

Final rule paragraph (b)(9) provides that wood platforms shall not

be covered with opaque finishes, except that platform edges may be

covered or marked for purposes of identification. Platforms may be

coated periodically with wood preservatives, fire-retardant finishes,

and slip-resistant finishes, but the coating may not obscure the top or

bottom wood surfaces. This paragraph is intended to ensure that

structural defects in platforms are not covered from view by the use of

an opaque coating or finish. Hairline cracks can significantly reduce

the strength of a wood member, so early detection of structural defects

is important. Opaque finishes can cover such cracks and make them

difficult to discover. The edges of platform units are excepted from

this rule to allow identification marks, grading marks, or other

similar type of marks to be placed on the unit edges.

This provision is virtually identical to proposed paragraph

(b)(10). The proposal addressed the use of wood preservatives, fire

retardant finishes and slip-resistant finishes in a ``note'', while the

final rule has incorporated the pertinent language directly into the

regulatory text. In short, those finishes may be used as long as they

do not obscure the top or bottom wood surfaces.

Final rule paragraph (b)(10) requires that scaffold components

manufactured by different manufacturers not be intermixed unless the

component parts fit together without force and the resulting scaffold's

structural integrity is maintained by the user. Scaffold components

manufactured by different manufacturers shall not be modified in order

to intermix them unless the resulting scaffold is determined by a

competent person to be structurally sound. OSHA expects that the

competent person who evaluates the scaffold will have the appropriate

knowledge, skill and experience regarding scaffold systems and

components.

This provision is identical to proposed paragraph (b)(11), except

that the proposal did not contain the phrase ``and the resulting

scaffold's structural integrity is maintained by the user''. The SIA

(Ex. 2-368) suggested the added language, citing the ``latest ANSI

A10.8 draft.'' The Agency acknowledges that a scaffold may lack the

requisite structural integrity even though the intermixed components

``fit together without force.'' OSHA agrees that the requirement to

maintain structural integrity should be clearly stated in this

provision and has revised the final rule accordingly.

One commenter (Ex. 2-29) stated ``[m]any, if not all, scaffold

manufacturers void any liability if their scaffold components are

intermixed * * * A standard requirement should not result in a lesser

degree of safety; neither should it encourage an employer to take a

course of action that could increase his liability.'' The SSFI (Ex. 2-

367) stated ``[i]t would be the Institute's recommendation that

scaffold components not be intermixed even though they may re[a]dily

fit together without force. Many times the capacity or bracing

alignment would not be the same as other types of scaffold, thus

creating a hazardous situation.'' OSHA agrees that an unsafe condition

could exist when parts are intermixed, unless adequate precautions are

taken, and believes that paragraph (b)(10), as modified, in conjunction

with Sec. 1926.451(a), provides for adequate precautions to be taken by

the employer to ensure against this eventuality.

Paragraph (b)(11) of the final rule provides that scaffold

components made of dissimilar metals shall not be used together unless

a competent person has determined that galvanic action will not reduce

the strength of any component to a level below that required by

Sec. 1926.451(a). This provision, while effectively identical to

proposed paragraph (b)(12), differs from Secs. 1926.451(c) (1), (2) and

(3) of OSHA's existing rule, which prohibit the use together of any

dissimilar metals on tube and coupler scaffolds. The proposed rule was

intended to extend the prohibition to all scaffolds, because the

problem of dissimilar metals causing galvanic action can occur on any

scaffold, not just tube and coupler scaffolds. However, the proposed

rule was not intended to prohibit all uses of dissimilar metals because

there are many combinations which do not produce significant galvanic

reactions.

One commenter (Ex. 2-41) expressed skepticism as to the ability of

a competent person to discern that galvanic action has not reduced the

strength of any component. However, OSHA finds that any competent

person, as defined by this subpart, would be able to identify the

causes and significance of any deterioration in

[[Page 46042]]

scaffold components. In particular, OSHA expects the competent person,

who is on site and required to inspect the scaffold, to recognize

deterioration due to galvanic reactions, and to take prompt corrective

action.

Paragraph 1926.451(c) Criteria for Supported Scaffolds

Final rule Sec. 1926.451(c) sets criteria for the use of supported

scaffolds. Paragraph (c)(1) of the final rule requires that supported

scaffolds with a height to base width ratio of more than four to one

(including outrigger supports, if used) be restrained from tipping by

guying, tying, bracing, or equivalent means. That provision is based on

existing Sec. 1926.451(e)(1), which covers manually-propelled mobile

scaffolds. Any type of supported scaffold can topple if its center-of-

gravity is too high, and OSHA has therefore expanded the coverage of

this paragraph in the final rule. Final rule paragraph (c)(1)(i)

provides that guys, ties, and braces shall be installed at locations

where horizontal members support both inner and outer legs. In

addition, paragraph (c)(1)(ii) requires, as follows:

(1) Guys, ties, and braces shall be installed according to the

scaffold manufacturer's recommendations or at the closest horizontal

member to the 4:1 height and be repeated vertically at locations of

horizontal members every 20 feet (6.1 m) or less thereafter for

scaffolds 3 feet (0.91 m) wide or less and every 26 feet (7.9 m) or

less thereafter for scaffolds greater than 3 feet (0.91 m) wide;

(2) The top tie, guy or brace of a completed scaffold shall be

placed no further than the 4:1 height from the top; and

(3) Such guys, ties and braces be installed at each end of the

scaffold and at horizontal intervals not to exceed 30 feet (9.1 m)

(measured from one end [not both] towards the other).

This provision of the final rule is essentially the same as

proposed paragraph (b)(13), except that the maximum vertical spacing

has been changed to allow for the scaffolds to be supported at their

strongest points. Proposed paragraphs (b)(13)(i) and (b)(13)(ii), which

specified the horizontal spacing for ties, guys, and braces, were

intended to replace existing Secs. 1926.451 (b)(4), (c)(12), and

(d)(7). These paragraphs of the existing rule required pole scaffolds,

tube and coupler scaffolds, and fabricated frame scaffolds to be tied

and braced at intervals no greater than 26 feet vertically (25 feet for

wood pole scaffolds) and 30 feet horizontally (25 feet for wood pole

scaffolds). These paragraphs have been misinterpreted over the years to

mean that scaffolds less than 26 feet high by 30 feet long (25 by 25

for wood pole scaffolds) do not need guys, ties, or braces. Proposed

paragraph (b)(13)(ii) was intended to replace the 26- and 25-foot

vertical rule and require all scaffolds required by the 4 to 1 rule to

have guys, ties, or braces also to have such connections installed at

each end of the scaffold and at horizontal intervals not to exceed 30

feet (measured from one end only).

The following are examples of how this requirement is to be

applied: (a) If a scaffold is five feet wide, 18 feet high and 50 feet

long, no vertical or horizontal ties and braces are required because

the height is less than four times the width and the four to one rule

does not require connections; (b) if the scaffold is five feet wide, 50

feet high, and 25 feet long, ties and braces are required at least at

the 20- and 40-foot levels at both ends of the scaffold (four ties and

braces in all); (c) if the scaffold is five feet wide, 50 feet tall,

and 70 feet long, ties and braces are required at least at the 20- and

40-foot levels. These would be installed starting from either end, at

least at the zero, 30, 60, and 70-foot horizontal distances (eight ties

and braces in all).

The SSFI (Ex. 2-367) disagreed with the 20-foot limit for bracing

intervals in proposed paragraph (b)(13)(i) and suggested a 20-foot

limit for scaffolds 3 feet wide or less, and a 26 foot limit for

scaffolds more than 3 feet wide. In addition, this commenter suggested

that bracing be at bearing locations or as recommended by the

manufacturer. OSHA agrees with this commenter's suggested bracing

intervals, because the Agency believes that properly erected scaffolds

more than 36 inches wide are more stable than those which are narrower,

and has modified this provision of the final rule accordingly.

The SIA (Ex. 2-368) stated:

We are in agreement with the proposed wording used to define the

location of guys and ties as a function of the scaffold base width

dimension. This proposed wording adequately defines where scaffolds

must be guyed or tied to achieve proper scaffold stability. To

correctly transmit the stabilizing forces through the scaffold,

however, the guys or ties must be placed at locations where

horizontal members support both the inner and outer legs. Guying or

tying a scaffold leg at mid span could buckle the leg and cause an

unexpected scaffold failure. To avoid this danger, it is recommended

that the tie be placed at the closest horizontal member above the

4:1 base to height ratio and repeated vertically at locations of

horizontal members every 20 to 26 feet in height thereafter. The top

tie shall be placed no further than a 4:1 base to height ratio from

the top.

OSHA agrees that guys, ties, and braces should be placed at points

of scaffold structural strength, and has modified this provision of the

final rule accordingly. Furthermore, the Agency agrees with the SIA's

recommendation that the top tie, guy, or brace be placed no more than

the 4:1 height to base ratio from the top of the scaffold, and has

modified the provision accordingly. However, OSHA does not agree with

the SIA suggestion that guys, ties and braces be installed at the

closest horizontal member above the 4 to 1 base to height ratio, and

has revised the language of this provision to reflect the Agency's

finding that these components be installed at the closest horizontal

member to the 4:1 height, whether above or below, to maximize

stability.

In addition, the SIA recommended that OSHA require employers to

consider loads due to wind and weather when guying, tying, or bracing

is installed, whenever scaffolds are partially or fully enclosed. The

Agency notes that these matters are addressed in the general capacity

requirements of final rule Sec. 1926.451(a) and in

Sec. 1926.451(f)(13), which requires that wind screens not be used

unless the scaffold has been secured against the forces imposed.

Another commenter (Ex. 2-38) suggested using the same language as

in existing Sec. 1926.451(e)(1), which requires that the height of a

manually propelled mobile scaffold not exceed four times the minimum

base dimension, ``because it is more understandable.'' Also, a

commenter (Ex. 2-40) stated ``since the standard does not address the

issue of cantilevered work platforms (or their effect on stability),

the allowable height to base width ratio of equal to four or less seems

high.''

Another commenter (Ex. 2-23) recommended a ratio of 3 to 1, but

provided no rationale to support its suggestion. OSHA notes that the

final rule 4:1 ratio is consistent with the requirement in ANSI A10.8-

1988, paragraph 4.31, that free-standing scaffolds with height to base

ratios of more than 4:1 be restrained from tipping by guying or other

means.

Based on these concerns, in the final rule OSHA has added paragraph

(c)(1)(iii), which requires that scaffolds with eccentric loads (such

as cantilevered work platforms) be restrained from tipping through the

use of ties, guys, braces or outriggers.

Final rule paragraph (c)(2) requires that supported scaffold poles,

legs, posts, frames, and uprights bear on base plates and mud sills or

other adequate firm foundation. In particular, final rule paragraph

(c)(2)(i) requires that such footings be level, sound, rigid, and

capable of supporting the scaffold in a

[[Page 46043]]

loaded condition without settling or displacement.

In addition, final rule paragraphs (c)(2) (ii) and (iii) provide

that unstable objects shall neither be used to support scaffolds or

platform units, nor be used as working platforms, respectively. The

reason for these requirements is almost self-explanatory: every

scaffold must stand on a firm footing if it is to withstand the load

that employees, equipment, and materials place on it.

Final rule paragraph (c)(2)(iv) provides that front-end loaders and

similar pieces of equipment shall not be used as scaffold supports

unless they have been specifically designed by the manufacturer for

such use. In addition, final rule paragraph (c)(2)(v) requires that

fork-lifts not be used to support scaffold platforms unless the entire

platform is attached to the fork and the fork-lift is not moved

horizontally while the platform is occupied. Both these requirements

relate to the need for solid support for scaffold platforms and reflect

the fact that front-end loaders, fork-lifts and other such equipment

are not generally designed for this purpose.

Paragraph (c)(2) of the final rule is identical to proposed

paragraph (b)(14), except for two provisions, final rule paragraphs

(c)(2) (iv) and (v), which have been added based on input generated by

responses to Issue 3 of the preamble of the NPRM. Proposed paragraph

(b)(14) consolidated existing requirements that scaffold uprights rest

upon a stable, firm, level footing.

Issue 3 asked if OSHA should prohibit the use of cranes, derricks,

forklifts, front-end loaders, and similar pieces of equipment for the

support of scaffold platforms. In addition, OSHA asked what pieces of

equipment should be prohibited and what other related provisions would

be necessary to ensure employee safety.

Several commenters from the Associated General Contractors of

America (AGC) (Exs. 2-20, 2-55, and 2-390) and the ACCSH (Tr. 6/9/87,

pp. 40-41) noted that OSHA had undertaken rulemaking regarding the use

of cranes and derricks to hoist personnel platforms (NPRM published

February 17, 1984, 49 FR 6280). The AGC commenters stated that the

proposed regulations for crane suspended work platforms already

addressed the concerns raised in Issue 3.

Another commenter (Ex. 2-53) called for the development and

issuance of specific crane suspended platform regulations, and one

respondent (Ex. 2-29) commented that the current regulations on crane

suspended work platforms were acceptable.

On August 2, 1988 (53 FR 29116), OSHA issued a final rule

(Sec. 1926.550(g)) which regulates the use of cranes and derricks to

hoist personnel platforms. Therefore, there is no longer a need for

subpart L to address that subject.

Regarding the use of front-end loaders, one commenter (Ex. 2-33)

responded, in part, that ``front-end loaders should not be used to

hoist worker-loaded scaffold platforms'' and added that the ``[u]se of

forklifts for this purpose should be limited in accordance with * * *

OSHA's General Industry Standards for powered industrial trucks, 29 CFR

1910.178(m)(12).'' The same commenter also stated ``If large platforms

are used in this manner, consideration should be given to requiring

bracing of forks to safeguard against tipping or slipping of the truck

or its forks.''

Another commenter (Ex. 2-70) stated simply ``[w]e do not utilize

forms of equipment to support platforms.'' Two other commenters (Exs.

2-367 and 2-368) stated ``the practice of using cranes, derricks, fork-

lifts, etc., [to support scaffold platforms] is unsafe and should be

prohibited.''

One commenter (Ex. 2-5), a manufacturer of heavy-duty materials-

handling equipment, including forklifts and cranes, stated that ``[f]or

years, we have made the users of our equipment aware that these are

intended solely for the handling of materials and not for personnel.''

The commenter went on to say their company recommends that ``OSHA

develop rules prohibiting the use of forklifts, front-end loaders and

similar pieces of equipment for the support of scaffold platforms,''

and provided the following rationale:

This class of equipment depends on a hydraulic cylinder(s) to

lift and hold the load[-]engaging means. When new, the cylinder has

little leakage past the sealing means, usually packings, but it does

have leakage. After use, the leakage increases. This allows the

load[-]engaging means to 'drift' downward, possibly endangering

personnel on the scaffold platform. Additionally, the load[-

]engaging means of a forklift are usually supported on bearings or

sliding members and chains. With use, wear occurs at these points.

If excellent maintenance is not performed, and worn parts [are not]

promptly replaced, sufficient wear can occur which is not evident

when handling heavy loads, since their gravitational mass overcomes

the friction and keeps the chain tight; however, when supporting a

light load such as a scaffold platform, there is insufficient mass

to overcome the friction with the load [-]engaging means left

suspended when the mechanism is lowered, with a sudden drop of the

load [-] engaging means when dislodged. We have knowledge of this

happening at least two times at Cape Kennedy when a work platform

was raised by a 15,000 pound[-]capacity forklift of our manufacture.

Each time serious injury to the man on the platform occurred.

The ACCSH has recommended (Tr. 6/9/87, pp. 32-48) that OSHA

prohibit the use of front-end loaders and other similar earth-moving

equipment for scaffold support. ACCSH also recommended that OSHA

develop rules allowing the use of forklifts as scaffold platforms only

while the equipment is stationary and while proper fall protection is

provided.

Several commenters (Exs. 2-13, 2-20, 2-22, 2-24, 2-54, 2-55, and 2-

390) favored allowing the use of cranes, derricks, front-end loaders,

and forklifts to support scaffold platforms, in general terms. Three

other commenters (Exs. 2-29, 2-33, and 2-176) favored allowing the use

of forklifts, under specified conditions, to support scaffolds.

Three commenters from the AGC (Exs. 2-20, 2-55, and 2-390) stated

that, in certain instances, where access to a work area was difficult

and the work assignment was of short duration, using scaffold framing

might be more hazardous than using equipment for work platform support.

They added that appropriate personal protective equipment could be used

for employee safety in these situations.

Another commenter (Ex. 2-22) opposed the contemplated prohibition,

stating ``[t]here are a variety of field situations in which the use of

such devices is the only safe way to handle a particular problem. Not

only is there no diminution in the safety level afforded to employees

in such situations, but the level of safety may actually be improved.''

Also, a commenter (Ex. 2-24) termed the ``suggestion that cranes,

forklifts, and other equipment could not be used as platform supports''

as ``totally unrealistic.'' The commenter provided some alternatives

and examples (e.g., long ladders) describing them as involving the use

of generally dangerous equipment. The commenter also noted that when

using this equipment as scaffold support, additional protective

measures would be necessary. These measures would include having the

operator at the controls at all times, having railings on platforms

used above 10 feet in height, and providing safety training.

The Boston Cement Masons and Asphalt Layers Union (BCMALU) (Ex. 2-

54) indicated that the use of this equipment to support scaffold

platforms might be practical in certain circumstances. This commenter

also added that employers ``should note the use of this equipment in

their Daily Report and explain why they used it.''

[[Page 46044]]

A carpentry contractor (Ex. 2-176) said that forklift scaffold(s)

with properly constructed scaffold platforms should be permitted,

provided they are equipped with proper railings, and added that ``[i]f

the workers working from the scaffold do not ride up and down, there is

no danger of their falling off.''

One commenter (Ex. 2-29) stated that ``[f]orklift[-]mounted work

platforms might also be acceptable provided suitable requirements and

restrictions are specified.'' Another commenter (Ex. 2-13), expressing

guarded support of the possible prohibition, stated that since this

``equipment is readily available at job sites * * * [it] will continue

to be used to support workers at elevated working locations.'' The same

commenter further suggested that a minimum requirement for the safe use

of such equipment would be to have a competent engineer responsible for

the design and safe use of the resulting scaffold.

After a careful review of the above comments, OSHA finds there is

insufficient reason to totally ban the use of forklifts, front-end

loaders, and other similar equipment as scaffold supports. OSHA notes

that the commenters are in general agreement that all equipment not

specifically designed to support scaffold platforms must not be used.

Accordingly, the Agency has promulgated new paragraphs (c)(2) (iv) and

(v) in the final rule to provide guidance for the safe use of specific

equipment as scaffold supports. In particular, the added provision

requires that, in the case of fork-lifts, the entire scaffold platform

be secured to the forklift. All supported scaffolds, including those

supported by forklifts, front-end loaders and similar pieces of

equipment, must comply with the applicable requirements of

Sec. 1926.451 for capacity, construction, access, use, and fall

protection.

Paragraph (c)(3) of the final rule requires that supported scaffold

poles, legs, posts, frames, and uprights be plumb and braced to prevent

swaying and displacement. This provision, which is identical to

proposed paragraph (b)(15), consolidates existing Sec. 1926.451

(a)(15), (b)(1), (c)(6) and (e)(8), all of which require that uprights

be secure, plumb, and braced to prevent swaying and displacement of the

scaffold.

Paragraph 1926.451(d) Criteria for Suspension Scaffolds

Final rule paragraph (d) sets criteria for the use of suspension

scaffolds. Paragraph (d)(1) of the final rule requires that all

suspension scaffold support devices, such as outrigger beams, cornice

hooks, parapet clamps, and similar devices, rest on surfaces capable of

supporting at least 4 times the loads imposed on them by the scaffold

operating at the rated load of the hoist (or at least 1.5 times the

loads imposed on them by the scaffold operating at the stall load of

the hoist, whichever is greater).

Proposed paragraph (b)(16) required all suspension scaffold support

devices such as outrigger beams, cornice hooks, parapet clamps, and

similar devices, to rest on surfaces capable of supporting the reaction

forces imposed by the scaffold hoist operating at its maximum rated

load. Both the proposed and final rule are based on existing

Sec. 1926.451(h)(9), which requires that outrigger beams rest on

suitable wood bearing blocks. Final rule paragraph (d)(1) differs from

the proposed provision regarding the way in which the load to be

sustained is expressed. The proposed rule used the term ``maximum rated

load'' instead of the final rule's terms ``rated load of the hoist''

and ``stall load'' of the hoist.

Three commenters (Exs. 2-64, 2-367 and 2-516) recommended a 4 to 1

safety factor based on the rated load of the hoist. Another commenter

(Ex. 2-41) stated that reaction force should include all forces, not

just those from the hoist, and indicated that some safety factor was

needed. The Agency agrees that a clarification is warranted here, and

has modified the final rule to reflect this input. In addition, the

text has been modified to be consistent with final rule Secs. 1926.451

(a)(2) and (a)(4). The Agency concludes that this is necessary in order

to adequately address the issue of the hoist reaching its stall load

when the scaffold strikes an obstruction. OSHA has determined that the

hoist stall capacity needs to be greater than the hoist rated capacity

so that the rigging system will be able to support the loads imposed by

obstructions as well as the load being lifted. This matter is addressed

in greater detail above, in relation to final rule Sec. 1926.451(a)(1).

Final rule paragraphs (d)(2), (d)(3) and (d)(4) set requirements

for outrigger beams used with suspension scaffolds. Paragraph (d)(2) of

the final rule requires that suspension scaffold outrigger beams, when

used, be made of structural metal, or equivalent strength material, and

be restrained to prevent movement. This is identical to proposed

paragraph (b)(17), except as discussed below. The proposal was based on

existing Secs. 1926.451(h)(4) and (k)(8).

The SIA (Ex. 2-368) stated that if the intent of proposed paragraph

(b)(17) was to prohibit the use of wood outrigger beams, the Agency

should simply say so. The proposed language clearly indicated that

outrigger beams must be made of structural metal. However, upon further

consideration of this provision, OSHA believes that other materials

should be allowed if their strength and other pertinent characteristics

are equivalent to those of structural metal. The Agency has therefore

revised the proposed rule accordingly. This revision is in line with

the Agency's policy to permit alternative materials or practices which

provide equivalent protection to employees. Also, OSHA has added the

words ``when used'' to indicate clearly that the provision does not

require outrigger beams to be used but only applies when outrigger

beams are used.

Final rule paragraph (d)(3) sets requirements for the stabilization

of outrigger beams. The introductory language of the paragraph requires

that outrigger beams be secured directly to the supporting surface or

be stabilized using counterweights, except that masons' multi-point

adjustable suspension scaffolds shall not be stabilized by

counterweights. The rule does not allow counterweights for stabilizing

such masons' suspension scaffolds because, with the large loads often

placed on masons' multi-point adjustable suspension scaffolds and the

large counterweights that would be necessary to anchor such systems,

OSHA is concerned that the supporting roof or floor would become

dangerously overloaded.

Final rule paragraph (d)(3) is identical to proposed paragraph

(b)(18), except for a few minor editorial changes as described below.

The final rule clarifies existing Secs. 1926.451 (h)(4) and (j)(5),

which require simply that outriggers be securely fastened or anchored.

Counterweights are not addressed in the existing standard. OSHA has

determined that it is necessary to set criteria for counterweights in

the final rule, however, because counterweights are often the only way

to anchor an outrigger beam without damaging the supporting surface.

Paragraph (d)(3)(i) provides that direct connections shall be

evaluated by a competent person who affirms, based on that evaluation,

that supporting surfaces can support the anticipated loads. In

addition, the paragraph requires masons' multi-point adjustable

suspension scaffold connections to be designed by an engineer

experienced in such scaffold design. OSHA anticipates that compliance

with these provisions will ensure that roof or floor decks are capable

of supporting the loads to be imposed.

[[Page 46045]]

Final rule paragraphs (d)(3)(ii) through (d)(3)(v) require that

counterweights be made of non-flowable material; be specifically

designed for use as scaffold counterweights; be secured to outrigger

beams to prevent accidental displacement; and not be removed from an

outrigger beam until the scaffold is disassembled, respectively. These

requirements are necessary to ensure that counterweights are used only

for their intended purpose and are not displaced or removed

prematurely.

Final rule paragraphs (d)(3)(vi) through (d)(3)(x) set requirements

for securing outrigger beams. In particular, outrigger beams not

stabilized by direct connections to the supporting surface shall be

secured by tiebacks (paragraph (d)(3)(vi)). Tiebacks must be as strong

as the suspension ropes (paragraph (d)(3)(vii)), be secured to a

structurally sound anchorage (paragraph (d)(3)(ix)), and be installed

perpendicular to the structure unless opposing angle tiebacks are

installed (paragraph (d)(3)(x)). In addition, paragraph (d)(3)(viii)

requires that outrigger beams be placed perpendicular to their bearing

support, with the exception described more fully below.

With regard to proposed paragraph (b)(18)(i) (paragraph (d)(3)(i)

in the final rule), a commenter (Ex. 2-40) stated ``we believe that

improper connections are almost always responsible for the failure of

scaffolds. Therefore, criteria for torsion strength evaluation of

bolted (direct) connections should be included in the standard.'' OSHA

believes that the corresponding requirement in final rule paragraph

(d)(3)(i) for evaluation of direct connections by a competent person

will provide adequate assurance that those connections are designed and

made appropriately, because the competent person must have the ability

to identify any problems with the direct connections and the authority

to have any problems corrected.

Proposed paragraph (b)(18)(ii) (paragraph (d)(3)(ii) in the final

rule) required that counterweights be made of non-flowable solid

material. That, in effect, prohibited the practice of using sandbags or

water-filled buckets as counterweights. The reason for the prohibition

is that counterweights are easily displaced and may leak. Final rule

paragraph (d)(3)(ii) is virtually identical, except that the word

``solid'' has been deleted, because that term is redundant with the

term ``non-flowable'', and a sentence has been added that explicitly

prohibits the use of sand, gravel and other similar material as

counterweights.

A commenter (Ex. 2-41) stated that the proposed paragraph would

cause confusion, inquiring whether, if five 70 pound weights are

considered ``solid,'' 350 one pound weights also would be considered

``solid''? The Agency would consider five 70 pound weights as meeting

this requirement, because objects of this weight would be unwieldy and

less prone to dislocation. However, 350 one pound weights would not

meet this requirement because their light weight would make them more

prone to being dislocated, thus possibly compromising their

effectiveness as a counterweight. OSHA has added the sentence ``Sand,

gravel, and similar materials that can be easily dislocated shall not

be used'' to indicate more clearly what materials are not allowed for

use as counterweights.

Paragraph (d)(3)(iii) of the final rule requires that

counterweights be specifically designed for use as counterweights. This

provision, which was not part of the proposed rule, has been added in

response to input received regarding Issue 26 in the preamble of the

NPRM. That Issue asked if OSHA should require that counterweights be

designed for no other purpose than to counterweight the system, thereby

prohibiting the use of construction materials, such as concrete masonry

units, rolls of felt, etc., as counterweights.

One commenter (Ex. 2-22) opposed requiring that counterweights be

designed for no other purpose than to counterweight the system. This

commenter stated that such a requirement would be unnecessarily costly.

This commenter also stated ``So long as the material used meets the

objective of the safety requirement, there is no need to cause the

expenditure of money on specific materials that do not enhance the

safety of the employee * * *''

Several commenters (Exs. 2-13, 2-29, 2-43, 2-53, 2-54, 2-64, 2-367,

2-368 and 2-465) supported a requirement that counterweights be

specifically designed for no other purpose than to counterweight the

system. These commenters also supported a ban on the use of

construction material as counterweights. The SIA (Ex. 2-368) added that

such a requirement would be practical, feasible, of negligible cost and

would prevent accidents which occur when construction materials used as

counterweights are removed for other purposes.

Another commenter (Ex. 2-13) stated:

Counterweights should be designed for their specific use and

permanently marked with their weight otherwise they are worthless.

Construction material, of any kind, should be banned for use as

counterweights. There is no assurance that proper counterweighting

is being accomplished with construction materials. Also, the

material could be removed for use by others, thus providing an

unstable condition.

Two commenters (Exs. 2-64 and 2-367) stated that there should be a

requirement that counterweights be identified or marked. The SSFI (Ex.

2-367) recommended that ``each counterweight be identified as to its

weight'' and should also ``have the ability to be fastened directly to

the outrigger system.'' Another commenter (Ex. 2-64) wanted

counterweights to be ``clearly marked with their actual weight

(stamped, painted, etc.), so that workers will use the proper amount of

weight.''

In addition, a commenter (Ex. 2-8) stated ``[c]onstruction

materials should not be use[d]. We have seen masons remove block used

as counterweight.''

Also, the ACCSH (Tr. pp. 188-190, 6-9-87) recommended that

counterweights be designed for no other purpose than to counterweight

the system. One member stated ``Certainly OSHA should require

counterweights be designed for no other purpose. It seems to me that

the same day I first read this question I received from OSHA a copy of

`Fatal Facts' that involved this very issue.''

After carefully considering the above comments and the ACCSH

recommendation, OSHA has determined that it is reasonably necessary to

require that counterweights be designed for no other purpose than to

counterweight the system, and to prohibit the use of construction

materials as counterweights. In addition, OSHA has determined that it

is appropriate to require the marking of counterweights with their

weights because that information is needed for the proper design,

selection and installation of counterweights.

Proposed paragraph (b)(18)(iii), which required that counterweights

be connected to outrigger beams by mechanical means, is identical to

final rule paragraph (d)(3)(iv), except that the phrase ``to prevent

accidental displacement'' has been added to the final rule to clarify

the Agency's regulatory intent. The BCMALU (Ex. 2-54) recommended that

the Agency clarify the reason for this provision. The Agency agrees and

has revised the provision accordingly.

Proposed paragraph (b)(18)(iv) required that counterweights not be

removed from a scaffold until the scaffold is disassembled. Final rule

paragraph (d)(3)(v) is identical to the proposed paragraph, except that

the

[[Page 46046]]

final rule specifies that the counterweights may not be removed from

the ``outrigger beam'', rather than from the ``scaffold.'' One

commenter (Ex. 2-41) pointed out that counterweights used with

suspension scaffold outrigger beams are not placed on the scaffold, as

stated in the proposed rule, but are installed on the outrigger beam

above. The Agency agrees, and has revised the provision accordingly.

Proposed paragraph (b)(18)(v) required outrigger beams to be

secured by tiebacks equivalent in strength to the suspension ropes.

This provision was intended to provide a backup system in case the

counterweights became displaced. Although tiebacks alone may not keep a

scaffold from tipping, they will keep the system from falling to the

ground and from causing a progressive failure of nearby scaffolds and

scaffold sections. The intent of the proposed paragraph has been

carried forward in final rule paragraphs (d)(3)(vi) and (vii), which

require the use of tiebacks when direct connections are not used, and

require tieback strength equivalent to that of the suspension ropes,

respectively.

The SSFI and the SIA (Ex. 2-367 and 2-368) noted that outrigger

beams which are bolted to the structure become part of the structure

and do not require tiebacks. The Agency agrees that only

counterweighted outrigger beams need to be secured with tiebacks and

has incorporated appropriate language into paragraphs (d)(3)(vi) and

(d)(3)(vii) accordingly.

In addition, final rule paragraph (d)(3)(viii) requires that

outrigger beams be placed perpendicular to the face of the structure,

except that, where the employer establishes that such placement is

prevented by obstructions, the outrigger shall be placed as near to the

perpendicular as possible and shall be secured using opposing angle

tiebacks. This provision has been added as a partial response to a

commenter (Ex. 2-41) who stated that requiring tiebacks to be installed

parallel to the centerline of the beam, as required by proposed

paragraph (b)(18)(vii), is only safe when the beam is perpendicular to

the edge. OSHA agrees with this comment because a non-perpendicular

beam/tieback arrangement creates a pendulum effect that could endanger

employees. However, the SIA (Ex. 2-368) has pointed out that there may

be circumstances where obstructions prevent the outrigger beam from

being placed perpendicular to the edge. The SSFI and the SIA (Exs. 2-

367 and 2-368) suggested that, in such cases, opposing angle tiebacks

be required. OSHA agrees that opposing angle tiebacks are appropriate

where obstructions prevent perpendicular placement of outriggers, and

has revised the final rule language accordingly.

Proposed paragraphs (b)(18) (vi) and (vii) required that tiebacks

be secured to structurally sound anchorages and that they be parallel

to the outrigger beam. Those provisions correspond to final rule

paragraphs (d)(3) (ix) and (x). OSHA has revised this language, drawing

on examples in the preamble of the NPRM, to provide more specific

direction regarding what constitutes a structurally sound anchorage.

Three AGC commenters (Exs. 2-20, 2-55 and 2-390) stated that the

OSHA interpretation of what is considered an acceptable point of

anchorage (51 FR 42686) was too strict and that the Agency should

permit the use of any available roof structural anchor points since

they are only accommodating a back-up or secondary support system. The

Agency disagrees with this position because the secondary support

system must be capable of providing adequate support in the event of

rigging failure. The revised final rule paragraph specifically

identifies structural members of the building or structure as

appropriate anchor points, and identifies standpipes, vents, other

piping systems, and electrical conduit, as structural elements that do

not provide appropriate anchorages.

Proposed paragraph (b)(18)(vii) required that tiebacks be installed

parallel to the centerline of the beam. The proposed language has been

revised in final rule paragraph (d)(3)(x) to recognize that opposing

angle tiebacks are acceptable alternative means of installation. In

addition, OSHA has replaced the proposed term ``parallel'', with the

term ``perpendicular'' for the sake of clarity.

A commenter (Ex. 2-29) stated ``since tieback anchorages are not

always available exactly where needed, perhaps the wording of these

requirements should be revised to allow tiebacks to be at an angle,

e.g., not to exceed 10 degrees from the centerline of the outrigger * *

*.'' OSHA acknowledges that anchorages are not always conveniently

located and that there may be circumstances where it is necessary to

install the tieback at an angle. However, OSHA believes that when this

is done, it is also necessary to require an opposing angle tieback to

be used so that the pivot radius of the beam is minimized.

Consequently, single tiebacks installed at an angle are not allowed by

the final rule.

Paragraph (d)(4) of the final rule specifies the construction

requirements for outrigger beams used with suspension scaffolds. This

provision requires that suspension scaffold outrigger beams be:

provided with stop bolts or shackles at both ends; securely fastened

together with the flanges turned out when channel iron beams are used

in place of I-beams; installed with all bearing supports perpendicular

to the beam center line; and set and maintained with the web in a

vertical position. In addition, when an outrigger beam is used, the

shackle or clevis with which the suspension rope is attached to the

outrigger beam shall be placed directly over the hoisting machine,

i.e., over the center line of the stirrup. (These requirements are

found in paragraphs (d)(4)(i) through (d)(4)(v).)

These requirements are effectively identical to those in proposed

paragraph (b)(19). The SIA (Ex. 2-368) recommended that OSHA drop the

word ``single'' from proposed paragraph (b)(19)(v) because this

requirement applied to all outrigger beams, not just to ``single

outrigger beams''. The Agency agrees, and has revised this provision of

the final rule accordingly.

Final rule paragraph (d)(5) sets requirements for suspension

scaffold support devices other than outrigger beams. These devices

include cornice hooks, roof irons, parapet clamps, or similar devices.

Under this provision, those devices must be: made of steel, wrought

iron, or materials of equivalent strength; supported by bearing blocks;

secured against movement by tiebacks installed at right angles to the

face of the building or structure unless opposing angle tiebacks are

installed and secured to a structurally sound point of anchorage on the

building or structure (sound points of anchorage include structural

members, but do not include standpipes, vents, other piping systems, or

electrical conduit); and tiebacks shall be equivalent in strength to

the strength of the hoisting rope.

Final rule paragraph (d)(5) is identical to proposed paragraph

(b)(20), except that some minor edit

This text is long and has been trimmed here. Open the source document for the complete record.