Restructuring of Cylinder Specifications Requirements

Federal RegisterMay 23, 1996

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SUMMARY: RSPA is amending the Hazardous Materials Regulations (HMR) by

restructuring the cylinder specification requirements in its

regulations on Specifications for packagings. The intended effect of

this rulemaking is to reduce the size of the HMR through consolidation

of repetitive requirements and other formatting changes. This action

eliminates approximately 45 pages of regulations from the Code of

Federal Regulations without substantially changing the regulatory

requirements or affecting safety. It is in response to President

Clinton's March 4, 1995 Regulatory Reinvention Initiative memorandum to

heads of departments and agencies calling for a review of all agency

regulations. RSPA is also making corresponding reference changes

throughout the HMR.

DATES: Effective date: October 1, 1996.

Incorporation by reference date: The incorporation by reference of

certain publications listed in these amendments has been approved by

the Director of the Federal Register as of October 1, 1996.

FOR FURTHER INFORMATION CONTACT: John A. Gale, (202) 366-8553; Office

of Hazardous Materials Standards, RSPA, Department of Transportation,

Washington, DC 20590-0001.

SUPPLEMENTARY INFORMATION:

I. Background

On March 4, 1995, President Clinton issued a Regulatory Reinvention

Initiative memorandum to heads of departments and agencies calling for

a review of all agency regulations and elimination or revision of those

regulations that are outdated or in need of reform. RSPA has performed

an extensive review of the Hazardous Materials Regulations (HMR; 49 CFR

Parts 171-180) and associated procedural rules (49 CFR Parts 106 and

107) in response to the President's directive.

The President also directed that front line regulators ``* * * get

out of Washington and create grassroots partnerships'' with people

affected by agency regulations. On April 4, 1995, RSPA published in the

Federal Register (60 FR 17049) a Notice of Public Meetings and request

for comment on its hazardous materials safety program. Comments were

requested on ways to improve the HMR and the kind and quality of

services its customers want. RSPA held seven public meetings and

received over 50 comments in response to the notice. On July 28, 1995,

RSPA published a second Notice of Public Meetings in the Federal

were held from September 1995 through January 1996.

One area identified by RSPA in its review of the HMR was the need

to reform the cylinder specifications in 49 CFR Part 178. On March 4,

1996 (61 FR 8328), RSPA proposed to amend the HMR by restructuring the

cylinder specifications in Part 178. RSPA estimates that by

consolidating duplicative requirements in 23 cylinder specifications,

that it will eliminate at least 45 pages from the CFR. By reformatting

the specifications, RSPA proposes to eliminate over 450 sections from

Part 178 of Title 49. The combined effect of these changes will be to

make the regulations shorter and easier to use and help RSPA move

toward its goal of issuing the HMR in one volume of the Code of Federal

Regulations, rather than two.

This rulemaking also serves as the model for a comprehensive

rulemaking, being developed by RSPA in cooperation with the Compressed

Gas Association, for which a notice of proposed rulemaking is

anticipated later this year. In this latter rulemaking, under Docket

HM-220, RSPA intends to propose substantive changes to the cylinder

specifications to accommodate contemporary manufacturing techniques,

eliminate obsolete requirements, contemporize regulatory language and

make safety enhancements to the regulations.

II. Summary of Amendments

RSPA received approximately 10 comments to the NPRM. All of the

comments were in support of the proposal. One commenter stated that the

changes proposed under Docket HM-220B are a valuable contribution to

simplification of the cylinder specifications. Another commenter stated

that it strongly supports the amendments proposed in Docket HM-220B to

simplify and update existing regulations and to reduce the size of the

HMR by consolidation of the text. Several commenters also raised

concerns that were beyond the scope of the proposed rule; however, they

may be considered in future rulemakings.

In this final rule, RSPA is revising the HMR by restructuring the

cylinder specification requirements in 49 CFR Part 178. This

restructuring of the cylinder specifications: (1) consolidates similar

sections; (2) reformats subpart C of Part 178 for consistency with the

format of the rest of Part 178; and (3) revises section references

throughout the HMR to correspond to the revised sections. RSPA intends

to streamline the cylinder specification requirements without making

substantive changes to them.

Sections that have been consolidated are the sections of each

specification addressing compliance, authorized inspectors, duties of

the inspector, the inspector's report, record retention, defects,

safety relief devices, and marking. These sections have been

consolidated into a new Sec. 178.35. Section 178.35, entitled ``General

requirements for specification cylinders'' prescribes the general

requirements for all DOT specification cylinders. However, because some

of the duties of the inspector and marking requirements are specific to

individual cylinder designs, some specifications have additional

marking and inspector requirements remaining in their sections.

For the inspector's report, RSPA has adopted the inspector report

formats in Compressed Gas Association (CGA) Pamphlet C-11,

``Recommended Practices for Inspection of Compressed Gas Cylinders at

Time of Manufacture.'' The report formats can be modified to represent

the inspection of specific cylinders. Additional information may be

required as stated in each specification. In order to help facilitate

transition into the new reports, RSPA is allowing inspectors an

additional year, until October 1, 1997, to use the old report format

required by the HMR.

Those sections remaining in each specification have been

consolidated into a single section. Presently, each specification is

set forth in approximately 22 different sections. Under this final

rule, there is only one section for each specification. For example,

Specification 3B was set forth in 24 sections, Secs. 178.38 through

178.38-23. In this final rule, Specification 3B is set forth in one

section, Sec. 178.38, and some of its requirements are relocated in

Sec. 178.35. Sixteen of the old sections are converted to paragraphs

(a) through (o) of Sec. 178.38. As an aid to the reader, the regulatory

[[Page 25941]]

text in this final rule includes all of the requirements for cylinders

in the current Subpart C of part 178, even though not all of the

requirements are changed.

In response to comments, RSPA has made several changes to the

original proposal. RSPA has corrected the minimum service pressure for

the DOT Specification 4E cylinder to 225 psig. In the NPRM, RSPA

incorrectly proposed the minimum service pressure for the 4E cylinder

at 250 psig.

In the NPRM, RSPA proposed to revise the marking requirements for

the DOT Specification 39 to indicate that the highest monetary penalty

under the Federal hazardous materials transportation law was $500,000

and not $25,000. One commenter, citing the costs of updating silk-

screens, requested that RSPA not adopt this change. RSPA has not

adopted this commenter's suggestion because the marking should

accurately reflect the requirements of the Federal hazardous materials

transportation law. However, RSPA is adding a ``grandfather'' provision

for those containers marked prior to October 1, 1996.

In Sec. 178.35(b)(2), RSPA is adding a reference to the DOT

Specification 3E. RSPA had inadvertently left reference of that

specification out of that section.

The purpose of this rulemaking action is to reduce the size of the

HMR and make it easier to use. It is not intended to make substantive

changes to regulatory requirements and no adverse impacts are

anticipated on the regulated community.

III. Regulatory Analyses and Notices

Executive Order 12866 and DOT Regulatory Policies and Procedures

This final rule is not considered a significant regulatory action

under section 3(f) of Executive Order 12866 and was not reviewed by the

Office of Management and Budget. The rule is not considered significant

under the regulatory policies and procedures of the Department of

Transportation (44 FR 11034). The economic impact of this rule is

minimal to the extent that the preparation of a regulatory evaluation

is not warranted.

Executive Order 12612

This final rule has been analyzed in accordance with the principles

and criteria contained in Executive Order 12612 (``Federalism''). The

Federal hazardous materials transportation law (49 U.S.C. 5101-5127)

contains an express preemption provision that preempts State, local,

and Indian tribe requirements on certain covered subjects. Covered

subjects are:

(i) the designation, description, and classification of hazardous

material;

(ii) the packing, repacking, handling, labeling, marking, and

placarding of hazardous material;

(iii) the preparation, execution, and use of shipping documents

pertaining to hazardous material and requirements respecting the

number, content, and placement of such documents;

(iv) the written notification, recording, and reporting of the

unintentional release in transportation of hazardous material; or

(v) the design, manufacturing, fabrication, marking, maintenance,

reconditioning, repairing, or testing of a package or container which

is represented, marked, certified, or sold as qualified for use in the

transportation of hazardous material.

The Federal hazardous materials transportation law provides that if

DOT issues a regulation concerning any of the covered subjects after

November 16, 1990, DOT must determine and publish in the Federal

5125(b)(2). That effective date may not be earlier than the 90th day

following the date of issuance of the final rule and not later than two

years after the date of issuance. RSPA has determined the effective

date of Federal preemption for these requirements is October 1, 1996.

This final rule deals with the packaging of compressed gases. Because

RSPA lacks discretion in this area, preparation of a federalism

assessment is not warranted.

Regulatory Flexibility Act

I certify that this final rule will not have a significant economic

impact on a substantial number of small entities. This final rule does

not impose any new requirements on persons subject to the HMR.

Paperwork Reduction Act

This final rule does not propose any new information collection

requirements.

Regulation Identifier Number (RIN)

A regulation identifier number (RIN) is assigned to each regulatory

action listed in the Unified Agenda of Federal Regulations. The

Regulatory Information Service Center publishes the Unified Agenda in

April and October of each year. The RIN number contained in the heading

of this document can be used to cross-reference this action with the

Unified Agenda.

List of Subjects

49 CFR Part 171

Exports, Hazardous materials transportation, Hazardous waste,

Imports, Incorporation by reference, Reporting and recordkeeping

requirements.

49 CFR Part 173

Hazardous materials transportation, Packaging and containers,

Radioactive materials, Reporting and recordkeeping requirements,

Uranium.

49 CFR Part 178

Hazardous materials transportation, Incorporation by reference,

Motor carrier safety, Packaging and containers, Reporting and

recordkeeping requirements.

In consideration of the foregoing, 49 CFR parts 171, 173, and 178

are amended as follows:

PART 171--GENERAL INFORMATION, REGULATIONS, AND DEFINITIONS

1. The authority citation for Part 171 continues to read as

follows:

Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.

2. In Sec. 171.7(a)(3), in the table, under the entry ``Aluminum

Standards and Data, Seventh Edition, June 1982'', the section reference

``178.65-5'' is revised to read ``178.46 and 178.65'', under the entry

National Institute of Standards and Technology the entry for ``USDC,

NBS Handbook H-28'' is amended by adding a section reference to read

``; 178.46'', under the entry American Society for Testing and

Materials the entries for ASTM A 240-82, and ASTM B 557-84 are revised

and two new entries are added in appropriate alpha-numerical order, and

under the entry Compressed Gas Association, Inc., the entries for CGA

Pamphlet C-3 and CGA Pamphlet C-12 are revised and a new entry is added

in alpha-numerical order to read as follows:

Sec. 171.7 Reference material.

(a) * * *

(3) * * *

[[Page 25942]]

------------------------------------------------------------------------

Source and name of material 49 CFR reference

------------------------------------------------------------------------

* * * *

* * *

American Society for Testing and Materials

* * * *

* * *

ASTM A 240-82 Standard Specification for Heat- 178.57; 178.358; 179.100;

Resisting Chromium and Chromium-Nickel 179.200; 179.201;

Stainless Steel Plate, Sheet and Strip for 179.220; 179.400.

Fusion-Welded Unfired Pressure Vessels,

Revision A.

* * * *

* * *

ASTM B 557-84 Tension Testing Wrought and 178.46; 178.251.

Cast Aluminum and Magnesium-Alloy Products.

* * * *

* * *

ASTM E 112-88 Standard Test Methods for 178.44.

Determining Average Grain Size.

ASTM E 290-92 Standard Test Method for Semi- 178.46.

Guided Bend Test for Ductility of Metallic

Materials.

* * * *

* * *

Compressed Gas Association, Inc.,

* * * *

* * *

CGA Pamphlet C-3, Standards for Welding and 178.47; 178.50; 178.51;

Brazing on Thinned Walled Containers, 1975. 178.53; 178.54; 178.56;

178.57; 178.58; 178.59;

178.60; 178.61; 178.65;

178.68.

* * * *

* * *

CGA Pamphlet C-11, Recommended Practices for 178.35.

Inspection of Compressed Gas Cylinders at

Time of Manufacture, 1993.

CGA Pamphlet C-12, Qualification Procedure 173.34; 173.303; 178.59;

for Acetylene Cylinder Design, 1994. 178.60.

* * * *

* * *

------------------------------------------------------------------------

* * * * *

PART 173--SHIPPERS--GENERAL REQUIREMENTS FOR SHIPMENTS AND

PACKAGINGS

3. The authority citation for Part 173 continues to read as

follows:

Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.

Sec. 173.34 [Amended]

4. In Sec. 173.34, paragraph (h) is amended by:

a. Removing, in the first sentence, the phrase ``Secs. 178.36-9(a),

178.37-9(a), 178.38-9(a), and 178.40-9(a)'' and replacing it with the

phrase ``Sec. 178.36(e), 178.37(e), 178.38(e), and 178.40(e)''.

b. Removing, in the fourth sentence, the phrase ``Sec. 178.36-9(a),

Sec. 178.37-9(a), Sec. 178.38-9(a), or Sec. 178.40-9(a)'' and replacing

it with the phrase ``Sec. 178.36(e), 178.37(e), 178.38(e), or

178.40(e)''.

Sec. 173.316 [Amended]

5. In Sec. 173.316, in paragraph (a)(8), the section reference

``178.57-20(a)(4)'' is revised to read ``178.35'' and in paragraph

(c)(3)(ii) the section reference ``178.57-20'' is revised to read

``178.35''.

PART 178--SPECIFICATIONS FOR PACKAGINGS

6. The authority citation for Part 178 continues to read as

follows:

Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.

7. Subpart C of Part 178 is revised to read as follows:

Subpart C--Specifications for Cylinders

Sec.

178.35 General requirements for specification cylinders.

178.36 Specification 3A and 3AX seamless steel cylinders.

178.37 Specification 3AA and 3AAX seamless steel cylinders.

178.38 Specification 3B seamless steel cylinders.

178.39 Specification 3BN seamless nickel cylinders.

178.42 Specification 3E seamless steel cylinders.

178.44 Specification 3HT seamless steel cylinders for aircraft use.

178.45 Specification 3T seamless steel cylinders.

178.46 Specification 3AL seamless aluminum cylinders.

178.47 Specification 4DS welded stainless steel cylinders for

aircraft use.

178.50 Specification 4B welded or brazed steel cylinders.

178.51 Specification 4BA welded or brazed steel cylinders.

178.53 Specification 4D welded steel cylinders for aircraft use.

178.55 Specification 4B240ET welded or brazed cylinders.

178.56 Specification 4AA480 welded steel cylinders.

178.57 Specification 4L welded insulated cylinders.

178.58 Specification 4DA welded steel cylinders for aircraft use.

178.59 Specification 8 steel cylinders with porous fillings for

acetylene.

178.60 Specification 8AL steel cylinders with porous fillings for

acetylene.

178.61 Specification 4BW welded steel cylinders with electric-arc

welded longitudinal seam.

178.65 Specification 39 non-reusable (non-refillable) cylinders.

178.68 Specification 4E welded aluminum cylinders.

Subpart C--Specifications for Cylinders

Sec. 178.35 General requirements for specification cylinders.

(a) Compliance. Compliance with the requirements of this subpart is

required in all details.

(b) Inspections and analyses. Chemical analyses and tests as

specified must be made within the United States unless otherwise

approved in writing by the Associate Administrator, in accordance with

Sec. 173.300b of this subchapter. Inspections and verifications must be

performed by--

[[Page 25943]]

(1) An independent inspection agency approved in writing by the

Associate Administrator, in accordance with Sec. 173.300a of this

subchapter; or

(2) For DOT Specifications 3B, 3BN, 3E, 4B, 4BA, 4D (water capacity

less than 1,100 cubic inches), 4B240ET, 4AA480, 4L, 8, 8AL, 4BW, 39

(marked service pressure 900 p.s.i.g. or lower) and 4E manufactured in

the United States, a competent inspector of the manufacturer.

cylinder made is in conformance with the applicable specification.

Except as otherwise specified in the applicable specification, the

inspector shall perform the following:

(1) Inspect all material and reject any not meeting applicable

requirements. For cylinders made by the billet-piercing process,

billets must be inspected and shown to be free from pipe, cracks,

excessive segregation and other injurious defects after parting or,

when applicable, after nick and cold break.

(2) Verify the material of construction meets the requirements of

the applicable specification by--

(i) Making a chemical analysis of each heat of material;

(ii) Obtaining a certified chemical analysis from the material

manufacturer for each heat of material (a ladle analysis is

acceptable); or

(iii) If an analysis is not provided for each heat of material by

the material manufacturer, by making a check analysis of a sample from

each coil, sheet, or tube.

(3) Verify compliance of cylinders with the applicable

specification by--

(i) Verifying identification of material is proper;

(ii) Inspecting the inside of the cylinder before closing in ends;

(iii) Verifying that the heat treatment is proper;

(iv) Obtaining samples for all tests and check chemical analyses;

(v) Witnessing all tests;

(vi) Verify threads by gauge;

(vii) Reporting volumetric capacity and tare weight (see report

form) and minimum thickness of wall noted; and

(viii) Verifying that each cylinder is marked in accordance with

the applicable specification.

(4) Furnish complete test reports required by this subpart to the

maker of the cylinder and, upon request, to the purchaser. The test

report must be retained by the inspector for fifteen years from the

original test date of the cylinder.

(d) Defects. A cylinder may not be constructed of material with

seams, cracks, laminations, or other injurious defects.

(e) Safety devices. Safety devices and protection for valves,

safety devices, and other connections, if applied, must be as required

or authorized by the appropriate specification, and as required in

Secs. 173.34 and 173.301 of this subchapter.

(f) Markings. Markings on a DOT Specification cylinder must conform

to applicable requirements.

(1) Each cylinder must be marked with the following information:

(i) The DOT specification marking must appear first, followed

immediately by the service pressure. For example, DOT-3A1800.

(ii) The serial number must be placed just below or immediately

following the DOT specification marking.

(iii) A symbol (letters) must be placed just below, immediately

before or following the serial number. Other variations in sequence of

markings are authorized only when necessitated by a lack of space. The

symbol and numbers must be those of the manufacturer. The symbol must

be registered with the Associate Administrator; duplications are not

authorized.

(iv) The inspector's official mark and date of test (such as 5-95

for May 1995) must be placed near the serial number. This information

must be placed so that dates of subsequent tests can be easily added.

An example of the markings prescribed in this paragraph (f)(1) is as

follows:

DOT-3A1800

1234

AB 5-95

Or;

DOT-3A1800-1234-XY

AB 5-95

Where:

DOT-3A=specification number

1800=service pressure

1234=serial number

xy=symbol of manufacturer

AB=inspector's mark

5-95=date of test

(2) Additional required marking must be applied to the cylinder as

follows:

(i) The word ``spun'' or ``plug'' must be placed near the DOT

specification marking when an end closure in the finished cylinder has

been welded by the spinning process, or effected by plugging.

(ii) As prescribed in specification 3HT (Sec. 178.44) or 3T

(Sec. 178.45), if applicable.

(3) Marking exceptions.

(i) A DOT 3E cylinder is not required to be marked with the

inspector mark.

(ii) An identifying lot number may be marked on the cylinder in

place of a serial number for cylinders not over 2 inches outside

diameter or for cylinders with a volumetric capacity not exceeding 60

cubic inches. Each lot shall not have over 500 cylinders.

(4) Unless otherwise specified in the applicable specification, the

markings on each cylinder must be stamped plainly and permanently on

the shoulder, top head, or neck.

(5) The size of each marking must be at least 0.25 inch or as space

permits.

(6) Other markings are authorized provided they are made in low

stress areas other than the side wall and are not of a size and depth

that will create harmful stress concentrations. Such marks may not

conflict with any DOT required markings.

(g) Inspector's report. Each inspector shall prepare a report

containing, at a minimum, the applicable information listed in CGA

Pamphlet C-11 or, until October 1, 1997, in accordance with the

applicable test report requirements of this subchapter in effect on

September 30, 1996. Any additional information or markings that are

required by the applicable specification must be shown on the test

report. The signature of the inspector on the reports certifies that

the processes of manufacture and heat treatment of cylinders were

observed and found satisfactory.

(h) Report retention. The manufacturer of the cylinders shall

retain the reports required by this subpart for 15 years from the

original test date of the cylinder.

Sec. 178.36 Specification 3A and 3AX seamless steel cylinders.

(a) Type size and service pressure. In addition to the requirements

of Sec. 178.35, cylinders must conform to the following:

(1) A DOT-3A cylinder is a seamless steel cylinder with a water

capacity (nominal) not over 1,000 pounds and a service pressure of at

least 150 pounds per square inch.

(2) A DOT-3AX is a seamless stainless steel cylinder with a water

capacity not less than 1,000 pounds and a service pressure of at least

500 pounds per square inch, conforming to the following requirements:

(i) Assuming the cylinder is to be supported horizontally at its

two ends only and to be uniformly loaded over its entire length

consisting of the weight per unit of length of the straight cylindrical

portion filled with water and compressed to the specified test

pressure; the sum of two times the maximum tensile stress in the bottom

fibers due to bending, plus that in the same fibers (longitudinal

stress), due to hydrostatic test may not exceed 80

[[Page 25944]]

percent of the minimum yield strength of the steel at such maximum

stress. Wall thickness must be increased when necessary to meet the

requirement.

(ii) To calculate the maximum longitudinal tensile stress due to

bending, the following formula must be used:

S=Mc/I

(iii) To calculate the maximum longitudinal tensile stress due to

hydrostatic test pressure, the following formula must be used:

S=A1P/A2

where:

S=tensile stress--p.s.i.;

M=bending moment-inch pounds--(wl2)/8;

w=weight per inch of cylinder filled with water;

l=length of cylinder-inches;

c=radius (D)/(2) of cylinder-inches;

I=moment of inertia--0.04909 (D4-d4) inches fourth;

D=outside diameter-inches;

d=inside diameter-inches;

A1=internal area in cross section of cylinder-square inches;

A2=area of metal in cross section of cylinder-square inches;

P=hydrostatic test pressure-p.s.i.

(b) Steel. Open-hearth or electric steel of uniform quality must be

used. Content percent may not exceed the following: Carbon, 0.55;

phosphorous, 0.045; sulphur, 0.050.

suitable method, except that plates and billets for hot-drawn cylinders

must be marked with the heat number.

(d) Manufacture. Cylinders must be manufactured using equipment and

processes adequate to ensure that each cylinder produced conforms to

the requirements of this subpart. No fissure or other defect is

permitted that is likely to weaken the finished cylinder appreciably. A

reasonably smooth and uniform surface finish is required. If not

originally free from such defects, the surface may be machined or

otherwise treated to eliminate these defects. The thickness of the

bottoms of cylinders welded or formed by spinning is, under no

condition, to be less than two times the minimum wall thickness of the

cylindrical shell; such bottom thicknesses must be measured within an

area bounded by a line representing the points of contact between the

cylinder and floor when the cylinder is in a vertical position.

(e) Welding or brazing. Welding or brazing for any purpose

whatsoever is prohibited except as follows:

(1) Welding or brazing is authorized for the attachment of

neckrings and footrings which are non-pressure parts and only to the

tops and bottoms of cylinders having a service pressure of 500 pounds

per square inch or less. Cylinders, neckrings, and footrings must be

made of weldable steel, the carbon content of which may not exceed 0.25

percent except in the case of 4130X steel which may be used with proper

welding procedures.

(2) As permitted in paragraph (d) of this section.

(3) Cylinders used solely in anhydrous ammonia service may have a

\1/2\ inch diameter bar welded within their concave bottoms.

(f) Wall thickness. For cylinders with service pressure less than

900 pounds, the wall stress may not exceed 24,000 pounds per square

inch. A minimum wall thickness of 0.100 inch is required for any

cylinder over 5 inches outside diameter. Wall stress calculation must

be made by using the following formula:

S=[P(1.3D2+0.4d2)]/(D2-d2)

Where:

S=wall stress in pounds per square inch;

P=minimum test pressure prescribed for water jacket test or 450 pounds

per square inch whichever is the greater;

D=outside diameter in inches;

d=inside diameter in inches.

(g) Heat treatment. The completed cylinder must be uniformly and

properly heat-treated prior to tests.

(h) Openings in cylinders and connections (valves, fuse plugs,

etc.) for those openings. Threads are required on openings.

(1) Threads must be clean cut, even, without checks, and to gauge.

(2) Taper threads, when used, must be of length not less than as

specified for American Standard taper pipe threads.

(3) Straight threads having at least 6 engaged threads are

authorized. Straight threads must have a tight fit and calculated shear

strength of at least 10 times the test pressure of the cylinder.

Gaskets, adequate to prevent leakage, are required.

(i) Hydrostatic test. Each cylinder must successfully withstand a

hydrostatic test, as follows:

(1) The test must be by water-jacket, or other suitable methods,

operated so as to obtain accurate data. The pressure gauge must permit

reading to an accuracy of 1 percent. The expansion gauge must permit

reading of total expansion to an accuracy of either 1 percent or 0.1

cubic centimeter.

(2) Pressure must be maintained for at least 30 seconds and

sufficiently longer to ensure complete expansion. Any internal pressure

applied after heat-treatment and previous to the official test may not

exceed 90 percent of the test pressure. If, due to failure of the test

apparatus the test pressure cannot be maintained the test may be

repeated at a pressure increased by 10 percent or 100 pounds per square

inch, whichever is the lower.

(3) Permanent, volumetric expansion may not exceed 10 percent of

the total volumetric expansion at test pressure.

(4) Each cylinder must be tested to at least \5/3\ times service

pressure.

(j) Flattening test. A flattening test must be performed on one

cylinder taken at random out or each lot of 200 or less, by placing the

cylinder between wedge shaped knife edges having a 60 deg. included

angle, rounded to \1/2\-inch radius. The longitudinal axis of the

cylinder must be at a 90-degree angle to knife edges during the test.

For lots of 30 or less, flattening tests are authorized to be made on a

ring at least 8 inches long cut from each cylinder and subjected to

same heat treatment as the finished cylinder.

(k) Physical test. A physical test must be conducted to determine

yield strength, tensile strength, elongation, and reduction of area of

material as follows:

(1) The test is required on 2 specimens cut from 1 cylinder taken

at random out of each lot of 200 or less. For lots of 30 or less,

physical tests are authorized to be made on a ring at least 8 inches

long cut from each cylinder and subjected to same heat treatment as the

finished cylinder.

(2) Specimens must conform to the following:

(i) Gauge length of 8 inches with a width of not over 1\1/2\

inches, a gauge length of 2 inches with a width of not over 1\1/2\

inches, or a gauge length of at least 24 times thickness with width not

over 6 times thickness is authorized when cylinder wall is not over \3/

16\ inch thick.

(ii) The specimen, exclusive of grip ends, may not be flattened.

Grip ends may be flattened to within 1 inch of each end of the reduced

section.

(iii) When size of cylinder does not permit securing straight

specimens, the specimens may be taken in any location or direction and

may be straightened or flattened cold, by pressure only, not by blows.

When specimens are so taken and prepared, the inspector's report must

show in connection with record of physical tests detailed information

in regard to such specimens.

(iv) Heating of a specimen for any purpose is not authorized.

(3) The yield strength in tension must be the stress corresponding

to a permanent strain of 0.2 percent of the

[[Page 25945]]

gauge length. The following conditions apply:

(i) The yield strength must be determined by either the ``offset''

method or the ``extension under load'' method as prescribed in ASTM

Standard E8.

(ii) In using the ``extension under load'' method, the total strain

(or ``extension under load'') corresponding to the stress at which the

0.2-percent permanent strain occurs may be determined with sufficient

accuracy by calculating the elastic extension of the gauge length under

appropriate load and adding thereto 0.2 percent of the gauge length.

Elastic extension calculations must be based on an elastic modulus of

30,000,000. In the event of controversy the entire stress-strain

diagram must be plotted and the yield strength determined from the 0.2

percent offset.

(iii) For the purpose of strain measurement, the initial strain

must be set while the specimen is under a stress of 12,000 pounds per

square inch and the strain indicator reading must be set at the

calculated corresponding strain.

(iv) Cross-head speed of the testing machine may not exceed \1/8\

inch per minute during yield strength determination.

(l) Acceptable results for physical and flattening tests. Either of

the following is an acceptable result:

(1) An elongation at least 40 percent for a 2-inch gauge length or

at least 20 percent in other cases and yield strength not over 73

percent of tensile strength. In this instance, the flattening test is

not required.

(2) An elongation at least 20 percent for a 2-inch gauge length or

10 percent in other cases and a yield strength not over 73 percent of

tensile strength. In this instance, the flattening test is required,

without cracking, to 6 times the wall thickness.

(m) Leakage test. All spun cylinders and plugged cylinders must be

tested for leakage by gas or air pressure after the bottom has been

cleaned and is free from all moisture subject to the following

conditions and limitations:

(1) Pressure, approximately the same as but no less than service

pressure, must be applied to one side of the finished bottom over an

area of at least \1/16\ of the total area of the bottom but not less

than \3/4\ inch in diameter, including the closure, for at least 1

minute, during which time the other side of the bottom exposed to

pressure must be covered with water and closely examined for

indications of leakage. Except as provided in paragraph (n) of this

section, a cylinder that is leaking must be rejected.

(2) A spun cylinder is one in which an end closure in the finished

cylinder has been welded by the spinning process.

(3) A plugged cylinder is one in which a permanent closure in the

bottom of a finished cylinder has been effected by a plug.

(4) As a safety precaution, if the manufacturer elects to make this

test before the hydrostatic test, the manufacturer should design the

test apparatus so that the pressure is applied to the smallest area

practicable, around the point of closure, and so as to use the smallest

possible volume of air or gas.

(n) Rejected cylinders. Reheat treatment is authorized for rejected

cylinders. Subsequent thereto, cylinders must pass all prescribed tests

to be acceptable. Repair by welding or spinning is not authorized. Spun

cylinders rejected under the provisions of paragraph (m) of this

section may be removed from the spun cylinder category by drilling to

remove defective material, tapping and plugging.

Sec. 178.37 Specification 3AA and 3AAX seamless steel cylinders.

(a) Type, size and service pressure. In addition to the

requirements of Sec. 178.35, cylinders must conform to the following:

(1) A DOT-3AA cylinder is a seamless steel cylinder with a water

capacity (nominal) of not over 1,000 pounds and a service pressure of

at least 150 pounds per square inch.

(2) A DOT-3AAX cylinder is a seamless steel cylinder with a water

capacity of not less than 1,000 pounds and a service pressure of at

least 500 pounds per square inch, conforming to the following

requirements:

(i) Assuming the cylinder is to be supported horizontally at its

two ends only and to be uniformly loaded over its entire length

consisting of the weight per unit of length of the straight cylindrical

portion filled with water and compressed to the specified test

pressure; the sum of two times the maximum tensile stress in the bottom

fibers due to bending, plus that in the same fibers (longitudinal

stress), due to hydrostatic test pressure may not exceed 80 percent of

the minimum yield strength of the steel at such maximum stress. Wall

thickness must be increased when necessary to meet the requirement.

(ii) To calculate the maximum tensile stress due to bending, the

following formula must be used:

S=Mc/I

(iii) To calculate the maximum longitudinal tensile stress due to

hydrostatic test pressure, the following formula must be used:

S=A\1\P/A\2\

Where:

S=tensile stress-p.s.i.;

M=bending moment-inch pounds (wl\2\)/8;

w=weight per inch of cylinder filled with water;

l=length of cylinder-inches;

c=radius (D)/(2) of cylinder-inches;

I=moment of inertia-0.04909 (D\4\-d\4\) inches fourth;

D=outside diameter-inches;

d=inside diameter-inches;

A\1\=internal area in cross section of cylinder-square inches;

A\2\=area of metal in cross section of cylinder-square inches;

P=hydrostatic test pressure-p.s.i.

(b) Authorized steel. Open-hearth, basic oxygen, or electric steel

of uniform quality must be used. A heat of steel made under the

specifications in Table 1 of this paragraph (b), check chemical

analysis of which is slightly out of the specified range, is

acceptable, if satisfactory in all other respects, provided the

tolerances shown in Table 2 of this paragraph (b) are not exceeded.

When a carbon-boron steel is used, a hardenability test must be

performed on the first and last ingot of each heat of steel. The

results of this test must be recorded on the Record of Chemical

Analysis of Material for Cylinders required by Sec. 178.35. This

hardness test must be made \5/16\-inch from the quenched end of the

Jominy quench bar and the hardness must be at least Rc 33 and no more

than Rc 53. The following chemical analyses are authorized:

Table 1.--Authorized Materials

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Inter- mediate

Designation 4130X (percent) NE-8630 (percent) 9115 (percent) 9125 (percent) Carbon-boron manganese

(see Note 1) (see Note 1) (see Note 1) (see Note 1) (percent) (percent)

--------------------------------------------------------------------------------------------------------------------------------------------------------

Carbon.......................... 0.25/0.35......... 0.28/0.33......... 0.10/0.20......... 0.20/0.30......... 0.27-0.37......... 0.40 max.

[[Page 25946]]

Manganese....................... 0.40/0.90......... 0.70/0.90......... 0.50/0.75......... 0.50/0.75......... 0.80-1.40......... 1.35/1.65.

Phosphorus...................... 0.04 max.......... 0.04 max.......... 0.04 max.......... 0.04 max.......... 0.035 max......... 0.04 max.

Sulfur.......................... 0.05 max.......... 0.04 max.......... 0.04 max.......... 0.04 max.......... 0.045 max......... 0.05 max.

Silicon......................... 0.15/0.35......... 0.20/0.35......... 0.60/0.90......... 0.60/0.90......... 0.3 max........... 0.10/0.30.

Chromium........................ 0.80/1.10......... 0.40/0.60......... 0.50/0.65......... 0.50/0.65.

Molybdenum...................... 0.15/0.25......... 0.15/0.25

Zirconium....................... .................. .................. 0.05/0.15......... 0.05/0.15

Nickel.......................... .................. 0.40/0.70.........

Boron........................... .................. .................. .................. .................. 0.0005/0.003.

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Note 1: This designation may not be restrictive and the commercial steel is limited in analysis as shown in this Table.

Table 2.--Check Analysis Tolerances

----------------------------------------------------------------------------------------------------------------

Tolerance (percent) over

the maximum limit or

under the minimum limit

Element Limit or maximum specified (percent) -------------------------

Under Over

minimum maximum

limit limit

----------------------------------------------------------------------------------------------------------------

Carbon........................................ To 0.15 incl.......................... 0.02 0.03

Over 0.15 to 0.40 incl................ .03 .04

Manganese..................................... To 0.60 incl.......................... .03 .03

Over 0.60 to 1.15 incl................ 0.04 0.04

Over 1.15 to 2.50 incl................ 0.05 0.05

Phosphorus\1\................................. All ranges............................ ........... .01

Sulphur....................................... All ranges............................ ........... .01

Silicon....................................... To 0.30 incl.......................... .02 .03

Over 0.30 to 1.00 incl................ .05 .05

Nickel........................................ To 1.00 incl.......................... .03 .03

Chromium...................................... To 0.90 incl.......................... .03 .03

0.90 to 2.90 incl..................... .05 .05

Molybdenum.................................... To 0.20 incl.......................... .01 .01

Over 0.20 to 0.40..................... .02 .02

Zirconium..................................... All ranges............................ .01 .05

----------------------------------------------------------------------------------------------------------------

\1\ Rephosphorized steels not subject to check analysis for phosphorus.

suitable method except that plates and billets for hot-drawn cylinders

must be marked with the heat number.

(d) Manufacture. Cylinders must be manufactured using equipment and

processes adequate to ensure that each cylinder produced conforms to

the requirements of this subpart. No fissure or other defects is