Federal Motor Vehicle Safety Standards; Air Brake Systems, Devices That Remove Moisture and Contaminants

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 95-65; Notice 2]

RIN 2127-AF72

Federal Motor Vehicle Safety Standards; Air Brake Systems,

Devices That Remove Moisture and Contaminants

AGENCY: National Highway Traffic Safety Administration (NHTSA),

Department of Transportation.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to amend Standard No. 121, Air brake

systems, to require that each air brake-equipped truck, truck tractor,

and bus be equipped with a means of automatically removing moisture and

contaminants from the air system. The purpose of this proposal is to

improve the safety of air-braked vehicles by improving the reliability

and durability of antilock braking system (ABS) modulator valves and

pneumatic control valves. This document also proposes to delete the

requirement for a supply reservoir since its function (i.e., the

elimination of moisture and contaminants) would be accomplished by the

addition of such automatic means. Accordingly, the deletion would not

adversely affect the safety of those vehicles.

DATES: Comments must be received on or before January 3, 1997.

ADDRESSES: Comments should refer to the docket and notice numbers above

and be submitted to: Docket Section, National Highway Traffic Safety

Administration, 400 Seventh Street, SW., Washington, DC 20590. Docket

hours are 9:30 a.m. to 4 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For non-legal issues: Mr. Richard

Carter, Office of Crash Avoidance, National Highway Traffic Safety

Administration, 400 Seventh Street, SW., Washington DC 20590, (202)

366-5274. FAX (202) 366-4329.

For legal issues: Mr. Marvin L. Shaw, NCC-20, Rulemaking Division,

Office of Chief Counsel, National Highway Traffic Safety

Administration, 400 Seventh Street, SW., Washington, DC 20590, (202)

366-2992.

SUPPLEMENTARY INFORMATION:

I. Background

A. Current Regulations

B. Petition for Rulemaking

C. Notice Requesting Comments About Devices that Remove

Contaminants

D. Comments on the Notice

II. Agency Proposal

A. General Discussion

B. Cost Considerations

III. Rulemaking Analyses and Notices

A. Executive Order 12866 (Regulatory Planning and Review) and

DOT Regulatory Policies and Procedures

B. Regulatory Flexibility Act

C. National Environmental Policy Act

D. Executive Order 12612 (Federalism)

E. Civil Justice Reform

I. Background

A. Current Regulations

Federal Motor Vehicle Safety Standard No. 121, Air Brake Systems,

requires air-braked vehicles to be equipped with certain equipment,

including one or more air service reservoir systems from which air is

delivered to the brake chambers. (See S5.1.2) In addition,

manufacturers are required to either (1) equip air-braked vehicles with

an additional supply reservoir 1 between the service reservoir(s)

and the compressor, or (2) equip each service reservoir with an

automatic condensate drain valve.2 Both options remove moisture.

The supply reservoir collects moisture and solid particulate matter

before it can enter the service reservoir or reservoirs. An automatic

condensate drain valve automatically removes moisture and certain solid

contaminants that become trapped in the bottom of a reservoir.

Regardless of which option is chosen, all air reservoirs must be fitted

with a condensate drain valve that can be manually operated.

Accordingly, an automatic condensate drain valve must also be manually

operable. (see S5.1.2.4 for trucks and buses and S5.2.1.3 for

trailers).

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\1\ The colloquial term for a supply reservoir is ``wet'' tank.

\2\ The colloquial term for an automatic condensate drain valve

is ``spitter valve.''

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The Federal Motor Carrier Safety Regulations (FMCSRs) require

drivers of commercial vehicles to inspect specified features on their

vehicles, including service brake system, prior to driving to ensure

those features are ``* * * in good working order.'' (49 CFR 392.7)

However, the FMCSRs do not require that air reservoirs be drained on

any fixed periodic basis.

B. Petition for Rulemaking

On July 28, 1994, Domenic F. Coletta, M.D. submitted a petition for

rulemaking requesting that Standard No. 121 be amended to require a

condensate drain valve that automatically purges the moisture and

contaminants from each reservoir tank on air-brake equipped vehicles.

Dr. Coletta claimed that automatic drain valves would better ensure

safety than manual valves since drivers frequently fail to remember to

manually purge moisture and contaminants from reservoirs. The

petitioner supplied a video showing New Jersey State police purging

significant amounts of liquid and contaminants from the air reservoirs

of heavy vehicles during roadside safety inspections.

C. Notice Requesting Comments About Devices That Remove Contaminants

On July 24, 1995, NHTSA issued a notice requesting information

about devices that remove moisture and other contaminants from air

brake systems (60 FR 37864). The agency explained that keeping air

brake systems clean and dry prevents degraded brake performance and

valve freezing, which can lead to brake failure. The agency was

especially concerned about potential problems with antilock brake

systems (ABS) malfunctioning, since their modulator valves have smaller

orifices and therefore are more sensitive to contaminants. NHTSA

explained that certain equipment such as automatic and manual drain

valves and air dryer systems can keep air brake systems, particularly

the air reservoirs, dry and free from contaminants. Drain valves purge

the reservoirs of liquid condensate and contaminants suspended in that

liquid. Manual drain valves must be opened by a truck driver or

maintenance person to drain the reservoir. While ideally this should be

done each morning before the vehicle is started, some drivers do not do

so. Automatic drain valves periodically drain the reservoir without the

need for human intervention.

There are a variety of devices that reduce the amount of moisture

and other contaminants in an air brake system by cleaning and drying

the air. Among the most common are desiccant style air dryers and

``after-cooler'' air dryers. In a typical desiccant style system, the

incoming air is routed into the bottom end of an air dryer, where a

large portion of the oil and water mist fall to its bottom. This

partially cleaned air then goes through an oil separator. Next the air,

which is still moist with both oil and water vapor, is passed through a

``drying bed'' of desiccant material that absorbs the remaining

moisture. These dryers are equipped with an automatic drain valve that

periodically purges moisture and contaminants from the air system. In

contrast, in a typical ``after-cooler''

[[Page 56653]]

system, which uses an air cleaner only, not all the moisture is

removed, since the air is not passed through a drying bed of desiccant

material.

NHTSA stated that according to AlliedSignal, over 80 percent of new

air braked heavy trucks are being built with air dryers and that more

than 90 percent of the dryers are the desiccant type. Moreover, that

company predicted that in five years almost all air braked vehicles

will be equipped with an air cleaning and drying system.

NHTSA posed several questions about whether it should nevertheless

initiate rulemaking to require devices to remove moisture and other

contaminants from air brake systems. These included questions whether

contaminants in air brake systems cause a significant safety problem,

whether devices such as automatic drain valves and air dryers are

effective in removing moisture and contaminants from air brake systems,

and whether requiring such devices would be cost effective.

D. Comments on the Notice

NHTSA received 34 comments from vehicle and equipment

manufacturers, a safety advocacy group (Advocates for Highway and Auto

Safety) (Advocates), the Truck Manufacturers Association (TMA), the

Heavy Duty Brake Maintenance Council (HDBMC), the Truck Trailer

Manufacturers Association (TTMA), the National Truck Equipment

Association (NTEA), the National School Transportation Association

(NSTA), the American Trucking Associations (ATA), individual truck

operators and fleets, Senator Frank R. Lautenberg, the petitioner, and

numerous private citizens.

The manufacturers and associations generally stated that a Federal

requirement was not necessary, claiming that the present use of air

dryers, and the trend towards their increased use, was sufficient to

maintain a safe level of performance. ATA, AlliedSignal, NTEA, NSTA,

Navistar, TTMA, and TMA stated that they had no records of any

accidents or crashes caused by contaminated air. TMA stated that while

contaminants in air brake systems can cause reliability problems in

specific components, they believe contamination does not result in a

significant safety problem. TMA, Penske Truck Leasing, and ATA stated

that a desiccant style air dryer with an integral automatic drain valve

more effectively removes moisture and other contaminants from an air

brake system than an automatic drain valve by itself. TMA requested

that instead of a supply reservoir, the agency should allow either an

automatic drain valve on each service reservoir or a desiccant style

air dryer. ATA also stated that desiccant air dryers were more

effective in keeping air in the brake system clean than automatic drain

valves. That organization stated that ``automatic drain valves have not

been found to be an effective device for removing contaminants.''

The petitioner (Dr. Coletta), manufacturers of automatic drain

valves, Advocates, and a number of private citizens commented that

significant safety problems result from moisture and contaminants in a

vehicle's air system. The petitioner stated that it is very important

to keep the air reservoir system dry and free of contaminants to

prevent the contamination and deterioration of the brake system, which

can result in serious safety problems. To support this claim, Dr.

Coletta referenced a National Transportation Safety Board (NTSB) study

of 18 heavy vehicle crashes 3 in which NTSB investigated the

extent to which brake system performance caused or increased the

severity of heavy vehicle crashes. Inadequate brake system maintenance

and poor brake adjustment were either the primary or a contributory

causal factor in most of the crashes investigated. While not

specifically mentioned as a primary or direct contributory factor to

these crashes, the NTSB report noted that in 4 of the 18 cases (22

percent), significant amounts of moisture and sludge were found in the

air reservoirs, thereby contributing to the overall poor functioning of

the vehicles' brake system.

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\3\ Heavy Vehicle Air Brake Performance (NTSB/SS-92/01; 1992)

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Dr. Coletta and others stated that the agency should require that

each service reservoir be equipped with an automatic drain valve

instead of a manual drain valve, because truck drivers typically do not

manually drain the reservoirs. They further claimed that air dryers are

not an effective way to solve the problem of contaminants and moisture

in air systems, since air dryers do not remove all moisture from the

system and are difficult to maintain. These commenters also stated that

truck drivers will not perform the routine maintenance necessary for

desiccant systems.

II. Agency Proposal

A. General Considerations

Based on the available information, NHTSA has decided to propose

amending Standard No. 121 to require that each air brake-equipped

truck, truck tractor, and bus be equipped with an automatic means of

removing moisture and contaminants from the air brake system. The term

``contaminants'' includes, but is not limited to, carbon and other

particulates, dirt, oil, soot, and sludge. The agency believes that

removing moisture and contaminants would increase the reliability and

durability of both ABS and pneumatic control valves of air brake

systems, thereby increasing the safety of these vehicles. This is so

because contaminants cause valves to stick, thereby preventing

sufficient air pressure from being delivered to the brake. The proper

functioning of ABS valves is especially important since heavy vehicles

will be required to be equipped with ABS, beginning in March 1997. In

addition, the proposed requirements would ensure that air supply lines

are clear and that maximum air reservoir capacity is available to

drivers when braking.

NHTSA is proposing to require air braked vehicles to be equipped

with a means of automatically removing moisture and contaminants from

the air brake system for the following reasons. First, according to

NHTSA's extensive fleet study 4 of ABS-equipped heavy vehicles,

ABS-equipped truck tractors that were also equipped with desiccant-

style air dryers performed better than truck tractors without these air

dryers. In particular, vehicles with desiccant-style air dryers did not

experience leaks in their relay valves. Second, the previously

mentioned NTSB study of heavy vehicle crashes found that in 4 of 18

cases (22 percent), significant amounts of moisture and contaminants

were found in the vehicles' air reservoirs. The agency emphasizes that

while the study is not a statistically representative sampling of all

heavy vehicle crashes, it suggests that air system contamination may be

a problem. Third, AlliedSignal recently conducted a voluntary recall

5 to address freezing relay valves because the valves failed due

to exposure to solvents and chemicals such as antifreeze and glycol.

Apparently, some drivers and mechanics attempted to unfreeze the valves

by pouring antifreeze into the trailer's air supply and control lines.

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\4\ Klusmeyer, L.F., Gray, A.W., Bishop, J.S., and Van Schoiack,

M. An In-Service Evaluation of the Performance, Reliability,

Maintainability, and Durability of Antilock Braking Systems (ABSs)

for Semitrailers, USDOT Report No. HS 808 059, October 1993.

\5\ Ref. Voluntary Recall No.94-E-027.

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To achieve this rule's objective, i.e., keeping air brake systems

dry and free of contaminants, NHTSA considered a number of regulatory

approaches and decided to propose a broad-based

[[Page 56654]]

equipment requirement rather than specifying a specific device,

detailed design specifications, or general performance requirements.

This is the same approach the agency used in establishing S5.1.8 which

requires that ``wear of the service brakes on newly manufactured heavy

vehicles to be compensated for by means of a system of automatic

adjustment.'' (57 FR 47793, October 20, 1992). Moreover, the agency

believes today's proposal is consistent with the agency's desire to

avoid issuing regulations that are unnecessarily design specific. NHTSA

is wary of specifying a particular device, an action that might

preclude the development of new technologies, particularly in light of

a recent paper 6 by the Society of Automotive Engineers (SAE) that

discussed a number of devices and methods that can remove moisture and

other contaminants from compressed air systems. These methods include

filtration, desiccant absorption, coalescing, centrifugal force, or a

combination of these processes. The SAE paper stated that the most

effective device would employ a combination of these processes,

particularly filtration, coalescing, and desiccant. These devices would

be permitted by this proposal.

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\6\ Fitzsimmons, D. Synergy in Air Dryers, Multiple-State

Processes and Application Requirements, SAE Paper No. 952675,

November, 1995.

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Another device that would be permitted under this proposal is the

automatic condensate drain valve, the solution suggested in Dr.

Coletta's petition. These devices eliminate moisture (i.e., liquid

condensate) and solid contaminants suspended in that liquid that

collect at the bottom of the supply reservoir.

NHTSA has decided at this time not to develop a test procedure and

performance requirements to evaluate the dryness and cleanness of an

air brake system for several reasons. First, the practicality of

developing such a test procedure is unclear at this time. To ensure

that all (or substantially all) contaminants had been removed, it might

be necessary for the test procedure to assess the performance of the

entire air system, including all piping and valves. Such a test could

be expensive, since the piping and valves are very extensive. Moreover,

it might be necessary to develop different test set-ups to evaluate the

wide range of air systems. Second, to the agency's knowledge, criteria

for evaluating the amount of contamination removal do not currently

exist. Developing such a test procedure and criteria would have been

too time-consuming.

For these reasons, NHTSA has decided to propose an equipment

requirement at this time. Nevertheless, the agency would prefer

ultimately to establish performance requirements for this equipment.

Federal law generally requires Federal agencies to use technical

standards that are developed or adopted by voluntary consensus

standards bodies when such technical standards are available; see

section 12(d) of Pub. L. 104-113. The subject of moisture and solid

contaminant removal from air brake systems appears to present an

opportunity for NHTSA to adopt consensus performance requirements

developed by an organization such as the Society of Automotive

Engineers (SAE). SAE would be performing a service to the public by

developing such consensus performance requirements, as well as

permitting a significant savings in resources for the government. NHTSA

is aware of and has been monitoring the efforts of the SAE to develop a

Recommended Practice for assessing the amount of airborne moisture and

solid particulate matter contaminant levels present at the output side

of the service reservoirs. If the SAE can reach consensus on some

performance requirements, NHTSA anticipates relying on those consensus

requirements in its further consideration of this issue.

NHTSA requests comments on its decision to propose requiring that

air-braked vehicles be equipped with a means of automatically removing

moisture and other contaminants rather than proposing a test procedure

and performance requirements. The agency also invites comments about

the proposed terminology used to describe the equipment that the

amendment would require, especially whether various devices would

comply with the proposal.

NHTSA has decided to propose deleting the requirement for a supply

reservoir since the service reservoirs in an air system would be

equipped with an automatic means of removing moisture and contaminants

from the air system. The agency believes that removing supply

reservoirs would not compromise air brake system performance, provided

that a means of automatically removing moisture and contaminants is

added. Nevertheless, the agency invites commenters to submit data and

test results comparing the durability and reliability of air brake

systems on vehicles that are equipped as follows: those vehicles

equipped with a supply reservoir but are not equipped with a means for

automatically removing moisture and contaminants versus those vehicles

that are not equipped with a supply reservoir but are equipped with a

means for automatically removing moisture and contaminants. Also, the

agency requests comments about the likelihood that a purchaser would

decide not to equip its vehicles with supply reservoirs, if the

proposed amendment were adopted.

NHTSA has decided to retain the requirement of S5.1.2.4 that each

reservoir be fitted with a manual draining capacity. The agency

believes this capability is needed as a supplemental means of verifying

that the primary means of automatically removing moisture and

contaminants is functioning properly. Periodic manual purging checks to

ascertain that liquids are not collecting in service reservoirs should

accomplish this function. Automatic condensate drain valves (or an air

dryer with an automatic drain valve) that can be manually actuated,

would comply with this requirement.

B. Cost Considerations

In its notice requesting comments, NHTSA estimated that devices

that would comply with requirements to keep the air system clean and

dry could range from $75-$400 per vehicle. The commenters generally

concurred with these estimates. The agency estimates that the annual

production of air braked vehicles is approximately 209,000 (148,000

truck tractors and approximately 61,000 single unit trucks and buses),

based on its earlier analysis in the Final Regulatory Evaluation for

the ABS final rule (60 FR 13216, March 10, 1995). NHTSA estimates that

90 percent of all currently manufactured truck tractors are already

equipped with a means of automatically removing moisture and

contaminants and that 75 percent of all single unit trucks and buses

are so equipped. This proposal would affect the remaining 30,000

vehicles (14,800 truck tractors + 15,200 single unit vehicles). They

would need to be equipped with these devices at a total annual cost of

between $2.25 million to $12 million.

NHTSA notes that some of these costs might be offset by savings if

manufacturers choose to eliminate the supply reservoirs from the

estimated 209,000 air brake equipped truck tractors, trucks and buses

that are manufactured each year. The amount of these offsetting savings

could vary appreciably, depending on a number of factors. First,

removing one of the three air reservoirs could necessitate increasing

the size of the remaining two service reservoirs to meet the reservoir

sizing requirements of S.5.2.1.1. Nevertheless, two larger reservoirs

[[Page 56655]]

would cost less than three reservoirs and their associated piping and

fittings. The agency estimates that there would be a savings of between

$10-$75 per vehicle. Second, the extent to which manufacturers and

heavy vehicle users decide to no longer equip their vehicles with a

supply reservoir is uncertain.

Accordingly, for the purposes of this analysis, the agency has

conservatively assumed that between 0-50 percent of newly manufactured

air-braked power units would no longer be equipped with supply

reservoirs. Based on this assumption, the agency estimates that no

longer equipping vehicles with supply reservoirs would offset the

proposal's costs by between $0-$7.8 million per year, with a

conservative estimate being $1 million. The agency invites comments on

these cost estimates. After reviewing this information, NHTSA will

factor in these cost savings in assessing the rulemaking's overall

cost.

Based on applying this $1 million cost savings to the costs

associated with requiring air-braked vehicles to be equipped with a

means of automatically removing moisture and contaminants, NHTSA

estimates that a total cost of $1.25 million to $11 million would be

incurred to comply with the proposed requirements. In addition, by

ensuring dry and clean air, today's rulemaking would contribute to more

fully achieving the anticipated benefits expected from equipping heavy

vehicles with ABS.

NHTSA decided not to propose requiring a means of automatically

removing moisture and contaminants separately on both towing and towed

units in a combination-unit vehicle. The agency reasoned that since the

air used on trailers is supplied by the towing unit, having the means

to automatically remove moisture and contaminants on the towing unit

would be sufficient to ensure dry and clean air on towed units as well.

The agency further reasoned that sufficient safety enhancement,

relative to the costs incurred, would be achieved by specifying such a

requirement only for the towing unit. The agency estimates that it

would cost an additional $13.9 million to $74 million per year to equip

the 186,100 heavy truck trailers that are manufactured each year. The

agency solicits additional data and comments on its decision not to

propose requiring that trailers be equipped with a means of

automatically removing moisture and contaminants.

Rulemaking Analyses and Notices

A. Executive Order 12866 (Regulatory Planning and Review) and DOT

Regulatory Policies and Procedures

This notice has not been reviewed under Executive Order 12866.

NHTSA has considered the impacts of this rulemaking action and

determined that it is not ``significant'' within the meaning of the

Department of Transportation's regulatory policies and procedures. The

agency's Final Economic Assessment of the final rules amending Standard

No. 105 and Standard No. 121 to require medium and heavy vehicles to be

equipped with ABS, concluded that the benefits associated with those

requirements exceeded the costs that would result. The additional costs

associated with adding a means of automatically removing moisture and

contaminants to those vehicles that would otherwise not be equipped

with them, would increase the costs of the ABS rule by 0.2 percent to

1.7 percent. This small increase does not alter the agency's original

determination. Based on the discussion above and this consideration,

NHTSA believes that the impacts are so minimal as not to warrant

preparation of an additional full regulatory evaluation.

B. Regulatory Flexibility Act

NHTSA has also considered the effects of this proposal under the

Regulatory Flexibility Act. I hereby certify that it would not have a

significant economic impact on a substantial number of small entities.

Accordingly, the agency has not prepared a preliminary regulatory

flexibility analysis.

NHTSA concluded that the March 1995 final rule amending Standard

No. 121 did not have a significant impact on a substantial number of

small entities. The agency concluded then that a small number of

intermediate and final stage manufacturers that are small businesses

might be affected by the rule, but that the impact would not be

substantial. That conclusion is equally valid for this proposal, since

today's proposal addresses the same types of manufacturers as addressed

in the March 1995 action, and since the costs of this rulemaking are

much less.

C. National Environmental Policy Act

NHTSA has analyzed this rulemaking action for the purposes of the

National Environmental Policy Act of 1969. The agency has determined

that implementation of this action would not have any significant

impact on the quality of the human environment. No changes in existing

production or disposal processes would result.

D. Executive Order 12612 (Federalism)

NHTSA has analyzed this action under the principles and criteria in

Executive Order 12612. The agency believes that this rulemaking action

would not have sufficient Federalism implications to warrant the

preparation of a Federalism Assessment. No State laws would be

affected.

E. Civil Justice Reform

This rulemaking would not have any retroactive effect. Under 49

U.S.C. 30103, whenever a Federal motor vehicle safety standard is in

effect, a State may not adopt or maintain a safety standard applicable

to the same aspect of performance which is not identical to the Federal

standard, except to the extent that the State requirement imposes a

higher level of performance and applies only to vehicles procured for

the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial

review of rulemakings establishing, amending or revoking Federal motor

vehicle safety standards. That section does not require submission of a

petition for reconsideration or other administrative proceedings before

parties may file suit in court.

Public Comments

Interested persons are invited to submit comments on the proposal.

It is requested but not required that 10 copies be submitted.

All comments must not exceed 15 pages in length. (49 CFR 553.21).

Necessary attachments may be appended to these submissions without

regard to the 15-page limit. This limitation is intended to encourage

commenters to detail their primary arguments in a concise fashion.

If a commenter wishes to submit certain information under a claim

of confidentiality, three copies of the complete submission, including

purportedly confidential business information, should be submitted to

the Chief Counsel, NHTSA, at the street address given above, and seven

copies from which the purportedly confidential information has been

deleted should be submitted to the Docket Section. A request for

confidentiality should be accompanied by a cover letter setting forth

the information specified in the agency's confidential business

information regulation. 49 CFR part 512.

All comments received before the close of business on the comment

closing date indicated above for the proposal will be considered, and

will be available for examination in the docket

[[Page 56656]]

at the above address both before and after that date. To the extent

possible, comments filed after the closing date will also be

considered. Comments received too late for consideration in regard to

the final rule will be considered as suggestions for further rulemaking

action. The NHTSA will continue to file relevant information as it

becomes available in the docket after the closing date, and it is

recommended that interested persons continue to examine the docket for

new material.

Those persons desiring to be notified upon receipt of their

comments in the rules docket should enclose a self-addressed, stamped

postcard in the envelope with their comments. Upon receiving the

comments, the docket supervisor will return the postcard by mail.

List of Subjects in 49 CFR Part 571

Imports, Motor vehicle safety, Motor vehicles, Rubber and tires.

PART 571--[AMENDED]

In consideration of the foregoing, the agency proposes to amend

Standard No. 121, Air Brake Systems, in Title 49 of the Code of Federal

Regulations at Part 571 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

1. The authority citation for part 571 would continue to read as

follows:

Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166;

delegation of authority at 49 CFR 1.50

Sec. 571.121 Standard No. 121; Air Brake Systems

2. Sec. 571.121 would be amended by revising S5.1.2 and by adding a

new section S5.1.9, which would read as follows:

Sec. 571.121 Standard No. 121; Air Brake Systems

* * * * *

S5.1.2 Reservoirs. One or more service reservoir systems, from

which air is delivered to the brake chambers.

* * * * *

S5.1.9 Contamination Removal. Each truck, truck tractor and bus

shall be equipped with a means of automatically removing moisture and

contaminants from the air system.

Issued on: October 29, 1996.

L. Robert Shelton,

Associate Administrator for Safety Performance Standards.

[FR Doc. 96-28228 Filed 11-1-96; 8:45 am]

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