ID: nht78-2.42

DATE: 01/06/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: National Tire Dealers & Retreaders Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your October 27, 1977, letter asking whether a tire retreader is permitted to change the designation of a tire from "tubeless" to "tubetype".

Standard No. 117, Retreaded Pneumatic Tires, requires that the information appearing on the tire sidewall be the same as that which appeared on the tire as originally manufactured. This is indicated by the language in paragraph S6.3. If a retreader changed the tire designation from "tubeless" to "tubetype", he would be altering the information that was associated with the original tire. Thus, a retreader is not permitted to change the tire designation in the manner you describe.

SINCERELY,

TIRE RETREADING INSTITUTE

October 27, 1977

John Diehl Department of Transportation Tire Identification and Record Keeping

Dear John:

By this letter we seek a clarification on the subject of using tubes in tubeless tires.

It is our understanding that some new tires manufactured as tubeless are labeled as being tubetype. We understand that the word "tubeless" on the tire sidewall is removed and the word "tubetype" is substituted. Further, we understand that no safety related aspect is involved in making the substitution.

(Accordingly, we seek your concurrence that a tire labeled "tubeless" being processed as a retread, may be labeled "tubetype" at the option of the retreader). We recognize that such an option cannot be exercised if safety considerations dictate otherwise. For example, a tube cannot be used in a retread in lieu of making a needed repair. Yes.

Your early confirmation that retreaders be afforded the same option of re-labeling as is available to new tire manufacturers is sought.

Philip H. Taft Director

November 2, 1977

Philip H. Tafts Director Tire Retreading Institute

Dear Mr. Taft:

Your October 27, 1977 to Mr. John Dill has been referred to this office for reply.

The tire manufacturer is the one who determines whether a tire is a tubeless or tube type tire.

The retreader does not have the option to re-label the tire cord body inorder to retread the tire, and sell it as a tube type tire, because the original tire manufacturer has followed the labeling requirements of (Illegible words) of FMVSS std. 109.

There are no safety related aspects associated with the reclassification of a tubeless tire to tube type, because inner tubes were used in tires that had a special gum insert on the first or band ply before tubeless tire were in successful production.

The above (Illegible Word) a recent article stating that the placement of a tube in a tubeless tire will cause the assembly to run hot and possibly lead to failure.

Also to aid in the understanding of reclassified tires from tubeless to tube type is the fact that the tube type tire is (Illegible Word) completely through the side wall to allow any entrappes air to escape when the tire contains an inner tube in a tubeless tire.

We hope we have clarified your position on tubeless and tube type tires he re-classified by the retrader.

Drill no control

Legal Concurrence!

(Illegible Word)

ID: nht78-2.43

DATE: 04/13/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: E. A. Santiago

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Raycor Industries' March 13, 1978, question whether Standard No. 121, Air Brake Systems, applies to an air dryer that is installed in the air brake system of trucks that must comply with the standard.

The answer to your question is no. Paragraph S3 (Applicability) of Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some specified exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the Raycor air dryer unit. The vehicles in question must, of course, conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale.

A copy of Standard No. 121 is enclosed for your information.

ID: nht78-2.44

DATE: 03/29/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Stanley Kuny

TITLE: FMVSS INTERPRETATION

TEXT: Joan Claybrook has asked that I respond to your February 24, 1978, letter asking whether the seller of a school bus that contains a safety-related defect is responsible for correcting the defect, whether the buyer would otherwise be entitled to a refund for the price of the defective equipment, and whether a brake pressure limiting valve may be installed on the front axles of school buses whose antilock systems are disconnected pursuant to a recall campaign. You also ask about the status of the reimplementation of requirements for school bus service brake stopping distance performance contained in Standard No. 121, Air Brake Systems.

Section 154 of the National Traffic and Motor Vehicle Safety Act (the Act) (15 U.S.C. 1414) requires the vehicle manufacturer to provide an adequate repair of safety-related defects found in its products, unless replacement of the vehicle or refund of its purchase price is undertaken. International Harvester (IH) is in the process of field-testing its remedy for these school buses and it should be available fairly soon.

As for the installation of front-axle brake pressure limiting valves, Federal regulations for vehicles in interstate commerce prohibit the installation of manual limiting valves in 121-equipped vehicles and regulate the installation of automatic limiting valves. Also, section 108(a)(2)(A) of the Act prohibits, with one exception, the knowing rendering inoperative by commercial facilities of a device or element of design installed in satisfaction of a Federal safety standard such as Standard No. 121. A private party is not prohibited under this provision, but the vehicle manufacturer should be consulted about safest configuration of the vehicle brake system. In this case, IH's notice on antilock disconnection explained that the deactivation would render the brake system identical to those produced by IH since the "no lockup" requirement was suspended in January 1976. Thus IH does not recommend any further modification of the brake system.

With regard to your belief that the antilock systems may have cost $ 1200.00, I would like to clarify that Standard No. 121 contains many requirements for improved braking, and the incremental price increase for the improved brakes is attributable only in part to the antilock systems. At present, the Kelsey-Hayes antilock system used on IH school bus chassis costs $ 412.11, and this price would presumably be lower if the system was installed on all bus production as standard equipment.

As for the status of the reimplementation of service brake stopping distance requirements for school buses on April 1, 1978, the NHTSA expects to reach a decision soon and publish it in the Federal Register. I have asked a member of my staff to call you when a decision is made public.

ID: nht78-2.45

DATE: 01/06/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Arent, Fox, Kenter, Plotkin & Kahn

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 1, 1977, request for agreement by the National Highway Traffic Safety Administration that the installation as original or aftermarket equipment of an electric retarder on the driveline of an air-braked vehicle would not affect its compliance with Standard No. 121, Air Brake Systems.

Section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. @ 1397(a)(1)(A)) requires, among other things, that no person manufacture or sell any motor vehicle manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect unless it is in conformity with such standard. As your letter indicates, you are aware that this provision makes it impossible for the NHTSA to "approve" the compliance of a vehicle configuration in advance of manufacture of the vehicle, because there can be no certainty that the vehicle as manufactured will actually comply. In this case, for example, the retarder's weight or the manner in which it is mounted would affect the actual compliance of the vehicle in which it is installed.

Jacobs' September 20, 1977, analysis evaluated the likelihood that certain retarders to be imported or manufactured by Jacobs would affect compliance. With regard to these retarders, it appears that their installation as original equipment or in the aftermarket in the fashion described would not affect compliance of the vehicle with Standard No. 121. This finding is of necessity limited to the retarders evaluated in the September 20, 1977, analysis.

ID: nht78-2.46

DATE: 01/26/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: AM General Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 12, 1977, request for confirmation that an air-braked electric trackless trolley may be tested for compliance with S5.3.1 of Standard No. 121, Air Brake Systems, with its transmission selector control in the "DRIVE" position if the drive wheels and motor are permanantly mechanically connected and the motor automatically provides retardation when the service brake control is depressed. Your other requests for interpretation have been answered by separate letters.

Section S6.1.3 of Standard No. 121 specifies:

S6.1.3 Unless otherwise specified, the transmission selector control is in neutral or the clutch is disengaged during all decelerations and during static parking brake tests.

This test condition does not permit testing for compliance with the transmission selector control in the "DRIVE" position. The performance levels of the standard were established at levels intended for the foundation brakes alone, exclusive of engine braking, and it is for this reason that the selector must be in neutral or the clutch disengaged. This is true both for vehicles with manual and automatic transmissions.

It does appear that a case may be made for testing the bus you describe with the selector in "DRIVE". One important factor would be whether the field in the motor generator is permanent or electrically induced. In the event you wish to petition for an amendment of S6.3.1, information of this nature should accompany your petition.

In response to your other question, the agency's July 10, 1974, letter to Flyer Industries remains valid.

ID: nht78-2.47

DATE: 01/10/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Briskin Manufacturing Company

TITLE: FMVSS INTERPRETATION

TEXT: I would like to advise Briskin Manufacturing Company as a producer of air reservoirs for use on vehicles that comply with Standard No. 121, Air Brake Systems, that the National Highway Traffic Safety Administration (NHTSA) has decided to withdraw its December 14, 1977, interpretation of the requirement that reservoirs "withstand" internal hydrostatic pressure (copy of interpretation enclosed).

While the NHTSA simply intended to clarify its existing interpretation of the requirements, information brought to the agency's attention indicates that the revised interpretation would have the unintended effect of increasing the stringency of the requirements. Any such upgrading of the integrity requirements for air reservoirs would be preceded by notice and opportunity for public comment.

The agency expects to publish notice that its interpretation is withdrawn in the Federal Register in the near future.

ID: nht78-2.48

DATE: 05/23/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: The Johnson Manufacturing Co.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Johnson Manufacturing's May 4, 1978 request for confirmation that the requirement in Standard No. 121, Air Brake Systems, that reservoirs "withstand" specific pressure does not require testing of a multi-compartment reservoir compartment-by-compartment.

Your understanding of the "withstanding" requirement in S5.1.2.2 and S5.2.1.3 is correct. Although the agency sought to clarify that compartment-by-compartment testing was the proper interpretation of this requirement (42 FR 64630; December 27, 1977), problems with the interpretation resulted in its withdrawal (43 FR 9149; March 6, 1978) and adherence to the existing interpretation that there be no rupture or permanent circumferential deformation of the reservoir. Under this interpretation only the circumference of the outer reservoir shell is measured, and internal baffles are not stressed by separate compartment-by-compartment testing.

ID: nht78-2.49

DATE: 01/05/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Kelsey-Hayes Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Kelsey-Hayes' September 2, 1977, request to know whether Standard No. 121, Air Brake Systems, allows a burnish of the brake friction elements immediately prior to the parking brake tests of S5.6, and whether the service line air pressure limitation of 100 p.s.i. specified in S5.4.2.1 can be exceeded monentarily.

A burnish prior to the parking brake test is not permitted by Standard No. 121, except that S6.1.8 specifies burnish of the parking brake friction elements before testing in those cases where the parking brake system does not utilize the service brake friction elements. The National Highway Traffic Safety Administration (NHTSA) would consider a provision to deal with the condition of the brake linings prior to the parking brake test upon receipt of technical data showing justification for such an action.

Section S5.4.2.1 of the standard specifies a procedure that states "[the] service line air pressure shall not exceed 100 p.s.i. during any deceleration." You describe a condition in which the service line pressure exceeds 100 p.s.i. for a short period (typically 0.1 seconds), which might be traced to characteristics of the friction material, brake mechanism, dynamometer, or instrumentation.

The NHTSA recognizes that peak pressure may be momentarily increased by the initial rush of air pressure into the brake chamber, or by other anomolies. In the case of such momentary pressure increases, the NHTSA interprets S5.4.2.1 to mean that the source of air pressure for applying the brake must never exceed 100 p.s.i. Thus, it would be permissible to experience momentary pressures above 100 p.s.i. in the service line as long as the pressure source never exceeds that level. Sustained periods of pressure above 100 p.s.i. would not be permissible.

SINCERELY,

KELSEY-HAYES COMPANY

September 2, 1977

Joseph J. Levin, Jr. National Highway Traffic Safety Administration

RE: Request for Interpretation FMVSS-121, Air Brake Systems @ 5.3.1 Stopping Distance-Trucks and Buses

Kelsey-Hayes Company, a domestic manufacturer of motor vehicle equipment including antilock systems, requests an interpretation of the above referenced section of Standard 121.

It is the nature of newly manufactured braking systems to have residual coatings of various materials deposited upon the brake components together with surface irregularities as a result of the manufacturing process.

FMVSS-121, as well as FMVSS-105, allow for this by providing burnish stops to remove foreign substances and to condition brake linings at the outset of the testing sequence. In addition to the initial burnish, some test procedures including FMVSS-105 specify burnishing at specific intervals during the test.

Reburnishes at specific intervals are provided in recognition of the fact that a rapid series of test stops will generate high temperatures and cause surface glazing on the brake lining material. To accurately gauge the effectiveness of the braking system, FMVSS-105 allows the brakes to be reburnished before the parking brake test. While perhaps not intended by FMVSS-105, the snub burnish procedure has the effect of paralleling actual vehicle use as it is normal to expect a driver to apply the service brakes in a routine fashion prior to parking the vehicle. No identical language appears in FMVSS-121, although Table 1-Stopping Sequence does provide for a burnish in its initial step.

The authors of FMVSS-105 recognized the abnormal conditions which develop during the harsh testing sequence. Further, they recognized that lining surface glazing will impair the holding characteristics of a braking system, perhaps to the extent that an otherwise completely adequate design will fail this standard for an unintended reason.

It is with these thoughts in mind that Kelsey-Hayes Company respectfully requests an interpretation by the NHTSA as to whether step 1 of Table 1 of FMVSS-121 will allow a burnish of the parking brakes immediately prior to step 5-parking brake test.

Thank you for your consideration.

David M. Thompson

ID: nht78-2.5

DATE: 11/28/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT:

NOV 28 1978

NOA-30

Mr. W. G. Milby Manager, Engineering Service Blue Bird Body Company P.O. Box 937 Fort Valley, Georgia 31030

Dear Mr. Milby:

This responds to your August 3, 1978, letter asking how to compute the area of a sample of a body panel when testing for compliance with Standard No. 221, School Bus Body Joint Strength.

In your letter, you suggest that the net cross-sectional area of the sample is determined by multiplying the width of the sample by its thickness and then subtracting the area of each discreet fastener hole. The National Highway Traffic Safety Administration agrees that this procedure yields the correct area of the sample, and is the method used by the agency in its compliance testing.

Sincerely,

Joseph J. Levin, Jr. Chief Counsel

August 3, 1978

Mr. Joseph J. Levin Chief Counsel National Highway Traffic Safety Administration Washington, D.C. 20590

Dear Mr. Levin:

The purpose of this letter is to seek confirmation of our interpretation regarding FMVSS 221, School Bus Joint Strength.

It is our understanding that in meeting the requirements of S5, that the area to be used for calculating purposes, when discreet fasteners are used, is the net area of the weakest joined body panel. We define the net area as the width of the sample multiplied by its thickness, less the projected area of each discreet fastener hole.

We look forward to receiving an early written confirmation of this interpretation.

Thank you.

Very truly yours,

W. G. Milby Manager, Engineering Services

sw

ID: nht78-2.50

DATE: 01/20/78

FROM: AUTHOR UNAVAILABLE; F. Berndt for J. J. Levin, Jr.; NHTSA

TO: The Bendix Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Bendix Corporation's November 9, 1977, request for confirmation that S5.6.4 of Standard No. 121, Air Brake Systems, does not prohibit the use of a two-valve sequential means to release the parking brakes on a towed vehicle.

I have enclosed for your information two interpretations that address this question, stating that a two-valve sequential release is permissible under S5.6.4. I have also enclosed a copy of an outstanding rulemaking proposal that would standardize the parking brake control as specified in the Society of Automotive Engineers Recommended Practice J680b. I am unable to advise you whether the National Highway Traffic Safety Administration intends to make final this proposal.

I would also like to remind you of the requirement in S5.6.4 that "[the] control shall be identified in a manner that specifies the method of control operation." So long as different control arrangements are used, it is critical that the means of operation be clearly marked.