Interpretation ID: 1985-03.11

TYPE: INTERPRETATION-NHTSA

DATE: 07/09/85

FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA

TO: V. Stuart James -- Executive Vice President, X-Ten Corporation

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. V. Stuart James Executive Vice President X-Ten Corporation 855 Sansome Street San Francisco, California 94111

 

 

 

 

This responds to your letter to Mr. Kratzke of my staff, asking for an interpretation of the requirements of Standard No. 121 Air Brake Systems (49 CFR S571.121). Specifically you asked if the timing requirements of S5.3.3 and S5.3.4 must be satisfied by trailers which are "heavy hauler trailers" within the meaning of S4. As Mr. Kratzke told you conversation, heavy hauler trailers are exempted from all the requirements of S5.3, including the timing requirements.

 

 

You stated that your company is manufacturing extendable container chassis trailers. The brake lines in those vehicles are designed to extend with the vehicle frame. S4 of Standard No. 121 defines, in part, a heavy hauler trailer as a trailer whose "brake lines are designed to adapt to separation or extension of the vehicle frame...." Thus, your trailer would be considered a heavy hauler trailer for the purposes of Standard No. 121.

 

 

Section S5.3 sets forth road test requirements, compliance with which must be certified for all trucks, buses and trailers. Generally, all trailers are required to be certified as complying with the timing requirements of S5.3.3 and S5.3.4. This general rule is limited by the last sentence of S5.3, which specifies, "However, a heavy hauler trailer and the truck and trailer portions of an auto transporter need not meet the requirements of S5.3." Emphasis added Thus, heavy hauler trailers are expressly exempted from all of the requirements of S5.3, including the timing requirements.

If you have any further questions, please let me know.

Sincerely,

 

 

Jeffrey R. Miller Chief Counsel

 

 

 

May 24, 1985

 

 

 

 

Dear Mr. Kratzke:

 

 

I refer you to our telephone conversation of Wednesday, May 22, 1985 reference X-Ten Corporation's extendable container chassis trailer, VersachassisTM. You may recall that a clarification is needed on the applicability of 49 CFR 571.121 Paragraphs S 5.3.3 and S 5.3.4. The trailer in its present form meets all requirements of 49 CFR 571.121 but may not meet the timing requirements detailed in these paragraphs.

 

 

It is X-Ten's submission that the trailer is not required to meet the timing specification because the trailer is classifiable as a "heavy hauler trailer" or other specially equipped trailer in accordance with 49 CFR 571.121 Paragraph S 4 "Definitions". One of the characteristics of a "heavy hauler trailer" is defined as having "brake lines designed to adapt to separation or extension of the vehicle frame". This characteristic and language precisely describe the air line arrangement on X-Ten's trailer.

 

 

Further, Truck Trailer Manufacturer's Association Recommended Practice number RP 58-81 dated June 10, 1981 (copy enclosed) suggest that the trailer is exempt from the timing requirement. The method and series of decisions used to reach this conclusion are marked on the "flow chart" enclosed.

 

 

The trailer has a tare weight of approximately 8,200 pounds, a Gross Vehicle Weight Rating of 60,000 pounds, a Gross Axle Weight Rating intermediate (1) of 26,000 pounds, and a Gross Axle Weight Rating intermediate (2) of 34,000 pounds.

 

 

To summarize, X-Ten Corporation understands that the trailer is to comply with all aspects of 49 CFR 571.121 except Paragraphs S 5.3.3 and S 5.3.4 from which the trailer is specifically excluded. X-Ten would appreciate an opinion expressed by the Office of Chief Counsel to either confirm or refute this understanding.

 

 

Thank you for your prompt attention to this matter. Very truly yours, V. Stuart James Executive Vice President VSJ:eg