Interpretation ID: nht88-2.73
TYPE: INTERPRETATION-NHTSA
DATE: 07/14/88
FROM: DERRAL T. CRANCE -- AUTOMOTIVE ENGINEER, SALT RIVER PROJECT
TO: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA
TITLE: NONE
ATTACHMT: ATTACHED TO LETTER DATED 04/03/89, FROM ERIKA Z. JONES -- NHTSA TO DERRAL T. CRANCE, REDBOOK A33 (2), STANDARD 121
TEXT: Dear Ms. Jones:
Recently Salt River Project ordered sixteen material/reel trailers and two transformer oil trailers. The trailers were built in 1987 by an out of state manufacturer and delivered to Salt River Project via a local vendor representing the manufacturer. A description of the two types of trailers is as follows:
A. Material/Reel Trailer
GVWR - 20,000 lbs.
Drawbar - Lunette eye
Length - 211 inches overall
Width - 92 inches
Height - 90 inches
Deck - 30 inches from ground
Axles - Tandem 10,000 GAWR each
Brakes - S-Cam air actuated
Parking Brakes - Spring applied air released
B. Transformer Oil Trailers
GVWR - 22,000 lbs.
Drawbar - Lunette eye
Length - 244 inches
Width - 90 1/2 inches
Height - 102 inches
Bottom of Tank - 24 inches from ground Axles - Tandem 12,000 GAWR each
Brakes - S-cam air actuated
Parking Brakes - Spring applied air released
I have attached a copy of a vehicle data record for a tank trailer and a photo of a material/reel trailer for clarification of the two types of trailers. Salt River Project's interpretation is that the trailers need to conform to Motor Vehicle Safety St andard No. 121 Air Brake System (as amended through Docket 79-03; Notice 4 - issued June 9, 1980). Our concerns specifically are in the reservoirs and the required protection system as set forth in FMVSS 121.
Please issue an interpretation to clarify the following items:
1) Are the trailers as outlined above required to conform to MVSS 121 (as amended through Docket 79-03; Notice 4 - issued June 9, 1980)?
2) If conformance to 121 is required, then is a protected reservoir for parking brake release required?
3) If conformance to 121 is required, then is it a requirement that the service reservoirs be protected by check valves or equivalent?
Sincerely,
Attachment
[SEE ILLUSTRATION IN ORIGINAL]
[SEE ILLUSTRATION IN ORIGINAL]
(PHOTOGRAPH OF TRAILER OMITTED)