Interpretation ID: 1984-3.5

TYPE: INTERPRETATION-NHTSA

DATE: 08/17/84

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Terralab Engineers

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Douglas MacGregor Terralab Engineer 3585 Via Terra Salt Lake City, Utah 84115

Dear Mr. MacGregor:

The Administrator has asked me to respond to your letter of June 6, 1984, regarding the modification of fuel systems conforming to Standard No. 301, Fue1 System Integrity. You were concerned about the installation of motor vehicle accessories, such as cab and engine block heaters, which utilize fuel from the fuel system of the vehicles. You are concerned that if the installation of those accessories invalidates the manufacturer's certification as to Standard No. 301, the installer would have to do crash testing to verify the installed system conforms with the standard.

You requested the agency to set requirements for "interconnection systems" which would allow the accessories to be connected to the primary fuel line and the fuel tank and to permit the use of those interconnection systems in lieu of crash testing. We do not believe it is necessary to set requirements for "interconnection systems" since a person altering a fuel line or fuel tank can recertify the system without having to do a crash test.

I have enclosed an information sheet which provides a detailed discussion of the implications of installing auxiliary fuel tanks and systems in vehicles under the National Traffic and Motor Vehicle Safety Act. Please note that Standard No. 301 does not require testing; it only requires that the vehicle meet the performance requirements that are specified. The test procedures do, however, state how the agency will test a vehicle to determine compliance. A vehicle alterer's legal responsibility is to exercise due care to ascertain that a vehicle it has altered does in fact comply with these performance requirements. An alterer can rely upon such things as engineering analyses and computer simulations, rather than crash testing, in making the determination that the vehicle meets the specified performance requirements.

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

Sincerely, Frank Berndt Chief Counsel

Enclosure

6 June 1984 Diane Steed National Highway Traffic Safety Administration (NHTSA) Department of Transportation 400 Seventh Street SW Washington, D.C. 20590

REQUEST FOR RULING

Dear Administrator Steed:

A problem which needs to be solved by a ruling by the Administration is that of interraction of two fuel systems in a single vehicle.

Specifically, motor vehicle accessories such as cab heaters and engine block heaters which utilize fuel from the fuel system of the vehicle are installed by manufacturers other than the vehicle manufacturer.

An example would be the installation of an engine block heater or a cab heater by an OEM who has purchased a chassis certified to MVSS301.

Even though the block or cab heater may be certified to 301, the insertion of a "T" in the fuel line, or the addition of a second dip tube into the gas tank, invalidates the vehicle manufacturer's 301 certification.

The expense of crash testing to 301 is extreme, and presents a serious burden to manufacturer, the heater manufacutrer of the OEM is difficult to determine.

We therefore request that the Administration determine allowable interconnection systems whereby the primary fuel line may be entered as a fuel source for accessories, and also an allowable method for entry into a fuel tank for a fuel line to such an accessory, and proper test procedures for the acceptability of such connections, and issue, based upon its findings, a ruling which would allow the use of conforming interconnections without the necessity of crash testing.

Sincerely,

Douglas MacGregor DMG:hm