ID: nht75-3.50

DATE: 06/10/75

FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA

TO: Volvo of American Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Volvo of America Corporation's May 9, 1975, request for reconsideration of the NHTSA's March 31, 1975, determination that a Volvo brake system that employs air pressure modulated by the vehicle operator to provide the energy used to actuate the brake is an air brake system subject to Standard No. 121, Air brake Systems.

Having reviewed all of the data submitted with your letter, it is concluded that the Volvo system is an air brake system subject to Standard No. 121. In the development of separate air brake and hydraulic brake system standards, the NHTSA had to make a determination of the status of brake systems which employ both air and hydraulic fluid as a means of transmitting force to the vehicle brakes. The agency decided that use of air as a means of power and transmission of the brake force would quality the system as an air brake system. This decision permits manufacturers to determine with certainty whether a standard applies to their products.

Since the withdrawal of applicability to trucks of Standard No. 105-75, Hydraulic brake systems, our decision has had the beneficial effect of ensuring that "air over hydraulic" systems are subject to a braking standard. If you are aware of any adverse safety consequences of our decision, I would appreciate hearing from you.

Sincerely,

May 9, 1975

James Schultz, Acting Chief Counsel National Highway Traffic Safety Administration

Re: Request for interpretation, FMVSS 105-75 - Hydraulic Brake Systems, and FMVSS 121 - Air Brake Systems

This correspondence is a follow-up to our request for interpretation dated March 3, 1975, your response dated March 31, 1975, and a subsequent telephone conversation between the undersigned and Mr. Richard Dyson, Esq. of your office.

In our March 3rd request we described a somewhat unique truck service brake system employing both air and hydraulic subsystems and asked for your concurrence that the described system was in fact a "hydraulic brake system" with a "brake power unit" as defined in 571.105-75 S4 and, therefore, not subject to the requirements of 571.121. In your March 31st response you disagreed with Volvo's proposed interpretation, stating in part that the system in question appeared to be an "air over hydraulic" system and cited an earlier interpretation contained in the preamble to 571.121 which defines the term "air brake system" as including brake configurations commonly referred to as "air over hydraulic", in which failure of either medium can result in complete loss of braking ability.

Having reviewed your response very carefully, we are presently of the opinion that your classification of the described Volvo brake system as "air over hydraulic" may be somewhat arbitrary and it appears you may have overlooked some important characteristics of the system. This could be in part due to overly simplified technical information supplied with our original request. It is, therefore, our intention to submit more detailed technical information as well as additional arguments to support our position at this time, in hopes that you will review and revise your original interpretation.

It is Volvo's contention that the brake system in question is a "Hydraulic brake system" as defined in 571.105-75 S4 in that it uses hydraulic fluid as the primary medium for transmitting force from the service brake control to the service brake and in that it incorporates a "brake power unit" as also defined in S4. The "brake power unit" provides the energy required to actuate the brakes, with operator action consisting of only modulating the energy application level. It is our belief that the subject Volvo system, to be described more fully, is in principal identical to currently used hydraulic brake systems in all major respects, except that it is a power brake and that the energy source which the driver modulates happens to be derived from compressed air rather than vacuum or hydraulic pressure. This single factor is not, in our opinion, decisive for classifying the Volvo system as an "air brake system", inasmuch as failure of a single air or hydraulic subsystem will not result in complete loss of braking ability, as you imply is the case with "air over hydraulic" systems.

A complete set of specifications and working description of the Volvo brake system in question, including illustrations and braking performance characteristics, is provided as Attachment No. I. Additionally, we are providing as Attachment No. II a group of pictorials depicting the actual layout of the components on the truck chassis.

The subject Volvo brake system has the following major characteristics in common with other truck "hydraulic brake systems":

1. The main chassis plumbing consists of hydraulic lines connecting the master cylinders to the wheel brake cylinders.

2. The medium transmitting force between the master cylinders and the wheel brake cylinders is hydraulic brake fluid.

3. The brake shoes are activated by hydraulic wheel cylinders.

In addition to the mentioned similarities, the subject Volvo brake system offers the following features and characteristics which we believe are superior to most current truck hydraulic brake systems:

1. Volvo offers a "split service brake system" with completely independent hydraulic circuits for the front and rear axles. plus split "brake power" (air) circuits which are isolated from each other and other air powered equipment in case of leakage.

2. We are confident that Volvo trucks equipped with the subject system offer stopping performance which is superior to most competitive trucks with hydraulic system in compliance with Federal Motor Carrier Safety Regulations, 393.40.

3. Volvo offers an air controlled parking brake system which can be effectively modulated and used for emergency braking.

4. The Volvo system includes a load sensitive valve which proportions hydraulic pressure to the rear axle.

The air portion of the subject Volvo brake system, as described in principal in Attachment No. I, will meet all applicable requirements of 571.121 S5.1. Additionally, the hydraulic fluid used meets the requirements of 571.116, and all brake hoses, both air and hydraulic, meet the requirements of 571.106.

We hope that the foregoing information and discussion will enable your office to revise its previous interpretation rendered to us on this topic. Before reaching a final decision, however, we would welcome an opportunity to meet with your technical and legal personnel to discuss the Volvo braking system in detail, and to further clarify our position in this matter. Due to pressing time constraints, we would appreciate your cooperation in arranging such a meeting before the end of May, 1975.

We thank you in advance for your cooperation.

VOLVO OF AMERICA CORPORATION Product Engineering and Development

Donald W. Taylor Manager, Product Safety & Quality

cc: B. Klingenberg/Truck Div.

ID: nht75-3.6

DATE: 11/11/75

FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA

TO: American Honda Motor Co., Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of October 14, 1975, in which you request an interpretation of Standard No. 301 as it applies to a vehicle with an electric fuel pump that operates only when the ignition switch is in the "ON" position and the engine oil pressure is within the normal operating range.

You indicate in your letter that, in effect, the fuel pump can only operate when the vehicle's engine is running. Paragraph S7.1.3 of Standard No. 301 requires that an electrically driven fuel pump be operating at the time of the crash tests if the pump "normally runs when the vehicle's electrical system is activated." It appears from your letter that activation of the electrical system by switching the ignition to "ON" will not by itself activate the fuel pump. As a result, the pump need not be operating at the time of the crash tests.

SINCERELY,

October 14, 1975

Richard Dyson NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION Department of Transportation

This is to request your official interpretation as to the applicability of S7.1.3 of F.M.V.S.S. 301 to the system described below.

The fuel pump is electrically driven but operates only when the ignition switch is in the 'ON' position and the engine oil pressure is within the normal operating range. The engine must be running in order to produce this condition.

Your earliest response in this matter would be appreciated.

AMERICAN HONDA MOTOR CO., INC.

Brian Gill Assistant Manager Safety & Environmental Activities

ID: nht75-3.7

DATE: 11/18/75

FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA

TO: Nissan Motor Co., Ltd.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of October 15, 1975, in which you request an interpretation of paragraph S7.1.3 of Standard No. 301, as to whether it is permissible to stop an electric fuel pump prior to the rollover test.

Paragraph S7.1.3 provides that "If the vehicle has an electrically driven fuel pump that normally runs when the vehicle's electrical system is activated, it is operating at the time of a barrier crash." The static rollover test specified by S6.4 is not a barrier crash, and therefore is not covered by S7.1.3. In the amendments to Standard No. 301 published on October 15, 1975 (40 FR 48352), the addition of the phrase "In meeting the requirements of S6.1 through S6.3" to S7.1.3 clarifies the intent of the agency not to require that an electric fuel pump be operating at the time of the rollover test, because the rollover test is required by paragraph S6.4. Therefore, you may turn off the pump if it is still working at the time of the static rollover test.

SINCERELY,

October 15, 1975

Frank Berndt Office of Chief Council National Highway Traffic Safety Administration

I would like to ask your interpretation of the following phrase which is found in MVSS 301, S.7.1.3 :

"at the time of the barrier crash"

My understanding is that this phrase means that we should turn on the electric system which activates the electric fuel pump before the barrier crash test and leave it on through the subsequent roll over test.

The breakage of the battery and the wiring disconnection, due to the crash, may or may not stop the electric fuel pump, but if it is still working, we should not turn off the switch.

Is my understanding on the above mentioned phrase correct, or may we turn off the pump if it is still working during the roll over test?

Your interpretation on the above will be greatly appreciated.

There may have been a discussion on this matter before. It would be a great help if you could send us the documents on the resolution of that discussion.

Thank you.

NISSAN MOTOR CO., LTD.

Naoyoshi Suzuki

Staff, Safety

ID: nht75-3.8

DATE: 09/16/75

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: The Hardy Heater Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of July 30, 1975, in which you inquire as to any rules and regulations to which you may be subject with respect to your pre-heater defroster. Your letter was referred to this office by the Environmental Protection Agency.

We assume, from the material submitted with your letter, that your pre-heater is sold for installation in used cars and supplements the vehicle's existing defrosting system. If our assumption is incorrect, please advise us. If your pre-heater is installed in a motor vehicle prior to its first purchase or if it replaces an existing defrosting system, you will be subject to regulations in addition to those mentioned in this letter.

The National Traffic and Motor Vehicle Safety Act provides that a manufacturer, dealer, distributor, or repair shop may not render inoperative any safety device or design in a motor vehicle after its first purchase by the owner. This means that the installation of the pre-heater must not take the vehicle out of compliance with an applicable Federal Motor Vehicle Safety Standard. The standard with which you will likely be most concerned is Standard No. 103, Windshield Defrosting and Defogging Systems (copy enclosed).

(Graphics omitted)

In addition, if the fuel used in your pre-heater has a boiling point greater than 32 degrees F, you must ensure that the pre-heater fuel system complies with Standard No. 301, Fuel System Integrity (copy enclosed).

Thank you for your interest in motor vehicle safety.

YOURS TRULY

THE HARDY HEATER COMPANY

July 30, 1975

Director E. P. A.

I am having manufactured and will market a pre-heater defroster for auto's as shown in the attached documents which are a part of my (Illegible Words).

Please advise me if I am required by rules, regulations or otherwise to obtain any (Illegible Word)) permits to prior to marketing my heater nationwide.

As you (Illegible Words) cylinder of L. P. (Illegible Words) am primarily concerned with any legal requirement with respect its use in automobiles.

I will appreciate any information on the subject.

Frank Hardy

Teddy's drivers in cold climates are not satisfied each day entering a miserably cold auto, with limited or no vision because of condensation, frost, ice, snow, build-up on the glassed areas.

A majority of the over 80 million cars on our highways, and the over 10 million being built each year, need this heater to provide a warm, safe comfortable car from the start. This device fills a gap that has been completely overlooked in automotive engineering.

Please note how many vehicles you see on the highway, especially in the morning, in cooler climates, driving virtually blind, until the standard heater defroster clears the glass area. My heater eliminates this dangerous condition, and provides a comfortable temperature inside the car from the start.

A common cold weather practice is to start the auto engine on cold mornings and let it set and run until the conventional heating process warms and defrosts the car. This practice causes excessive engine wear and long periods of cold engine idle, which is a major factor in air pollution by automobiles. This inconvenience, wear, and pollution can be eliminated with the use of my heater.

Volume sales will be to gasoline powered vehicles; however, it will be a natural as an inducement for all who are thinking of conversion or have converted to propane from gasoline as a motor fuel, as certain basic components such as fuel tank controls, etc., could serve both installations.

Attached is information on a unique gas fired auxiliary and independent automobile heater, that will eliminate the misery and danger of a cold automobile, with frosted glass area, when you first enter it in cold weather. It can provide home-like comfort 24 hours a day, or may be shut off to automatically come on several hours before returning to the car, at which time it will be heated and frost free for safe and comfortable driving from the start.

I have a patent pending for this heater, and am interested in working with a manufacturer for mutual benefits in the production and sale of this item.

I am available for an interview to discuss any ideas or interest you might have concerning my situation.

Warren Frank Hardy

(Graphics omitted)

(Graphics omitted)

ID: nht75-3.9

DATE: 11/28/75

FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA

TO: Ford Motor Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of September 24, 1975, in which you ask whether it is permissible to test certain 1978 vehicles for compliance with Standard No. 301, Fuel System Integrity, with open vapor vent tube pressure relief valves.

The Federal motor vehicle safety standards do not specify the tests which you must perform. They do specify the conditions and procedures under which the National Highway Traffic Safety Administration (NHTSA) will conduct its compliance testing. S7.1.1 and S7.1.2 of Standard No. 301 specify that the vehicle's fuel system shall contain Stoddard solvent rather than fuel and, by implication, that the engine shall not be running. If, as you indicate, one consequence of the engine's not running is that a certain pressure relief valve in the vapor vent tube is closed, then that valve must remain closed during the NHTSA's compliance testing; the existing standard could not be interpreted otherwise. Although in an actual collision any rollover would probably occur immediately after the initial impact, in some accidents vehicle occupants would be trapped for some period of time after rollover. Therefore, we do not consider that this interpretation creates, as you suggest, an artificial condition by subjecting the fuel tank to a potential vapor pressure build-up during preparation for the rollover test.

Sincerely,

ATTACH.

September 24, 1975

James B. Gregory -- Administrator, National Highway Traffic Safety Administration

Dear Dr. Gregory:

Re: Request for Interpretation in Relation to Conducting FMVSS 301-75 Tests with Proposed 1978 Evaporative Emission System

In preparing for compliance with 1978 California SHED evaporative emission requirements (presently under consideration by EPA for application in all areas), Ford Motor Company (Ford) is considering modifications to the fuel tank vapor venting system. At this time, Ford's primary design direction for certain of its 1978 vehicles is to incorporate a pressure relief valve in the vapor vent tube between the fuel tank vapor separator/rollover valve and the carbon canister (see Attachment).

When the engine is operating, this pressure relief valve will be open and the fuel tank will vent in a normal manner through the carbon canister. When testing according to the procedure set forth in FMVSS 301-75, the pressure relief valve would be closed, contrary to its normal open position when the engine is operating, and such closure would prevent venting of vapor from the fuel tank into the carbon canister. As a result, vapor pressure could build up within the fuel tank during FMVSS 301-75 testing, and indeed would do so if the fuel tank were exposed to elevated ambient temperatures during the substantial time period (in some instances several hours) required to ready the test vehicle for the rollover test following an impact test. If such pressure built up, it (taken together with the hydrostatic pressure of the Stoddard solvent in the tank) might force open the vacuum/pressure valve in the fuel tank cap and permit leakage through that valve (cap).

Such leakage would not occur in an accident involving a rollover because, in such a situation, vapor pressure would not build up in the fuel tank, and therefore, the vacuum/pressure valve in the cap would not open. Any rollover of the vehicle that may occur would happen immediately after the collision, before vapor pressure build-up. Hence the vacuum/pressure valve (cap) would remain closed after rollover. More particularly, just before the accident, the vapor vent tube pressure relief valve would be open, preventing vapor pressure build-up.

Accordingly, Ford proposes to perform tests relating to compliance with FMVSS 301-75 with the vapor vent tube pressure relief valve open, the better to simulate actual usage conditions. Before testing in this manner, Ford would appreciate receiving assurance from the Administration that it regards as appropriate the maintaining open of this pressure relief valve during rollover tests, and would conduct in that manner its rollover tests of those Ford vehicles equipped with such a valve.

As you are undoubtedly aware, in addition to design and development work, a test program required to obtain emission certification covers a period of many months. Therefore, since Ford has only a limited time in which to develop a 1978 evaporative emission system complying with the SHED requirements, an early response to this letter is urgently requested.

Respectfully submitted,

J. C. Eckhold -- Director, Automotive Safety Office, FORD MOTOR COMPANY

ATTACH.

PROPOSED 1978 EVAPORATIVE EMISSION SYSTEM

(Graphics omitted)

Automotive Safety Office September 22, 1975

ID: nht75-4.1

DATE: 11/17/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: MOTAC, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to MOTAC's September 18, 1975, question whether rebuilding a platform trailer constitutes the manufacture of a new vehicle subject to applicable motor vehicle safety standards when the running gear (the axles, wheels, suspension, and related components sometimes known as a bogie) and the platform of a wrecked trailer is used (1) in combination with entirely new frame members, (2) in combination with one main frame member of the wrecked vehicle and one new frame member, and (3) in combination with part of one or both main frame members. You also ask whether the addition of a second axle to a single axle trailer, or the deletion of one axle on a tandem axle trailer, qualifies as the manufacture of a new vehicle subject to applicable safety standards.

In response to your first question, the National Highway Traffic Safety Administration (NHTSA) has determined (in the Stainless Tank and Equipment letter to which you refer) that, as a minimum, the running gear and main frame of the existing trailer must be used to qualify the rebuilding operation as a repair where all other materials are new. This position does not apply to the three situations you describe in which only the main frame members, and perhaps several cross members, are replaced. Therefore a repair of this type is not considered the manufacture of a new trailer.

In response to your second question, the NHTSA would not consider the addition of a second axle to a single axle trailer, or the removal of one axle from a tandem axle vehicle, to constitute the manufacture of a new vehicle.

Sincerely,

September 18, 1975

National Highway Traffic Safety Administration

Attention: Frank A. Berndt Acting Chief Counsel

We would appreciate your clarification as to the extent that major repairs and/or modifications may be made to semi-trailers and pull trailers without the inclusion of the FMVSS 121 anti-lock brakes.

We have two items or catagories that we wished resolved and they are brought about thru your letter of 8/28/75, file number N40-30 addressed to Stainless Tank and Equipment, Inc., Cottage Grove, Wisconsin. This letter was transmitted to all members of T.T.M.A.

ITEM NO. 1

Assume that a platform trailer had been in a serious accident and possibly rolled over, thereby bending and twisting the main frame members severely. We will also assume that the damage is to such an extent that the main frame members cannot be straightened, which generally can be done.

The following conditions could then prevail for the required repair:

A. Cut the damaged portion off of one or possibly both main frame rails and repair with a new partial section or sections.

B. Replace one main frame rail completely.

C. Replace both main frame rails completely.

In the above hypothesis, the "Bogie", axles, wheels, tires, supports, etc. would all be used. The trailer would maintain the same model and serial number.

In a major repair of this sort will the standard 121 brakes be required? If so, then the old axles would have to be junked and new S-121 axle assemblies with computor/relay valves must be purchased and installed.

ITEM NO. 2

Six years ago, our company manufactured thirty (30) single axle container semi-trailers and thirty (30) tandem axle container semi-trailers, 25 foot long to haul 20 foot containers. The main frame rails, bolsters, supports, etc., are identical on both trailers.

The customer is now contemplating converting the single axle semi-trailers to tandem axle semi-trailers. This will entail relocating the existing front and rear spring hangers, adding a center equalizer hanger and rocker arm assembly, one set of springs, one axle, brake, tire and wheel assembly. The trailer will be reregistered as a tandem axle semi-trailer for state licensing.

In converting a single axle semi-trailer to a tandem axle semi-trailer will the Standard 121 brakes be required? Also, conversely, if a tandem axle semi-trailer should be converted to a single axle semi-trailer will the Standard 121 brakes be required?

MOTAC, INC.

Jack A. Johnson Chief Engineer

ID: nht75-4.10

DATE: 06/03/75

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Toledo Clutch & Brake Service, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your April 21, 1975, questions whether a 121-equipped chassis must be certified to Standard No. 121, Air brake systems, after installation of a tractor conversion kit, whether an antilock wiring harness may be spliced for purposes of frame extension, whether additional weight (such as a body) or an axle may be added to a vehicle after it is sold and put into use, and whether the standard regulates the replacement of worn brake components. You state that it should be assumed that the vehicle has been delivered to the first user.

The National Traffic and Motor Vehicle Safety Act prohibits the manufacture for sale, sale, offer for sale, introduction into interstate commerce, or importation of a vehicle which does not comply with all applicable standards in effect on the date of manufacture. (15 U.S.C. 1397(a) (1) (A)). However, the Act also provides that this prohibition no longer applies to a vehicle (except in the case of importation) after the first purchase of it in good faith for purposes other than resale. (15 U.S.C. 1397 (b) (1)). The Act also prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative a safety device or design (15 U.S.C. 1397 (a) (2) (A)).

These provisions mean that the manufacturer of the vehicle must assume responsibility for compliance and certification. Most trucks are built in several stages and completed by final-stage manufacturers like yourself. Cab-chassis are only incomplete vehicles which have not been certified, and therefore, whoever completes the vehicle and subsequently sells it or introduces it on the public highway must certify its compliance. In answer to your first question, it is the responsibility of the person who installs the fifth wheel, tractor protection system, etc., to certify compliance, whether or not the vehicle has been delivered to the first user. The owner himself would qualify as a final-stage manufacturer if he installed the conversion kit.

In answer to your third and fourth questions, the installation would be subject to certification unless it followed "the first purchase of it in good faith for purposes other than resale." "Good faith" means that the first user could not, for example, buy a completed vehicle, drive it around the block and then install a non-conforming tag axle. Installation of a body after delivery to the first purchaser without compliance with Standard No. 121 would in most cases not appear to be good faith because the vehicle is not capable of use without the body.

It is permissible to make modifications to a vehicle that is already in service after the first purchase in good faith. A private party may make any change, but as noted above, a manufacturer, distributor, dealer, or motor vehicle repair business such as yours cannot "knowingly render inoperative" a safety device in the process of modification. In answer to question number five, Standard No. 121 regulates the manufacture of new vehicles only and does not contain provisions which limit use of replacement parts. The only restriction in replacement would be to avoid knowingly rendering inoperative safety devices or design.

In answer to question number three, the standard establishes performance levels and does not contain any design requirements concerning the wiring harness of antilock systems. We would advise that you contact the antilock manufacturer or the vehicle manufacturer as to the wisdom of splicing antilock wiring.

For your information, I enclose a discussion of the standard which addresses final-stage manufacture at page seven.

YOURS TRULY,

April 21, 1975

National Highway Traffic Safety Admin.

Toledo Clutch & Brake Service, Inc. is a "Heavy Duty" brake shop. That is the majority of our sales is to fleets, school buses and off road equipment (earth moving equipment, cranes, quarry vehicles, etc.). By the nature of our business we must be and are a very safety oriented business, having held classes, clinics and seminars on brakes, brake safety and related subjects. We have followed the course of FMVSS 121 since its original proposal nearly five years ago. Our customers, and many of our competitors customers have relied on us to give them the latest up-date on FMVSS 121. However, since its implementation this year, many legal questions have arisen in the aftermarket that we feel only the Department of Transportation can clarify. We have listed a number of actual circumstances and some cases that we feel will arise in the future. We would like to have the Department of Transportations interpretation of these questions, assuming in all cases, except where noted, that the vehicle has been delivered to the first user with straight air brakes, and that any materials added comply with FMVSS 121:

1. A vehicle chassis is purchased, having no body (van, dump, stake, etc.), with the intention of converting to a tractor. Can a tractor convertion kit (hand valvue, tractor protection system and trailer outlets) be added after delivery to the first user, without recertification?

2. Can a truck frame be extended after delivery to the first user? If so, will a new anti-skid wiring harness be required or can the original one be spliced?

3. Can a tag axle be added to a vehicle that is already in service? A lift axle? A third axle to trailer? A twin screw to a tractor?

4. After delivery to the first user, can additional weight be added to a vehicle, such as saddle tanks, bodies, material to comply with up dated noise abatement laws etc?

5. When brake system parts (including foundation brake parts) wear out or become defective, through normal usage, can they be replaced with parts that are competetive with original equipment parts so long as the competetive or replacement parts are certified to comply with FMVSS 121?

Richard Schlichting President TOLEDO CLUTCH & BRAKE SERVICE, INC.

ID: nht75-4.11

DATE: 09/03/75

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Crane & Excavator Division

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your July 28, 1975, letter asking whether the unloaded vehicle weight of a mobile crane carrier would include components that are essential to its specialized function but are not removed for transit purposes. You also suggest alternative wording for a particular exclusion criterion proposed for mobile crane carriers and similar vehicles under Standard No. 121, Air Brake Systems.

I have enclosed a copy of a recent notice that amends Standard No. 121. The preamble to the notice deals with the issues you have raised and should make clear to you that vehicle components are not generally considered part of the rated cargo capacity and therefore would not be subtracted from a vehicle's gross vehicle weight rating to determine the unloaded vehicle weight.

YOURS TRULY,

FMC CORPORATION Crane & Excavator Division

July 28, 1975

Richard B. Dyson, Assistant Chief Council Department of Transportation National Highway Traffic Safety Administration

Ref: Your letter to me of July 2, 1975: N40-30 (TWH)

Thanks for the referenced letter of interpretation as requested by me on June 23, 1975.

I fully realize that NHTSA definition of GVWR (Gross Vehicle Weight Rating) does not require that the GVWR be the sum of the vehicles GAWR but must not exceed the sum of the vehicle GAWR's.

Your referenced letter states "Unloaded vehicle weight will normally be the GVWR of a vehicle minus its rated cargo load and its assigned occupant weight (at least 150 lbs.). The rated cargo load would not include the weight of portions of a vehicle which are essential to its specialized function but are removed in accordance with State regulation for transit purposes".

Therefore, I assume the following: "The rated cargo load would not include the weight of portions of a vehicle which are essential to its specialized function but are not removed in accordance with State regulation for transit purposes".

Please advise me if my assumption is correct.

To more fully allow our customers to meet the maximum number of State and local regulations it is necessary that our GVWR be a summation of the vehicle GAWR's. Therefore, few of our truck cranes will fall within the 95% or more of GVWR.

The regulation would be more meaningful and specific if you deleted "An unloaded vehicle weight that is not less than 95% of the vehicle GVWR" and replaced it with "An unloaded vehicle weight whose cargo portion is less than 5% of the vehicle GVWR". I recommend this change.

Please advise me if my assumption is correct and your comments on my recommendation.

H. Ray Cozad, Chief Engineer

ID: nht75-4.12

DATE: 11/24/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Realco Services, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Realco Services' October 10, 1975, question whether the replacement of the four rails in the sides of a monocoque-type van would qualify as a vehicle assembly operation subject to certification to new vehicle standards, including Standard No. 121, Air Brake Systems.

The answer to your question is no. The position of the NHTSA with regard to the use of used trailer components that was discussed in the Stainless Tank and Equipment interpretation letter applies only to situations in which a new trailer body is installed on used running gear. These limitations do not apply where most of the used body (along with used running gear) is retained, as where one or more rails are replaced in the sides of a used monocoque van.

Sincerely,

ATTACH.

October 10, 1975

Frank Berndt -- Acting Chief Counsel, National Highway Traffic Safety Administration

Dear Mr. Berndt:

Realco Services Incorporated, owner of over 30,000 trailers which are leased to railroads and steamship companies would appreciate a clarification of a new versus used trailer, in the repair of trailers and the compliance of Standard No. 121, Air Brake Systems.

In your letter to Mr. Paul Krueger, Stainless Tank and Equipment, Inc., dated August 28, 1975, File N40-30, you refer to manufacturers and to retaining the main frame of the units to qualify as a used chassis.

In monocoque construction, the trailer side walls constitute the main load bearing members.

In the maintenance of our equipment, we find it necessary to replace one or more items of the trailer sides, ranging from a bottom rail to possibly all four rails, top and bottom.

As you know, lifting devices used by the railroads do considerable damage to the trailer top and bottom rails which in many instances demands their replacement.

We interpret the ruling to cover only the manufacture of trailers, not the repairs to equipment over its normal life. We would appreciate your confirmation that this is correct.

Very truly yours,

J. A. Davies

cc: C. J. Calvin - T.T.M.A.; J. M. Lillis

ID: nht75-4.13

DATE: 08/25/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Dana Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Dana Corporation's July 11, 1975, question whether a system which controls a truck engine throttle from a remote location by means of compressed air from the truck's brake system would violate the requirements of Standard No. 121, Air brake systems.

The answer to your question is no. Standard No. 121 does not contain a prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle 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. For example, the compressor build-up pressure would still be required to meet S5.1 of the standard.

Although not a requirement of the standard, the NHTSA does consider it appropriate that a pressure protective valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.

SINCERELY,

DANA CORPORATION . TECHNICAL CENTER

July 11, 1975

Chief Council U.S. Department of Transportation

We are presently involved with the design and development of a system used in the control of truck engine throttles. The system will require compressed air for its actuation which will be obtained from the air supply used in the vehicle's air brake system. This system will primarily be used on refuse packers during the pack cycle. The time per pack cycle will be one minute or less with a system's air consumption of .375 cubic feet at a regulated pressure of 35 pounds per square inch and having a free air flow of .358 cubic feet.

With data available to you, I would like to know if, when using our system, the manufacturers will be in any violation of the FMVSS No. 121, Air Brake Systems. I am mostly concerned with paragraphs S5.1.1, S5.1.2, and S5.1.2.1 referring to compressors and reservoirs.

Having this information, we can assure the truck manufacturers that our system will not in any way put them in jeopardy of any vehicle safety standards set forth by the U.S. Department of Transportation.

If you have any questions, please feel free to contact me.

Robert J. Ostrander Development Engineer