ID: nht73-1.45

DATE: 02/05/73

FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA

TO: Mr. Harvey E. Schock, Jr.

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your memo of January 18, 1973, concerning glazing materials.

I am enclosing a copy of Federal Motor Vehicle Safety Standard No. 205,Glazing Materials.

Certification of conformance to Standard No. 205 is self-certification. No approval by the Federal Government is required.

If you are not aware of State approvals, you may want to contact Mr. Armand Cardarelli of the American Association of Motor Vehicle Administrators, Suite 500, 1828 L Street, N.W., Washington, D.C. 20036.

If I can be of further service, please do not hesitate to ask.

Sincerely,

Enclosure

No Control

M E M O

FROM: Harvey E. Schock, Jr.

To The Associate Administrator Motor Vehicle Programs National Highway Safety Administration

January 18, 1973.

RE:FR Docket 73-644 Prime Glazing Material Manufacturer Codes

Gentlemen:

I would appreciate information on the requirements and procedures for the certifying that glazing materials conform to Motor Vehicle Safety Standard No 205 "Glazing Materials"

I would appreciate a copy of the Standard and any additional information on this subject.

Thank you for your cooperation.

ID: nht73-1.46

DATE: 04/26/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Young Windows, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 27, 1973, requesting information on requirements for marking glazing materials for use in motor vehicles, and whether you must finish cleaning instructions for glazing you manufacture.

Your questions regarding marking requirements are similar to those raised by Mrs. Lewis Cook of your company, in a letter of February 20, 1973. We responded to that letter on April 4, 1973 (a copy is enclosed), and you should have received our response by this time. In that letter we stated that your responsibilities as a manufacturer who cuts glazing materials are to mark that material in conformity with section 6 of ANS Z26.1-1966. We should amplify our response in that letter by stating that if the glazing material as you receive it already contains the required markings, you may use those markings in meeting the requirements.

You indicate your question concerning requirements for cleaning instructions arises from a customer to whom you furnished Rohm and Haas Plexiglas. Paragraph S5.2.1.3 of Standard No. 205 provides that glazing materials designated AS-12 or AS-13 must be labeled (using a label that is removable by hand) with cleaning instructions. If the Rohm and Haas Plexiglas is of either of these glazing designations, it must be so labeled. If it is not, there are no requirements that cleaning instructions be furnished.

Yours truly,

Enclosure

March 27, 1973

Office of Chief Counsel National Highway Traffic Safety Administration

Dear Sirs:

We at Young Windows, Inc. are in the business of manufacturing custom windows for the transportation industry. Recently a few questions were raised that have sent me seeking the correct answers.

My questions concern certification of certain glazing materials we presently use in our windows. Before I go any farther, let me explain that we do not manufacture windshields for the automotive industry but rather windows for campers earthmoving equipment, marine windows, and some rear windows for the truck industry. Therefore, what type of certification is needed concerning Federal Standard Number 205 of the Safety Code. I have heard a label is needed on the window, a label could be placed on the outside of the box, or a tag,(Illegible Word) that the glass in the windows meets Standard 205. Since our glass comes in stenciled with all necessary markings, would this be sufficient? If not, what would we be required to do to meet and conform to Standard #205?

Another question has been brought to our attention by one of our customers. We recently shipped 360 windows to a manufacturer of food serving and ice cream vending trucks. We supplied the sliding serving window. Per customer request, we supplied the windows using Rohm and Haas Plexiglas. The material was branded with all the necessary marking. Our customer has now come back and ask for cleaning instructions on the Plexiglas. Are we required by any Federal Standard to supply cleaning instructions with these windows?

I would appreciate your kind and prompt reply, as we want to conform to all standards without delay.

Regards,

Yours truly,

YOUNG WINDOWS, INC.

Charles E. Smith,

Purchasing Manager

ID: nht73-1.47

DATE: 03/09/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Recreational Vehicle Institute, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of January 31, 1973, requesting several interpretations of Motor Vehicle Safety Standard No. 205, "Glazing Materials", as it applies to motor homes and campers.

We find the interpretations as to the use of item 3 glazing contained in your letter to be correct. Your interpretation of "levels not requisite for driving visibility" as meaning that other windows are available and more suited for driving visibility is reasonable, and acceptable for purposes of Standard No. 205.

We also find your interpretations on the use of items 4, 5, 8, and 9 glazing materials to be correct. We do not agree, however, with your suggestion of allowing items 5 and 9 glazing to be used in camper windows adjacent to the truck cab rear window without regard to driving visibility. We agree it is unlikely with respect to most vehicles that such windows will be requisite for driving visibility, and will accept a good-faith, reasonable judgment decision on the question by a camper manufacturer. Consequently we do not believe that the remaining "degree of uncertainty" will result in compliance problems for camper manufacturers.

Your conclusions regarding the application of items 6 and 7 glazing are correct. We do not agree, however, that it is necessary or desirable to use such materials in any forward-facing windows, including those adjacent to the rear window of the truck cab. We believe the possibility of impact into these windows precludes the safe use in them of these glazing items, and item 13 glazing as well.

Your conclusions regarding the application of item 12 and item 13 glazing are correct. We appreciate your pointing out the lack of continuity in subparagraph designations for items 6, 7, 8, and 9. This was unintentional on our part, and your conclusion that the added subparagraphs should be read as following immediately those existing, regardless of letter designation, is correct. Finally, you are correct in your conclusion that the amendments to Standard No. 205 should be seen as overriding the headings for the various glazing items in the ANS Z26 standard.

Yours truly,

January 31, 1973

Lawrence R. Schneider--

Chief Counsel,

National Highway Traffic Safety Administration

U.S. Department of Transportation

Dear Larry:

This letter seeks your confirmation of our interpretation of certain aspects of Standard No. 205, as amended on June 21, 1972 and November 11, 1972, or your advice as to proper interpretation if we are incorrect.

The language of the cited amendments leaves as a qualification on the use of various item of glazing materials the phrase "at levels not requisite for driving visibility" or a similar qualification slightly varied depending upon the item of glazing involved. Insofar as we are aware, there has not been an interpretation of this qualification and we have had member inquiries on its application to certain windows of our units. Our subsequent comments will refer to the questionable items of glazing as they are listed in ANSI Z.26.

Item 3. Paragraph S5.1.1.5 of the November 11 amendment prescribes that motor homes, as multipurpose passenger vehicles, will be treated as trucks where not otherwise specifically provided for in the standard. Thus we conclude that:

(1) Item 3 cannot be usedfor windows to the immediate right or left of the driver of a motor home unless such windows are at levels not requisite for driving visibility which we would take to mean windows not required for visibility to the right and left of the driver because other windows are available and more suited for that purpose.

(2) The rear window of a motor home, where so equipped, may utilize Item 3 where it is not in fact used for or designed for driving visibility because of the impracticability for doing so and where outside side view mirrors are provided in accordance with Standard No. 111. In this connection, we have reference also to the opinion by Mr. Francis Armstrong of April 16, 1971, advising that rearview mirrors are not required in motor homes of configurations which obstruct the view to the rear to such an extent it could not meet the requirements of the Standard No. 111; and the interpretation incorporated with Standard No. 111.

Items 4, 5, 8, 9:

(a) These items cannot be usedin windshields or windows of motor homes to the immediate rigth or left of the driver.

(b) These items can be usedIn all other windows and doors of motor homes including over-the-cab forward-facing windows in those configurations which have space over the vehicle cab and a forward-facing window therein; and including those relatively few configurations where there may be a window in the motor home and/or a window in the cab just behind the driving compartment. Some few configurations may use a truck chassis and cab without a passageway directly from the driving compartment into the living quarters.

(c) These items can be used in all windows and doors of slide-in-campers and pickup covers, including any over-the-cab forward-facing window and any window in the slide-in-camper or pickup cover immediately behind the driving compartment.

In connection with both (b) and (c) above, we note that Items 5 and 9 carry the qualification of use only "at levels not requisite for driving visibility". Items 4 and 8 are not so limited. Over-the-cab forward-facing windows in motor homes, slide-in-campers and pickup covers (these units are unlikely to have such windows) clearly are not at levels requisite for driving visibility. Windows in the slide-in-camper or pickup cover just behind the driving compartment of the pickup truck on which such units are temporarily mounted are not generally used for driving visibility since pickup trucks customarily carry outside side-view mirrors to provide requisite rearview capability in the light of their property carrying function when used separately from a slide-in-camper or pickup cover. Although pickup trucks are not required by a current standard to have side-view mirrors, it seems appropriate and consistent with the actual practice to recognize that, in fact, they do and thus the windows described are not "requisite to driving visibility", rather than leave a degree of uncertainty on the part of the manufacturer of slide-in-campers and pickup covers as to whether Items 5 and 9 can be used in such windows.

The conclusion with respect to motor homes is predicated on the same reasoning as applied under Item 3 above. These conclusions also seem consistent with the opinion rendered to Mr. Robert T. Sanders on July 5, 1972 by Mr. Dyson.

Items 6 and 7:

These items cannot be usedin windshields, forward-facing windows (including over-the-cab forward-facing windows), and windows to the immediate right or left of the driver in motor homes; similarly, they cannot be usedin forward-facing windows, including over-the-cab forward-facing windows of slide-in-campers and pickup covers.

We note that Item 6 is not limited by the qualification that the locations not be requisite for driving visibility but Item 7 is so qualified. For the same practical reasons as set forth in regard to Items 4, 5, 8 and 9, above, we would conclude that the small windows in slide-in-campers, pickup covers, and a few configurations of motor homes just behind the driving compartment of the pickup truck can use Items 6 and 7, except for the fact they are "forward-facing" in the directional sense; neither item requires compliance with a test related to penetration resistance; and the cited opinion of July 5, 1972 by Mr. Dyson. RVI still feels that safety does not require penetration resistance characteristics in these behind-the-cab windows and requests your reconsideration as to whether such windows must be considered as "forward-facing" windows in connection with the possible use of Items 6 and 7 in such behind-the-cab windows.

Items 12 and 13, Rigid and Flexible Plastics:

Both of these items, as authorized by the amendment of June 21, 1972 contain the limitation of use only at "specific locations at levels not requisite to driving visibility". Based on the reasoning and opinions above cited, we conclude that:

(1) Item 12 can be usedin over-the-cab forward-facing windows of motor homes, slide-in-campers, and pickup covers, and in all such units in the windows behind the cabs of motor homes which have such configurations and behind the cabs of pickup trucks on which slide-in-campers and pickup covers are mounted.

(2) Item 13 cannot be usedin over-the cab forward-facing windows of such units including windows behind cabs. However, for the same reasons as expressed in connection with Items 6 and 7, we request your reconsideration as to whether such behind the cab windows must be considered "forward-facing" windows.

Other matters of interpretation:

(1) We note that, in the process of the amendment of November 1, 1972, subparagraphs "j" and "k" were added to Items 6, 7, 8 and 9 of ANSI - Z.26 although the subparagraphs in those items do not go beyond "(d)", "(c)", "(e)" and "(c)", respectively. We interpret the amendments as adding paragraphs falling immediately after the numbering of the appropriate subparagraph.

(2) We note that the headings in the same items are generally descriptive of other units than motor homes, slide-in-campers, and pickup covers. We interpret the amendments as overriding the headings and as controlling in the case of these recreational units.

Very truly yours,

David J. Humphreys --

RVI Washington Counsel

ID: nht73-1.48

DATE: 11/08/73

FROM: JOHN G. WOMACK FOR RICHARD B. DYSON

TO: American Safety Equipment Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of October 5, 1973, concerning your proposed use of a tension reliever device in a seat belt retractor. As we understand the concept of the tension reliever, it allows a small amount of slack to be introduced into the webbing by a mechanism roughly similar to that of a window shade. If the webbing is pulled smoothly back and forth, the retractor exerts a normal retractive force. If, however, the retraction is halted at a certain point, as when the belt comes to rest against an occupant's shoulder, the reliever engages and the occupant is relieved of the active pull of the retractor until he moves forward by an inch or two and disengages the reliever.

Your initial question is whether a reliever-equipped retractor will be considered to meet the retraction force requirements of S4.3(j) (6) of Motor Vehicle Safety Standard No. 209. You state that it will meet the test so long as the procedures of S5.2(j) are strictly observed and no oscillations are introduced by the test apparatus. If the facts are as you state, it is our opinion that the retractor would meet. S4.3(j) (6).

Your other question, as clarified by telephone on November 1, 1973, is whether we have reservations about the concept of a tension reliever that would lead us to bar its use through amendment of Standard No. 209. Based on the information presently available, we have no such reservations.

ID: nht73-1.49

DATE: 08/30/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Physicians for Automotive Safety

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 12, 1973, concerning children's car harnesses and car seats.

In response to your inquiry about the "Auto-babe" car harness, it is our opinion that the harness is a Type III seat belt assembly under Standard No. 209 and we presently are investigating the product as an apparent noncompliance with the standard.

The next stage in the rulemaking on child restraints will be reached this fall with a notice of proposed rulemaking on dynamic test requirements. We will be interested to have your comments on this proposal when it is issued.

Yours truly,

PHYSICIANS FOR AUTOMOTIVE SAFETY

July 12, 1973

James Wilson -- Acting Administrator, NHTSA, U.S. Dept. of Transportation

Dear Mr. Wilson:

I am enclosing a brochure describing a child auto harness, and would very much like to know 1. does the device meet requirements of Standard 209, Type II, and 2. if not, what action will be taken to prevent manufacture of the device and recall of those still in the stores.

I should also like to receive information with respect to the date a proposal for the upgrading of Standard 213 can be expected.

Your help in this matter would be very much appreciated.

Sincerely,

Seymour Charles, M.D.

President

Enclosure

(Graphics omitted)

ID: nht73-1.5

DATE: 02/22/73

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

TO: Toyo Kogyo Co., Ltd. USA Rep. Ofc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of February 8, 1973 concerning the operating point of a hand-operating parking system (Standard No. 105a).

We intend to specify an operating point in the response to petitions for reconsideration of Standard No. 105a. This notice should be published not later than May 1, 1973.

Yours truly,

Richard B Dyson -- Assistant Chief Councel, National Highway Traffic Safety Administrator U.S. Government of Transportation

Dear Mr. Dyson

Re; Operating Point of Hand Parking System

Would you inform us your opinion regarded with 90 lb force applied to hand-operated parking system in MVSS 105A Docket No. 70-27 Notice 5 Section 5.2.

In this regulation we cannot find the operating point.

We would like to consider it on the middle finger in following figure.

Your kind reply will be high appreciated,

Sincerely yours,

ID: nht73-1.50

DATE: 08/20/73

FROM: Richard B. Dyson; NHTSA

TO: Takata Kojyo Company, Ltd.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 31, 1973, concerning the meaning of the term "75 percent extension" as used in S5.2(j) of Motor Vehicle Safety Standard No. 209.

The 75 percent extension point used in 85.2(j) is intended to represent the belt's extension during its use in a vehicle. The measurement of extension is therefore begun with the webbing retracted as fully as the design of hardware and the size of the retractor permit. It may be that when the belt is retracted to this point a considerable amount of webbing remains outside the retractor, as shown in Figure 2 of your letter. The measurement of extension nonetheless begins at this point, so that "75 percent extension" is 75 percent of the incremental webbing length between this point and the point of fullest extension.

To refer to the figures accompanying your letter, the measurement technique shown in Figure 2 is correct. That shown in Figure 1, which is based on 75 percent of the total length of the belt, is incorrect.

ID: nht73-1.6

DATE: 09/11/73

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

TO: Volkswagen of America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of August 8, 1973, to Mr. Schneider asking for confirmation of your interpretation of two sections of Standard No. 105a.

You ask first whether S5.3.1 requires that the activation of an indicator lamp upon application of 50 pounds of force be instantaneous, or whether a minimal time lag is permissible. You indicate that in a "panic stop" there is a time lag of approximately 100 milliseconds between application of 50 pounds of force and lamp activities in the VW system. Since, as you state, it is "humanly impossible" to discern such a minimal time lag, we consider that the VW system complies with S5.3.1, and that the lamp is activated upon application of 50 pounds of force.

You are also correct in your interpretation of S5.2.1 that the 5-minute requirement applies only to vehicles that do not exceed the limit of traction on a 30 percent grade.

Sincerely,

VOLKSWAGEN OF AMERICA, INC.

August 8, 1973

Lawrence R. Schneider -- Chief Counsel, National Highway Traffic Safety Administration

Dear Mr. Schneider:

This letter is a request for interpretation of certain language in S5.3.1 and S5.2.1 of FMVSS 105a, Hydraulic Brake Systems.

In regard to this matter a meeting was held on August 6, 1973 with personnel of the NHTSA and Volkswagen representatives. In attendance were Messrs. Taylor Vincent, E. Driver, C. Baker and V. Bloom of the NHTSA, and Messrs. G. Riechel, J. Kennebeck and K.H. Ziwica of Volkswagen of America.

1. S5.3.1 provides that "an indicator lamp shall be activated when the ignition (start) switch is in the "on" (run) position and whenever any of the following conditions occur: (a) a pressure failure in any part of the service brake system, other than a structural failure of a housing that is common to two or more subsystems, before or upon application of either (1) . . . or (2) 50 pounds of control force upon a fully manual service brake".

In the above mentioned meeting with the NHTSA, VW representatives described the conditions under which the brake failure system used by Volkswagen actuates if a failure in one of the subsystems has occurred. By using a normal or slow force application rate as shown in example "d" of attachment I, the failure indicator lamp will be activated before 50 pounds of control force are reached. By using a very fast application rate as shown in example "b" of attachment I, the indicator lamp will be activated with a certain time lag from the point where 50 pounds are reached. This characteristic is further illustrated in attachment II containing test data of a very slow control force application, and in attachment III for a panic brake force application.

In the discussion with the NHTSA representatives there was agreement that in regard to a fast control force application the wording in S5.3.1(a) "upon application of 50 pounds" does not mean that the failure indicator light must be activated instantaneously if a 50 pound control force is reached, but rather a certain time lag would be permissible before the warning light illuminates. For the panic brake situation, a time lag of approximately 100 ms, after 50 pounds control force are reached, was considered reasonable.

Based on the above mentioned discussion, we would appreciate it if you would provide us with written confirmation indicating that with a fast control force application the wording "upon application of 50 pounds" in S5.3.1(a) does not prohibit a reasonable time lag before the failure indicator lamp is activated. We want to emphasize that this interpretation would not detract from the safety intent of the requirement for failure indicators, as it is humanly impossible to discern such a minimal time lag.

2. According to S5.2.1, a parking brake system of a passenger car "shall be capable of holding the vehicle stationary (to the limit of traction of the braked wheels) for five minutes".

It is our understanding from the aforementioned discussion with the NHTSA personnel that the five minute requirement only applies to a vehicle which is able to be kept stationary by its parking brake at 30% inclination. A vehicle which slides down the 30% inclination with wheels locked by the parking brake is not required to meet the five minute requirement.

We also would appreciate receiving your written confirmation to this interpretation of S5.2.1 of FMVSS 105a.

Thank you for your cooperation in this matter.

Sincerely,

J.W. Kennebeck --

Manager,

Safety and Development

(Graphics omitted)

Attachment B

Broke Pedal applied very fast failure induced in rear circuit

ID: nht73-1.7

DATE: 09/14/73

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

TO: U.S. Technical Research Corp.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 24, 1973, asking for an interpretation of several aspects of Standard No. 105a.

You have asked the following questions

"1. Paragraph S.5.1.2. 'Partial failure.'

It is required that '. . . the remaining portion(s) of the service brake system shall continue to operate . . .' What is the exact meaning of 'continue to operate'? Does it mean that the remaining portion of the brake system must be permanently fed or does it mean that it is required to have temporary braking with the operative portion reserve capability? In this latter case, how many brake applications are required?"

"Continue to operate" means that the portion of the brake system that has not failed continues to operate indefinitely, i.e., to the point that it wears out or until a second failure occurs in the brake system. It requires a permanent feed and does not depend upon the reserve capability of operative portion of system.

"2. Paragraph S.5.1.3.3 'Brake power units':

What exactly constitutes the power source? On the Citroen D and S models, the front brake circuit is fed by the pressure prevailing in the rear suspension. The brake accumulator and the rear suspension are fed from the high pressure source (which includes an HP pump, a pressure regulator and a main accumulator) . . . What is meant by 'inoperative brake power unit'? Does that mean that the high pressure pump only is inoperative or also the other components of the power source (main accumulator and regulator)?. . . What is meant by 'when the inoperative unit is depleted of all reserve capability' (paragraph S.5.1.3.3.(ii))? Are we correct in assuming that it means that only the main accumulator is depleted of reserve capability? (It is obvious that if one considers that not only the main accumulator, but also the brake accumulator and the rear suspension are depleted, no braking is possible)."

The power source consists of pumps, accumulators and/or back up systems such as a separate electric or hydraulic pumps, etc. A primary power source would be the pump, while the accumulators would constitute a secondary source and would be the portions used in optional test. A high pressure source would include the pump, regulator and, in Citroen's case, the main accumulator.

"Inoperative brake power unit" could mean that the (1) main pump is out, but the accumulators are functioning, (2) the main pump is operating, but only one brake accumulator is operating, (3) the pump and brake accumulator are operating, but the suspension accumulator is out, (4) the pump or accumulator is out, and the system is operating on reserve or backup pump. This list is meant to be illustrative rather than exhaustive.

"When the inoperative unit is depleted of all reserve capability" means that one of the units (pump, accumulator, etc.) is completely non-functional, e.g., the pump has failed, the accumulator has failed, the check valve has failed, etc.

"3. Paragraph S.7.10.2 'Optional procedures'

We believe that subparagraph 'b' (vehicles with brake power unit) applies to our vehicles.

The test procedure mentioned in paragraph S.7.10.2(a) cannot be applied to our vehicles since, if the system is depleted of 'any residual brake power reserve capability', it is obvious that no braking is possible. We believe that the power source only should be depleted of any residual reserve (HP pump inoperative, main accumulator depleted), but not the entire brake system. Since, by definition, a 'brake power unit' is a unit where the operator action consists 'only of modulating the energy application level,' but not of supplying energy to the system, it is obvious that no braking is possible if all internal residual energy left in the brake system is depleted (since, in this case, there would be no energy available for braking from either the HP source, the driver or the system).

S7.10.2(b) does apply to Citroen. Your comments on S7.10.2(a) are correct.

Yours truly,

July 24, 1973

National Highway Traffic Safety Administration

Attention: Chief Counsel

Gentlemen:

In relation to Motor Vehicle Safety Standard No. 105a "Hydraulic Brake System", as published in the Federal Register vol. 38 No. 96 of May 18, 1973, we would like clarification of the following points.

1. Paragraph S.5.1.2 "Partial failure."

It is required that ". . . the remaining portion(s) of the service brake system shall continue to operate . . ." What is the exact meaning of "continue to operate"? Does it mean that the remaining portion of the brake system must be permanently fed or does it mean that it is required to have temporary braking with the operative portion reserve capability? In this latter case, how many brake applications are required?

2. Paragraph S.5.1.3.3 "Brake power units":

- What exactly constitutes the power source? On the Citroen D and S models, the front brake circuit is fed by a brake accumulator while the rear brake circuit is fed by the pressure prevailing in the rear suspension. The brake accumulator and the rear suspension are fed from the high pressure source (which includes an HP pump, a pressure regulator and a main accumulator). (see enclosed sketches)

We understand that the high pressure source is constituted by the HP pump, the pressure regulator and the main accumulator only. Are we correct?

- What is it meant by "inoperative brake power unit"? Does that mean that the high pressure pump only is inoperative or also the other components of the power source (main accumulator and regulator)?

We believe it should be considered that several failures cannot simultaneously happen to the same system. (as it is considered in equivalent European regulations).

- What is it meant by "when the inoperative unit is depleted of all reserve capability" (paragraph S.5.1.3.3.(ii))? Are we correct in assuming that it means that only the main accumulator is depleted of reserve capability? (It is obvious that if one considers that not only the main accumulator, but also the brake accumulator and the rear suspension are depleted, no braking is possible).

3. Paragraph S.7.10.2 "Optional procedures"

We believe that subparagraph "b" (vehicles with brake power unit) applies to our vehicles.

The test procedure mentioned in paragraph S.7.10.2(a) cannot be applied to our vehicles since, if the system is depleted of "any residual brake power reserve capability", it is obvious that no braking is possible. We believe that the power source only should be depleted of any residual reserve (HP pump inoperative, main accumulator depleted), but not the entire brake system. Since, by definition, a "brake power unit" is a unit where the operator action consists "only of modulating the energy application level," but not of supplying energy to the system, it is obvious that no braking is possible if all internal residual energy left in the brake system is depleted (since, in this case, there would be no energy available for braking from either the HP source, the driver or the system.)

We remain, of course, at your disposal should you need more information on the operation of our braking system, and, awaiting your answer, we are,

Very truly yours,

By Bernard Belier -- U.S. Resident Engineer for CITROEN S.A.

Enclosures: 1 print "Citroen SM braking"; 1 sketch "Citroen high pressure source"; 1 sketch "Citroen brake system"; 1 sketch "Suspension"; 1 plate No. 21 "Citroen brake accumulator"

ID: nht73-1.8

DATE: 08/20/73

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

TO: Renault, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of August 1, 1973, asking for clarification of S5.2.1 and S6.9 of Standard No. 105a.

You interpret the parking brake test as allowing "the vehicle to slide down the 30% incline (because of its weight) as long as the wheels remain locked". The parking brake must hold the vehicle on a 30% grade for 5 minutes. If vehicle weight distribution is such that the limit of traction is exceeded and the vehicle slides down the incline, no noncompliance would be indicated unless the parking brake failed to lock the wheels.

No skid number is specified for the "clean, dry, smooth, portland cement concrete" incline surface specified in S6.9.

Yours truly,

August 1, 1973

Lawrence R. Schneider -- Chief Counsel, Nat. Highway Traffic Safety Admins.

SUBJECT: FMVSS 105a - Docket 70-27, Notice 8

Dear Mr. Schneider:

Regie Nationale des Usines Renault would like to request a clarification regarding section S.5.2.1. and S.5.2.2.1 of the above Docket.

It is our understanding that in order for the parking brake to comply with these paragraphs, the wheels of the vehicle must remain locked, but the vehicle may slide down the 30% incline (because of its weight) as long as the wheels remain locked.

We would appreciate receiving a written confirmation of our interpretation.

In addition, we would appreciate the NHTSA informing us of the skid number of the "clean, dry, smooth, Portland cement concrete" referred to in paragraph S.6.9.

Thank you for your cooperation and consideration.

Very truly yours,

RENAULTINC --[Illegible Words] for Francois Louis, Manager, Technical Standards Dept.