NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: nht74-1.20OpenDATE: 07/23/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Toyo Rubber Industry Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This responds to your July 8, 1974, question whether publication of a brochure that lists the rims that may be used with the tires produced by Toyo Tire Corporation would meet the requirements of S5.1 of Standard No. 119, New pneumatic tires for vehicles other than passenger cars. Publication of such a brochure would meet the requirement of S5.1 so long as the tires are listed in accordance with S5.1(a), that is by manufacturer name or brand name, followed by a listing of rims that may be used with each tire listed. The brochure would have to be supplied to dealers of the manufacturer's tires, to any person upon request, and in duplicate to: Tire Division, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590. Yours truly, ATTACH. National Highway Traffic Safety Administration -- Docket Section SUBJECT: Federal Motor Vehicle Safety Standard No. 119, S5 Tire and Rim Matching Information Dear Sir: FMVSS No. 119 is requiring as follows: S5 Tire and Rim Matching Information S5.1 Each manufacturer of tires shall ensure that a listing of the rims that may be used with each tire that he produces is provided to the public in one of the following forms: (a) Listed by manufacturer name or brand name in a document furnished to dealers of the manufacturer's tires, to any person upon request, and in duplicate to: Tire Division, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590; or (b) Contained in publications, current at the date of manufacture of the tire or any later date, of at least one of the following organizations: The Tire and Rim Association. The European Tyre and Rim Technical Organization. Japanese Industrial Standards. Deutsche Industrie Norm. The Society of Motor Manufacturers & Traders, Ltd. British Standards Institution. Scandinavian Tire and Rim Organization. In case any particular tire and rim matching information is not contained in the publications mentioned in S5.1(b), and since S5.1(a) requires the tire manufacturer to provide a document to the public, we are going to use as a document a brochure which shows the tire and rim combination to be used. We understand that such a brochure would comply with the requirement of S5.1. Please let us know your opinion as to whether our understanding is correct or not. Should our understanding be incorrect, please let us know what kind of document we must provide to the public. Your prompt reply would be greatly appreciated. Sincerely, Y. Takami -- Technical Representative, TOYO RUBBER INDUSTRY COMPANY, LTD. |
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ID: 2702yOpen Mr. William D. Rogers Dear Mr. Rogers: We have received the (unsigned) petition of SportsCar America, Inc., for a temporary exemption from Motor Vehicle Safety Standard No. 208, on grounds of substantial economic hardship, and are returning all copies to you for the reasons stated below. SportsCar America wishes to undertake the importation and sale of passenger cars produced in Brazil. Pursuant to an "Exclusive Distribution Agreement" ("the Agreement") with Alfa Metais Veiculos Ltda. of Brazil, which you enclosed, it has imported a prototype vehicle for study, with reference to its status of conformance with the U.S. vehicle safety and emission standards. The proper petitioner for this exemption is Alfa Metais Veiculos Ltda., identified in the Agreement that you attached as the "Manufacturer." Under Section l of the Agreement, SportsCar America is to return the prototype to the Manufacturer with "those modifications necessary in order to meet the emission and safety standards necessary for the importation" of the cars, and the Manufacturer will then use it as a model for the production of vehicles for sale in the United States. Under 49 CFR Part 567, the Manufacturer must also attach its certification of compliance to the completed vehicle before its shipment to the United States. Part 555 restricts petitions for temporary exemptions to Manufacturers of motor vehicles. Although you identify SportsCar America as the "distribution agent", we have no record that the Manufacturer has filed the designation of agent pursuant to 49 CFR 551.45 that is required of Manufacturers offering their products for importation and sale in the United States. Presumably Alfa Metais would wish to appoint SportsCar America as its agent. Once it has done so, SportsCar America may submit the petition on behalf of the Manufacturer. The production and financial data (in dollars, please) must be those of the Manufacturer. However, we regard as relevant to conformance arguments the efforts that SportsCar America intends to make during the time a possible exemption is in effect, as outlined in your petition. Noting your requests for confidential treatment of information, we are returning all copies of your petition, with our comments. Generally, the agency does not like to accord confidential treatment to all financial data submitted. At a minimum, it would like to include in its notice asking comments from the public a dollar amount of the cumulative net profit or loss experienced by the Manufacturer in the three years preceding the filing of the petition. Similarly, it would like to publish a dollar figure in discussing the effects of a denial of the petition on the petitioner. The purpose of this is our policy that if the public is to make an informed comment on the issue of whether compliance would cause a Manufacturer substantial economic hardship, the public should have access to much the same data as is available to the agency in its determination. If you would like clarification of any of these matters, Taylor Vinson of this Office (202-366-5263) will be happy to provide them. Sincerely,
Paul Jackson Rice Chief Counsel Enclosures ref:555 d:l0/9/90 |
1989 |
ID: 2708yOpen Mr. William D. Rogers Dear Mr. Rogers: We have received the (unsigned) petition of SportsCar America, Inc., for a temporary exemption from Motor Vehicle Safety Standard No. 208, on grounds of substantial economic hardship, and are returning all copies to you for the reasons stated below. SportsCar America wishes to undertake the importation and sale of passenger cars produced in Brazil. Pursuant to an "Exclusive Distribution Agreement" ("the Agreement") with Alfa Metais Veiculos Ltda. of Brazil, which you enclosed, it has imported a prototype vehicle for study, with reference to its status of conformance with the U.S. vehicle safety and emission standards. The proper petitioner for this exemption is Alfa Metais Veiculos Ltda., identified in the Agreement that you attached as the "Manufacturer." Under Section l of the Agreement, SportsCar America is to return the prototype to the Manufacturer with "those modifications necessary in order to meet the emission and safety standards necessary for the importation" of the cars, and the Manufacturer will then use it as a model for the production of vehicles for sale in the United States. Under 49 CFR Part 567, the Manufacturer must also attach its certification of compliance to the completed vehicle before its shipment to the United States. Part 555 restricts petitions for temporary exemptions to Manufacturers of motor vehicles. Although you identify SportsCar America as the "distribution agent", we have no record that the Manufacturer has filed the designation of agent pursuant to 49 CFR 551.45 that is required of Manufacturers offering their products for importation and sale in the United States. Presumably Alfa Metais would wish to appoint SportsCar America as its agent. Once it has done so, SportsCar America may submit the petition on behalf of the Manufacturer. The production and financial data (in dollars, please) must be those of the Manufacturer. However, we regard as relevant to conformance arguments the efforts that SportsCar America intends to make during the time a possible exemption is in effect, as outlined in your petition. Noting your requests for confidential treatment of information, we are returning all copies of your petition, with our comments. Generally, the agency does not like to accord confidential treatment to all financial data submitted. At a minimum, it would like to include in its notice asking comments from the public a dollar amount of the cumulative net profit or loss experienced by the Manufacturer in the three years preceding the filing of the petition. Similarly, it would like to publish a dollar figure in discussing the effects of a denial of the petition on the petitioner. The purpose of this is our policy that if the public is to make an informed comment on the issue of whether compliance would cause a Manufacturer substantial economic hardship, the public should have access to much the same data as is available to the agency in its determination. If you would like clarification of any of these matters, Taylor Vinson of this Office (202-366-5263) will be happy to provide them. Sincerely,
Paul Jackson Rice Chief Counsel Enclosures ref:555 d:l0/9/90 |
1989 |
ID: 7980Open Mr. Richard Horian Dear Mr. Horian: This responds to your two letters of November 6, 1992, with respect to the allowability under Federal regulations of the "Sudden Brake Indicator Hazard Light." As you describe it, "when a driver engages in hard braking, a circuit activates a separate lighting system to warn other drivers to pay special attention to a potentially hazardous situation." This system will not utilize any of the existing rear lights on a vehicle, and will consist of a single lamp or pair of lamps, either mounted separately, or in the same housing as the center high-mounted stop lamp. The system will be red or amber in color, and either steady burning or flashing. The system is activated only when a predetermined threshold of pressure is reached upon depression of the brake pedal. Supplementary lighting systems such as the one you have described are permissible as original motor vehicle equipment under Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment if they do not impair the effectiveness of the lighting systems required by the standard, or if there is no provision of the standard that affects them. Paragraph S5.4 of Standard No. 108 specifically prohibits the physical combination of the center highmounted stop lamp with any other lamp or reflective device, thus your system could not be used in a common housing with the center light (see copy of enclosed letter to Mr. S. Suzuki on this subject). However, if the system is mounted separately, under the circumstances you have presented, we do not believe that there would be any direct impairment of the required rear lights, or indirect impairment such as might be created when confusion may result upon simultaneous operation of the supplementary light and any required light. As the letter to Mr. Suzuki indicates, passenger cars manufactured before September 1, 1985, were not required to be equipped with the center lamp. This means that your light could be combined in the same housing as a center lamp intended for installation on vehicles manufactured before September 1, 1985, but it could not be part of a replacement center lamp intended for use on vehicles manufactured subsequently. In addition, with the exception just noted, installation of the system on a vehicle in use would not appear to affect the safety functioning of any safety system necessary for continued conformance of the vehicle, it would appear that your system is acceptable for sale and installation in the aftermarket as well. However, the individual States have the authority to regulate lamps for vehicles in use, and we suggest that you contact the American Association of Motor Vehicle Administrators (AAMVA) for an opinion as to whether the system is permissible under State laws. AAMVA's address is 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely,
Paul Jackson Rice Chief Counsel Enclosusre ref:108 d.12/7/92 |
1992 |
ID: nht88-2.97OpenTYPE: INTERPRETATION-NHTSA DATE: 08/11/88 EST FROM: ERIKA Z. JONES -- CHIEF COUNSEL, NHTSA TO: SCOTT A. SNYDER TITLE: NONE ATTACHMT: MEMO DATED 3-10-88 TO NHTSA FROM SCOTT A. SNYDER TEXT: This is in reply to your letter of March 10, 1988, to the Department's regional office in Philadelphia, asking for a response concerning "ornamental lighting." In your opinion "a few extra lights on the side and rear of a vehicle would help other people see you better while driving at night." The agency is interested in the role that vehicle conspicuity plays in accidents and accident avoidance. With reference to motorcycles, we have amended our motor vehicle lighting standard to prescribe performance characteristics for headlamp modulation. We were prepared to amend the standard to require the activation of motorcycle headlamps when the ignition was turned on (but did not do so when we learned that almost all motorcycles were being wired to operate in that fashion). Some time ago we aske d the public to comment on ways of increasing the conspicuity of large vehicles as our research had indicated that reflective tape applied to the side and rear of wide trucks and trailers might lessen crashes and crash severity, and our research still co ntinues in this area. Most importantly we adopted the center highmounted stop lamp for passenger cars because of the ability it demonstrated in test fleets to reduce the frequency of rear end impacts. The type of lights of which you speak are referred to as "presence" lamps (as contrasted with "signal" lamps), and the agency over the years has acted with respect to all motor vehicles by requiring them to be equipped with side marker lamps, and by incr easing the lens area for stop lamps. As the Federal safety standards are by statutory definition "minimum" safety standards, the requirement that there be two taillamps, for example, does not mean that a manufacturer may not add two more if it wishes, o r any lighting device not covered by the standard. The sole restriction is that lighting devices added by the manufacturer or dealer that are in excess of the minimum must not impair the effectiveness of the equipment required by the standard. This cou ld happen, for example, if a fog lamp (not covered by the standard) was of an intensity and located so that it masked an adjacent front turn signal. With respect to nighttime operation, the critical issue would appear to be that additional lighting devi ces not create glare to oncoming and following drivers. The owner of the vehicle is not under a similar Federal restriction, and may personally add such additional lighting devices as seems desirable, subject to the laws of the States where the vehicle is registered and/or driven. However, the owner may not have these devices installed by a motor vehicle dealer or repair business if the result is to render wholly or partially inoperative any of the vehicle's original lamps or reflectors. We appreciate your suggestion for improving motor vehicle safety. |
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ID: 2796oOpen Mr. Scott A. Snyder Dear Mr. Snyder: This is in reply to your letter of March l0, l988, to the Department's regional office in Philadelphia, asking for a response concerning "ornamental lighting." In your opinion "a few extra lights on the side and rear of a vehicle would help other people see you better while driving at night." The agency is interested in the role that vehicle conspicuity plays in accidents and accident avoidance. With reference to motorcycles, we have amended our motor vehicle lighting standard to prescribe performance characteristics for headlamp modulation. We were prepared to amend the standard to require the activation of motorcycle headlamps when the ignition was turned on (but did not do so when we learned that almost all motorcycles were being wired to operate in that fashion). Some time ago we asked the public to comment on ways of increasing the conspicuity of large vehicles as our research had indicated that reflective tape applied to the side and rear of wide trucks and trailers might lessen crashes and crash severity, and our research still continues in this area. Most importantly we adopted the center highmounted stop lamp for passenger cars because of the ability it demonstrated in test fleets to reduce the frequency of rear end impacts. The type of lights of which you speak are referred to as "presence" lamps (as contrasted with "signal" lamps), and the agency over the years has acted with respect to all motor vehicles by requiring them to be equipped with side marker lamps, and by increasing the lens area for stop lamps. As the Federal safety standards are by statutory definition "minimum" safety standards, the requirement that there be two taillamps, for example, does not mean that a manufacturer may not add two more if it wishes, or any lighting device not covered by the standard. The sole restriction is that lighting devices added by the manufacturer or dealer that are in excess of the minimum must not impair the effectiveness of the equipment required by the standard. This could happen, for example, if a fog lamp (not covered by the standard) was of an intensity and located so that it masked an adjacent front turn signal. With respect to nighttime operation, the critical issue would appear to be that additional lighting devices not create glare to oncoming and following drivers. The owner of the vehicle is not under a similar Federal restriction, and may personally add such additional lighting devices as seems desirable, subject to the laws of the States where the vehicle is registered and/or driven. However, the owner may not have these devices installed by a motor vehicle dealer or repair business if the result is to render wholly or partially inoperative any of the vehicle's original lamps or reflectors. We appreciate your suggestion for improving motor vehicle safety. Sincerely,
Erika Z. Jones Chief Counsel ref:l08 d:8/ll/88 |
1970 |
ID: 86-1.41OpenTYPE: INTERPRETATION-NHTSA DATE: 02/21/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Mr. Yoshikazu Ito TITLE: FMVSS INTERPRETATION TEXT:
Mr. Yoshikazu Ito Manager, Operations Sect. Overseas Operations Dept. Tokai Rika Co. Ltd. Oguchi-cho Aichi Pref. 480-01 JAPAN
Dear Mr. Ito:
This is in reply to your letter of November 29. 1985, to Jeffrey R. Miller, former chief counsel of this agency, with reference to the acceptability of a headlamp switch under Federal Motor Vehicle Safety Standard No. 108. According to you, "upper and lower lamps light at the same time when a driver puts on the switch for headlamp horn in a daytime with light switch OFF...."
You have asked whether the circuit complies with Standard No. 108 and any SAE standards referenced in Standard No. 108. Standard No. 108 does not specify circuit design. The "optical horn" is neither required nor prohibited by Standard No. 108 and is viewed as permissible for its use for momentary signalling purposes. This would include simultaneous activation of both upper and lower beam filaments as in your design.
I believe that this uppers your other questions as well. Sincerely,
Erika Z. Jones Chief Counsel
November 29, 1985
Mr. Jeffrey R. Miller Chief Counsel National Highway Traffic Safety Administration US Department of Transportation 400 Seventh Street. S.W. Washington. D.C. 20590 U.S.A.
Re: Head Lamp Switch Circuit
Dear Sir:
We are automotive switch manufacturer in Japan and are making prototype of a head lamp switch for our customer's new car model for U.S.A. which has a circuit by which upper and lower lamps light at the same time when a driver puts on the switch for head lamp horn in a daytime with light switch OFF (please see an attached sheet). To our experience, the circuit has never been designed for cars which are to be marketed in U.S.A.
Would you like to answer the following questions?
1. Does the above-mentioned circuit comply with requirements of FMVSS and the concerned standards (SAE?) referred in FMVSSS: 2. What provision(s) of FMVSS and the standards involve this matter? 3. What are interpretation of the FMVSS and the standards provision(s)?
We really appreciate it if you could kindly send us your answers by December 27, 1985. Your kind assistances have been useful for us all the time.
Thank you for your assistance in advance.
Faithfully yours,
TOKAI RIKA CO., LTD.
Yoshikazu Ito, Manager Technical Operations Sect. Overseas Operations Dept. |
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ID: SEMAOpenMr. Stephen B. McDonald Vice President, Government Affairs Specialty Equipment Marketing Association 1317 F Street, NW, Suite 500 Washington, DC 20004 Dear Mr. McDonald: This responds to your letter requesting clarification of our notice of interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, published in the Federal Register (70 FR 65972) on November 1, 2005. The interpretation addressed how FMVSS No. 108 applies to replacement equipment. The issues you asked about are addressed below. In our interpretation, we noted that FMVSS No. 108s current requirement for replacement equipment, set forth in paragraph S5.8.1 of the standard, reads as follows: Except as provided below, each lamp, reflective device, or item of associated equipment manufactured to replace any lamp, reflective device, or item of associated equipment on any vehicle to which this standard applies shall be designed to conform to this standard. We explained: This language is relatively straightforward. For any particular item of lighting equipment, e.g., a lamp, FMVSS No. 108 states only that if a lamp is manufactured to replace a lamp on a vehicle to which the standard applies, it must be designed to conform to the standard. It does not say anything about the replacement lamps being required to have the same type of light source as the OE lamp. Moreover, while it is true that, unlike other lamps, FMVSS No. 108 specifically regulates headlamp systems including their light sources, neither the language of S5.8.1 nor any other language in the standard requires replacement headlamps to use the same light sources as the OE headlamps. 70 FR at 65974. In your letter, you stated that you agreed with this language, but asked for clarification of the immediately following paragraph, which reads as follows: Under our revised interpretation, it is our opinion that a lamp (or other item of lighting equipment, as relevant) manufactured to replace a lamp on a vehicle to which the standard applies is permitted under S5.8.1 so long as the vehicle manufacturer could have certified the vehicle to FMVSS No. 108 using the replacement lamp instead of the lamp it actually used. To the extent the vehicle manufacturer could have certified the vehicle using the replacement lamp, instead of the lamp it actually used, we believe the replacement lamp should be viewed as being designed to conform to FMVSS No. 108. This includes, but is not limited to, replacement headlamps using different light sources than the OE headlamps. You expressed concern that this paragraph could be construed as preventing new technologies from being used as replacement equipment, even though such equipment was in compliance with FMVSS No. 108. You stated, as an example, that if a technology could not have been certified in a new vehicle prior to 2005 because the technology was not yet developed, but was available in 2005, an unreasonably strict reading could limit the technology for use only in 2005 model year and subsequent model year vehicles. We confirm that the language was not intended to be so narrowly applied so as to prevent new technologies from being used as replacement equipment on earlier model year vehicles. With reference to your example, to the extent the manufacturer of the pre-2005 model year vehicle could have certified the vehicle using the later replacement lamp incorporating the new technology (had that technology been available at the time of vehicle manufacture), instead of the lamp it actually used, we believe the replacement lamp should be viewed as being designed to conform to FMVSS No. 108. You also asked to confirm that while the paragraph only references the vehicle manufacturer, it is not intended to exclude other segments of the industry that could have certified the vehicles lighting system using a replacement lamp. You stated that this could include a lighting manufacturer, dealer or alterer. As discussed below, for the sentence at issue, we agree that alterers (persons who make changes to vehicles prior to first sale) would be included along with vehicle manufacturers. However, lighting manufacturers and dealers would not be included unless they were also alterers. As indicated above, in the sentence at issue, we stated that it is our opinion that a lamp (or other item of lighting equipment, as relevant) manufactured to replace a lamp on a vehicle to which the standard applies is permitted under S5.8.1 so long as the vehicle manufacturer could have certified the vehicle to FMVSS No. 108 using the replacement lamp instead of the lamp it actually used. We referenced vehicle manufacturer because it is the vehicle manufacturer, rather than the equipment manufacturer, that is responsible for certifying new vehicles to FMVSS No. 108. The only entities other than vehicle manufacturers that could be certifying new vehicles to FMVSS No. 108 would be alterers. Under our regulations, alterers are persons who make changes to certified motor vehicles prior to first retail sale. Part 567.7, Requirements For Persons Who Alter Certified Vehicles, requires alterers to certify that the vehicle, as altered, complies with all applicable safety standards affected by the alteration. Since alterers may be certifying a new vehicle to FMVSS No. 108, it would be correct to reference them along with vehicle manufacturers in the above-quoted sentence. However, it would not be correct to include any entities that would not be certifying a new vehicle to FMVSS No. 108. Therefore, lighting manufacturers and dealers would not be included unless they were also alterers. I hope this information is helpful. If you have any further questions, please feel free to contact Edward Glancy of my staff at (202) 366-2992. Sincerely, Anthony M. Cooke Chief Counsel ref:108 d.8/24/06 |
2006 |
ID: 2658oOpen Mr. Gary W. Rossow Dear Mr. Rossow: This responds to your letter requesting an interpretation of Standard No. l2l, Air Brake Systems. You asked whether a proposed design would meet the requirements of S5.l.2. Your question is responded to below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its motor vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter. Under section S5.l.2, trucks and buses are required to have the following equipment: "Reservoirs. One or more service reservoir systems, from which air is delivered to the brake chambers, and either an automatic condensate drain valve for each service reservoir or a supply reservoir between the service reservoir system and the source of air pressure. You stated that some of your existing air braked trucks utilize a supply reservoir or wet tank between the service reservoir system and the air compressor without using automatic condensate drain valves on the service reservoirs. You noted that the supply reservoir functions as a means of removing excess water vapor from the air supply to avoid water contamination of the braking system and works on thermodynamic principles whereby water condenses to a liquid as the hot compressed air cools. Your proposed design would utilize an air dryer between the service reservoir system and the air compressor. According to your letter, the air dryer serves the same function as the supply reservoir in your existing system but works on a different principle. You stated that the moist, compressed air passes through a filter media contained in a small canister sized reservoir. The material, a desiccant, has a high chemical affinity for water. The water absorbs on the desiccant and is later purged by stored dry air. The air dryer would have an integral automatic condensate drain valve. Since your proposed design would not include an automatic condensate drain valve for each service reservoir, the issue raised by your letter is whether it complies with S5.l.2's option for "a supply reservoir between the service reservoir system and the source of air pressure." You stated that you believe the air dryer with automatic condensate drain is the functional equivalent of the more generally accepted embodiment of a supply reservoir in the context of S5.l.2. You also noted that Standard No. l2l does not specify a separate volume for the supply reservoir, although it does require in S5.l.2.l that the combined volume of all service reservoirs and supply reservoirs be at least l2 times the total service brake chamber volume. You suggested that if the volume of the service reservoirs is l2 times the volume of the service brake chambers, it would appear that there is no requirement for a specific volume in the supply reservoir. While Standard No. l2l does not include a definition for "supply reservoir," the term is one that is commonly understood. For example, you indicated in your letter that some of your current brake system designs utilize the "more generally accepted embodiment of a supply reservoir." In considering whether a particular item of equipment can be considered a "supply reservoir," we believe that effect must be given to both "supply" and "reservoir." The dictionary defines "reservoir" as "a receptacle or chamber for holding a liquid or fluid, as oil or gas." The word "supply" is defined as "to furnish or provide." Random House Dictionary of the English Language (unabridged edition). The Society of Automotive Engineers (SAE) defines "air reservoir" as "(a) storage container for compressed air." SAE Recommended Practice J656g, "Automotive Brake Definitions and Nomenclature." Thus, in order to qualify as a "supply reservoir," an item of equipment must hold or store air in order to furnish or provide the air to the rest of the brake system. The information provided with your letter does not provide sufficient information to determine whether your air dryer qualifies as a "supply reservoir." In particular, the information does not indicate whether the air dryer holds other than a de minimis amount of air. While your letter is correct that there is no requirement for a specific volume in the supply reservoir if the volume of the service reservoirs is l2 times the volume of the service brake chambers, an air dryer with a de minimis volume could not be considered to hold or store air in order to furnish or provide the air to the rest of the brake system. On the other hand, if a supply reservoir provides an air cleaning function as well as holding or storing air in order to furnish or provide the air to the rest of the brake system, it would still be a supply reservoir. Sincerely,
Erika Z. Jones Chief Counsel / NCC-20:EGlancy:mar:2/2/88:Wang l959o:62992:OCC 926 CONCURRENCE: NRM-0l, NEF-0l cc: NRM-0l, NEF-0l Redbook, Std. l2l Interps, Std. l2l |
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ID: 2672oOpen Mr. Gary W. Rossow Dear Mr. Rossow: This responds to your letter requesting an interpretation of Standard No. l2l, Air Brake Systems. You asked whether a proposed design would meet the requirements of S5.l.2. Your question is responded to below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its motor vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter. Under section S5.l.2, trucks and buses are required to have the following equipment: "Reservoirs. One or more service reservoir systems, from which air is delivered to the brake chambers, and either an automatic condensate drain valve for each service reservoir or a supply reservoir between the service reservoir system and the source of air pressure. You stated that some of your existing air braked trucks utilize a supply reservoir or wet tank between the service reservoir system and the air compressor without using automatic condensate drain valves on the service reservoirs. You noted that the supply reservoir functions as a means of removing excess water vapor from the air supply to avoid water contamination of the braking system and works on thermodynamic principles whereby water condenses to a liquid as the hot compressed air cools. Your proposed design would utilize an air dryer between the service reservoir system and the air compressor. According to your letter, the air dryer serves the same function as the supply reservoir in your existing system but works on a different principle. You stated that the moist, compressed air passes through a filter media contained in a small canister sized reservoir. The material, a desiccant, has a high chemical affinity for water. The water absorbs on the desiccant and is later purged by stored dry air. The air dryer would have an integral automatic condensate drain valve. Since your proposed design would not include an automatic condensate drain valve for each service reservoir, the issue raised by your letter is whether it complies with S5.l.2's option for "a supply reservoir between the service reservoir system and the source of air pressure." You stated that you believe the air dryer with automatic condensate drain is the functional equivalent of the more generally accepted embodiment of a supply reservoir in the context of S5.l.2. You also noted that Standard No. l2l does not specify a separate volume for the supply reservoir, although it does require in S5.l.2.l that the combined volume of all service reservoirs and supply reservoirs be at least l2 times the total service brake chamber volume. You suggested that if the volume of the service reservoirs is l2 times the volume of the service brake chambers, it would appear that there is no requirement for a specific volume in the supply reservoir. While Standard No. l2l does not include a definition for "supply reservoir," the term is one that is commonly understood. For example, you indicated in your letter that some of your current brake system designs utilize the "more generally accepted embodiment of a supply reservoir." In considering whether a particular item of equipment can be considered a "supply reservoir," we believe that effect must be given to both "supply" and "reservoir." The dictionary defines "reservoir" as "a receptacle or chamber for holding a liquid or fluid, as oil or gas." The word "supply" is defined as "to furnish or provide." Random House Dictionary of the English Language (unabridged edition). The Society of Automotive Engineers (SAE) defines "air reservoir" as "(a) storage container for compressed air." SAE Recommended Practice J656g, "Automotive Brake Definitions and Nomenclature." Thus, in order to qualify as a "supply reservoir," an item of equipment must hold or store air in order to furnish or provide the air to the rest of the brake system. The information provided with your letter does not provide sufficient information to determine whether your air dryer qualifies as a "supply reservoir." In particular, the information does not indicate whether the air dryer holds other than a de minimis amount of air. While your letter is correct that there is no requirement for a specific volume in the supply reservoir if the volume of the service reservoirs is l2 times the volume of the service brake chambers, an air dryer with a de minimis volume could not be considered to hold or store air in order to furnish or provide the air to the rest of the brake system. On the other hand, if a supply reservoir provides an air cleaning function as well as holding or storing air in order to furnish or provide the air to the rest of the brake system, it would still be a supply reservoir. Sincerely,
Erika Z. Jones Chief Counsel ref:121 d:2/18/88 |
1988 |
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