Interpretation ID: aiam0789
Manager
Emissions
Safety & Development
Volkswagen of America
Inc.
Englewood Cliffs
NJ
07632;
Dear Mr. Kreuger: This is in response to your letter of March 21, 1972, petitioning t amend Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' Your petition both requests that amendments be made to the standard, and comments on the notice of proposed rulemaking published May 26, 1971 (36 F.R. 9565). For the reasons indicated below, your petition is hereby denied.; You petition that the 4- inch-per-minute burn rate specified in th standard be changed to 12- inches-per-minute. Your argument is that a 4-inch-per-minute rate is unreasonable because variations in the burn rates of materials make it impossible, without averaging test results, to guarantee a 4-inch-per- minute rate for the majority of materials used in vehicle interiors. You suggest that a 12-inch-per-minute rate is reasonable because only 1.2 inches of material would burn in 6 seconds, the time you specify as necessary for a vehicle to be stopped from 70 mph, and maintain that a 12- inch-per-minute rate should at least be specified until the NHTSA compiles a list of approved fire retardant additives.; Your request to change the 4- inch-per-minute burn rate to one of 1 inches is denied. The 4-inch-per- minute rate was incorporated into the standard as a result of the agency's determination that it provides a flammability rate sufficiently low to provide adequate escape time from a vehicle, in the event fire should occur. In addition, the combustion by-products of some vehicle interior materials are such that the materials must burn at a rate that is low enough that vehicle occupants will not be overcome or panicked by harmful gases before they can escape from the vehicle. We believe that a 4-inch- per-minute burn rate is necessary to respond to this need. With respect to the justification you provide for a 12-inch-per-minute burn rate, the NHTSA does not agree that this test reflects adequate escape time. Testing at the University of Oklahoma has indicated, rather, that escape times that are needed exceed considerably the time needed to merely stop a moving vehicle. It must also be remembered that materials burn most slowly in the horizontal position, and therefore the laboratory horizontal burn rate cannot be used as a direct indication of how much material might be burned in an on-the-road event.; The NHTSA does not agree that the 4- inch-per-minute rate should b modified because the burn rates of identical materials may vary. While we understand that such variations do occur, this fact will be taken into account, along with the frequency and extent of test failures, in assessing whether a manufacturer has exercised due care in meeting the standard. It would not be appropriate, however, to respond to the problem of variability by relaxing the burn rate. Such an action would probably result simply in manufacturers choosing cheaper and less safe materials. With reference to your request that the standard provide for the averaging of burn rate results, the structure of the motor vehicle safety standards does not allow for the averaging of test results. This is because the NHTSA must be able to establish firmly that a material does not conform to the requirements, on the basis of a limited-sample test. This requires that each material meet the requirements when subjected to the test procedures of the standard. Again, minor and occasional deviations will be considered similarly to problems involving variability, in assessing whether a manufacturer has used due care.; Your request that the NHTSA approve flame-retardant treatments if th 4-inch- per-minute rate is maintained is denied. The NHTSA does not specify materials which manufacturers are to use to conform to standards. The responsibility for conformity rests with manufacturers and it is for them to determine which materials and treatments they should use to meet the standard's requirements.; You have requested a one-year delay in the effective date of th standard. This request is denied. The NHTSA believes the effective date of September 1, 1972, has provided sufficient time for manufacturers to conform to the standard's requirements.; With reference to the test procedures of the standard, you petitio that a test cabinet recommended by Daimler-Benz be substituted for the test cabinet specified in the standard, arguing that the Daimler-Benz cabinet provides better ventilation, faster dissipation of smoke, a lower heat buildup, and more uniform test results. The NHTSA will evaluate, as part of its compliance program, the test procedures of the standard. If the NHTSA determines that the test procedures should be modified to improve the reliability of results, the characteristics of the Daimler-Benz cabinet as well as other available information will be utilized in evaluating possible changes in these procedures. If manufacturers do use other test procedures, they should correlate, to support a showing of 'due care,' the results they obtain with results obtained using the procedures specified in the standard.; You also request that the standard be amended to provide for th conditioning of samples within a range of 73.5 degrees F. *+* 3.5 degrees, and a relative humidity of 50 *+* 5%. The standard presently specifies a conditioning temperature of 70 degrees F. at a relative humidity of 50%. This request is denied. Test conditions are specified as exact values in the motor vehicle safety standards because they represent a legal standard, not manufacturers' procedures. Manufacturers should design their tests, choosing their own procedures as necessary, to ensure that the materials will perform satisfactorily at the specified conditions.; You have also requested a more precise definition of the gas used i the test procedure, and that the standard specify a ventilated hood. These requests are denied. The NHTSA has judged the description of the gas to be used in the test cabinet to be sufficiently specific. With respect to ventilation of the test cabinet, manufacturers are free, subject to the limitations described above, to modify this aspect of the procedure as well.; You also request that the standard be amended to exclude smal components, and comment on the notice of proposed rulemaking of May 26, 1972, to the effect that neither testing both sides of materials nor testing separate padding materials should be required. Each of these points is being considered as part of our preparation of an amendment to the standard, based on the notice of May 26, 1971. Your comments on these matters have been considered in the preparation of this amendment, which we plan to publish in the near future.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;