Interpretation ID: nht70-1.43

DATE: 02/25/70

FROM: AUTHOR UNAVAILABLE; F. C. Turner; NHTSA

TO: FWD Corporation

TITLE: FMVSS INTERPRETATION

TEXT: RE: PETITION FOR RULEMAKING

This is in reply to your letter of October 16, 1969, requesting an exception from Paragraph S3.1 of Federal Motor Vehicle Safety Standard No. 205 ("Glazing Materials - Passenger Cars, Multipurpose Passenger Vehicles, Motorcycles, Trucks and Buses"), to allow the use of Lemen and Plexiglas in certain specified locations in twenty-one (21) fire fighting vehicles to be delivered to the city of New York.

You state the purpose of your request is to provide better protection for occupants of these fire fighting vehicles from objects thrown at them when, for example, the vehicles are enroute to a fire. Further, you state the use of these materials would eliminate replacing safety glass, which can be broken when hit by small objects. Because you are requesting a change in an existing standard your letter has been treated as a petition for rulemaking to amend Standard No. 205, pursuant to the provisions of 49 CFR @@ 353.31, 353.33. For the reasons stated below, your petition is denied.

It is not completely clear from your letter and the enclosed drawing where the interior or canopy partitions in which you wish to use Lexen and Plexiglas are located. Standard No. 205 presently permits the use of rigid plastics in interior partitions of fire fighting vehicles if these materials meet the requirements for plastics designated AS4 and AS5 (the latter can only be used when not requisite for driving visibility) in American Standards Association Test Z26.1-1966, July 15, 1966. We understand that Plexiglas meets these requirements and may therefore be used in this location. We also understand, however, that Lexen does not, failing specifically to meet certain chemical and abrasion resistance requirements applicable to AS4 and AS5 rigid plastics under the Standard. If our understanding regarding Lexen is correct, we believe its failure to meet these minimum requirements renders its unsuitable for use in areas of motor vehicles where a possible loss of transparency may affect the safe operation of the vehicle.

With reference to glazing in side and door windows of fire fighting vehicles, Standard No. 205 allows the use of glazing specified AS1, AS2, and AS10 in ASA Test-226.1-1966 and also allows the use of AS11 and AS3 glazing at levels not requisite for driving visibility. This glazing may be either laminated, tempered, or bullet resistant safety glass meeting the applicable requirements. Plastics meeting AS4 and AS5 requirements, while appropriate for certain locations such as partitions, are not considered appropriate for use in side and door windows as they do not possess chemical and abrasion resistance qualities necessary for exterior glazing and which the types of safety glass specified above possess. The occupant protection which you desire can be provided by using AS10 (and AS11 where appropriate) bullet resistant glass which contains both structural advantages over normally used safety glazing and satisfactory chemical and abrasion resistance for use in side and door windows.