The Federal Motor Vehicle Safety Standard No. 302
(FMVSS 302; ISO 3795)
The FTT FMVSS 302 is manufactured according to the Federal Motor Vehicle Safety Standard No. 302. The FMVSS 302 specifies the burn resistance requirements for materials used in the occupant compartments of motor vehicles (i.e. passenger cars, multipurpose passenger vehicles, trucks and buses). This is to reduce the deaths and injuries to motor vehicle occupants caused by vehicle fires, especially those originating in the interior of a vehicle from sources such as matches or cigarettes.
The combustion chamber is an enclosure constructed from stainless steel, with a heat resistant
window at the front for observation.
The test is conducted within the chamber which protects the test specimens from drafts. The interior
of the cabinet is 381mm long × 203mm deep × 356mm high. It has a high temperature resistant glass observation window which can be easily removed for cleaning, a thermal warning indicator to warn of hot surfaces, an opening to permit insertion of the specimen holder from the right hand side of
the unit, Bunsen burner, needle valve to control the gas flow, safety flashback arrestor, and specimen
support rails. For ventilation, the chamber is elevated 10mm by feet fitted to the base of the chamber.
Additionally, the chamber roof is raised by 13mm to allow ventilation.
Gas flow is controlled by a needle valve outside the chamber to produce flame stability. Connection is made at the top of the flash back arrestor, which is a standard 6mm hose barb.
A choice of Bunsen burner tubes is provided. The tube marked with ISO has a 9.5mm inside diameter
and is suitable for the ISO 3795 test. The tube marked with FM has a 10mm inside diameter and is
suitable for the FMVSS test. The Bunsen burner tube can be interchanged and cleaned very easily. A needle valve (located externally) is used to adjust the
flame height to 38mm. The gas supplied to the burner should have a calorific value of approximately
38MJ/m3. The suggested gas supply is natural gas or a flame temperature equivalent.
The test specimen is inserted between two matching U shaped stainless steel frames 25mm wide × 10mm high. The interior dimension of the FMVSS and the ISO 3795 U shaped frame is 50mm wide × 330mm long. A specimen that softens and bends at the flaming end so as to cause erratic burning is kept horizontal by supports consisting of thin, heat resistant wires 0.25mm diameter, spanning the width of the U shaped frame under the specimen at 25mm