Ignitability test for polyurethane foam in slab or cushion form.
1. The foam shall be tested in accordance with the method set out in BS 5852: Part 2 using cover fabric corresponding to the specification set out in paragraph 2 below.
2. The fabric shall be made of 100 per cent flame retardant polyester fibre. Its construction shall be woven to a plain weave. The yarn in the warp shall be of 1.6 decitex fibre, spun to a linear density of 37 tex, Z twist at 420 turns per metre. The fabric shall be woven to 20.5 yarn threads per centimetre in the warp.
The yarn in the weft shall be of 3.3 decitex fibre spun to a linear density of 100 tex, Z twist at 550 turns per metre. The fabric shall be woven to between 12.6 and 13 threads per centimetre in the weft.
The fabric finish shall be scoured and heat set. Its mass shall be 220 g per m2 plus or minus 5 per cent.
3. The test rig as specified in clause 6.1.1 of BS 5852: Part 2 shall have expanded steel platforms of not less than 28×6 mm mesh size. The test rig is placed on a metal tray of sufficient dimensions to collect any debris falling from specimens being tested. The rig and debris tray shall be mounted on a weighing balance with a remote readout having a full-scale deflection of at least 0 to 20 kg to an accuracy of 2 g.
4. The foam under test, cut to the specified dimensions is placed on the test rig, covered with the fabric specified in paragraph 2 above and tensioned with clips as set out in BS 5852: Part 2. An ignition source 5 crib is placed in position. The mass of the complete assembly is determined (“initial mass”). The test shall be carried out in accordance with BS 5852: Part 2. In particular flaming or smouldering failure shall be determined against the criteria of clause 4 of BS 5852: Part 2.
After flaming and smouldering has ceased, any debris which has become detached from the specimen shall be removed. The remaining mass of the assembly (“final mass”) is then recorded.
5. If failure against the criteria of clause 4 of BS 5852: Part 2 has occurred but only by way of damage exceeding the limits defined in clauses 4.1(e), 4.1(f) and 4.2(f) and provided that the resultant mass loss (initial mass less final mass) is less than 60 g the foam passes the ignitability test.