BS 476-6: Fire tests on building materials and structures- Part 6: Method of test for fire propagation for products.

BS 6853/BS 476-6:1989+A1:2009 test method:

This method of test, the result being expressed as a fire propagation index, provides a comparative measure of the contribution to the growth of fire made by an essentially flat material, composite or assembly. It is used primarily for the assessment of the performance of wall and ceiling linings. Fire propagation is determined by exposing the specimen to the fourteen jets of a gas pipe burner at a distance of 3mm.The heat evolved is 530J/s. The two electric elements with a total output of 1800W are switched on after two minutes forty-five seconds test duration. Their output is reduced to 1500Wat five minutes test duration and then maintained constant until the end of the test (twenty minutes).

The two curves are evaluated by establishing the temperatures from the calibration curve and test curve at:

       • Thirty second intervals from the start of the test to three minutes test duration

       • One minute intervals from four minutes to ten minutes test duration

       • Two minute intervals from twelve minutes to twenty minutes test duration

The total index I = i1 + i2 + i3

Some high construction, I index no more than 20 or materials of class 0

Materials of Class o, i≤6，I≤12。

BS 6853/BS 476-6:1989+A1:2009 Classification requirement

BS 6853:1999 requirement:

I≤12, i≤6