The Surface Spread of Flame Test of Building Materials and Structures

The fire disaster brings the endless to the people. It is crippled and fatal. It not only hurts life, but also destroys buildings and undermines commercial trade. Therefore, fire prevention measures for products and materials are urgent. Fire protection of products and materials can be achieved in a variety of ways.

BS 476 Part 7:1997+AC: 2014 Fire tests on building materials and structures-Part 7 method of test to determine the classification of the surface spread of flame of products

 The BS 476-7 test method is to burn samples inside of the combustion chamber. The ignition source is a gas radiant panel and a medium-sized gas burner. The radiant intensity of the radiant panel is 32.5 kW/m 2 (surface) from 75 mm, and the flame of the burner is 75-100 mm high, which is applied to the sample in the same direction as the radiant panel. The sample was exposed to a radiant heat source plate for 10 min. The degree of flame spread of the samples was recorded for 1.5 minutes and 10 minutes. The test results are divided into 4 grades. The grade 4 materials have a high fire hazard and are not allowed to be used as building materials.


Spread of flame at 1.5 min

Final spread of flame (10 min)


Limit (mm)

Limit for one specimen in sample (mm)

Limit (mm)

Limit for one specimen in sample (mm)

Class 1





Class 2





Class 3





Class 4

Exceeding the limits for class 3

Recommended Fire Testing Equipment: SKYLINE SL803 BS 476-7 Surface Spread Flame Tester

  • This Apparatus consists of a radiation panel mounted vertically in a surround and supported on a framework.
  • ​The radiation panel is sullied with an gas-air mixture.
  • ​The radiation panel is 850mm square for a porous refractory type burner block designed to give efficient combustion of the air-gas-air mixture, with no flaming occurring on the face of the panel under operational conditions.
  • ​The radiation panel and its surround are supported on a framework so that the center of the panel is about 1250±100mm above floor level.


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Post time: Nov-16-2019