BS 476-33:1993

Committees responsible
National foreword
Introduction
Method
1 Scope
2 Normative reference
3 Definitions
4 Principle
5 Fire test room
6 Ignition source
7 Heat flux instrumentation in the fire room
8 Hood and exhaust duct
9 Instrumentation in the exhaust duct
10 System performance
11 Preparation of test specimens
12 Testing
13 Test report
Annexes
Annex A (normative) - Recommended ignition sources
Annex B (informative) - Alternative ignition sources
Annex C (informative) - Instrumentation of test room
Annex D (informative) - Design of exhaust system
Annex E (informative) - Instrumentation in exhaust duct
Annex F (informative) - Calculation
Annex G (informative) - Specimen configurations
Annex H (informative) - Bibliography

Test method simulates a fire that, under well ventilated conditions, starts in the corner of a small room with a single open doorway. Time to flashover, rate of heat release, smoke obscuration and CO and CO₂ are measured.

This International Standard specifies a test method that simulates a fire that under well ventilated conditions starts in a corner of a small room with a single open doorway.

The method is intended to evaluate the contribution to fire growth provided by a surface product using a specified ignition source.

A standard ignition source is specified, but other alternatives are allowed. It should, however, be noted that the type, position and heat output of the ignition source will considerably influence the fire growth.

The method is especially suitable for products that for some reason cannot be tested in a small laboratory scale, for example thermoplastic materials, the effect of an insulating substrate, joints, surfaces with great irregularity.

The method is not intended to evaluate the fire resistance of a product.

A test performed in accordance with the method specified in this International Standard provides data for the early stages of a fire from ignition up to flashover.