1. Standard- BS6853 Annex D
BS6853 Annex D: Methods for measuring smoke density
BS6853:1999 Code of practice for fire precautions in the design and construction of passenger carrying trains.

2. Standard Brief-BS6853 Annex D
The smoke density measurement taken from a material under fire conditions gives an indication of the visibility through

the smoke, this is important as reduced visibility in a real fire situation makes it more difficult to escape from a

fire hence increasing the threat to human life from the toxic gases, flames and heat.

There are five different test methods which can be utilized to determine the smoke density produced from materials to be

placed on passenger carrying trains in the UK.

The five different methods are as follows:

BS6853 Annex D.8.3—smoke density test using small scale test method
BS6853 Annex D.8.4—smoke density test using Panel test method
BS6853 Annex D.8.5—smoke density test using seat test method
BS6853 Annex D.8.6—smoke density test using floor test method
BS6853 Annex D.8.7—smoke density test using cable test method

BS 6853 Annex D.8.3 is utilized for Minor Use Materials (Tables 7 and 8 of BS 6853: 1999) and Textiles (Table 11 of BS

6853: 1999).

BS 6853 Annex D.8.4 is utilized for interior and exterior vertical surfaces and horizontal prone surfaces (Tables 2, 3,

5 and 6 of BS 6853: 1999) and seat shell (table 10 of BS6853: 1999).

BS 6853 Annex D.8.5 is utilized for seats (Tables 9 of BS6853: 1999). NB. Tests should be performed on actual specimen

seats

BS 6853 Annex D.8.6 is utilized for interior and exterior horizontal supine surfaces (Tables 1 and 4 of BS 6853:1999)

and mattresses (table 12 of BS 6853: 1999).

BS 6853 Annex D.8.7 is utilized for interior and exterior cables (Tables 13 and 14 of BS 6853: 1999).

3. BS6853:1999 Standard requirement for Smoke density testing
Interior horizontal supine surface for BS6853 requirement: A0≤220
Interior vertical surface for BS6853 requirement: A0(ON)≤2.6 and A0(OFF)≤3.9
Interior horizontal prone surfaces for BS6853 requirement: A0(ON)≤2.6 and A0(OFF)≤3.9
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