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Fire Performance
The Building Regulations Approved Document B : 2000 requires that roofs of certain buildings meet specified performance levels for exposure to fire from external sources, the highest requirement being Ext, FAC. Insurance loss prevention consortia, such as Loss Prevention Council (LPC) or Factory Mutual (FM), may specify performance in excess of the mandatory requirement.
External fire performance of roof systems is assessed according to BS 476: part 3: 2004, where the roofing system is subjected to fire exposure from a simulated external burning brand comprising a gas flame. The external fire performance is expressed as a requirement for the whole roof construction including deck, vcl, insulation and covering, characterised by penetration of fire and spread of flame. Classification ranges from (highest) Ext. FAA (external flat, penetration rating A, spread of flame rating A) to Ext. FCD (lowest).
The Building Regulations Approved Document B: 2000 also makes fire resistance provisions for where fire exposure to the underside of the roof needs to be considered. These are listed in Table A1 of the approved document and apply:
- When the roof and its support structure are part of an escape route, including any opening within 3m of the escape route.
- When the roof performs the function of a floor.
Building designers should ensure that the client is aware of the Fire precautions (Workplace) Regulations: 1997 (as amended), wherein the employer is required to undertake the continual review of risk assessment to ensure that employees are not placed at risk from fire. It is recommended that a fire expert be consulted as part of this process.
© 2006 Sarnafil Ltd. Legal Disclaimer
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