FRA recommendations for timber framed building

[SeaBass]

I have recently come across a couple of FRA reports for modern purpose built blocks of flats which  the report author thinks might be timber framed buildings,  and has consequently suggested that the installed  BS 5839 L4  AFD&A system and the simultaneous evacuation strategy that is in place  in the building,  have been adopted  as a compensation for the timber frame structure.

I appreciate that modern timber frame construction has it?s detractors and some specific fire safety issues, but I?ve not come across any considered or reputable guidance that has suggested that such compensatory measures should be implemented. Have I missed something?

[kurnal]

No you have not missed anything. There is no reason to implement special measures for timber framed buildings per se.
However with timber framed buildings there is more potential for poor standards of construction, and the consequences of this can be much more significant. In particular internal voids, service shafts and firestops in the structural frame. Some of these are impossible to check post completion.

But in my view unless there is evidence of poor standards of construction (and this requires a thorough inspection)  it should be assumed that the BCO has done their job and the building is up to standard. A phone call can be useful in confirming the degree of supervision that was applied.

There should be no need for additional risk control measures if no shortcomings are found, perhaps the risk assessor should be asked why they made this recommendation?

[wee brian]

I agree, its entirely unnecessary.

The problems with TF construction relate to fire spread in the wall cavities. these are a nightmare to extinguish and cause a lot of damage (in comparison with the severity of the fire itself).  But there is ample time to evacuate the building if the fire service thinks this is necessary.

Further reading;

https://www.gov.uk/government/statistics/analysis-of-fires-in-buildings-of-timber-framed-construction-england-2009-10-to-2011-12

https://www.nhbcfoundation.org/publication/fires-in-cavities-in-residential-buildings/

[SeaBass]

Thank you Gents,  to be honest the last sentence in my  posting was a  little tongue in cheek, but you can never be too sure. Particularly as the report Author is on a life safety FRA register.