FD20

[Tadees]

As a risk assessor, is there an actual definition or list of key features in order to identify what is an FD20 door?  Is a substantial door 44mm thick (not hollow core) without smoke seals and intumescent strips sufficient to meet the FD20 requirement for a flat front door opening on to a balcony?

[Tom Sutton]

Nowadays no such an animal check out http://www.bwf.org.uk/assets/explaining_fd20s_factcard_13.pdf

[Tadees]

Well, the question I was asking was based on the fact that the purpose-built flats guide, which came after the 2009 BWF note allows FD20 doors as a benchmark standard, let alone in an existing block which I was enquiring about.

[wee brian]

Something of an old chestnut.

FD20 means a door that lasts 20 minutes in the BS fire test.

most door manufacturers don't make FD20s they just to FD30s.

Its common practice in the housebuilding industry to use FD30s wherever FD20 is specified but without installing the intumescent strips.

[Fishy]

The simple answer to the original post is that there's no simple answer!  There used to be guidance on identifying constructions that would achieve "X minutes" F/R but that has diminished greatly over the years (I suppose the bodies who had an interest in publishing documentation that encouraged the retention of what's there, rather than replacing it have reduced).  The older versions of BS 8214 had guidance, but the newer versions tend to concentrate on tested constructions.  There is the TRADA Wood Information Sheet WIS 1-32 "Upgrading timber doorsets for fire resistance" available here: http://bookshop.trada.co.uk/bookshop/view/D10C6B2E-F83F-445E-9082-396419185D02/upgrading+timber+doorsets+for+fire+resistance .

The BWF document is a statement on their position (representing some of the companies who flog fire doors) - it doesn't mean that an FD 20 doorset is not an available product.  As Wee B states you do see FD30 doorsets installed without intumescent seals in the places where FD 20s are recommended.