A painstaking programme of development and testing, conducted by the Steel Window Association's technical committee, has led to the UK's top-rated fire testing centre granting a half-hour test certificate for both single and double W20 doorsets.
Ongoing work by SWA member companies over the past eight months has culminated in the full fire test, carried out at the facilities of Exova Warrington, under BS 476:Pt 22: resulting in a 30-0 rating.
Where such tests are normally carried out on fire doors set into masonry or gypsum boarded wall constructions, the SWA opted to mount both the single and double doorsets within a glazed screen, replicating the situation in which they are routinely specified by architects and interior designers.
This now means that installations of single or double doorsets as part of full internal steel screens can be carried out in full compliance with building regulations; but will only be available through companies belonging to the Steel Window Association.
Although the W20 profiles employed were standard sections, careful consideration was given to both the assembly and fixing of the steel frames, along with the way the doors themselves were located. This included fitting steel ‘location blocks' at the top, bottom and mid height of the frames and, additionally, stabilising the coupling members between elements and uprating the glazing.
As a leading member of the SWA technical committee, David Northam of NSB Casements, was closely involved with the fire test programme. He commented, "Some of the steps taken, such as reducing the fixing centres and using bigger studs, are quite straightforward, but we also investigated a variety of technologies available across the fire industry; particularly for strengthening the lock side of the frame to prevent bowing under heat. Both assemblies easily achieved the half hour integrity mark, with the double door test being halted after 42 minutes and the single door test being halted beyond 40 minutes."
As a result, the fire door assemblies are all glazed with 7.2mm Pilkington Pyrodur® safety glass, seated on intumescent mastic tape, and then the perimeter filled with an intumescent silicone sealant. There is also an intumescent strip fitted around the entire doorframe to prevent smoke and flames escaping the side where a fire starts; although building regulations no longer require the installation of an automatic closer in these situations.
The SWA's President, Darren Lloyd of Govette Windows, confirmed: "We wanted to be able to create and provide Internal steel door partitions with fire certificates for domestic applications. This will enable any of the dozen companies which belong to the Steel Window Association to manufacture and install modular screens with single or double doors."
"The recognition under BS 476 will open up more opportunities; in particular for premises such as bars and restaurants which want to create defined spaces while keeping an attractive appearance and maintaining light transmission. Also the market for basement construction is still growing, especially around London where clients often want to divide a corridor from a new kitchen, but not lose any light."
Steel Window Association's members are able to offer a full selection of options for new build and replica refurbishment, as well as historic projects; including W20, W30, W40 and W50 frames able to comply with the requirements of Part L to the Building Regulations. Choosing an SWA member to manufacture and install your steel windows and doors ensures that you are receiving the highest standard of fabrication, Installation and customer service.