The LWF Blog

Passive Fire Protection for Building Professionals – Part 4

February 13, 2020 10:08 am

In LWF’s blog series on passive fire protection for building professionals, contractors and those with an interest in structural fire protection issues, we aim to give an overview of the important role passive protection plays in the overall fire safety provision of a building. In part 3, we began looking at of the most commonly seen passive fire protection methods. In part 4, we will take a look at other products in the passive fire protection category, starting with glass and glazing.

Fire Resistant Glass and Glazing

One of the most poorly understood passive fire protection product areas is that of glass and glazing. Without fire-rated fenestration, it would not be possible to maintain the structural integrity of compartments with windows for fire safety purposes. Ordinary, non-rated glass would crack and fall from the frame very quickly in a fire situation.

External windows are the most commonly seen use of fire-rated glazing, but vision panels and indoor windows in compartment walls must also be rated for integrity and installation in accordance with Approved Document B of the Building Regulations.

While the composition of the glazing itself is important, the way it is installed can make the difference between compartment integrity and failure. The glass should be bedded into the surrounding wall/door/substrate using the appropriate combination of beading glass and substrate which has been tested to British Standards. Without this, tests have shown that glass can fail catastrophically at a very early stage in a fire.

Services Penetrations and Ventilation

If the integrity of a compartment is essential in order to stop fire from spreading from one area to another, it follows that any holes made in fire-resisting construction would allow the spread of smoke and flame if it were unchecked.

Ventilation systems are one example of a way fire can find its way from one area to the next and so must be appropriately fire stopped. Air handling units and ducting must be installed using fire-rated ducting or fire rated construction or fire dampers which restrict the spread of fire and its associated products.

Other service penetrations in construction, commonly known to cause issues with the passive fire protection provision if inadequately fire-stopped, are cabling, pipes, waste-water pipework or the removal of sealed services leaving apertures. Penetration seals should be used appropriately, the absence of which can lead to passage of the flammable gases produced by fire spreading through the inadequately stopped gap.

The use of pink polyurethane foam filler is not appropriate and has never been an adequate solution to fire stopping. Testing of a four-hour rated foam has shown that it may offer as little as ten minutes of protection in a fire situation.

The ineffective maintenance of compartmentation in a building by the owner, tenant or their representative builder can make some small financial savings at the time which would prove very costly should a fire happen at the premises. In addition, property insurers may consider that the owner was negligent in not using appropriately experienced and qualified personnel to provide adequate fire-stopping services and products.

In part 5 of this series, LWF will look at third-party accredited products and contractors. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please do not hesitate to contact this office on freephone 0800 410 1130.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.


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