Getting a Fix on Fire
Timber frame buildings are vulnerable to fire during construction but, as Mike Stevenson, Development Director at Sidey, points out; there are simple measures to reduce risks.
In recent years there has been a spate of heavily publicised fires involving timber frame construction that has raised concern within the construction industry and challenged us to find answers to the problem of arson.
The first serious case was in 2006, when a six-storey housing development under construction in Colindale, North London burnt to the ground in less than nine minutes. More recently, in 2010, a construction site in Peckham, South London burnt so fiercely that it swept to nearby housing forcing tenants to be evacuated as the fire spread through their housing estate. This year the £50 million Radclyffe Park development in Ordsall, Salford – again under construction – was destroyed by fire.
The media coverage has – predictably – focussed on the severity of the blaze and the rapid collapse of the unprotected frame but fire officers have raised more informed concerns, with Peter Holland Vice President of the Chief Fire Officers Association and Chief Fire Officer of Lancashire Fire and Rescue Service (CFOA), commenting: “Where a fire occurs in a timber framed building, particularly one under construction, the outcome is totally devastating”.
The point, though, that was recognised that the timber frame construction itself is not a fire risk – the structural timber used in construction is not easy to set alight – it requires effort, so all the major construction site fires involving timber frame are the result of determined, deliberate and malicious damage.
Nonetheless the CFOA and the Greater London Assembly were so concerned that they called for an overhaul of the Building Regulations, a call that was rejected. But the timber frame industry has had to answer this challenge and has done so in several ways.
One response from the UK Timber Frame Association (UKTFA) has been to produce guides to construction site management that minimise the opportunity for arson. It has written “16 Steps to Fire Safety” in collaboration with experts such as the London Fire Brigade and Health & Safety Executive, together with “Reducing the Risk of Timber Frame Fires during Construction”.
In this the focus is not simply upon securing the site against arsonists and upon making the best use of timber frame’s speed of construction: Exposed timber frame structures can burn and generate a lot of radiant heat but its rapid erection means that full fire protection can be in place long before other methods of construction. In particular its recommendation on “Removing opportunity for fires” says that “it is appropriate to look at the construction process to include windows to be installed as early as possible or to use robust wire mesh temporary windows and doors. In addition, once watertight, plaster boarding and fire proofing of the ground floor level is recommended as a further measure to reduce risk of ignition to exposed timber surfaces.”
This is the point at which proprietary systems can make a real difference as timber frame manufacturers can devise various means of contributing to site safety through improving the speed at which structures are erected and installing doors and windows earlier in the production process – offsite where possible.
Sidey’s own patented contributions to speeding the pace of construction are KitFix® and Scratchguard, two products that enable a greater proportion of the construction process to take place safely off-site within the factory. Together they enable developers to erect buildings more quickly, hold fewer materials on site and produce a fire-protected envelope.
Designed specifically for off-site manufacturing, the patented KitFix® System enables timber frame kit manufacturers to install fully glazed, fully finished windows and doors into their panels as part of the production cycle which can then be stacked, stored and transported as normal.
This glazing, whether in windows or doors, is protected from damage on site and in transit with Scratchguard, a factory applied protective coating that also provides a semi-transparent but opaque glass coating that increases site security while allowing enough light into the building for work to continue.
Using KitFix® , windows and doors are factory fitted in less than three minutes and final fixed in less than two minutes. As a result buildings can be made wind and watertight in one day without any need for scaffolding adjustment – step-ups, for instance – and follow on trades can start sooner.
Once the building is ready for handover, the Scratchguard can be peeled off, cleaning the glass as it comes off. This operation takes just seconds, far faster than window cleaning, and so speeds up the handover process. Once peeled, the coating can be rolled into a ball and disposed of as it is wholly biodegradeable as well as non-flammable.
By using these two products it is possible to follow the UKTFA guidelines in three ways: by installing windows as quickly as possible in the construction process; producing a watertight building that can be plaster boarded and fire-protected far sooner than is possible using conventional methods of window installation; and reducing the amount of potentially flammable material kept on site.
Proprietary systems such as these all help towards minimising the risk of arson but only as part of a comprehensive approach such as the SiteSafe initiative where speed of construction works hand in hand with site security and good housekeeping.
Developed by UKTFA, SiteSafe aims to minimise the risk of fire on timber frame construction sites by ensuring that all contractors involved in timber frame sites are fully briefed on identifying fire risks during the construction phase. It provides a framework through which any risk can be consistently communicated so that appropriate action can be taken and if fully endorsed by the CFOA. As Peter Holland of CFOA noted: “A timber frame construction site that has adopted and applied SiteSafe is really doing as much as it can to minimise the risk of fire on site.”
Although SiteSafe was developed for large projects (four storeys or more and/or with an aggregate floor area of more than 2,500 m2) its basic tenets and approach can be applied successfully to smaller jobs, in particular its insistence on liaising with the local Fire and Rescue Service during construction.