The Regs: The fire at the Mac is a clarion call to protect our precious historic buildings
The recent fire at Charles Rennie Mackintosh’s Glasgow School of Art raises questions about fire safety in some of the most important buildings in the country. Nearly every year significant historic structures are destroyed by fire and, although they can be rebuilt, the original fabric is irreplaceable. In Scotland alone it is estimated that one historic building is lost every month due to fire.
Unlike modern buildings, which are controlled under Building Regulations and designed from the start to prevent and contain a fire, historic buildings are more difficult to adapt. The traditional approach - to subdivide the building into smaller, defined fire compartments - is difficult, especially as the original structure may well have been built over or adapted, creating hidden voids. The Hampton Court Palace and Windsor Castle fires showed that once fire enters these voids they contribute to its rapid spread, and seriously hamper attempts by the fire service to prevent major damage.
For many years conservationists have resisted improvements to buildings due to the intrusive effects of fire safety measures. As the Regs did not apply retrospectively to these buildings, and the Fire Precautions Act 1971 was statute-barred, there was no legislation forcing the upgrade of fire safety measures until the last decade. The Regulatory Reform (Fire Safety) Order 2005 has brought about a change of thinking, and all buildings must now be assessed and upgraded where the risk is too great.
Automatic fire detection is usually the first consideration in this process, and there are now a variety of options for operation, appearance and concealment. The traditional ‘yoghurt pot’ detectors have given way to low-profile heads that are less obvious and can be coloured to match surroundings. Optical beam detectors can be installed to large ceiling areas where point detectors are undesirable. Aspirating (air sampling) systems, comprising a series of small-diameter flexible pipes with holes along their length, are another option. Here a sampling unit remotely draws air from the room into the sampling-unit chamber, which detects the presence of smoke particles. These systems can be concealed above the ceiling structure with small penetrations made in the ceiling fabric to allow the air to be drawn and sampled.
In some historic buildings replacing the doors and walls can be avoided by introducing a fan pressurisation system. In the event of a fire, these systems operate by rapidly pressurising the escape route and forcing smoke to leave the building through vents introduced in the rooms. However, the systems have limited application as they can only be used where a staircase is enclosed, and accommodating the large amount of plant required is difficult. Another option is concealed smoke curtains within the structure, maintaining an open-plan layout day to day, but dropping to form small, fire-tight cells in a fire.
However, without doubt the most effective solution is automatic fire suppression, such as sprinklers or gas-based systems. Here again, the installation has been resisted on the basis of appearance, practicality and also misunderstanding of the systems themselves. Films such as The Towering Inferno and Die Hard have given the impression that traditional water-based systems do more damage to the fabric and contents than a fire itself. In truth, only the sprinkler heads in the immediate vicinity of a fire would activate, and then would apply only a fraction of the water that an attending fire service would. Also, the very latest water-mist systems use a small amount of the water that a traditional system would use, further reducing the risk.
While English Heritage has been slow to promote sprinklers, the case for fitting them north of the border has been set out for some time in Historic Scotland’s Technical Advice Note 14 (1998). Ironically, the Glasgow School of Art was scheduled to be fitted with a water-mist system and was just weeks away from commissioning when the fire broke out. Had it not been for the bravery of the Scottish Fire and Rescue Service, the damage could have been much worse, and I would urge you to push for the urgent installation of fire suppression in our priceless heritage buildings.
Geoff Wilkinson is managing director of Approved Inspectors Wilkinson Construction Consultants