Historic structures are an important architectural and physical representation of local culture and history. It’s estimated there are more than 550,000 protected structures throughout the UK and Ireland. While careful preservation of historical buildings take place all over the world, there have been many cases of historical buildings being destroyed or severely damaged due to fire, most notably the Notre Dame Cathedral in Paris.
Fire safety in historic buildings can be a challenge for a number of reasons. Because historic structures weren’t constructed in the time of modern building regulations, it’s extremely difficult to adapt old buildings to new fire regulations. Many were originally constructed for a different use than the one that is now intended – such as a stately castle now being used as a museum, or an old warehouse converted into residential lofts. In addition, these structures were often constructed from timber and other materials that are more combustible than modern materials such as concrete and steel.
So, how do we apply modern fire safety and protection principles to historic buildings while still preserving the past?
Balanced Approach
Most fire protection legislation has been developed as a response to fire disasters. Regulations and codes have evolved over many years based on historical experience of fires and consensus-based decisions of committees. The result is a standard "prescriptive" approach which relies mainly on passive measures and is relatively straightforward to apply, especially to new buildings – not old ones. The problem is compounded by the fact that historic buildings are protected by conservation regulations and there is often a conflict between the two. This is where a fire engineered, or performance-based approach can be used.
A performance-based approach to fire safety in historic buildings is a more balanced way of providing an equivalent level of fire safety to what the prescriptive code would dictate. It provides more options and greater flexibility in design.
Historic buildings often have inherent features which can contribute to the standard of fire safety. For instance, historic buildings may have higher ceilings than modern buildings. By using fire engineering modeling techniques, it can be demonstrated that they take longer to fill with smoke. This can be used to minimize prescriptive measurements such as protected lobbies, or to justify extended travel distances.
Sprinkler systems can be incorporated into a historic building without compromising the interior. Not only can these be used as part of a fire engineering solution, they can also contribute to the protection of the building itself. There is a widespread misconception that sprinklers activate as soon as smoke is detected and that all of them operate at the same time, resulting in water damage. In reality, sprinklers are thermal devices and only operate when there is sufficient heat – or in other words – a real fire. In addition, only the sprinkler heads closest to the fire activate, minimizing water damage. The amount of water damage is small when compared to that discharged by firefighters who may arrive on the scene too late to save the building from the fire.
Protection and preservation of historic buildings are important so they can be shared with the public. To do this, we must get creative as fire safety professionals. Simply adhering to modern building codes would diminish the aesthetics and architectural design of many historic buildings. A balanced approach, rooted in fire science and developed in partnership with the architect, building owner or local building regulator is the best of both worlds.