The LWF Blog

Heritage Buildings Pt 1 | Sympathetic fire protection

December 4, 2013 11:01 am

Heritage buildings are an integral part of our culture and our history and, as such, it is vital that we take care of these precious buildings. In the past, many lessons have been learnt where serious fires in historic structures have occurred; the fires at Hampton Court (1986), Windsor Castle (1992) and Cutty Sark (2007) are examples of some of the highest profile heritage fires in the UK in recent years. The total damage of these premises was estimated to cost millions and what was lost cannot be replaced.

Unlike most other structures, heritage buildings with significant architectural and historic integrity are exposed to greater vulnerability because of their unique and irreplaceable contents, and the lack of fire precautions included within their original construction. The aftermath of fires often shows that spaces not directly affected by the flames or heat may be damaged by smoke, falling debris or by the huge volumes of water used by the Fire Service for fire fighting.

Based on the global experience of devastating fires in heritage buildings, it has been demonstrated that better strategic fire safety approach and management are needed to prevent further disastrous fires. 

In many cases, fire safety measures such as fire doors, fire resistant construction, automatic suppression and smoke detection systems have been incorporated into buildings of historical interest, with the aim of detecting and preventing the spread of fire.

However, the introduction of these elements can have an unfavourable effect on the architectural value of the historic buildings. The building owner or English Heritage are forced into making a choice between satisfying fire safety legislation and insurance requirements, and staying true to the original design. 

Several key problems have been identified which arise when dealing with heritage buildings. As a consequence, fire engineers are often asked to step in and provide innovative approaches to meet adequate fire safety levels, while retaining the original character of the building. 

This short series of articles will look at the key problems found when protecting historic buildings, different innovative fire safety designs and fire safety management that can be incorporated within historical structures and how these can satisfy and benefit the building owner’s needs.

Problems encountered with Historic Buildings

In practise, the current Building Regulations – Approved Document B primarily applies to building works only. However, they can also be applicable where there is a ‘material change of use’, such as when the use of building is changed, for example a church is turned into a school or a Grade listed country house to a hotel.

From a fire safety point of view, it is desirable for all buildings to fully meet the requirements of contemporary Building Regulations. But with many historic buildings, this may not be feasible, because most of our heritage buildings were built prior to the adoption of the Regulations. 

As such, it can be accepted that some heritage structures will not meet the functional requirements. For example, in terms of means of escape, the travel distances may be longer than that recommended in the current guidance, or there may be no alternative escape routes provided in certain parts of the building. 

These issues are generally dealt with by applying additional fire safety measures. Fire safety measures may include the provision of new staircases, automatic smoke detection systems, suppression systems and alteration of building elements etc. All these installations could potentially compromise and affect the architectural character of the historic building or cause disturbance to its fabric. 

However, these fire safety measures are essential in order to prevent fire spread. Fire can spread when heat is conducted through materials and also by radiation when a heated surface ignites materials which are located several metres away. This problem exists in heritage buildings because the architectural features are, in general, built in continuous and interconnecting voids behind panelling (old chimneys or shafts), void linings or undivided roof spaces. Once ignited this, and other combustibles, could assist in the rapid development of hidden spread of fire. Exposed timber floor structures and wood panelling against the internal perimeter walls are examples of this type of constructional arrangement.

 

Another area that needs to be considered is the fire resistance of elements e.g. wall, ceiling and structural fire resistance. All heritage buildings are unique in their architectural features and contents. This is achieved by using a wide range of building materials such as timber, brick, natural fibres, ironwork and untested materials. Therefore, it can be a challenging task to determine the existing fire resistance and the propagation properties of the building elements. 

The implementation of the prescriptive fire safety regulations can have a significant impact on the architectural construction and general aesthetics of the building and this method is not generally the best approach for all parties concerned. The challenge that fire engineers face is to find a robust and practical solution. A fire engineering approach has the potential to reduce negative dramatic impact on the historical and architectural value of the building. 

Next week’s blog article will look at fire engineering solutions for buildings of historical and architectural value in more depth. In the meantime, if you have any queries or would like to discuss your own project with us, please contact Peter Gyere on 02086688663

LWF are fire engineering and fire risk management consultants with over twenty six years experience in the development of fire engineered technology and the application of fire safety standards including fire engineered techniques.