The strategy of protection of historical building against fire risk is different from almost any other type of building. In the most of case, the objective of fire protection, in fact, is preserving occupants of buildings or the their structure. Sometimes the concern is both. In the case of fire protection of historical buildings, preservation must find solutions that are consistent with the particular needs of the building: such goal needs freedom e cannot be achieved with prescriptive approaches, which have been developed with the typical building in mind.
The most common gap of prescriptive systems, when applied to heritage buildings, in that they do not work well in unique buildings, when the possible solutions are constrained. Frequently encountered constraints include aesthetic objections to:
- the degree of compartmentation required in the regulations;
- the inability to meet egress requirements such as the required number of exits or maximum travel distances;
- The frequent impossibility in installing active fire fighting systems
When these situations occur, designers usually use the equivalency provisions included in most prescriptive regulations. But such provisions normally have been studied for specific occupancy types and must be continually recalibrated as the prescriptive requirements evolve.
In this situation, performance-based regulations allow to meet conservation needs with safety standards provisions.
Explicit goals and objectives for life safety and historic preservation can be applied to performance solutions. Hazards and safety deficiencies should be identified in order to determine compliance options that satisfy safety objectives, respecting historical/aesthetical features. Solutions can be selected from traditional, prescriptive solutions or performance analysis approaches. Using such method, it’s fundamental that all parties involved in the construction understand the significant features that are to be preserved.
Other issues of paramount importance in dealing with fire safety of cultural heritage is the need for special care during:
- work projects when the structure is particularly vulnerable. When there are temporary collections of combustibles and construction equipment as well as operations that can represent sources of ignition not normally present. Ceilings and walls may be open for repair, exposing combustible structural elements and void spaces that might allow a fire to spread throughout the structure. Existing fire protection equipment may be disabled or removed as a part of the work.
- special events that may bring large occupant loads, consumption of alcohol that may impair these occupants, and catering or special food preparation activities that can involve additional quantities of combustibles and ignition sources. All activities at special events need to be evaluated and precautions taken to avoid threats.
Performance-based approach can help all the parts interested in preserving and using cultural heritage buildings in reaching safety goals without sacrificing the buildings themselves or their possibility to be used. Fire safety engineering can help in designing safety features as well as special events and construction/renovation works. Existing codes can be used as reference in order to check the performance of the buildings against safety level of common buildings.