Hazard Fires in heritage buildings
Heritage buildings present unique hazards, having been built in a period without fire safety regulations, using traditional materials and construction methods. Utilities and associated fire protection measures are unlikely to meet current standards. Wiring may have deteriorated, and electrical circuits may have no isolation point or isolation may not control all circuits. Heritage buildings that are open to the public, or have had recent alterations, may have been modified to meet current regulations more closely.
A building may have been altered or extended during its lifetime, using different materials and methods, which can cause the structure to behave in unexpected ways. In older buildings, internal studded walls may support part of the weight of the structure.
It is common for heritage buildings to have mezzanine floors, basements, cellars, tunnels and attics.
Heritage buildings and their contents may be of economic or cultural importance, irreplaceable or of national significance. For more information refer to Firefighting – Preventable damage.
The materials and design of heritage buildings can increase the expected rate of fire growth and spread. Firespread may travel in hidden voids, behind facades and in cavities, to unexpected sections of the building. Vaults and ducts can cause there to be unchecked firespread underfoot.
Lack of compartmentation can cause fires to spread to additional rooms. Firespread may also occur between buildings if there are shared roof spaces or voids. Heritage buildings may be in close proximity, allowing fire to spread to other buildings or structures.
A build-up of flammable materials in voids, or oil impregnated timbers in industrial heritage buildings, can encourage firespread.
Retrofitting of fixed installations, and sections built or altered after the introduction of regulations, may be appropriate for the period. However, many heritage buildings will not have fixed installations, such as dry risers or sprinklers.
If fixed installations have been fitted, it should not be assumed that they are constructed to modern standards; dry risers may not cover every floor or may be limited to the highest point of the building.
Construction materials, period furnishings and wall coverings are more likely to be flammable. Flammable insulation, build-up of paint and unconventional substrates, such as lath and plaster or wooden panelling, may encourage fire development and allow hidden firespread.
Depending on the age of the building, cast iron, stone or heritage timber may have been used in construction. Consider the age of the building and refer to Site-Specific Risk Information (SSRI) to identify its construction materials.
Glass in heritage buildings is unlikely to be heat treated or laminated and is more likely to melt or shatter if subjected to heat. Window frames may form part of the structural integrity of walls. Failure of glass or window frames will affect the rate of collapse, fire development and present a hazard of falling from height. Doors may not have intumescent seals to control the spread of smoke.
Consideration should also be given to the presence of asbestos. For more information refer to Hazardous materials – Health hazards – Safe method of work: Asbestos.
Prior to the introduction of building regulations, there was little control over the construction of staircases. Height and depth of tread, available head clearance, width and structural integrity of staircases may vary, making travel on staircases hazardous. Levels of protection are unlikely to meet the standards required for firefighting shafts, which should be considered when positioning bridgeheads.
Narrow streets, gated or arched entrances and unconventional paving materials may affect positioning of fire and rescue service vehicles. Bridges may have weight restrictions that restrict the route to the incident. For more information refer to Operations - Driving to incidents.
As firefighting water sources may be limited, it may be necessary to consider using alternative water supplies, such as lakes or ponds. For more information refer to Fires and Firefighting - Water and extinguishing media management and planning.
Layouts of buildings may be complex, with hidden access points or sections that have been blocked off or obscured. Extended travel distances and variation in ceiling heights should be anticipated.
Some buildings may have floors, such as attics, that are not accessible by all staircases, have varying floor heights and may not have windows; this may make it difficult to identify floors.
Chimneys in heritage buildings may not meet the required standard; beams or supports may intrude into the chimney. Chimneys may service several hearths, split over floors or across levels. This can allow fire or smoke to spread unchecked.
- Control measureSituational awareness: Fires in heritage buildings