Sandwich Panels Sandwich panels consist of insulating material between two, usually light alloy panels. The insulating materials can be polyurethane or styrene foam, which as mentioned earlier, can decompose from the excess heat, give off flammable gases and aid the spread of fire. Sandwich panels are a common building material used in newly built structures, but they do have an additional problem of falling out of their framework which undermines the compartmentation of the building, allowing smoke and flames to spread, which could possibly lead to building collapse. Ventilation Systems Ventilation systems have previously been discussed in element 3, which mentions ventilation systems and the contribution of oxygen. A fire alarm system can be linked to the forced ventilation system, which automatically shuts down the ventilation system when the fire alarm has been activated. This will stop the additional supply of oxygen and prevent smoke and toxic fumes from spreading to other parts of a building. When fire alarms are tested, the ventilation should also be checked to ensure it shuts down when the alarm has been activated. Means of preventing external fire spread Construction of external walls and roofs The construction of external walls and roofs can dictate how fast a fire can spread. The structures should be able to withstand the effects of a fire. The case for fire resistance is a minimum of 30 minutes and in most cases 60 minutes. Roof coverings are finished with materials that are not readily combustible, so a roof is not normally vulnerable to fire from an external source. Generally, it is the manner in which roofs are constructed rather than the material used that is the major concern when dealing with the potential spread of fire. The pitched roof design is the most common method of construction and by its design, presents problems because of the large unused spaces that exist, i.e., lofts, attics, and voids between the ceiling of the rooms below and the weather covering. In some types of houses, for example, terraced properties and rows of cottages, these voids can extend unbroken over several dwellings, or in some cases, over the whole of a block of properties.
©SHEilds – All rights reserved FC V 5 JUN 2021
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