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Australian Fire Engineering Guidelines abcb.gov.au Page 106 Step 5 Determine the possibility and time of spread due to the loss of stability of the boundaries (barriers) of the enclosure of fire origin. Barrier failure due to loss of stability involves the collapse of the barrier that may or may not be a structural element of the building. The ignition of combustibles in the adjacent enclosure may be due to radiation from hot gases and flames and the factors discussed in Step 4 apply. However, barrier failure alone may be taken as a criterion for flame spread into the adjacent enclosure. Step 6 Determine the possibility and time of failure of structural elements of the building due to the impact of the fire in the enclosure of fire origin based on information from the PBDB. Structural adequacy and the time to failure of structural components should be evaluated in terms of stability if their continued function is required for occupant evacuation or fire service intervention or to prevent collapse or impact on adjacent buildings or structures” Consideration to impacts on other items should also be given, such as people who may be walking past the building on the street, etc.. The extent and sophistication of the analyses applied to the structural elements in the presence of fire should be established during the preparation of the PBDB. The evaluation of the collapse mechanisms of complex and redundant structures may require input from structural engineers. Barriers that are supported by structural elements, or are structural elements themselves supported by other elements, may also fail when the supporting element fails. Thus, the time of failure of the structural element should be evaluated to ensure that the barrier it is supporting does not fail prematurely. If the analysis proceeds past the failure of the structural element, then the consequence of the failure of the element on other barriers (or elements) needs to be considered. Step 7 Determine if the end time has been reached. This is when:
the fire has extinguished |