外文翻译--对防火安全因素的讨论
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外文原文 DISCUSSION OF FIRE SAFETY MATRIX The fire safety matrix considers the building height, sprinkler protection and the emergency strategy as the primary variables. This is due to the high influence that the interactions of these variables have on other fire safety measures. In addition to this, the fire engineer can specify the emergency strategy and sprinkler protection for the building that will provide flexibility to the matrix. Therefore once the extent of these three variables has been determined the remaining fire safety systems can be selected to suit the building. The objective of the fire safety recommendations is to address key issues that result from a given set of building characteristics, while providing multiple levels of protection for occupants in the event of a fire. This provides a backup or redundancy in the design in the event of one part of the system failing. For example, if the sprinkler system fails the occupants will be protected with passive protection and smoke control systems. The following sections discuss the three building height limits with respect to the fire safety measures that have been recommended. The staged evacuation strategy has not been discussed separately as it is a combination of the other two strategies and the same fundamental principles apply. 14.1 Buildings greater than 25m in height. Once buildings exceed 25m in height, the ability of the fire brigade to rescue occupants externally becomes limited. Therefore, a higher level of fire safety needs to be provided to the stairs and escape paths. Emergency lifts are also considered an option to provide rapid access for the fire brigade and egress for disabled occupants. As buildings become taller the level of fire protection needs to increase. This is due to: Further travel distances, resulting in a higher chance of exposure to fire and fire products, and longer exposure time. The reduced ability of the fire brigade to rescue people externally The increased time for the fire brigade to reach upper levels More occupants, resulting in a higher risk of injury and deaths There is a greater variability in occupant abilities and human behaviour, due to the greater number of occupants There are more sources of ignition and fire 14.1.1 Evacuation in buildings greater than 25m An evacuation strategy relies on the protection of egress paths, as well as the protection of occupants in their apartments before evacuation. The protection of egress paths is critical to ensure occupants are not evacuating through untenable conditions. In buildings greater than 25m high, egress distances can be consider able and therefore, the time occupants spend in escape paths can be significant. In a sprinkler protected building, protection is provided by: 1. The sprinkler system. The sprinklers will activate and extinguish or control the fire, reducing the threat to occupants. 2. Compartmentation and mechanical systems. Rooms, corridors and stair shafts are recommended to have a FRR of at least 30 minutes. This will contain the fire in the room of origin and protect occupants before and during egress. Self-closers provided on doors are to ensure the fire does not spread to the corridor. The stairs are to be pressurised to limit smoke spread, provide a partial safe egress paths and provide a smoke free area for the fire brigade. 3. The final level of protection is the fire brigade. The fire brigade’s role would be to assist any remaining occupants and extinguish the fire. A connection n to the fire brigade will be provided to achieve a faster response. In a non-sprinkler protected building the systems of protection are 2 and 3, as listed above,however the following other fire safety measures will be introduced to increase the level of protection: 1. An increased FRR to 60 minutes minimum. This is to provide additional time for occupant evacuation and fire brigade intervention. If occupants choose to stay in their apartments the increased FRR will provide a higher level of protection. 2. Connection to the fire brigade. To ensure a faster response by the brigade to a fire. 3. Emergency lifts to aid egress and fire brigade access 4. Zoned smoke control system. This is to ensure smoke spread through the building is minimised. This should include stair and corridor pressurisation to reduce the chance of smoke spread into the escape paths. 5. Lift and stair lobbies to provide an additional barrier against smoke and an area where occupants can wait for lifts or further instructions. These areas can be used as refuge areas or other pressurised refuge areas should be provided. 6. Emergency warning and intercommunication system. This will allow occupants to communicate with the fire brigade and inform them if assistance is required. 7. Additional protected stairs or reduced travel distances, as a trade-off for the limited ability of the fire brigade to externally rescue occupants. 14.1.2 Non-evacuation in buildings greater than 25m A non-evacuation strategy relies on the protection of the occupants in their apartments. There is a greater reliance on the fire brigade to extinguish the fire and assist occupants, if evacuation is necessary, during and after the fire is extinguished. In a sprinkler protected building, protection is provided by: 1. The sprinkler system. 2. Compartmentation and mechanical systems. The rooms are recommended to have a FRR of at least 60 minutes and to protect the occupants. The fire resistance rating should be designed so complete burn out of the apartment will not result in further fire spread. Self-closers and smoke seals should be provided on all doors opening into corridors. This is to contain the fire in the apartment of origin and reduce smoke spread to other apartments. In theory, there will be at least two doors with smoke seals between the fire and occupants. 3. The final level of protection is the fire brigade. The building alarm should be connected to the fire brigade to reduce the response time. In a non-sprinkler protected building the systems of protection are 2 and 3, as listed above, however the following other fire safety measures will be introduced to increase the level of protection: 1. Increase FRR to 90 minutes (minimum). This is to ensure complete burnout occurs before further fire spread. 2. Emergency lifts to aid egress and fire brigade access 本文来源：https://www.wddqw.com/doc/c0f63ca3824d2b160b4e767f5acfa1c7ab00828a.html