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10 Cards in this Set
- Front
- Back
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Signs and causes of collapse of BEAMS in a building |
• Steel column or beams may buckle or bend due to high temperatures and if unprotected • Cast iron columns or beams may or shatter if rapidly cooled following exposure to high temperatures • Stone/concrete columns or beams may spall when hit with a jet |
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Signs and causes of collapse in WALLS in a building |
• Expansion of the inner face of the wall due to heat bowing the wall out of vertical. Cracks in the lower parts of the wall indicate danger • Walls can be made unstable by the collapse of floors leaving high walls unsupported • Collapse of beams or floor joists can lever wall off balance |
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Signs and causes of collapse in FLOORS in a building |
• Collapse of a building can leave high walls unsupported • The joists or beams built into a wall can have a leaving effect should they fall • if the floor collapses, the weight of the floor plus the rooms contents will drop at a speed onto the floor below creating a shock load. If this floor were to collapse then twice the weight would drop to the next floor down and rapid collapse of the building could happen |
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List of signs of building collapse |
• fall of pieces of mortar, stone etc • floors coming away from walls • collapse of floor • columns or beams bending or falling • cracks in walls particularly horizontally • spalling of concrete • collapse of arches above openings • damage or collapse of the wall of a protected shaft |
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Operational considerations/hazards with Floors |
• burning and smoke travel under floorboards • carpets and other floor covering may suppress smoke and hide damage • most electrical wirings run through this space • collapsing floor joists may lever a wall off balance |
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Operational considerations/hazards with Stairs |
Timber Burns well, may be burning underneath and show no sign of danger until collapse Concrete Best fire resistance material for stairs Steel Often outside and retain strength until fire is serious. It loses 2/3 of its strength at 600•C and conducts heat Cast Iron Will crack when exposed to heating and localised cooling Stone If heated then cooled with a jet can cause the stone to spall and crack. Only used in exceptional circumstances e.g to gain access to life |
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Operational considerations/hazards with Gang Nails |
• can be severely damaged by fire • takes 7 minutes to char to a depth of 4mm • any failure on the roof member can lead to immediate collapse |
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What is a Sandwich Panel |
A sheet of material that has become commonly used to cover the lightweight steel or precast concrete structural frames. It is low costing and easy to install |
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Hazards and risks with Sandwich Panel |
• PVC coating allows for rapid surface fire spread • heat conducts through sheet metal, rapidly degrading the core and causing extensive smoke production • can release flammable and toxic gas e.g hydrogen cyanide and carbon monoxide • are not structurally solid when subjected to heat, leading to collapse without warning • extinguishing media cannot be used easily • sheet may fall away causing hazards |
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What is the Evacuation Signal, who initiates it and how to act when its heard |
The signal consists of short repeated blasts on the acme thunder whistle It is sounded when the incident commander or other personnel become aware of a risk or injury due to the detection of unsafe working conditions
• Repeat the signal • Withdraw from area quickly and safely. Crews closest withdraw, crews in least danger protect exit routes • leave any equipment • report to the booking in point e.g initial command pump or command unit |
