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13 Cards in this Set
- Front
- Back
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What is ventilation? |
The removal of heated air, smoke or other airborne contaminants from a structure, and their replacement with a supply of fresher air. |
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What's the purpose of ventilation ? |
The release the products of combustion from a building compartment, to prevent fire spread and damage to property.
If managed - reduces temp and improve visibility Incorrect tactic = rapid fire development |
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The 3 ways a fire can be ventilated : |
1 - Self ventilation- eg roof collapse = increase in ventilation 2 - Automatic ventilation - eg pre-installed vents such as roof lights/windows 3 - Tactical ventilation - used to assist FF and requires FF to release products of combustion and allows fresher air to enter. |
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What are the benefits of tactical ventilation?
AIRSI |
A - Assist the escape of ocupants and FF by restricting spread of smoke I - Improve conditions fro FF and trapped occupants R - Reduce fire spread and property damage by controlling movement of hot smoke and gases S - speed up rescue operation and fire attack by reducing heat and smoke I - improve visibility |
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What are the basic principles of ventilation HHHOC |
H - hot gases should be released from area at greatest height possible and replacement of fresh air should be at a low level H - high level vent should be downwind of low level to take advantage of the wind introduced air flows H - high level of vent should be made before low level vent O - Outlet vents should be protected By FF in BA with charges branch (cool hot gases to prevent ignition and fire spread) C conditions indicate signs of a potential back draught, the compartments should be ventilated from outside the building when possible |
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Stages of a fire where tactical ventilation can be introduced |
After the arrival of LFB but before control is achieved After controls before fire extinction After fire extinction |
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Types of ventilation 2 types |
Defensive ventilation Offensive ventilation |
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Defensive ventilation characteristics |
Carried away from fire - improves escape route, access and searching conditions Venting adjoining and outer compartment fires has been isolated and supressed |
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Offensive ventilation characteristics |
Carried out to directly affected bu fire itself, to limit fire spread, improve conditions within fire compartment Approach is safer for FF Before outlet vent ope ed in offe sibe operations, vent just be covered with charged branch Don't direct water through vent when ventilation taking place. |
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What are the two ventilation options |
Vertical ventilation Horizontal ventilation |
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Characteristics of vertical ventilation |
- placed as high as possible - used when fire is in or has spread to the roof or structural voids - where there are verertical shafts with building - use roof lights or dormer if not make vent by removing slates or tiles etc
Advantages:
min risk of backdraught Min fire spread Rapid smoke clearance
Disadvantage:
Might need to be in roof = hazardous Fewer opp to make vehicle vent |
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Characteristics of horizontal ventilation |
Do as high as possible on a wall Make use of doors and windows - try not to break window and be sure door stays open Should be carried out from outside if possible after appropriate control methods are implemented |
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What should the IC before tactical ventilation can take place
MUDSMIN
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M - make sure adequate resources available U - undertake DRA D - decide whether horizontal/ vertical is more appropriate S - select inlet and outlet vent are covered with a charged branch 45mm M - Make outlet before inlet vent I - Identify wind direction N - notify all crew members of the intention to start ventilation
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