Ventilation Flashcards
Describe windward
Up-wind side
Describe leeward
Down-wind side
4 benefits of ventilation
- Replenishing oxygen and reducing carbon monoxide levels
- controlling temperature and humidity
- Removing moisture, dust and other airborne contaminates
- improving visibility and aiding navigation
Tactical ventilation can be defined and applied by two main approaches
Offensive
Defensive
Tactical ventilation can be separated into two types:
Natural ventilation
- this is the process of supplying and removing air through a structure or space without using mechanical systems.
Forced ventilation
- this is the process of using fans, blowers or other mechanical systems to assist in creating, redirecting and managing air flow into and out of a structure or location so that the heat, smoke and fire gases are forced out.
There are two basic Ventilation techniques
Vertical ventilation
Horizontal ventilation
Examples of forced ventilation
Positive pressure ventilation (PPV) - using the fan to increase the speed of ventilation.
Negative pressure ventilation (NPV) -
referees to extracting the hot air and gases from the outlet vent. This applies the Venturi principle and can be achieved by fans or water sprays (hose reel)
HVAC and fire engineered systems -
These systems are often engineered into buildings so that in the event of a fire, they can be operated to ventilate public areas and support safe evacuation as well as improve conditions for responding firefighters.
These systems are using automatic but can also be operated by a manual override. HVAC -HEATING, VENTILATION AND AIR CONDITIONING.
Powered smoke and heat exhaust systems - these systems are generally operated automatically and are likely to be operating before the arrival of firefighters.
Can also be used manually.
Positive pressure ventilation phases
Phase 1: post fire ventilation
Once the fire has been completely extinguished, a defensive tactic.
Phase 2: ventilation
After control of the fire but before extinction.
Phase 3: Ventilation
Before Control of the fire. Offensive tactic.
CURRENTLY LINCOLNSHIRE FIRE AND RESCUE ONLY USE PHASE 1 - POST FIRE