Explain the difference between open-circuit BA and closed-circuit BA?
Open-circuit BA
- Air that is exhaled by the BA wearer is expelled to the atmosphere.
- Working time of 24 mins
Closed-circuit BA
- The cylinder holds compressed oxygen
- Carbon dioxide is absorbed by the equipment and unused oxygen is re-circulated.
- Working time of up to 4 hrs
Why is a pressure scaling test conducted on a BA?
Ensures the BA cylinder is not leaking
Performed every 5 years
What are the (4) atmospheric hazards BA protects our airway from?
High air temperature
Oxygen deficiency
Toxic atmospheres
Smoke concentration
What are the (12) fundamental
expectations of FFs using BA?
- Don BA in fresh air.
- Work in teams of at least two (2).
- Select the designated fireground channel on portable radios.
- Deposit BA tally tags at a BA entry prior to entering a building.
- Enter correct and relevant details on the BA tally tag.
- Report to the BA entry and collect their BA tally tags on exiting the fire/incident.
- Check time out/low-air periodically.
- Exit the fireground accompanied by at least one (1) other member of the team when the cylinder pressure gauge of their BA reaches a pre-determined level, or the cylinder low-air warning signal operates.
- Proceed toward the sound of a full alarm or distress signal. Rendering assistance is to take precedence over the work in hand. Communication of the situation to BA Entry Officer/IC is required.
- All crews will withdraw immediately upon the operation of the evacuation alarm.
- Use guidelines on the instruction of the IC.
- Report to BA Service after collecting BA tally tags from the BA entry (if one is in operation).
How is working duration calcualted?
Air Contents of cylinders (L)/Consumption Rate (60 L/m) - Exit/Decon time (mins)
ie. (2040L/60L/m) - 10mins = 24mins
