Vaporising Liquid Extinguishers (BCF & Halotron)
Vaporising Liquid extinguishers are the global and Australian standard for aircraft safety. They use specialised gas agents that leave no residue and are safe for use around delicate flight instruments and engines. While Fireshift does not currently service these units, they are a critical part of the Australian fire protection landscape.
Identification
Under AS/NZS 1841.1, Vaporising Liquid extinguishers are identified by a yellow band on a Signal Red cylinder. Because they are often manufactured to international aviation standards (such as UL ratings), they may be smaller and more compact than standard commercial units.
The Two Primary Types in Australia
There are two main agents used in Australian aviation, dictated by the age of the aircraft:
- Halon 1211 (BCF): Also known as Bromochlorodifluoromethane. This is the “legacy” agent. It is exceptionally effective but is a potent ozone-depleting substance.
- Halotron I (HCFC Blend B): The modern, environmentally preferred “Clean Agent” replacement for Halon. It offers similar performance but with a significantly lower impact on the ozone layer.
Fire Classes and Technical Ratings
According to CASA Airworthiness Bulletin AWB 26-002, these units are rated for:
- Class E: Electrically energised equipment. This is their primary role on an aircraft (cockpit electronics and cabin wiring).
- Class B: Flammable liquids (aviation fuel and hydraulic fluid).
- Class A: Limited effectiveness on ordinary combustibles.
Suppression Mechanism (Chemical Interference)
Unlike CO2 extinguishers which smother a fire by displacing oxygen, Vaporising Liquids work by chemically interrupting the combustion chain reaction.
- The agent is discharged as a liquid that rapidly “flashes” into a gas.
- It seeks out the fire’s chemical radicals and neutralises them.
- Because it does not displace oxygen to the same degree as CO2, it is safer for use in the confined spaces of an aircraft cockpit.
Regulatory and Compliance Constraints
The use of these extinguishers in Australia is strictly controlled:
- The Halon Ban: Under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989, Halon (BCF) is banned for general use. It is only permitted for “essential uses,” with aviation being a primary exemption.
- Licensing: Technicians handling or decommissioning Halon units must hold an Extinguishing Agent Handling Licence (EAHL) issued by the Fire Protection Industry Board.
- Aircraft Dates: As of 31 December 2018, all new aircraft manufactured or registered in Australia must be equipped with Halon-free extinguishers (such as Halotron I or SFFF for specific zones) where possible.
Technical Specification Table
| Feature | Halon 1211 (BCF) | Halotron I (Clean Agent) |
| Australian Band Colour | Yellow | Yellow |
| Primary Use | Aviation / Cockpit | Aviation / Clean Rooms |
| Ozone Depletion | High (Regulated) | Low (Approved Replacement) |
| Residue | Zero | Zero |
| Standard | AS/NZS 1841.7 | AS/NZS 1841.7 |
Export to Sheets
Why They Aren’t Used in Buildings
Vaporising liquid extinguishers are significantly more expensive than Dry Chemical Powder or CO2 units. Due to the high cost of the agent and the environmental regulations involved, they are reserved for high-value assets like aircraft and server rooms where “zero-residue” clean-up is a non-negotiable requirement.