Guidelines for Health and Safety on Board Small Fishing Boats

Many small vessels are fitted with refrigeration systems to either chill their holds, or freeze catch. Refrigerant gas or liquid:

• is poisonous to humans,
• affects running machinery and
• is bad for the environment if leaked.

There are a range of refrigerant gases used and all are hazardous. For this reason these systems have to be well maintained and crew have to be aware of the dangers and action required in the event of a leak.

Refrigerants used

In the past chlorofluorocarbon (CFC) refrigerants R-11, R-12 and R-502 were common. The Ozone Layer Protection Act (1996) meant that CFCs could no longer be used in refrigeration systems. New refrigeration systems use more environmentally friendly hydrochlorofluorocarbon (HFC) refrigerants.

These days, the most common refrigerants used on small vessels are Freon R-22 and Freon 134a. Freon is actually a trade name, so the number is the important identifier.

Don’t inhale refrigerant gas!

Refrigerant hazards

• Freon cannot be seen or smelt!
• Freon is heavier than air so it will “fall” into the vessel and stay sitting in the bottom of the compartments.
• Freon is extremely harmful if it comes into contact with the eyes.
• Freon is suffocating because it displaces air.
• If you inhale high concentrations of Freon, it attacks the nerve system.
• When Freon comes into contact with hot surfaces and starts to burn, it can give off poisonous gases.
• Freons, if released into the air, may cause depletion of the Ozone Layer which contributes to the greenhouse effect. Refrigerants are not to be released into the atmosphere. They must be drawn into the condenser/receiver or into a separate cylinder.
• Most refrigerants mix with oil so oil drained from a refrigeration system must be clearly labelled and disposed of separately.
• Refrigerants must not be mixed.

If you start feeling faint or dizzy as you enter a compartment - don't think twice - evacuate!

If a refrigerant leak occurs

• Evacuate compartment immediately.
• Sound alarm and get crew in an up-wind position.
• If leak is in engine room shut down machinery.
• Turn vessel into wind if still possible.
• Do not enter compartment without ventilating the compartment.
• Ventilate compartment. Remember Freon sinks to the bottom of the compartment and is very hard to remove. Try to force airflow down into the bottom of the compartment to force the Freon upwards.

Maintenance points.

• Refrigerant pipes are lagged and constantly damp. This means that pipe coatings and surface can deteriorate relatively quickly. Check pipes regularly and make sure the coating is maintained.
• Where flexible hoses are used, only use refrigerant tolerant hoses. Try to avoid using flexible hoses wherever possible.
• Maintain fittings such as valves and gauges in good order.
• Mark pipes to show what type of refrigerant they have in them.
• Refrigerants are supplied in metal cylinders which will corrode in the salt environment. Make sure these are left in dry storage (preferably ashore).