NT WorkSafe recently issued a safety alert highlighting the dangers of using pressurised canisters following an incident in which a worker was injured.
The worker, a Darwin refrigeration mechanic, was injured when a flushing canister he was using to clean an air conditioning system over pressurised and ruptured.
Flushing canisters are primarily used by refrigeration and auto mechanics to service refrigeration and air conditioning systems.
The flushing canister contained a cleaning solution used to flush out and clean the pipes of air conditioning units. The flushing canister, which had a safe operating pressure of 1034 kpa was connected to a nitrogen cylinder via a pressure regulator.
The storage capacity of the cylinder was 16,000 kpa of pressurised gas, and the flushing canister ruptured when the worker released the handheld flow control.
The safety alert suggested a number of required actions:
Consider other options to clean the internal pipes that avoid using high-pressure gas (eliminate the risk).
If pressurised gas flushing system is used, all components of the pressure equipment should be thoroughly inspected for wear or damage before connection and use.
The flushing canisters should be fitted with an engineered pressure relief device.
Before the flushing canister is connected, the flow pressure from the regulator must be set according to the flushing canisters manufacturer’s instructions so that the delivery pressure cannot exceed the safe working pressures of the components it supplies.
If a pressurised flushing system is to be used ensure that before releasing the handheld control valve, the operator first isolates the supply of gas at the cylinder valve and wait for the regulator gauge to drop and indicate “0” pressure. The hand control can then be released.