Oxy-acetylene: Flash Back Arrestor
The incident started immediately after an attempt was made to ignite the burner torch of (new) oxy-acetylene equipment.
The operative felt the 'flash back' retreat into the acetylene hose and then heard a loud bang in the vicinity of the gas trolley outside. Whilst the flashback arrestor prevented the flame entering the cylinder the inline type of arrestor being used did not shut off the flame.
On approaching the trolley it could be seen that the acetylene hose had parted from the top of the cylinder and a large flame was being emitted from the open end of the flash back arrestor; the flame was trained on the side of the oxygen bottle.
The emergency services were called and, on arrival, the fire brigade set up a 200m exclusion zone around the cylinders and dowsed them with water.
ACCIDENT / INCIDENT IMAGES
LEARNING POINTS / ACTIONS TAKEN
Main Learning Points:
This incident is similar to one in 2009 when a fire broke out on a ship and again highlights the need to ensure the correct flashback arrestors are fitted and that they are regularly maintained.
All Oxy-acetylene and similar equipment should be checked as soon as possible. It is recommended that you consult with your equipment provider to ensure the correct protective devices are fitted.
Regulators on gas bottles and flashback arrestors should be checked prior to use and formally inspected every year, they should be replaced after 5 years (The British Compressed Gases Association (BCGA Code of Practice CP7)).
Arrestors that automatically shut off the gas supply and need to be reset should be used, particularly for full size gas cylinders and hoses longer than 5 metres.
Emergency procedures should be in place for all hot work and users of such equipment should be aware of them.
Whilst on this occasion, the equipment being used was complete, new and in good condition, supervision was in place and hot work permits etc had been complied with, users should ensure that;
- the correct type of flashback arrestor is used, that non return valves are fitted to hoses at the torch end, that pre use and regular formal checks are carried out.
- there is a written scheme that identifies all equipment and ensures annual inspections are carried out by a competent person.
- operatives including contractors are properly trained and regularly refreshed in the safe use of equipment including regulators, flashback arrestors and the opening/closedown procedures e.g. purging of hoses.
(see additional pdf
LEARNING POINTS / ACTIONS IMAGES
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