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Being heavier than air, CO2 does not dissipate easily. Low levels of exposure can result in headaches and dizziness, higher levels lead to laboured breathing and in worst cases, asphyxiation.
How to deal with a gas leak
To protect yourself and your staff against an accidental gas leak:
- make sure that you comply with all the regulations which apply to licensed premises
- always follow 'best practice' cellar management procedures
- install a gas monitor such as the Cellaguard CO2 monitor
Carbon dioxide (CO2)
CO2 is a toxic gas. It is heavier than air and, if there is a leak from a CO2 cylinder, it tends to accumulate on the floor and pushes the oxygen-rich air upwards.
Air normally contains about 0.03% carbon dioxide, but breathing air with increased concentrations of the gas can lead to effects ranging from heavy breathing and a feeling of suffocation through loss of consciousness to asphyxiation.
Nitrogen is not toxic but can cause asphyxiation by reducing the concentration of oxygen in the air.
Dealing with a gas leak
You should check your dispensing systems every day for faults by checking that all nuts and seals are tight and by listening for hissing sounds.
If you suspect that a leak has occurred, you must put emergency gas procedures into operation immediately.
Small gas leaks
A small gas leak may occur if, for example, a nut is not tightened or a gas seal is faulty. If you suspect a small gas leak has occurred, take the following steps:
- ventilate the cellar by opening all doors and cellar flaps (ensure there are barriers around the open flaps)
- prevent anyone from entering the cellar
Then enter the cellar...
- tell someone that you are about to go into the cellar, why, and how long you think you will be there
- turn and close off the carbon dioxide or mixed gas cylinder valve
- if possible, isolate the problem by switching off the individual secondary regulator valve, or checking connections if the leak is upstream of the secondary valves
- spray the cellar floor with water (carbon dioxide is very soluble in water)
- when you return from the cellar, tell the person you informed earlier
- let someone know whether it is now safe to enter
If at any time you feel the effects of increased carbon dioxide concentration (feeling short of breath, breathing faster), leave the cellar immediately and call for assistance.
Major gas leaks
A major gas leak can be caused by plant failure, or by a pipe or bursting disc rupturing.
A bursting disc is a quick pressure release system which ruptures if the pressure in the cylinder rises above a certain limit. It is designed to release the contents so that the cylinder itself does not burst. If a bursting disc ruptures there will be a sudden loud noise and a plume of white vapour as the gas is released. Also, the cylinder may fall over.
If there is a major gas leak, take the following steps:
- if you can do so without entering the cellar, turn off the gas supply
- inform all staff and evacuate the affected area
- call for assistance
- do not let anyone go into the cellar - under any circumstances - until you are sure it is safe to do so (emergency service personnel may enter if using self-contained breathing apparatus)
- open all outside doors and windows to ventilate the area
- close all doors to passages leading to any area where carbon dioxide could accumulate
- leave the cellar refrigeration switched on - the fans will help to disperse the gas
- if a bursting disc has ruptured, the cylinder surface temperature will be below freezing - do not touch a frosted cylinder without wearing protective gloves
If a gas leak results in a medical emergency (i.e. if someone has lost mobility or consciousness as a result of breathing a high concentration of carbon dioxide or nitrogen), take the following actions:
- call the medical and fire and rescue emergency services
- if the victim is in the cellar, do not go down to attend the victim as you may also be affected
- if the victim is not in the cellar, keep the victim warm
- apply artificial respiration if breathing has stopped
- follow the instructions of emergency services personnel