Central Gas System Safety

• Heavier than air: it accumulates at low level, so detectors sit near the floor and low areas are ventilated.
• Flammable within a specific concentration range: the engineering objective is preventing that mixture from forming at all.
• Stored as liquid, used as vapour: the available withdrawal rate is limited by vaporisation in the tank.
• Odourised to aid detection, but odour is never a substitute for a detection system.

• Design: keeping storage away from occupied spaces and defining safe, inspectable routes.
• Installation: suitable materials and connections, disciplined workmanship, tightness testing before covering.
• Ventilation: preventing accumulation in enclosed and low areas.
• Detection: detectors in correct positions wired to a control panel.
• Shut-off: an automatically closing solenoid valve plus manual valves in known positions.
• People: trained staff who know the emergency procedure and where the shut-off valve is.

• Shut off the gas at the main valve or the emergency stop.
• Do not switch any electrical device or switch on or off in the area.
• Open natural ventilation and evacuate people from the space.
• Exclude any ignition source from the surroundings.
• Do not restore service before a technical inspection identifies and resolves the cause.

Protection systems age silently: a detector whose sensor has expired, a valve untested for years, a cracked flexible connection behind an appliance. Documented periodic inspection is the difference between real protection and installed devices nobody knows still work.

• Disabling a detector or disconnecting the sounder because it is a nuisance.
• Storing materials in front of the shut-off valve or around the tank.
• Adding new appliances to a network whose capacity was never reviewed.
• Using unsuitable or expired flexible connections.
• No emergency-procedure training for new staff.