IGEM/UP/2 Edition 3, Relating To Boiler Rooms

IGEM/UP/2 Edition 3 – Installation pipework on industrial and commercial premises

Within IGEM/UP/2 it highlights the potential risks surrounding the control of gas solenoid valves (AIV’s) and automatic restarting.

POTENTIAL HAZARDS

“A potential hazard could arise from the use of an AIV (valve) if it were to close and reopen without ensuring that any appliance installed downstream is isolated.”

“Under such circumstances, when the valve is re-opened, gas would escape from any appliance which had not been turned off (automatically or manually) thus creating a potential hazard.”

“A potential hazard is most likely to occur on a valve that restores itself automatically to an open position on removal of the fault which caused it to close.”

Examples of such an event are:

• a transient loss of electrical supplies (which can lead to significant operational problems).
• activation upon testing a fire alarm.
• a transient or intermittent fault of an interlock that actuates the valve.

It is argued that a boiler installation is a sealed installation and all appliances have flame safety devices fitted (FSD) so therefore gas proving is not required.

However, if you consider that flame safety devices can take several seconds to close after a valve has isolated, the gas pressure between the closed valve and the burner can be significantly reduced which would then require a tightness test before the supply could be restored.

Let us take the example of a fire system activation, emergency stop activation or power failure which deactivates a safety shut off valve controlling the gas supply to the boiler room.

After the test or activation, the control panel is reset, and the gas supply is normally automatically re-established. The boilers are then relit and operated as normal. In most cases, the supply has been re-established successfully with no apparent hazard or risk.

However, we must note, as indicated by the Health and Safety Executive and the gas industry in general, where we identify any risks which may create a hazard we should introduce control measures such to either alleviate or reduce these risks.

Gas pressure proving is used as a measure to confirm the integrity of the system either to negate any leakage or, if confirmed, warrant investigation and repair.

The installation of a gas proving system has many additional benefits the main one being that if the system is isolated as a result of a power failure or fire alarm activation, once power is resumed or the fire alarm has been reset, the system will automatically restart and perform a pressure prove, reducing the potential for site downtime or damage subsequent to pipes freezing.

If you require any additional information on our systems to help meet these design standards or wish to discuss the standards further please don’t hesitate to contact us.