Gas information sheet 24: Raising gas pressure to 2.75 kPa in existing installations
The purpose of this Information Sheet is to explain the requirements where the metering pressure of an existing gas installation is to be raised to 2.75 kPa.
Gas company approval
Gas retailer approval must be sought and given prior to work commencing because adjustments are required to be made when calculating actual gas usage for billing purposes.
For technical reasons associated with the gas distribution network, not all areas can be provided with the higher pressure at this time.
For ‘Standard Installations’ a Compliance Certificate number must be provided to the gas company prior to final acceptance.
For ‘Complex Installations’, an Application for Acceptance of Complex Gas Installations and Type B Appliances must be submitted to ESV prior to supply approval being given.
Gas companies will not increase the metering pressure until the procedure is completed.
Existing consumer piping
Existing consumer piping is to be tested at 4 kPa (lock-up pressure). There is no allowable leakage rate; therefore the installation must be sound.
Pipe-sizing can be verified using the appropriate tables in AS/NZS 5601.1: 2013 or any other acceptable method with an allowable pressure drop of 0.75 kPa.
Installations containing old galvanized steel piping should be examined for corrosion, particularly at each joint.
There is no change to appliance operating pressures. Type A appliances operating on Natural Gas have a burner pressure of 1 kPa or less.
Most modern appliances are fitted with a gas pressure regulator that will operate satisfactorily with a 2.75 kPa metering pressure.
However, regulator adjustment may be necessary when the metering pressure is increased. The burner pressure of each appliance must be checked.
Occasionally, there will be appliances that have a pilot supply taken off before the gas pressure regulator (most storage water heaters). There are two alternatives:
(a) adjust the pilot gas rate and check the flame understanding and flowing gas pressure conditions
(b) install a suitable regulator upstream of the appliance.
Appliances over fifteen years should be treated with caution as they may not be suitable for the higher pressure. It is advisable to:
(a) inform the customer that the appliance may be obsolete or unsuitable for the higher pressure; and
(b) if the appliance is operating well, fit an upstream gas pressure regulator; and
(c) replace any obsolete regulator.
For further information please phone the Gas Safety Technical Information Line on 1800 652 563.