Tightness Testing Quiz

Several of the tests that may be undertaken when tightness testing specify the pass criteria as ‘No Perceptible Movement’, when testing with a suitable electronic gauge accurate to two decimal places this means a gauge movement of:

• 0 mbar.

• Less than 0.25 mbar.

• Less than 0.5 mbar.

• Less than 1.0 mbar.

What is the MAXIMUM permissible pressure drop during the tightness test on an existing natural gas installation consisting of a U6 (diaphragm) meter, a maximum pipework diameter of 22 mm, a volume of 0.008 m³, appliances connected but not isolated and no smell of gas?

• 0 mbar.

• 2 mbar.

• 4 mbar.

• 8 mbar.

What test medium may be used when testing a new installation before it is connected to a live natural gas supply?

• Air.

• Nitrogen.

• Carbon Dioxide.

• Liquefied Petroleum Gas (LPG).

If, after the completion of a satisfactory tightness test, a smell of gas occurs around a lit appliance but disappears when the appliance is turned off the gas operative should:

• Contact the Gas Safe Register.

• Notify the Health & Safety Executive (HSE).

• Check pipework downstream (on the outlet) of appliance control taps, flame supervision devices, etc. with leak detection fluid.

• Contact the Emergency Service Provider (ESP) in order that they can check the service pipe upstream (on the inlet) of the gas meter / emergency control valve for gas escapes.

When carrying out a tightness test on an installation supplied through an electronic token meter (ETM) the gas operative must ensure great care is taken to prevent the:

• Gas pressure from falling below 24 mbar.

• Anti-tamper device on the meter activating, shutting off the supply to the installation.

• Anti-tamper device on the regulator activating, shutting off the supply to the installation.

• Anti-tamper device on the regulator activating, increasing the pressure to the installation.