Page 66 - kursus eBook

DRAFT GUIDELINE ON DOMESTIC GAS PIPING SYSTEM

NATURAL GAS PIPING SYSTEM PRESSURE / LEAK TEST REQUIREMENTS

Type of Test Test Duration (minutes)
Maximum Test Pressure
Scope Operating kPa (psi)
Pressure Test Medium Above Buried
kPa(psi) ground

Hydrostatic Water 345 (50)
or 1.5 MOP
From service / area Nitrogen 120 1440
station up to final Above 140 whichever is
stage regulator / (20) Pneumatic/ leak Air higher
meter
Leak (during
commissioning) Natural gas Operating Pressure
Up to Hydrostatic Water
140 (20)
345 (50) 120 1440
Nitrogen

From service / area Pneumatic/ leak
station up to final Air
stage regulator /
meter
Leak (during
commissioning) Natural gas Operating Pressure

Pneumatic/ leak Nitrogen 30 1440
(appliances 140 (20)
After final stage disconnect) Air
regulator / meter
Leak (during
Up to 7 (1) commissioning) Natural gas Operating Pressure

Note:
* Pressure chart recorders shall be used when underground piping systems are involved.
** Soapy water solution shall be used when a Gas detector is not available.

After the gas installation is satisfactorily tested for gas tightness as above, purging should
be carried out by using an inert gas throughout the entire gas installation in order to remove
all air or other gas mixture. If the gas installation is not to be used at once it shall be sealed
off at every outlet with the appropriate fitting.

Any loose connection in the gas installation used in the purging procedure and seal after the
purging procedure shall be retightened and shall be retested for gas tightness.

Upon the commissioning of the gas installation, the gas to be supplied through the
installation shall be conveyed into the entire gas installation to remove all the inert gas
present in the gas pipeline.

OPERATION & MAINTENANCE

Gas piping systems in service are subjected to various degrading or abnormal operating
conditions such as third party activities, corrosive environment, ground erosion, excessive
pressure fluctuations, malfunctioning or breakdown of components, material wear and tear,
and tampering.

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