Page 65 - kursus eBook

DRAFT GUIDELINE ON DOMESTIC GAS PIPING SYSTEM

INSPECTION, TESTING AND COMMISSIONING

Prior to acceptance and initial operation, all piping installations shall be inspected and tested
by a competent person to ensure that the materials, design, fabrication and installation
comply with the technical and safety requirements of the Gas Supply Regulations and
applicable standards.

Inspection shall consist of visual examination during or after fabrication, assembly or test as
appropriate.

Corrosion protective coating shall be subjected to holiday testing (test of the continuity of
protective coating) and coating defects or damage that may impair effective corrosion
control shall be repaired prior to installation in the ditch as specified by the relevant codes
such as MS 830 or National Association of Corrosion Engineers (NACE) Recommended
Practice.

The pressure or leak test medium shall be air or an inert gas (e.g. nitrogen, carbon dioxide).
Gas may be used as the test medium at the maximum pressure available in the system at
the time of the test.

Pipe joints including welds shall be left exposed for examination during the test. Expansion
joints shall be provided with temporary restraints, if required for the additional thrust load
under test.

Soapy water solution test may be used to locate leaks if all joints are accessible during the
test. The test pressures and duration for various sections of natural gas and LPG piping
systems are summarised in the table below:

LPG PIPING SYSTEM PRESSURE / LEAK TEST TEST REQUIREMENTS

Scope Maximum Type of Test Test Test Duration (minutes)
Operating Pressure
Pressure Test Medium kPa (psi) Above buried
kPa(psi) ground
Nitrogen
Pneumatic/ leak 1900 (275) 60
From tank/ Up to 1725 Air
manifold up to (250)
st
1 Stage Leak (during LPG Operating
Regulator commisioning) Pressure
Nitrogen
Pneumatic/ leak 345 (50) 60 1440
From 1 Stage Up to Air
st
Regulator up to 140 ( 20)
nd
2 Stage Leak (during Operating
Regulator commissioning) LPG Pressure
Nitrogen
Pneumatic / leak 40 (20) 30 1440
(appliances
disconnect) Air
nd
After 2 Stage Up to 7 (1) Leak (during Operating
Regulator commisioning) LPG Pressure

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