Commissioning Activities


Piping line walk before commissioning shall revisit the ITR-A, ITR-B and punch list during
pre-commissioning. It must be ascertained that all test packs and findings have been
closed out.

All Category B punch lists captured during line walk prior to commissioning work shall be
rectify ed and cleared. It shall be witnessed and signed off by the client.

Prior to pre-commissioning and commissioning, the contractor shall carry out line check/
line walk to check the facilities for correct erection and installation, operability, maintenance
requirement and safety of plant and personnel during operations in accordance with
accepted engineering practices. The company representatives must be present to witness
this. The contractor shall carry out all modifi cations and corrections in accordance with the
final punch list prepared jointly by the contractor and the company.

ITR-A and ITR-B with supporting documents, such as mill certifi cates, calibration certifi –
cates, etc., shall be made available prior to commencing ITR-C. Below is the ITR-C for
piping commissioning:

a) Reinstatement leak test
i. The leak test has been completed and accepted as per company procedure.
ii. Leak test result (leak rate and maximum permitted leak rate).
iii. The completed system has been de-pressurized and all signs and barriers have been
iv. All test equipment has been removed and line reinstated using witness joint
v. All associated P&IDs have been redlined as-built.
vi. The completed system shall be preserved with nitrogen (N 2 ) gas at one bar of

b) Witness joint
i. Prior to conducting reinstatement leak test, flange faces have been examined and
seen to be clean and damage free.
ii. Gaskets are of correct type and size.
iii. Nuts and stud bolts examined and seen to be not damaged and of correct size and
iv. Flange faces parallel.
v. Joint pulled up evenly on diametrically opposing stud bolts.
vi. All nuts pulled up to required tightness.
vii. No visible damage to gasket when joints completed.
viii. Maximum allowable of two threads through each nut.
ix. No excessive length of stud bolt protruding through each nut.
c) Purging
i. Verify that the reinstatement leak test for the system/sub-system/test package above
has been completed and accepted.
ii. The system shown on the attached P&ID (test package) has been purged and
achieved 7% O 2 content.

Mechanical completion of a system includes the following but is not limited to:
a) All design and engineering work has been completed.
b) All installation work for that system, including equipment, has been completed in accordance
with “Approved for Construction” drawings, specify cations, applicable codes and
regulations and good engineering practices. All tie-in connections have been made, all
testing and inspection completed and system/facilities are ready for pre-commissioning.
c) All instruments have been installed.

d) All factory acceptance tests and other testing and inspection activities have been
e) The contractor has obtained all relevant approvals from the company.
f) Safety studies have been completed and requirements of all the safety studies have been
met and all documentation put in place.
g) All required documentation and certify cation documents required by the contract have
been supplied.
h) All operating procedures and maintenance procedures have been forwarded to the company
well in advance for review.
i) All items for which the contractor is responsible for obtaining third-party, regulatory
or company approval have been obtained, and confirmation documentation has been
provided to the company.
Mechanical completion is defined as the state where all systems, including utility and
auxiliary facilities, have reached the condition of pre-commissioning stage and accordingly
been certify ed by the company.

“Release for commissioning” means the point at which the company issues a certifi cate to
the contractor saying that the system is ready for commissioning. Ready for commissioning
status shall be jointly reviewed by the company/contractor.
At this point, all systems and equipment shall be at a stage where process fluids can be
safely introduced and equipment can be safely operated with all control and safety devices
in-service/functional to meet the requirements as per design and specify cations.


Handbook of Oil and Gas Piping

Murali Sambasivan
School of Business, Taylors University Lakeside Campus,
Subang Jaya, Selangor, Malaysia

Sekar Gopal
Muhibbah Engineering (M) Bhd, Klang, Selangor, Malaysia

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1 Response

  1. Sultan says:

    All the subject it useful

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