After
all preparation work is complete to the satisfaction of the supervisor, toolbox
talk held and risk assessments Implemented; the test may commence using the
following:
The
individual system documentation i.e. test pack shall be available prior to any
testing and shall include information such as test limits, test pressure, test
medium, duration, test blinds, blind flanges, vents and drains.
The
use of marked up P& Ids coupled with isolation registers should be utilized
to identify the locations of blinds, valves, vents and drains.
Testing
equipment such as pumps, manifold, pressure and temperature recorders, pressure
gauges should be within calibration/certification (as per company procedures)
and connected to the lowest convenient connection within the system to ensure
best results.
Pressure
gauges should be fitted at both low and high point when testing large volume
systems.
The
potential of failure due to brittle fracture of material or freezing of the
medium should be considered.
The
system shall be filled from the lowest available point; all vents and high
point connections shall be open during this operation to allow the air in the
system to vent off.
After
the system has been completely vented all vents and drains should be plugged or
blinded. Verify that valves are in place and open/closed as required.
Barriers
shall be erected and where practical, Public Address announcements made and
access restriction procedures such as permit to work implemented prior to any
pressurization commencing.
For
high-pressure systems the test pressure shall be reached in stages, each stage
allowed to stabilize then visually checked for leaks. Once the pressure has
been reached the system shall again be visually checked for leaks.
Under
no circumstances should anyone other than an authorized person be allowed
within the safety barriers.
If
a leak is found the system shall be de-pressurized and the source repaired.
After
any leaks have been repaired the system shall again be pressurized to the test
pressure in stages.
The
test should be witnessed and accepted by a third party, client representative
or a responsible person within the company and signed as accepted.
Pressure
and ambient temperatures should be recorded throughout the complete test cycle.
These charts should form part of the Hydrostatic Test Documentation.
On
completion of the test, the system shall be depressurized by controlled means
and all vents opened prior to draining of the system to avoid any vacuum within
the system.
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