1. De-energize electrical equipment and cover
When piping is under repair, secure and tag out the
isolation and cutout valve connecting the dead
with a waterproof material.
portion(s) with the live portion to indicate that
NOTE: If it is not possible to de-energize the
personnel are working on the dead portion(s). Do not
electrical equipment before work on the piping system
remove the tags until it is determined that this will not
begins, completely cover with a rubber sheet or other
create a hazard to personnel working on the dead
portion or until the work on the dead portion is
nonconductive waterproof material. Do not restrict
completed. Open drain connections to atmosphere on
ventilation to the point that equipment will overheat.
all the dead interconnecting systems for visual drainage
2. Open piping away from electrical equipment, at
a lower level if feasible, to ensure that the line is
completely drained and unpressurized.
PRECAUTIONS FOR BREAKING LINE
Early detection and correction of defects will
AND VALVE BONNET
reduce the amount of effort required for repair and will
provide more satisfactory operating conditions.
Before breaking a line or valve bonnet joint, or
cutting into a line, ensure that the following conditions
are in effect:
1. Shut and secure valves isolating the section in
such a manner that they cannot be opened accidentally,
either locally or remotely.
Take up small leaks in gaskets immediately. If
allowed to persist, the leaks will become progressively
2. Completely drain the line or vent with no
pressure on the line.
worse and may eventually cause a blowout. In addition,
flange faces in high-pressure joints will become cut and
3. Take precautions to prevent fire or explosion
require rebuilding and refacing.
from flammable fluid.
When continuing or repeated leakage, breakage, or
4. Shut and tag out valves isolating the section
according to current shipboard and applicable OPNAV
failure occurs in a piping system, determine and correct
the cause. Common causes are as follows:
5. Provide adequate ventilation.
6. Provide any compartment that contains a fluid
Inadequate allowance for thermal expansion,
energy accumulator (or to which a large volume of fluid
working of the ship, and other movements
energy can be released) with two-barrier protection if
the released volume, in standard cubic feet, is twice the
Hydraulic transients (water hammer)
In breaking flanged joints, make sure that the two
diametrically opposite securing nuts remain tight while
Rapid temperature changes
the remainder are slackened. Then slacken these two
nuts sufficiently to permit breaking the joint. After the
joint is broken and the line or valve proven clear,
remove all nuts.
PROTECTION OF ELECTRICAL
Before working on any piping system, make a
It is of the utmost importance that NO
survey to ensure that under no condition can any liquids
explosive conditions exist prior to using
splash on exposed electrical equipment. If there is any
spark-producing tools or burning equipment.
possibility of splashing a switchboard or other electrical
equipment, take the following steps: