wT 1255/12
Page 7
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when applying internal pressure for the first time (pressure test, trial operation) a
sufficient safety distance is to be maintained.
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it is prohibited to open screw connections (with the exception of those on hand
levers and handwheels), when pressurized (medium).
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installation and removal of valves is only carried out with a depressurized and
drained pipeline.
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all connections, following loosening, are again correctly tightened afterwards.
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no screws are loosened on pressure-retaining parts, unless described so in the
operation manual.
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no screwed connections are forcibly opened.
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during longer shutdown periods, in the event of freezing media, the valve is drained
and/or that depressurization is achieved in case of expanding media.
6.3
Hazard Warnings
Mechanical hazards:
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Beware of possible sharp or protruding parts posing risk of injury.
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Extra care is required during putting into operation: Do not reach into the bore
opening during the valve closing process, as this poses a risk of injury.
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Be careful of falling parts during transportation, maintenance and putting into
operation.
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When manipulating lifting appliances, the safety regulations for lifting appliances
must be complied with.
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Unauthorized and improper handling can result in undesired and spontaneous
pressure loss and can result in significant damage.
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With regard to valves featuring a mounting bracket it must be ensured that moving
valve parts do not result in a risk of injury.
Electrical hazards:
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With regard to valves featuring electric actuators, the operating manual and the
safety instructions of the actuator manufacturer must be complied with.
Thermal hazards:
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During operation, the surfaces of valves may feature high / low temperatures.
Caution: Burn hazard.
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Caution: The hot surfaces can cause self-ignition of flammable materials through
either contact or heat emission.
Hazard generated by noise:
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Depending on the application conditions, high levels of noise can be created by
the cavitation processes, which bear the risk of hearing damage.
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Opening an internally pressurized valve can result in major noise exposure as a
result of exiting media; hearing damage hazard.
Vibration hazard:
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Caution: Abrupt opening or closing of a valve can lead to undesired surges and
vibrations in the pipe, which may possibly damage the valve or the pipeline system.