Page 110 - CHEF Guide

Experience and Historical Incidents

Table 6-1 Common failure modes, causes, consequences, design considerations for fluid transfer equipment

Failure mode Causes Consequences Design considerations
Stopping Power failure Consequence to upstream or Power indication on pump
downstream equipment (HIRA
Mechanical failure Low flow alarms/interlocks
needed)
Control system action See Reverse Flow Level alarms and interlocks in other
(failure or intended) equipment
Deadheading or Pump/compressor Loss of containment due to Overpressure protection
Isolation outlet blocked in by: high temperature and
pressure causing seal, gasket, Minimum flow recirculation lines
Closed valves expansion joint, pump or
(manual, control, piping failure. Possible phase Alarms/interlocks to shut down the pump or
compressor on low flow or power
block) on discharge changes, reactions.
side, Limit closing time for valves
Plugged lines

Blinds left in
Cavitation / Blocked suction by: Loss of containment due to Low flow alarms/interlock to shut down the
Surging damage to seals or impellers pump or compressor
Closed inlet valves
Vibration alarms/interlocks
Plugged
filters/strainers
Reverse Flow Pump or compressor Loss of containment upstream Non-Return (Check) valves on discharge side
stops (Check valves are difficult to count on, their
Overpressure upstream
dangerous failure modes are difficult to
Contamination upstream diagnose or test for until they are actually
needed.)
Automatic isolation valves
Overpressure protection upstream
Positive displacement pump

Seal Leaks Particulates in feed Loss of containment due to Alarms or interlocks on seal fluid system to
damage to seals shutdown pump/compressor
Loss of seal fluids or
flushes Double mechanical seals with alarm on loss
of one seal
Small bore
connections Sealless pumps
Age (wearing out)
Contamination / Liquid in compressor Compressor damage Knock out pots before compressor
change of fluid feed
See Seal leaks

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