Page 112 - CHEF Guide

Experience and Historical Incidents

Table 6-2 Common failure modes, causes, consequences, and design considerations for heat exchange
equipment.

Failure Causes Consequences Design Considerations
Mode
Leak from heat Corrosion from Loss of containment Periodic inspection
transfer contaminants in the process
surface fluids, and cooling fluids, Inadvertent mixing and Choice of materials of construction
contamination of low
and/or loss of treatment Choice of heat transfer fluid
chemicals. pressure side, potential
reactions, (HIRA needed) Shell expansion joints
Anaerobic attack under
sediments and scale. Non shell and tube design
Thermal stress (e.g. Control of introduction of process fluids
extreme heat/cold) during startup and shutdown
Monitoring of low pressure side fluid
Toxic fluids in tubes, monitor shell side.
Treatment chemicals
Rupture from Corrosion Potential rupture of heat Emergency relief device
heat transfer exchanger
surface Thermal stress (e.g. Control of introduction of process fluids
extreme heat/cold) Loss of containment during startup and shutdown
Operation out of design
temperature range resulting
in stress cracking or
weakening of tubes or
tubesheet (see loss of
cooling or heating load)
Blocking in one fluid side
during operation
Loss of cooling Loss from supply Loss of process control Alarms / interlocks on low flow or pressure
or heating fluid (HIRA needed) of heat transfer medium
Control system malfunction
High pressure High or low temperature alarms on process
Pluggage or Mis-valving
side
Inadequate Fouling Loss of process control Ability to clean
heat transfer (HIRA needed)
Accumulation of non- High or low temperature alarms on process
condensable gases (mostly High pressure side
condensers)

6.5 Mass Transfer: Distillation, Extraction, and Absorption

Mass transfer operations are used to separate materials, purify products, and detoxify waste streams. Knowledge of
the properties of the materials being handled is necessary to assess the hazards of the potential failures of mass transfer
equipment.

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