Page 3 - LOPC Survey

Analyzing Loss-Of-Containment Scenarios with Typical Preventive Safeguards

In 2008, the Center for Chemical Process Safety (CCPS) published its Third Edition of Guidelines for
Hazard Evaluation Procedures [1]. The Guidelines differentiate between safeguards, containment and
control, as illustrated in Figure 1.5 of that document. In the context of process hazard analyses, a
safeguard is defined as any device, system, or action that would likely interrupt the chain of events
following an initiating cause or mitigate the loss event impact [1].

Many process hazard analysis (PHA) scenarios that could lead to loss of containment focus heavily on
preventive safeguards, as illustrated by the following Hazard and Operability (HAZOP) Study scenario:

Guide Deviation Cause Consequences Safeguards
word

MORE Fluid pressure Pressure Overpressurize downstream • Vent excess pressure to
> [high limit] to regulator piping and/or vessels; fail flare automatically
downstream fails open primary containment; release • Pressure safety valve sized
process to surroundings for regulator failure

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