Guideline for Safety Consequence Severity Assessment

B.1. Introduction

For consequences that may have impact on safety, those associated with release of an hazardous fluid due to loss of containment, in the following sections a guideline to assess the consequence severity is detailed.

The associated leakage rate/size, see Tables here below, can be also used to assess environmental consequences, if safety consequence severity are not the governing (worst) case.

The following parameters are taken into account in the severity assessment:

r ratio between the release pressure (max pressure that may be reached in the system due to a process upset), divided by the equipment / piping design pressure

dT difference between the release temperature (max temperature that may be reached in the system due to a process upset), and the equipment / piping design temperature

Released fluid characteristics (toxic / highly toxic, flammable / highly flammable)

DP Equipment / piping design pressure