A loss of containment and subsequent release of fluids can cause adverse consequences (i.e., impact safety, health, and environment, cause production losses, and
incur maintenance and reconstruction costs). The risk analysis should consider the nature of the hazards and ensure that appropriate factors are considered for the equipment items being assessed.
Flammable Events (Fire and Explosion)
Flammable events occur when BOTH a leak and ignition occur. The ignition could be through an ignition source or by auto-ignition. Flammable events may cause damage in
two ways: thermal radiation and blast overpressure. Most of the damage from thermal effects tends to occur at close range, but blast effects may cause damage over a larger distance from the blast center.
Typical categories of fire and explosion events include
- vapor cloud explosion
- pool fire
- jet fire
- flash fire
- boiling liquid expanding vapor explosion (BLEVE)
Consequence of Flammable Events
The consequence of flammable events should typically be derived from a combination of the following elements:
- location and type of ignition sources
- the volume of fluid released
- ability to flash to a vapor
- possibility of auto-ignition
- effects of higher pressure operations
- engineered safeguards
- personnel, equipment, and infrastructure exposed to damage (on-site and off-site)
Toxic Releases
Toxic releases may cause effects at greater distances than flammable events, and unlike flammable events, toxic releases do NOT require an additional event (e.g., ignition, as in the case of flammables) to cause personnel injuries.
The RBI program typically focuses on acute toxic risks that create an immediate danger. Other programs should typically address chronic risks from low-level exposures.
Consequences of Toxic Releases
Consequence should typically be derived from a combination of the following elements:
- the volume of fluid released and toxicity
- ability to disperse under the expected range of process and environmental conditions
- detection and mitigation systems
- population in the vicinity of the release
Releases of Other Hazardous Fluids
Other hazardous fluid releases are of most concern to RBI analysts when they affect personnel. These fluids may cause thermal or chemical burns if a person comes in contact with them. Common fluids, including steam, hot water, acids, and caustics, may have a safety consequence and should be considered as part of an RBI program. Generally, the consequence of this type of release is significantly lower than for flammable events or toxic releases because the affected area is likely to be much smaller and the magnitude of the hazard is less.
Consequence should typically be derived from a combination of the following elements:
- the volume of fluid released
- personnel density in the area
- type of fluid and nature of the resulting injury
- safety systems (e.g., personnel protective clothing and showers)
Source: ASME PCC-3