CCPS Process Safety Glossary

A gas with density less that of air at ambient temperature.

Generic term for subdivided solid material, comprising pellets, granules, and dust. Pellets have a diameter greater than 2 mm and typically above 3 mm, although they may contain granules and small quantities of dust. Granules (e.g., granulated sugar) have a diameter between 0.42 and 2 mm, although granular powders typically contain dust. Dusts have a diameter less than 0.42 mm and as low as 1 micron. Suspended particles smaller than 1 micron are known as fumes. In European publications, pellets are typically described as granules.

A systematic and thorough check of a process prior to the introduction of a highly hazardous chemical to a process. The PSSR must confirm the following: Construction and equipment are in accordance with design specifications; Safety, operating, maintenance, and emergency procedures are in place and are adequate; A process hazard analysis has been performed for new facilities and recommendations have been resolved or implemented before startup, and modified facilities meet the management of change requirements; and training of each employee involved in operating a process has been completed.

An equipment maintenance strategy based on measuring the condition of equipment in order to assess whether it will fail during some future period, and then taking appropriate action to avoid the consequences of that failure.

In a compartmented system in which there are separate but interconnected volumes, the pressure developed by the deflagration in one compartment causes a pressure rise in the unburned gas in the interconnected compartment, so that the elevated pressure in the latter compartment becomes the starting pressure for a further deflagration. This effect is known as pressure piling, or cascading.

See Pressure Relief Valve

A barrier designed to interrupt the chain of events leading up to a loss event, given that an initiating event has occurred.
Note: Specific to the hazards evaluation of an incident sequence, a preventive barrier is in between the initiating event (the cause) and a loss event, helping reduce the frequency of the incident scenario, and thus, helping reduce the scenario's risk.  

Measures taken at the initial stages of a runaway to avoid further development of the runaway or to reduce its final effects.

A basic independent event for which frequency can be obtained from experience or test.

The expression for the likelihood of occurrence of an event or an event sequence during an interval of time, or the likelihood of success or failure of an event on test or on demand. Probability is expressed as a dimensionless number ranging from 0 to 1.

A random variable with a mean of 5 and a variance of 1, which is used in various effect models. Probit-based models derived from experimental dose-response data, are often used to estimate the health effect that might result based upon the intensity and duration of an exposure to a harmful substance or condition (e.g., exposure to a toxic atmosphere, or a thermal radiation exposure).

A broad term that includes the equipment and technology needed for petrochemical production, including reactors, tanks, piping, boilers, cooling towers, refrigeration systems, etc.

A diagram that shows the material flow from one piece of equipment to the other in a process. It usually provides information about the pressure, temperature, composition, and flow rate of the various streams, heat duties of exchangers, and other such information pertaining to understanding and conceptualizing the process.

A PSM program element that includes work activities to gather, organize, maintain, and provide information to other PSM program elements. Process safety knowledge primarily consists of written documents such as hazard information, process technology information, and equipment-specific information. Process safety knowledge is the product of this PSM element.

The stages that a physical process or a management system goes through as it proceeds from birth to death. These stages include conception, design, deployment, acquisition, operation, maintenance, decommissioning, and disposal.

CCPS RBPS Element 03: This Element is a system that focuses on the collective skills and essential resources that the facility needs to manage its process safety risks.

CCPS RBPS Element 01: This Element refers to a positive and nurturing process safety culture where employees at all levels, especially senior leadership, are committed to process safety.

An event that is potentially catastrophic, i.e., an event involving the release/loss of containment of hazardous materials that can result in large-scale health and environmental consequences.

A management system that is focused on prevention of, preparedness for, mitigation of, response to, and restoration from catastrophic releases of chemicals or energy from a process associated with a facility.

A standard of measurement or indicator of process safety management efficiency or performance.

A process safety system comprises the design, procedures, and hardware intended to operate and maintain the process safely.

Chemicals produced during a reaction process

An implementation program level under the EPA RMP Rule. Applies to certain facilities perceived to have the potential for offsite consequences in the event of an accidental release. The accidental release prevention program requirements for this program level are less rigorous than the Program Level 3 requirements. xiv Glossary

An ongoing commitment to managing risk, improving continuously, reacting to emerging trends, and Keeping current on evolving transportation risk analysis practices.