CCPS Process Safety Glossary | AIChE

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CCPS Process Safety Glossary

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Acute Hazard

The potential for injury or damage to occur as a result of an instantaneous or short duration exposure to the effects of an incident.

Analysis Data Base

A data base that contains all input data for a CPQRA, including the System Description, as well as environmental data (e.g., land use and topography, population and demography, meteorological data).

Antecedent-behavior-consequence (ABC) analysis

A human performance analysis tool that examines how human behavior is influenced by previous experiences with similar situations and expectations of reward or punishment.

Apparent cause analysis (ACA)

A less formal investigation method that focuses on the immediate causes of a specific incident.

Audit (process safety audit)

An inspection of a plant or process unit, drawings, procedures, emergency plans, and/or management systems, etc., usually by an independent, impartial team. (See "Safety Review" for contrast.)

Basic Process Control System (BPCS)

A system that responds to input signals from the process and its associated equipment, other programmable systems, and/or from an operator, and generates output signals causing the process and its associated equipment to operate in the desired manner and within normal production limits.

Bioprocess engineering

the sub-discipline within biotechnology that is responsible for translating the discoveries of life science into practical products, processes, or systems that can serve the needs of society.

Bioprocessing

Bioprocessing makes use of microorganisms, cells in culture or enzymes to manufacture products.

Cause (in Hazard Evaluation)

In the context of hazard evaluation procedures, an initiating cause.

Cause-Consequence Analysis [Cause-Consequence Diagrams]

A method for illustrating the possible outcomes arising from the logical combination of selected input events or states. A combination of Fault Tree and Event Tree models.

Central Processing Unit (CPU)

The portion of a computer's or microprocessor's logic which executes the program.

Checklist Analysis

A hazard evaluation procedure using one or more pre-prepared lists of process safety considerations to prompt team discussions of whether the existing safeguards are adequate.

Chemical Process Industry

The phrase is used loosely to include facilities which manufacture, handle and use chemicals.

Chemical Reactivity Hazard

A situation with the potential for an uncontrolled chemical reaction that can result directly or indirectly in serious harm to people, property or the environment. The uncontrolled chemical reaction might be accompanied by a temperature increase, pressure increase, gas evolution or other form of energy release.

Chronic Hazard

The potential for injury or damage to occur as a result of prolonged exposure to an undesirable condition (e.g., smoking, with the potential for causing lung cancer).

Consequence Analysis

The analysis of the expected effects of incident outcome cases, independent of frequency or probability.

Cost-Benefit Analysis

Part of the management decision-making process in which the costs and benefits of each risk reduction option are compared and the most appropriate alternative is selected.

Covered Process

A process subject to regulatory requirements established under the OSHA PSM Standard or the EPA RMP Rule.

Critical Process Measurement

A sensor whose operation has safety implications.

Differential Thermal Analysis (DTA)

A technique in which the temperature difference between a substance and reference material is measured as a function of temperature while the substance and the reference material are subjected to a controlled temperature program. (ASTM E 1445)

Dust Hazard Analysis (DHA)

A systematic review to identify and evaluate the potential fire, flash fire, or explosion hazards associated with the presence of one or more combustible particulate solids in a process or facility.

Equipment Failure Analysis

A systematic approach for analyzing equipment failures to determine the failure mechanism(s) and the root cause(s) that resulted in the failure.

Event Tree Analysis

A method used for modeling the propagation of an initiating event through the sequence of possible incident outcomes. The event is represented graphically by a tree with branches from the initiating cause through the success or failure of independent protection layers.

Failure Mode and Effects Analysis

A hazard identification technique in which all known failure modes of components or features of a system are considered in turn and undesired outcomes are noted.

Failure Modes, Effects, and Criticality Analysis (FMECA)

A variation of FMEA that includes an estimate of the potential severity of consequences of a failure mode.

Fault Tree Analysis

A method used to analyze graphically the failure logic of a given event, to identify various failure scenarios (called cut-sets), and to support the probabilistic estimation of the frequency of the event.

Hazard

An inherent chemical or physical characteristic that has the potential for causing damage to people, property, or the environment.

Hazard Analysis

The identification of undesired events that lead to the materialization of a hazard, the analysis of the mechanisms by which these undesired events could occur and usually the estimation of the consequences.

Hazard and Operability Study (HAZOP)

A systematic qualitative technique to identify process hazards and potential operating problems using a series of guide words to study process deviations. A HAZOP is used to question every part of a process to discover what deviations from the intention of the design can occur and what their causes and consequences may be. This is done systematically by applying suitable guidewords. This is a systematic detailed review technique, for both batch and continuous plants, which can be applied to new or existing processes to identify hazards.

Hazard Checklist

An experience-based list of hazards, potential incident situations, or other process safety concerns used to stimulate the identification of hazardous situations for a process or operation.

Hazard Classifications

Broken into three categories, "Safety and Environmental", "High Business Risk", and "Low Business Risk."

Hazard Evaluation

Identification of individual hazards of a system, determination of the mechanisms by which they could give rise to undesired events, and evaluation of the consequences of these events on health (including public health), environment and property. Uses qualitative techniques to pinpoint weaknesses in the design and operation of facilities that could lead to incidents.

Hazard Frequency of Potential Hazards

(i.e., Demand Rate) times the Fractional Deadtime of Safety Systems describes the relationship between hazard rate and demand rate.

Hazard Identification

Part of the Hazards Identification and Risk Analysis (HIRA) method in which the material and energy hazards of the process, along with the siting and layout of the facility, are identified so that a risk analysis can be performed on potential incident scenarios.  

Hazard Identification and Risk Analysis (HIRA)

A collective term that encompasses all activities involved in identifying hazards and evaluating risk at facilities, throughout their life cycle, to make certain that risks to employees, the public, or the environment are consistently controlled within the organization's risk tolerance.

Hazard Rate

The frequency with which hazards occur. Dimension (Time -1). The frequency at which failures lead to hazardous events. Also known as the Time-Related Equipment Failure Rate, is an Instantaneous Failure Rate function of time.

Hazard Warning Structure

A modified form of fault tree highlighting event mitigating feature pairs. These are often pairings of incident precursors and protective devices or event terminating features which are combined through an AND gate.

Hazard Zone

For an incident that produces an outcome such as toxic release, the hazard zone is the area over which the airborne concentration equals or exceeds some level of concern. For a flammable release, the area of effect is based on a specified level of thermal radiation. For a release that results in explosion, this is the area defined by specified overpressure levels.

Hazardous Chemical

A material that is toxic, reactive, or flammable and is capable of causing a process safety incident if released. Also Hazardous material.

Hazardous Chemical Reactivity

Any chemical reaction with the potential to exhibit rates of increase in temperature and/or pressure too high to be absorbed by the environment surrounding the system. Included are reactive materials and unstable materials.

Hazardous Energy Control Procedure

Written procedure for affixing appropriate lockout devices or tag out devices to energy isolating devices, and to otherwise disable machines or equipment to prevent unexpected energization, start up or release of stored energy in order to prevent injury to employees.

Hazardous Event

See Loss event.

Hazardous Material

In a broad sense, any substance or mixture of substances having properties capable of producing adverse effects to the health or safety of human beings or the environment. Material presenting dangers beyond the fire problems relating to flash point and boiling point. These dangers may arise from, but are not limited to, toxicity, reactivity, instability, or corrosivity

Hazardous Particulate Solids

In a broad sense, any particulate solids or mixture of particulate solids having properties capable of producing adverse effects to the health or safety of process equipment, human beings, or the environment. These can include such properties as combustibility, flammability, explosibility, toxicity, corrosiveness, etc.

Hazardous Waste (40 CFR 261)

Hazardous waste can be classified as follows: Ignitable: Based upon the flash point of a liquid waste; for a solid, the capability to cause fire through friction or absorption of moisture, and to burn vigorously and persistently; solids that meet the 49 CFR definition of oxidizer; and, compressed gases that are ignitable under the DOT definition. Corrosive: Liquid wastes that have a pH of plain 2 or 12.5, or that corrode steel at a rate of greater than 0.25 inch per year. Reactive: Wastes that are unstable and readily undergo violent change; that react violently with water or when mixed with water generate toxic vapors or fumes; that are cyanide or sulfide bearing and can generate toxic gases, vapors, or fumes at pH conditions between 2 and 12.5; that are readily capable of detonation or explosion at standard temperature and pressure if subjected to a strong initiating force or if heated under confinement; or DOT forbidden explosives. Toxic: Liquid wastes or extract from waste solids that fail the Toxicity Characteristic Leaching Procedure (TCLP) analytical test because they contain certain designated metals, pesticides, or organic chemicals at concentrations equal to or, in excess of, specified regulatory limits.

Health Hazard

A chemical for which there is statistically significant evidence based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed employees. (OSHA 1994)

Highly Hazardous chemical

A material that is toxic, reactive, or flammable and is capable of causing a process safety incident if released. These materials are included in OSHA's PSM Standard, 29 CFR 1910.119.

Human Reliability Analysis (HRA)

A method used to evaluate whether system-required human-actions, tasks, or jobs will be completed successfully within a required time period. Also used to determine the probability that no extraneous human actions detrimental to the system will be performed.

Individual Hazard Index (IHI)

The Fatal Accident Rate (FAR) for a particular hazard, with the exposure time defined as the actual time that a person is exposed to a hazard of concern.

Job Safety Analysis (JSA)

A procedure that systematically identifies: 1) job steps, 2) specific hazards associated with each job step, and 3) safe job procedures associated with each step to minimize accident potential. Also called job hazard analysis