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.
Building Siting Evaluation
The procedures used to evaluate the hazards and establish the design criteria for new buildings and the suitability of existing buildings at their specific locations.
Cause (in Hazard Evaluation)
In the context of hazard evaluation procedures, an initiating cause.
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).
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.
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.
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.
Physical Hazard
A chemical for which there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive) or water reactive.
Process Hazard Analysis
An organized effort to identify and evaluate hazards associated with processes and operations to enable their control. This review normally involves the use of qualitative techniques to identify and assess the significance of hazards. Conclusions and appropriate recommendations are developed. Occasionally, quantitative methods are used to help prioritized risk reduction.
Risk Evaluation
Comparison of results of a qualitative or quantitative risk analysis coupled with an appraisal of the significance of the results, both overall and from individual events.
Risk Evaluation Criteria
A qualitative or quantitative expression of the level of risk that an individual or organization is willing to assume in return for the benefits obtained from the associated activity.
System Evaluation
A phase in the development of computerized systems in which the system is compared with its requirements to determine possibilities for growth and improvement and to preserve the lessons of that development project in preparation for the next one.
Technical Evaluation Condition
An equipment condition requiring further technical evaluation to determine suitability for continued service.
Toxic Hazard
In the context of these guidelines, a measure of the danger posed to living organisms by a toxic agent, determined not only by the toxicity of the agent itself, but also by the means by which it may be introduced into the subject organisms under prevailing conditions.