PT Notes
Managing Process Risks
PT Notes is a series of topical technical notes on process safety provided periodically by Primatech for your benefit. Please feel free to provide feedback.
Responsible risk management requires that the risks from industrial processes be managed. In process safety, the concern is with catastrophic accidents involving highly hazardous chemicals, and the term risk is used to address what can go wrong, how bad it can be, that is, its severity, and how often it might happen, that is, its likelihood. All three aspects must be considered in managing process risks and appropriate risk tolerance criteria should be used.
Formal risk measures are not used in the U.S. Occupational Safety and Health Administration's Process Safety Management (PSM) standard or in the U.S. Environmental Protection Agency's Risk Management Plan (RMP) rule. Consequently, neither the PSM standard nor the RMP rule necessarily ensures that tolerable risk has been achieved, or that comparable risks are posed by comparable facilities, which would seem to be a reasonable desired result. Indeed, the nature of the regulations is such that different companies are able to perform at different risk levels and, thus, comparable facilities actually may pose different levels of risk. Moreover, no one knows what levels of risk actually are achieved by facilities that comply with these regulations. This situation is hardly satisfactory.
Normally, if one wishes to manage some aspect of an organization, a performance measure and desired target value are established, for example, a production level or occupational injury rate. Numerous jurisdictions around the world have developed risk tolerance criteria for use in process safety. For example, the United Kingdom Health and Safety Executive has created the Tolerability of Risk framework that incorporates the As Low As Reasonably Practicable (ALARP) principle which is used to set performance targets for facility risk.
Increasingly, the use of risk criteria is being driven by the use of Layers of Protection Analysis. However, the subject of risk criteria still can be the proverbial elephant in the room that people prefer to ignore. The reality is that in managing process risks, ultimately, the overall performance of a facility in meeting risk goals is what truly matters. Thus, a process safety program is a paper tiger without some form of risk targets to guide it. In the absence of federal risk criteria for process safety, companies should ensure their process safety programs include some form of meaningful and appropriate risk tolerance criteria.
This topic was addressed in a letter to the editor:
Managing process risks, Process Safety Progress, Volume 34, Issue 2, page 106, June 2015.
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Risk Tolerance Criteria for Process Safety
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