A requirement that defines necessary results without defining the specific means to accomplish them, the "what to do," but not "how to do it." The means for producing the desired results is left up to the discretion of the facility based on an evaluation of its needs and conditions, and on industry practices. For example, the requirement to implement a MOC system that considers the impact of safety and health as part of the review/approval process, and to prevent changes that pose an unacceptable risk to workers, is a performance-based requirement. The implementer must define the process to identify and review risk associated with changes, determine what level of risk is tolerable, and evaluate the risk in sufficient detail to demonstrate that they have met a level of acceptable practice, which in this case may be to provide a safe work environment. (See also Prescriptive requirement, which differs from a performance-based requirement in that a prescriptive requirement states how the activity should be performed.)
Go to Process Safety Glossary