• Familiarization with key terms associated with process safety management can help employers and employees avoid associated hazards.

It is important to recognize and be familiar with key terms and definitions related to process safety management (PSM) so that potential hazards are understandable and clear.

• Atmospheric tank: A storage tank designed to operate at pressures from atmospheric through 0.5 pounds per square inch gauge (p.s.i.g), 3.45 kPa (kilopascal).
• Boiling point: The boiling point of a liquid at a pressure of 14.7 pounds per square inch absolute (p.s.i.a.) (760 mm.). For the purposes of this section, where an accurate boiling point is unavailable for the material in question, or for mixtures which do not have a constant boiling point, the 10 percent point of a distillation performed in accordance with American Society for Testing and Materials (ASTM) D-86-62 may be used as the boiling point of the liquid.
• Catastrophic release: A major uncontrolled emission, fire, or explosion involving one or more highly hazardous chemicals that presents serious danger to employees in the workplace.
• Facility: The buildings, containers, or equipment which contain a process.
• Highly hazardous chemical (HHC): A substance possessing toxic, reactive, flammable, or explosive properties and specified by paragraph 1910.119(a)(1).
• Hot work: Work involving electric or gas welding, cutting, brazing, or similar flame or spark-producing operations.
• Normally unoccupied remote facility: A facility which is operated, maintained, or serviced by employees who visit the facility only periodically to check its operation and to perform necessary operating or maintenance tasks. No employees are permanently stationed at the facility. Facilities meeting this definition are not contiguous with, and must be geographically remote from, all other buildings, processes, or persons.
• One Percent Rule: The rule the Occupational Safety and Health Administration (OSHA) uses to determine if a mixture contains a covered volume of hazardous chemical. OSHA uses a one percent concentration cut-off.
• Process: Any activity involving an HHC including any use, storage, manufacturing, handling, or the on-site movement of such chemicals, or combination. For purposes of this definition, any group of vessels which are interconnected and separate vessels that are placed in a location where a highly hazardous chemical could be involved in a potential release are considered a single process.
• Replacement in kind: A replacement which satisfies the design specification.