OSHA Endorsement of ANSI/ISA S84.01 RE: Application of Safety Instrumented Systems for the Process Industries


		AcuSafe -> July 2000 Newsletter
		OSHA Endorsement of ANSI/ISA S84.01 RE: Application of Safety Instrumented Systems for the Process Industries

The PSM standard contains a number of requirements for equipment associated with a covered process (See, for example, the Process Safety Information and Mechanical Integrity elements). Equipment, including safety instrumented systems (SIS) must comply with "recognized and generally accepted good engineering practices." But what practices are acceptable? OSHA deliberately drafted the PSM rule to leave this question open to offer flexibility because different industries may have different sets of practices and because practices evolve and improve over time.

While the flexibility available under the PSM rule is a sound way for the standard to remain relevant over time, it introduces uncertainty too. It is with this background that OSHA's endorsement of ANSI/ISA-S84.01-1996 (S84.01), Application of Safety Instrumented Systems for the Process Industries should be examined.

The SIS addressed in S84.01 includes electrical, electronic and programmable electronic technology. It provides information related to the design and manufacture of SIS products, selection, application, installation, commissioning, pre-startup acceptance testing, operation, maintenance, documentation, and ongoing testing. According to OSHA, "As S84.01 is a national consensus standard, OSHA considers it to be a recognized and generally accepted good engineering practice for SIS." In evaluating whether an employer's engineering practices with respect to SIS comply with PSM, "OSHA would consider among other factors, whether the employer meets the requirements of S84.01."

OSHA also hinted that it would be scrutinizing employers' SIS for processes that are not covered under PSM. Under the General Duty Clause (§5(a) of the OSH Act), employers have a duty to "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees." While the compliance letter did not address the Clean Air Act Amendments of 1990 General Duty Clause, the implications of the letter suggest that it would apply too. It states in pertinent part that facilities must" design and maintain a safe facility taking such steps as are necessary to prevent releases, and to minimize the consequences of accidental releases which do occur." According to the March 23 compliance letter, "[t]he employer may be in violation of the General Duty Clause…if SIS are utilized which do not conform with S84.01 and hazards exist related to the SIS which could seriously harm employees."