Process Development

Any safety and health process begins as an evolving entity. If safety and health is not part of the development of the process itself, the process will have inherent flaws. As engineers formulated their concept for a process, the design that takes place should incorporate occupational safety and health from the very beginning of a process. Each step of the process design, development, and implementation should be reviewed to assure that hazardous potentials have been analyzed to determine exposure prevalence, degrees of risk, energy sources, and how best to protect the workers.

Process Hazard Analysis

The process hazard analysis (PHA) is a thorough, orderly, systematic approach for identifying, evaluating, and controlling the hazards of processes involving highly hazardous chemicals. The employer must perform an initial PHA (hazard evaluation) on all processes covered by this standard. The PHA methodology selected must be appropriate to the complexity of the process and must identify, evaluate, and control the hazards involved in the process.

First, employers must determine and document the priority order for conducting PHAs based on a rationale that includes such considerations as the extent of the process hazards, the number of potentially affected employees, the age of the process, and the operating history of the process. All initial PHAs should be conducted as soon as possible, but at a minimum, the employer must complete no fewer than 25% by May 26, 1994; 50% by May 26, 1995; 75% by May 26, 1996; and all initial PHAs by May 26, 1997. Where there is only one process in a workplace, the analysis must be completed by May 26, 1994.

PHAs completed after May 26, 1987, that meet the requirements of the PSM standard are acceptable as initial PHAs. All PHAs must be updated and revalidated, based on their completion date, at least every 5 years.

The employer must use one or more of the following methods, as appropriate, to determine and evaluate the hazards of the process being analyzed:

  • • What-ifs
  • • Checklist
  • • What-ifs/checklist
  • • Hazard and operability study (HAZOP)
  • • Failure mode and effects analysis (FMEA)
  • • Fault tree analysis
  • • An appropriate equivalent methodology

A discussion of these methods of analysis is contained in OSHA 3133, Process Safety Management—Guidelines for Compliance. Whichever method(s) is used, the PHA must address the following:

  • • The hazards of the process.
  • • The identification of any previous incident that had a potential for catastrophic consequences in the workplace.
  • • Engineering and administrative controls applicable to the hazards and their interrelationships, such as appropriate application of detection methodologies to provide early warning of releases. Acceptable detection methods might include process monitoring and control instrumentation with alarms, and detection hardware such as hydrocarbon sensors.
  • • Consequences of failure of engineering and administrative controls.
  • • Facility siting.
  • • Human factors.
  • • A qualitative evaluation of a range of the possible safety and health effects on employees in the workplace if there is a failure of controls.

The Occupational Safety and Health Administration (OSHA) believes that the PHA is best performed by a team with expertise in engineering and process operations, and that the team should include at least one employee who has experience with and knowledge of the process being evaluated. Also, one member of the team must be knowledgeable in the specific analysis methods being used.

The employer must establish a system to address promptly the team's findings and recommendations; ensure that the recommendations are resolved in a timely manner and that the resolutions are documented; document what actions are to be taken; develop a written schedule of when these actions are to be completed; complete actions as soon as possible; and communicate the actions to operating, maintenance, and other employees whose work assignments are in the process and who may be affected by the recommendations or actions.

At least every 5 years after the completion of the initial PHA, the it must be updated and revalidated by a team meeting the standard's requirements to ensure that the hazard analysis is consistent with the current process.

Employers must keep on file and make available to OSHA, on request, PHAs and updates or revalidation for each process covered by PSM, as well as the documented resolution of recommendations, for the life of the process.

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