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Process Hazard Analysis: Creating a Safer Workplace

Process hazard analyses are the starting point for promoting process safety and developing strong risk management programs.

When is the last time you and your team performed a process hazard analysis (PHA) of your manufacturing operations? For many industrial facility managers and operators, this assessment tool, which can play an important role in improving site safety and preventing accidents, is familiar. If you use highly hazardous chemicals in your facilities, you have to complete one every 5 years at minimum according to federal mandates. Whether or not you are bound by law to perform a PHA, it can offer a good starting point for evaluating and mitigating a multitude of potential system risks.

PHAs have been around for decades. The U.S. Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) define a PHA as “a thorough, orderly, systematic approach for identifying, evaluating and controlling the hazards of processes involving highly hazardous chemicals.” The concept was formalized in the early 1990s, when OSHA and EPA issued their respective “Process Safety Management” and “Risk Management Program” standards. These rules included a list of hazardous chemicals that, if found onsite above a certain quantity, required implementation of the standards including completion of an initial PHA with updates to be performed every 5 years.

Completing a PHA can take weeks or months, depending on the complexity of the plant and its processes. Various methodologies for performing one exist and are widely accepted, including hazard and operability studies (or HAZOPs), What If? checklists and failure mode and effects analyses (or FMEAs). Led by a team familiar with the plant’s systems, PHAs are, at their most basic level, a series of analytical questions. Staff scrutinize process equipment, instrumentation and utilities, employee behaviors and external factors, looking for potential causes and consequences of hazardous chemical spills, chemical releases, explosions and fires.

With process and instrumentation diagrams and operating guidelines in hand, the PHA team challenges each component of their system, asking an exhaustive set of questions (e.g., What if this pressure relief valve failed? Are there functioning redundancies in place if power is lost? What if a vapor is released? How do we protect staff and prevent exposure?) After thoroughly analyzing potential sources of system errors or failures, the team can assess the probability of risks turning into problems, prioritize their criticality and develop corrective action plans accordingly.

What does this look like in practice? CDM Smith recently worked with a multinational food, snack and beverage company to complete multiple PHAs of their ammonia systems; ammonia is used widely in the industry for refrigeration. A major point of focus in these PHAs was safety system efficiency. Because ammonia is flammable, it was critical that plant staff were working in rooms with leak detection and fan ventilation systems in good working order. Another important component of these PHAs was training. No matter if the facility was a large or small plant, for example, it was recommended that employees know all the ins and outs of the systems—not just how to turn them on—so that they could respond effectively in the event of an emergency.

Improved worker safety is the most obvious beneficial outcome of a PHA. Another big benefit for businesses is protection of brand integrity.

Improved worker safety is the most obvious beneficial outcome of a PHA. Another big benefit for businesses is protection of brand integrity. Putting mitigative measures in place reduces the possibility of accidents that could negatively affect customer and public perception of a company and its products.

The benefits of PHAs can also extend beyond the list of hazardous chemicals that OSHA and EPA regulate. The PHA process can be applied to non-covered activities; for example, a PHA could be performed before beginning remediation activities near a community, where avoidance of spills is critically important.

It is important to recognize that PHAs are a good first step but only one tool in creating a safer workplace. OSHA’s Process Safety Management program contains a number of additional require­ments in addition to PHAs, including mechanical integrity evaluations and standard operating procedures development. While not the be-all end-all step in fostering a safe work environment and meeting compliance goals, a PHA is an excellent way for manu­fac­tur­ers to evaluate their system, measure it against industry standards and make sure it is operating at the level of efficiency and safety they expect.

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