The importance of Process Hazard Analysis studies

Posted on 23/04/2021

In this article, ESC principal consultant Esteban Bernechea reflects on Process Hazard Analysis studies and the importance to follow procedures to prevent huge fines and most importantly to keep workers, the public, the environment, and the company assets safe from harm.

The importance of Process Hazard Analysis studies

Recently a chemical manufacturing company was fined approximately half a million pounds after an HSE investigation, following an accident in which one of their employees suffered a life-changing injury.

The injury was sustained during the cleaning of a section of the plant. This was not an unexpected or abnormal operation, as it was known that it had to be performed periodically; therefore, the procedure to do it should have been properly documented and risk assessed. However, the procedure had not been updated to reflect changes to the cleaning operation over the years.

While initially the cleaning operation was performed without pressurising a vessel downstream the equipment involved, over time the way in which the operation was performed changed to include the pressurisation of the vessel.

This resulted in an unexpected and unidentified event in which boiling water used for cleaning was released when the worker opened a valve to discharge the water into the pressurised vessel. Upon opening the valve, the pressure in the vessel pushed the boiling water out of an open path, resulting in the worker being doused in the boiling water and scalded.

This event could have been avoided through the application of Process Safety Management practices, such as a robust Management of Change system, including risk assessment of operations when they are changed.

Engineering Safety Consultants Limited can help their clients avoid such scenarios by performing Process Hazard Analysis studies in their operations, such as Hazard and Operability (HAZOP), Hazard Identification (HAZID) studies or others.

It is always helpful to have a team of process, instrumentation, safety, and risk analysis specialists, joined by the operators performing the tasks in real-life to identify the potentially hazardous scenarios associated with any operation (even when they do not seem dangerous at first glance).

Having a team discuss potential issues in a systematic way helps prevent not only the fines but more importantly, the life-changing impacts on the affected workers and their families. A procedural HAZOP for the cleaning operation in the example could be completed in a session of a day or less; a very low cost when compared to the impact of the preventable accident.

It is also important to remember that if any hazardous scenarios are identified, it is the responsibility of the PHA team and ultimately, the employer, to ensure that the risk is sufficiently reduced.

This can be done by different means, including the use of Safety Instrumented Functions (SIFs), which do not necessarily need to be bypassed during maintenance operations. A robust Functional Safety Management System can help companies define which scenarios require the application of SIFs and whether they need to be overridden or bypassed during maintenance or cleaning operations.

It is always crucial to remember why Process and Functional Safety exist, to prevent scenarios such as the one in this example from occurring; to keep the workers, public, the environment and the company assets safe from harm.

by Esteban Bernechea

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