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PT Notes

Hazard Analysis Using Simultaneous Operation (SIMOP) Review

PT Notes is a series of topical technical notes on process safety provided periodically by Primatech for your benefit. Please feel free to provide feedback.

Simultaneous operations occur within process facilities when two or more activities occur at the same time and place. They may interfere or clash with each other and involve risks that are not identified when each activity is considered by itself. They may increase the risks of the activities or create new risks resulting in undesired events or circumstances with adverse impacts on people, the environment, property, etc.

Simultaneous operations often involve work in the same area by multiple contractors and subcontractors or multi-disciplinary workers whose work may overlap and/or interact. Often, they occur when non-routine work is performed, including safe work and commissioning and startup of processes. They are of particular concern whenever construction, modification, or maintenance work is performed within or near live processes and during turnarounds when process equipment is not de-inventoried. Construction and maintenance activities on one unit may bring many people into close proximity with the hazards from other operating units. Congestion in facilities, for example, as found on offshore oil and gas platforms and in some on-shore facilities, increases the possibility of adverse interactions between activities.

The situations addressed by SIMOP reviews usually are not considered during process hazard analysis (PHA) studies which focus attention on individual process operation. Furthermore, PHA teams may not recognize the importance of examining how simultaneous operations may interfere with each other. Moreover, it is difficult to do so within the constraints of a regular PHA study such as a hazard and operability (HAZOP) study. Consequently, SIMOP reviews are an important adjunct to the performance of PHA studies.

A procedure for conducting a SIMOP review is provided in the article:

Simultaneous Operations (SIMOPS) Review: An important hazard analysis tool, Process Safety Progress, Volume 36, Issue 1, pages 62–66, March 2017.

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