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PT Notes

Addressing Domino Effects in PHA

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.

Domino effects involve a primary event, such as an explosion, triggering secondary and higher order events, such as toxic releases, resulting in escalating consequences. Each event may spawn other events in multiple locations throughout and beyond the process where they originate. One hazard is realized and triggers the realization of one or more additional hazards of the same or different types, and so on, in what can become a complex sequence of events. They have not received the attention they deserve in process hazard analysis (PHA).

Domino effects have played a role in numerous incidents. Often they involve multiple fatalities and they have destroyed entire facilities. Their consequences are among the greatest that can occur in process facilities. Consequently, they are very important contributors to the risks of processes.

Domino effects may result from thermal radiation or flame impingement from fires; overpressure or blast wave and projectiles from explosions; toxic or other hazardous material releases; and the impact of various physical effects on the process or its personnel, for example, the failure of rotating equipment may generate projectiles.

Domino scenarios can be addressed best using an approach that combines the identification of domino scenarios that may originate within each process section with the consideration of the impacts on the process section from domino scenarios that may originate in other process sections.

The identification of domino effects is discussed in greater detail in the article:

The Treatment of Domino Effects in PHA, Process Safety Progress Vol. 34, Issue 3, pages 220–227, September 2015.

For information on Primatech’s PHA consulting and facilitation services, click here.

For information on certification of personnel in PHA click here.

For information on a related software tool click here.

Click on the links below for information on related training courses:

Process Hazard Analysis (PHA) for Team Leaders

Advanced Process Hazard Analysis (PHA) for Team Leaders

Managing Psychological and Human Aspects of PHA Facilitation

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