pse tier 1 meaning in oil and gas

Process Safety Event - Tier 1

A Tier 1 Process Safety Event (T-1 PSE) is a loss of primary containment (LOPC) with the greatest consequence as defined by API RP 754. A T-1 PSE is an unplanned or uncontrolled release of any material, including non-toxic and non-flammable materials (e.g. steam, hot condensate, nitrogen, compressed CO2 or compressed air), from a process that results in one or more of the consequences listed below: Note: Non-toxic and non-flammable materials (e.g., steam, hot water, nitrogen, compressed CO2 or compressed air) have no threshold quantities and are only included in this definition as a result of their potential to result in one of the other consequences. — an personnel, contractor or subcontractor “days away from work” injury and/or fatality; — a hospital admission and/or fatality of a third-party; — an officially declared community evacuation or community shelter-in-place; — a fire or explosion resulting in greater than or equal to $25,000 of direct cost to the Company; — a pressure relief device (PRD) discharge to atmosphere whether directly or via a downstream destructive device that results in one or more of the following four consequences: — liquid carryover; — discharge to a potentially unsafe location; — an on-site shelter-in-place; — public protective measures (e.g. road closure); and a PRD discharge quantity greater than the threshold quantities in Table 14; or — a release of material greater than the threshold quantities described in Table 1 in any one-hour period.