LOPC Threshold Checker

LOPC = Loss of Primary Containment. Checks an incident's consequences against API RP 754 criteria to determine whether it classifies as a Tier 1 or Tier 2 Process Safety Event (PSE).

Scope note: API RP 754 Tables 1 and 2 (Annex E/F) specify substance-specific release threshold quantities by hazard category — these vary by material and are not reproduced here. Enter your own Table 1/Table 2 threshold quantity for the specific substance released (from your company's API RP 754 reference tables) to complete the quantity-based check. This tool applies the consequence-based criteria directly from API RP 754 and simply compares your entered release quantity against the threshold you provide.

Tier 1 Criteria — any one triggers Tier 1 TIER 1

Fatality — employee, contractor, subcontractor, or third party

Days-away-from-work injury — employee, contractor, or subcontractor

Hospital admission of a third party

Officially declared community evacuation or shelter-in-place (including precautionary)

On-site shelter-in-place or evacuation (excluding precautionary on-site actions)

Tier 2 Criteria — any one triggers Tier 2 (if Tier 1 not already met) TIER 2

Recordable injury — employee, contractor, or subcontractor (not days-away-from-work)

Fire / Explosion Direct Cost

Direct Cost of Fire/Explosion Damage ($) ≥ $100,000 triggers Tier 1. ≥ $2,500 (and < $100,000) triggers Tier 2. Leave at 0 if no fire/explosion occurred.

Release Quantity vs. Threshold (1-Hour Period)

Actual Release Quantity (1-hr period) Same units as your threshold values below.

Unit (for display only)

API RP 754 Table 1 Threshold (Tier 1) From your company's substance-specific API RP 754 Table 1 reference.

API RP 754 Table 2 Threshold (Tier 2) From your company's substance-specific API RP 754 Table 2 reference.

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PSE CLASSIFICATION

API RP 754 Cost Thresholds (2016 Update, Still Current)

Tier 1 fire/explosion cost	≥ $100,000 direct cost (raised from $25,000 in the 2nd Edition update)
Tier 2 fire/explosion cost	≥ $2,500 direct cost (unchanged)
Between $25,000–$99,999.99	Falls to Tier 2 (post-2016 criteria)

Reference

This checklist reflects the consequence-based Tier 1/Tier 2 criteria in API RP 754 (Process Safety Performance Indicators for the Refining and Petrochemical Industries) and the API Guide to Reporting Process Safety Events. Annex E/F Tables E.1–E.16 provide detailed worked examples, and Annex H's decision logic tree (Figure H.1) provides the official flowchart for edge cases.