(106b) Dust Explosion Consequence Categories for Semi-Quantitative Risk Assessment

Semi-Quantitative Risk Assessment (SQRA) is an effective tool for the chemical process industries. SQRA relies on acceptable risk criteria; release, capital loss and downtime consequence levels; and failure frequencies in the assessment of risk. Since this set of tools was derived from process industry experience, the release consequence level is focused on liquid and vapor processing. This limits its application for industries that process solids.

This paper proposes an addition to the consequence levels. The focus is on dust release. The framework for the table is inspired by the liquid/vapor release table as published by the Center for Chemical Process Safety. The release characteristic and release size distinctions for dust release were derived by comparing dust explosion mechanisms, existing literature categorizations, and energy released to those for vapor explosions. In this way, the proposed table is consistent with the CCPS vapor/liquid release consequence table.

The proposed table has been used in the food process industry to assess risk. The LOPA application led to the identification of recommended action items for operating dust handling processes. These action items are consistent with case-specific recommendations found in the literature. This table can be added to the CCPS LOPA release, downtime and capital loss tables to extend the breadth of LOPA applications.