Chemical Hazard Engineering Fundamentals (CHEF) documentation provides the underlying compilation of calculations and methods which are used in RAST. The CHEF informational package provides the theoretical details of the methods, techniques, and assumptions which are used in RAST for the different hazard evaluation and risk analysis steps shown in Figure 1.
Included in CHEF are the:
- Identification of chemical (flammability, toxicity and reactivity) and operational hazards
- Techniques for development of incident scenarios
- Source models for estimation of leak rate, evaporation rate, vapor dispersion, and explosions
- Effect models for estimation of human harm from toxic releases, flammable releases, and explosions
- Techniques for evaluation of likelihood (historical data, fault tree, and event tree), and
- Quantification of risk (i.e., risk is a function of the frequency times consequence).
CHEF also includes an Excel calculation aid to help users understand and utilize the – correlations used to model and evaluate the estimated airborne quantities, vapor dispersions, and explosion overpressures and their impact. These correlations provide the RAST users with a powerful screening tool to help an organization prioritize its overall process safety risks – a bridge between the qualitative approach and quantitative approach – before it invests in complex, detailed quantitative hazards and risk assessments (e.g., Quantitative Risk Assessments, QRAs).
Questions: Please contact us with questions, comments, or suggestions about CHEF.