Preliminary Hazard Analysis (PrHA) is typically conducted at the early stages of the project or system development when plant location and layout are being considered, often during the R&D stage, Feasibility Study (F/S), or conceptual design phase. This allows for the identification of potential hazards before they become more difficult and costly to address.
Preliminary Hazard Analysis (PrHA) is normally used on new facilities to get an overview but not a detailed view of process operation.
Workflow of the Preliminary Hazard Analysis
The workflow of PrHA is to prepare the study, subdivide the process, identify process hazards, list the credible causes, specify the consequence, assign the criticality ranking, and identify the recommendation.
Preliminary Hazard Analysis guidewords
| Category | Guideword |
| Natural and Environment Hazards | Climate Extremes Lighting Earthquakes Erosion Subsidence |
| Chemical Hazards | Physical Acute toxicity limit Chronic toxicity limit Exposure limits Aquatic toxicity Odor threshold corrosivity/erosivity Reactivity Stability Flammability Explosivity |
| Process Hazards | Inventory Toxic Release Fire Explosion Fugitive emission Critical Equipment |
| Facility surrounding | Proximity to population Adjacent land use Proximity transport corridor Vulnerability fauna Visual impact |
| Acquire regulation | Air quality control Wastewater quality control Solid waste disposal Noise level limitation Sanitary Sewage Collection |
| Emergency operation | Power blackout Fire Fighting Equipment |
PROcess Safety TASK 