RAST Overview | AIChE

RAST is designed to provide both qualitative and qualitative risk analysis for processes that handle hazardous chemicals, materials, and energies. Since RAST can be configured to a company’s specific risk profile and its risk tolerance levels, RAST is an excellent tool for those using the principals of the Center for Chemical Process Safety (CCPS) Risk Based Process Safety (RBPS).

RAST allows users to input the chemicals, reactivity data equipment type, operating conditions (e.g., pressures, temperatures), and facility layout. RAST then provides an initial list of risk scenarios based on generic Hazards and Operability (HAZOP) information, estimates "worst" consequences, and creates a Layer of Protection (LOPA) worksheet for the risk scenarios selected by the user.

RAST uses simplified models and empirical correlations, which have been quality-checked and verified. These relationships allow the RAST software to perform screening analyses on systems, processes, or scenarios in "real" time such that a study team has information available immediately to help make better informated decisions. 

RAST can be used for new projects, for comparing between inherently safer designs, for evaluating changes to existing processes (i.e., Management of Change, MOC), and during incident investigations (i.e., help identify other potentially unrecognized hazardous scenarios). In addition to providing more quantitative assessments during a Process Hazard Analysis (PHAs), specific scenarios can be prioritized for use in a Layer of Protection analysis (LOPA).

RAST is ideal for small and mid-sized companies that may not have the complex, daunting, and expensive analytical tools within their company. With RAST, these companies have an analytical tool to help them screen for their worst case scenarios and associated risks such that they can prioritize, develop and implement approaches to help improve their overall process safety performance. 

The following information is entered and used for the risk screening evaluations in RAST:

  • Chemical material safety data, including chemical reactivity data, either from a prepopulated list within RAST or by user-defined and entered information
  • Type of equipment and specific equipment characteristics (used when evaluating failure mechanisms, failure likelihoods, and potential release rates)
  • Processing conditions (such as temperatures, pressures, etc.),  and
  • Facility layout information (used to evaluate dispersion characteristics and distances).

Questions? Please contact us with questions, comments, or suggestions about RAST.