Systematic Guideline for Safety Assessment based on Process Information

Written by: Muhammad Firdaus Husin

In chemical engineering, one of the targets of the process design is the creation or modification of flow diagrams capable of manufacturing the desired chemical. It is also essential to consider safety aspects when designing any new process or in the case of retrofitting. As a result, several methods have been introduced for safety assessment during process design phase [1]. To date, there are lacks of guideline in selecting an appropriate method for him/her based data availability, target of assessment and budget constraints. To fill in this gap, a heuristic framework are designed for assisting users in conducting safety assessment during chemical process design.

Figure 1 shows a summary of designing framework for process safety assessment in chemical process design methods and their strategies for minimization of hazards or risks which are based on inherent safer design (ISD) keywords [2]. For all methods, the calculated index or risk values and hazards will be compared with the respective benchmark. If the value of calculated index or risk is not acceptable, four ISD keywords (minimization, substitution, moderation and simplification) are taken-over to reduce or eliminate the hazard as much as possible. Finally, the re-assessment of hazards can be performed until the index values and all hazards are at acceptable range. The frameworks shall serve as a great help for engineers to select appropriate method for safety assessment based on the availability of process information during the chemical process design. Instead of assessing the safety level of process design phase, this framework can also be used to analyse the root of the safety problems and recommend the possible solutions.

References

 [1] Khan, F. I. and Abbasi, S. A. (1998c). Techniques and methodologies for risk analysis in chemical process industries. Journal of Loss Prevention in the Process Industries, 11(4), 261-277.

[2] Kletz, T. A. (1991). Plant Design for Safety : User-friendly Approach.