Inherent Safer Design
ECH 5503: DESIGN FOR SAFE HANDLING OF INDUSTRIAL CHEMICALS
INHERENT SAFER DESIGN:
BHOPAL DISASTER CASE STUDY
INHERENT SAFER DESIGN
Inherently safer design (ISD) evaluation are important for identifying fundamental process improvements that can eliminate hazards or reduce the consequences of plant accidents. They are typically performed at the earliest stages of process design, where changes are most cost-effective. As the detailed design comes into focus, inherently safer options are rarely revisited because the designer’s emphasis has shifted. Although fundamental changes during later design phases are more difficult, they may still be opportunities to entertain new ideas of inherently safer design. Thus, engineers should continue to look for new mechanisms to improve plant safety throughout the design process.
Process Safety Risk Management Strategies
Chemical process safety measures or process safety risk management strategies are frequently categorized as:
1. Inherent
Eliminate or modify the hazard and/or risk by changing the process to use materials and conditions that are nonhazardous or much less hazardous and/or employing one of four strategies of substitution, minimization, moderation, simplification.
2. Passive
Minimize the hazard by process and equipment design features which reduce either the frequency (likelihood) or consequences of the hazard without the active functioning of any device.
3. Active
Manage risk using process control systems, Safety Instrumented System (SIS), safety interlocks and mitigation system such as emergency shutdown systems to detect and correct process deviations. These may prevent an incident or reduce the consequences of the incident.
4. Procedural
Using operating procedures, administrative checks, safety rules, emergency response and management systems to manage the risk.
Elements of Inherent Safer Design (ISD)
Inherent safety is usually
INHERENT SAFER DESIGN:
BHOPAL DISASTER CASE STUDY
INHERENT SAFER DESIGN
Inherently safer design (ISD) evaluation are important for identifying fundamental process improvements that can eliminate hazards or reduce the consequences of plant accidents. They are typically performed at the earliest stages of process design, where changes are most cost-effective. As the detailed design comes into focus, inherently safer options are rarely revisited because the designer’s emphasis has shifted. Although fundamental changes during later design phases are more difficult, they may still be opportunities to entertain new ideas of inherently safer design. Thus, engineers should continue to look for new mechanisms to improve plant safety throughout the design process.
Process Safety Risk Management Strategies
Chemical process safety measures or process safety risk management strategies are frequently categorized as:
1. Inherent
Eliminate or modify the hazard and/or risk by changing the process to use materials and conditions that are nonhazardous or much less hazardous and/or employing one of four strategies of substitution, minimization, moderation, simplification.
2. Passive
Minimize the hazard by process and equipment design features which reduce either the frequency (likelihood) or consequences of the hazard without the active functioning of any device.
3. Active
Manage risk using process control systems, Safety Instrumented System (SIS), safety interlocks and mitigation system such as emergency shutdown systems to detect and correct process deviations. These may prevent an incident or reduce the consequences of the incident.
4. Procedural
Using operating procedures, administrative checks, safety rules, emergency response and management systems to manage the risk.
Elements of Inherent Safer Design (ISD)
Inherent safety is usually
References: 1. Design an inherently safer plant, Steven T. Maher, Kristin D. Norton and Sernem Surmeli, CEP Magazine, January 2012, p. 43-47. 2. Inherently Safer Chemical Processes: A Life Cycle Approach, 2nd Edition, Center for Chemical Process Safety (CCPS), John Wiley & Son, 2009.