Performance-based safety standards : an ISA TECH 1997

In the last decade efforts are being directed toward establishing performance-based practices and standards using quantified risk as the basic performance parameter. The objective of these efforts is to establish a consistent and widely acceptable methodology to evaluate process risks and propose alternative solutions that reduce risk to acceptable levels, These efforts have culminated in several standards, such as OSHA 29 CFR Part 1910, EPA 40 CFR Part 68, ISA S84.01, and the draft standard IEC 1508. This paper discusses performance-based standards using a safety life cycle model and focuses on the assessment of process risk using quantitative techniques. It also discusses qualitative risk assessment methodologies used in DIN 192540 and CCPS, and compares the two approaches showing both benefits and disadvantages. Furthermore, the design, performance and certification of safety-dedicated electrical, electronic and programmable electronic (E/E/PE) systems based on IEC 1508 and DIN 0801 are briefly discussed and compared. Finally, the paper presents an umbrella risk assessment program that follows an "integrated" approach. It includes the impact of undesired events to property, business operations, the environment as well as personnel. The "integrated risk" program is developed by combining specifications and requirements from several national and international standards, such as IEC 1508, ISA S84.01, OSHA 29 CFR Part 1910 and EPA 40 CFR Part 68.