All Resources


published on

November 2017

Murtaza Gandhi, Senior Process Safety Engineer, is scheduled to present his paper titled, “Approaches to Calculate Scenario Coverage Factor for Fire and Gas Mapping and It’s Impact to the Achieved Risk Reduction,” on November 8th at the 2017 Process Control & Safety Symposium and Exhibition.

The Exhibition will be held at the Houston Marriott Westchase in Houston, Texas from November 7 – 9, 2017, in collaboration with the 2017 International Instrumentation Symposium (IIS) also being held at the hotel from November 7 – 8th.

Click here for more information on these conferences. The abstract for Murtaza Gandhi’s paper is below.


Approaches to Calculate Scenario Coverage for Fire and Gas Mapping and Its Impact to the Achieved Risk Reduction

Fire and gas mapping and detection is slowly becoming an integral part of project life cycles. ISA has developed TR7 under ISA84 standard that provides guidance on calculating the availability of fire and gas detection/shutdown system. One of the steps in the calculation of the achieved risk reduction from fire and gas system is determining coverage factor. This paper discusses two approaches to calculate scenario coverage: basic approach which defines scenarios based on simple consequence modeling assumptions and a more detailed approach which defines scenarios based on release locations, elevations, release directions and wind probabilities. Based on how the scenarios are defined, the coverage factor and hence the risk reduction provided by the system differs. This could substantially change the outcome of the study and may require additional means or redundancy to achieve the necessary risk reduction. This paper performs a case study on the achieved risk reduction for the same detector array and shutdown system using the above mentioned approaches.