Safety Integrity Level (SIL) & Failure Rates Estimation – Why Indian Industry should have its own database
Technical Paper Synopsis
- Introduction of functional safety -SIS
- Basics of functional safety
- Hazard & Risk Assessment
- Reliability Analysis & Failure Rates of Instrumentation
Reliability of any system, item or a component depends on its design, manufacturing technique, environmental stresses, failure modes and operator skills and maintenance procedures. Besides, the life of equipment/item and particularly its frequency of failure is very much dependent on its operating environment and O&M culture of the company(Rao, 1998). Hence, it is very essential that we have a structured and comprehensive data on failure of such equipment items/components to efficiently estimate their reliability. Historically, we have been using failure data from popular databases such as OREDA, MechRel, PERD etc, which predominantly collects failure data from sites in EU and US. The environmental conditions and the maintenance culture in these regions is vastly different than in India. Besides, the failure modes and causes are also expected to differ in proportion due to different environmental and operating factors(Rao, 1998). It is known to reliability engineers that change in failure data directly impacts the Reliability, Availability and Maintainability of the item/components. It significantly changes the calculations related to equipment downtimes, spare parts availability and maintenance schedules. Hence, having enormous impact on the reliability of safety and production processes.
As an example, the offshore wind farm industry in UK found that the failure causes of similar components used in offshore oil/gas industry is very different when used in wind turbine applications. Hence to improve the reliability of the wind turbine system they generated a separate database known as SPARTA (System Performance, Availability and Reliability Trend Analysis) for wind farm industry.
India has decades of experience in oil/gas industry and already possess enormous database. Since our operating, maintenance culture and environmental conditions are very different than in EU and US, this paper tries to invoke a sense of awareness and encourage Indian industry to collect failure data from their installations and compare with existing foreign databases. At the least it is expected that the outcome of this exercise will be recorded as an effort to scientifically validate and compare the effect of sub-continent conditions and maintenance culture on failure data of common components/items used in oil/gas industries in other parts of the world.