LOPA and SIS/SIL

Facility siting allows you to identify possible risks to personnel, equipment, structures and surrounding areas from fire, explosion and toxic substances. OSHA Process Safety Management (PSM) regulations require facility siting assessments as part of a comprehensive process hazard analysis:

  • How bad is it?
  • How much protection is needed?
  • What type of protection is needed?

LOPA answers all of the above questions in a risk-based approach which is usually part of a PHA performed by a team. LOPA is used in compliance with IEC 61511/ISA 84 standards. IEC 61511/ISA84 requires the allocation of safety functions to layers of protection and to determine the Safety Integrity Level (SIL). LOPA is one method that can be used for selecting the appropriate SIL of your Safety Instrumented Systems.

ioMosaic has a proven track record of performing LOPAs. Our team has performed assessments on a wide range of facilities such as refineries, chemical plants, pharmaceutical plants, tar sands, crude oil refineries, LNG facilities, and rail and marine transportation terminals. ioMosaic can help you make risk-based decisions with confidence.

LOPA and SIS/SIL Defined

Effective risk management always involves some type of hazard assessment process, which is designed to determine if adequate protection layers are in place to bring the risk to an acceptable level. There are many ways to perform this activity with varying degrees of complexity and effectiveness. The assessment methods range from qualitative (subjective) to quantitative (detailed, numerically intensive and time consuming). Layer of Protection Analysis (LOPA) was introduced to bridge the gap between the two extremes.

A Safety Instrumented System (SIS) is an instrumented system used to implement one or more safety instrumented functions, composed of any combination of sensor(s), logic solver(s), and final element(s). These functions have a common attribute — to reduce risk. Independent Protection Layers (IPLs) are safeguards used to mitigate the process risk. The quantity of risk reduction is specified by an order-of-magnitude level called the Safety Integrity Level (SIL).

ioMosaic LOPA Tools

ioMosaic uses our state-of-the-art software tool Process Safety Office® component PHAGlobal® to conduct LOPAs. PHAGlobal® has all the functionality necessary to conduct a LOPA. ioMosaic has conducted a number of LOPAs and understands the importance of reliable, consistent data.

How We Can Help You

Our experts are at the forefront of pipeline Process Safety Management proficiency.

We prepare expert opinion reports and provide expert testimony for process incident cases.

Experienced engineers who have performed LOPAs on a wide range of facilities and terminals.

Helping manage risk with facility siting studies, assessments and recommendations.

Senior knowledgeable process safety engineers prepare, organize, lead and document PHAs.

Proven track record of performing QRAs for facilities, pipelines and transportation routes.

Integrating best practices with cost-effective solutions to address program deficiencies.

Decades of experience leading incident investigations for process industry companies.