Our Solutions: Consulting

Layers of Protection Analysis


LOPA: Assess and Analyze

LOPA is a risk assessment tool that is designed to identify and address the efficiency of the safeguards identified for a hazard scenario. Most often used as a follow-up tool to provide a more granular image of the risk associated with a hazardous scenario identified during a Process Hazard Analysis (PHA) or a process. By applying LOPA to identified high-risk scenarios from a PHA, it allows for a more numerical analysis of risks.

LOPA applies a value for initiating event frequency to the cause of the hazardous scenario. The event frequency is then modulated by enabling event probabilities such as likelihood of ignition or occupancy of an area. The LOPA then addresses what independent safeguards (layers of protection) are in place for the scenario with a probability for failure on depend (likelihood to not function as desired) this accounts for safeguards that can be used to prevent or mitigate a consequence and what the risk reduction function of each is. The independent safeguards modify the frequency of the consequence of the scenario.

The updated risk of the scenario accounting for the enabling factors and layers of protection is compared to the pre-determined acceptable risk. If there is a gap between the acceptable level of risk and the calculated risk of the scenario, the level of risk reduction required to bring the scenario to an acceptable risk level is determined, and recommendations that reduce the risk to an acceptable level are made.


What are the advantages of performing LOPA?

There are several advantages of using LOPA:

  • Allows for a more in-depth review of specific hazard scenarios that are deemed of interest

  • Proves that due diligence is being performed to verify that safeguards being used are truly independent

  • Allows for a more numerical review prior to committing resources to high-cost recommendations from PHAs

The Sigma-HSE Advantage

Our expert consultants apply a practical strategy that draws on our decades of plant experience and in-depth understanding of published industry norms to perform a LOPA of your facility.

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Frequently asked questions

If your facility has conducted a PHA and has scenarios that are high risk, have recommendations that have a high capital cost, or if you’d like to see a more calculated assessment of scenarios, a LOPA allows for a more detailed approach to hazardous scenarios to ensure the risk is appropriately calculated and recommendations meet the level of risk reduction required.

The values used can come from Center for Chemical Process Safety (CCPS) literature, company information on failure rates of equipment, manufacturer ratings for failure on demand, and other literature sources.

If you find yourself asking, ‘Do I need a LOPA at my facility?’, connect with us today. One of our subject matter experts will guide you through any questions you may have.

For businesses in the EU or UK, or for those wishing to comply with DSEAR/ATEX Directives, please click here to find out more on our dedicated DSEAR/ATEX pages. 

Enhance safety through our LOPA solutions, meticulously analyzing protective layers to uncover and address potential risks

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