Published: 08 September, 2016
Howie Emerson, implementation consultant, Bentley Systems, looks at safety and asset health monitoring in the power industry and how to avoid complacency and encourage strong responses to weak signals.
It is a nightmare shared by workers, plant managers, CEOs and shareholders around the world. A major incident has occurred in your power plant; workers’ lives have been lost, families have been destroyed, and nearby neighborhoods are in shambles. Beyond the human tragedy, your business’s reputation has taken a major hit as the news (some accurate, some not) blasts through media outlets and social networks. There is pressure for government to move in and tighten regulations; financial institutions begin to view you more skeptically, pushing up borrowing cost and deflating your share price. All this could have been avoided by focusing on safety at your power plant.
A common attitude in the workplace is that we are not in control of our personal safety and the responsibility for safe working environments belongs to others. However, we are not powerless in the face of asset failure. By accepting ownership of safety and taking a disciplined approach to ensure it, organisations can stop tragedies from occurring.
Managing risk is everyone’s job. It starts and ends with proper leadership and accountability at all levels. Failure prevention can only come with discipline to process. We cannot become complacent in anything we do because we are integral to the process. Risk control systems for the power plant, for the process, and most importantly for the people that drive your organization are required. When the consequence and cost of asset failure can be so high, why take a chance? Safety analysis is a critical component in a company’s overall strategy to create a safe work environment, which protects human life and shareholder capital.
A safety analysis is a type of study that examines system-level and related assets to determine loss of containment scenarios, identify risk levels, decide whether a safety instrumented system (SIS) is required, and define the provisions that protect against, or mitigate loss of containment. It is a key component of integrity management. Other components of integrity management include process design, alarm identification and management, protective devices, and community and plant emergency response plans. These actions form a layer of protection around critical systems.
James Reason’s “Swiss cheese model” for process safety illustrates how major accidents and catastrophic system failures actually uncover multiple, smaller failures leading up to an actual hazard. In the model, each slice of cheese represents a safety barrier for a particular hazard and that no single barrier is fool-proof, each having ‘holes.’ When the holes align a catastrophic failure occurs that can result in serious consequences.
To protect ourselves from these holes, systems need to be properly managed, inspected, and tested to verify their on-going reliability. The procedure for defining this process needs to be documented and designs reviewed. A safety instrumented functions (SIF) study assesses system risk, defines risk mitigation or elimination actions required to return the system to a safe state when conditions such as pressure or temperature reach a threshold level. A SIF detects a specific hazard and brings the process to a safe state. It provides a defined level of risk reduction or safety integrity level (SIL) for a specific hazard by automatic action using instrumentation.
The framework of a SIF study is built around your systems and their related assets. The study begins with a HAZOP analysis to generate checklist items for the safety study. Next, failure modes are defined against this HAZOP checklist. Once a failure mode and its related effects are defined, the next step is to define the risk level of that failure mode. This could involve environmental considerations, reputation considerations, economic considerations, and safety considerations. This process will give you your initial risk SIL score.
After determining the risk of a failure mode, we must now create a plan to mitigate that risk. This is done through creating provisions on the failure mode. A provision describes the systems and processes that are put in place to prevent or mitigate a hazard. Each provision has an SIL reduction factor, and each provision added will reduce the risk score of the failure mode. Each provision includes steps and actions to take to reduce the identified risk. These steps and actions will then be built out on the action plan to implement into your maintenance program.
Asset health monitoring
An asset health monitoring program is a process that focuses on the physical health of your plant’s assets. While complementing a safety analysis, a properly structured asset health monitoring program identifies failing assets and give insight into what assets need replacing. Asset health is monitored by creating organized, indexed data using criteria established by you. Sources of inputs into this criteria can include best practices, inspection standards, and industry regulation.
Once established, a proper safety analysis combined with an effective asset health monitoring program provides these benefits to your organisation:
1. It produces actionable maintenance and inspection plans that, when implemented, will reduce risk to your organization to an acceptable level.
2. It provides a traceable roadmap from the work items that you preform to the safety reasons for why you are doing them.
3. A properly structured SIF study is complementary to other strategy development analysis your organisation may be undertaking such as RCM or FMEA.
4. Asset health monitoring can signal when critical assets have begun to fail.
Using software, completing a safety analysis, and creating an asset health monitoring program can be accomplished relatively quickly and effectively. There is software available that helps you to more effectively manage and analyse large amounts of data that may be available to you in your CMMS system. Software will also provide the ability to run very complex calculations that you may wish to use for your asset health monitoring program. Given the cost of failure, the adoption of a rigorous safety strategy at your organisation is one of the easiest and best decisions you can make.