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Oil & Gas: Too Much Safety?
update on 2012-05-10
Creating a safe work environment is vital in the oil and gas industry. By Rajiv Kurup, Safety & Security Consultant, Honeywell Process Solutions, India.
Due to the high-risk work environment nature of the industry, it no surprise that the oil and gas industry is one of the most tightly regulated industries in the world when it comes to safety.
As such, a big challenge energy companies face is the implementation and up keeping of effective safety management systems. This is critical to help protect their workers, the public and the environment.
Today, in the wake of the 2010 oil spill in the Gulf of Mexico — thought to be the worst US environmental disaster to date — and the growing proliferation of social media, the oil and gas industry has come under more scrutiny than ever before.
With watchful eyes closely monitoring every move, energy companies have to continuously up their game to evaluate and improve their safety programs and prevent accidents.
Delving deeper into why safety is critical to energy companies, an expert paper published in the UK stated that there ‘are three commonly accepted reasons for reducing accidents at work ie: legislation, humanistic and moral considerations, and economic considerations. Very often though the last one, economic considerations, tends to be forgotten.’
The author also pointed out that in the industry, however, ‘it is accepted that good safety is good business.’
His viewpoints are echoed in the hard facts. According to the American Petroleum Institute and the American Chemistry Council, the largest accidents in chemical and hydrocarbon processing facilities have severely injured or killed hundreds of people, and contaminated the environment — resulting in greater than US$8 billion in property damage losses.
The actual cost of these accidents are much higher if associated business interruption costs, cleanup costs, legal fees, fines and losses of market share are also considered. So, improving safety is an essential part of protecting personnel, assets, the environment, and profitability.
An Integrated Approach To Safety
Ensuring safety means reducing the risk of incidents, faults and failures that cost money. This effort goes far beyond simply installing fail-safe controllers or a safety instrumented system.
In fact, to mitigate the risk of serious incidents that can cause injury to personnel, equipment, and the environment, as well as disruption of production capability, it is important to consider safety from all aspects of a plant’s operation.
This goes right back to the heart of the question, ‘Are we safe enough?’
Plant safety today requires a comprehensive approach including managing operator effectiveness, constant monitoring of distress indicators, personnel tracking and mustering applications, and ongoing asset monitoring and maintenance for asset health.
This integrated approach demands not only understanding safety’s relationship to human error, but also the inter-relationships among root causes and interventions by plant systems and plant personnel. We advocate an integrated approach to plant safety to help customers improve their business performance and peace of mind.
This solution includes independent yet interrelated layers of protection to deter, prevent, detect, and mitigate potential threats. Woven throughout these layers are features that offer ongoing assessment, as well as design, implementation, and assessment plans that directly improve work, people, and technology processes.
Layers Of Protection
There are many factors to take into account when designing process safety. It starts with putting in place a basic process control system. Monitoring systems need to be in order, and an operator has to be on alert and supervising the system at all times.
While a solid process control system may help to minimise risks and contain damages, it is also important to remember prevention and mitigation.
To prevent accidents, a mechanical protection system, process alarms and operation system should be in place. Safety Instrumented Prevention and Mitigation Systems need to be layered on top of the Basic Process Control System to bolster the entire safety process.
Bearing in mind that accidents and incidents may not always be prevented or mitigated, it is essential to have a robust plant emergency response and a wider community emergency response ready to go.
One of the key aspects of achieving plant safety is to recognise the importance of different layers of protection, as shown in Figure 1.
In order to maximise plant effectiveness, a systematic approach to safety is required. This approach must minimise risks to safety and security, and it requires independent but interrelated layers of protection to be in place across an organisation. The concept of layers of protection is widely recognised by the process industry, and the term is clearly defined in industry safety standards such as IEC 61508 and IEC 61511.
As shown in figure 1, at the core of the layered architecture is a well-designed and implemented process design that is the embodiment of the business, safety, and production considerations necessary for effective operations. The process must be controlled by a secure process control network that extends across the entire plant and business networks.
As one moves through the layers of protection further away from the core of process design, mitigating risk due to human error is key to ensuring safety. Implementing tools and procedures such as boundary and alarm management and early event detection reduces incidents and prevents escalation.
Working across the various layers of protection, a plant or facility must operate in a secure and protected atmosphere, including protection of the perimeter, facility, people, and assets. With the correct work practices and technology in place, in the event that an abnormal situation occurs, an emergency response plan can be executed, controlled and monitored to minimise the impact of the incident.
Safety Related Systems, comprising of emergency shutdown systems and the fire and gas systems, have received a lot of attention in the recent past across the process industry. There are various safety standards that specify the basic requirements and functionalities to be met by these systems. With the emergence of latest International Safety Standard - IEC 61508/61511, the focus on functional safety has taken precedence for achieving total plant safety.
These standards help to quantify the safety requirement in terms of safety integrity level and probability of failure on demand. Table 1 shows the relationship between these parameters.
Safety Integrity Level: These are discrete level for specifying the safety integrity requirements of the safety functions to be allocated to the safety-related systems, where safety integrity level 4 (SIL-4) has the highest level of safety integrity and safety integrity level 1 (SIL-1) has the lowest.
Probability of Failure on Demand (Risk Reduction): This is a statistical measurement of how likely it is that a process, system, or device will operate and be ready to serve the function for which it is intended. Among other things, it is influenced by the reliability of the process, system, or device, the interval at which it is tested, as well as how often it is required to function.
Management of Functional Safety: This is to specify the management and technical activities during the overall hardware and software safety lifecycle phases which are necessary for the achievement of the required functional safety. It specifies the responsibilities of the persons, departments and organisations responsible for each overall, hardware and software safety lifecycle phase or for activities within each phase.
To this effect, TÜV certifies organisations based on the work processes followed at various stages of the safety system implementation for compliance to IEC 61508. Honeywell is one such organisation certified by TÜV as a safety system integrator in India.
People Competency: It is vital to have competent people managing activities involving safety related systems like design, engineering, testing and maintenance.
The Automation, Software and Information technology (ASI) wing of TÜV offers a functional safety training program that supports persons in the functional safety business to deepen their expertise in the area.
In the revised edition of IEC 61508 (April 2010), competency of people involved in safety projects is now Normative (Informative in Previous edition of IEC 61508).
Safety PLC Vs General Purpose PLC
There are certainly many similarities between a safety Programmable Logic Controller (PLC) and a general purpose PLC. However the PLC was not originally designed to be fault tolerant and fail-safe. This is the fundamental difference. Safety PLCs are special purpose machines that are used to provide critical control and safety applications for automation users. These controllers are an integral part of Safety Instrumented Systems (SIS) which are used to detect and manage dangerous process situations.
In a safety PLC many special design considerations are taken into account. It emphasises on internal diagnostics, a combination of hardware and software that allows the machine to detect improper operation within itself. It is also designed to ensure software reliability, redundancy to maintain operation even when parts fail and extra security on any reading and writing via a digital communications port.
Research has shown that abnormal situations cost many millions of dollars. Manufacturers pay dearly for these catastrophes. This indicates the need for focusing on layers of protection to provide a safer work environment, while at the same time increasing process availability and reducing total cost.