By Barry Young
Operational error is the single biggest reason for unscheduled shutdowns in process plants, causing several millions of dollars in damages and losses per year. Combine this with an aging skilled workforce leaving the work place, with inexperienced people to replace them, and there is no doubt that process plants face a challenging problem.
Yokogawa executives recently briefed ARC Advisory Group about a new market-driven, standards-based, integrated approach to help alleviate these problems. Yokogawa calls this approach Advanced Decision Support. ADS provides an integrated consulting solution that brings together existing concepts, standards, and capabilities to help improve the effectiveness of all operators.
Key takeaways from this briefing include:
- ADS is aimed at improving the effectiveness of operator decisions to support, rather than replace, operator judgment.
- ADS integrates existing, but separate, industry standards into a cohesive solution.
- ADS is based upon research into human-automated path planning and decision support.
Operational Losses Cause Financial Losses
|Yokogawa's Advanced Decision Support Concept|
For many years, operating losses due to mechanical failure, operational error, process upsets, and design errors have caused process plants significant financial losses, some approaching as much as 100 million dollars per incident. Of all these loss types, operational losses are the most significant. The role of an operator includes managing the process under all conditions to maximize production, reduce costs, and—if an unplanned event should occurs—return the process to a normal state as quickly and safely as possible.
Today's operators have become reactive in their approach, typically "operating by alarm," and often supported by non-rationalized alarm subsystems (and the resulting alarm storms) and poorly maintained graphics. So, while today's automation systems were intended to create a safer environment and better graphics, in reality, they are often somewhat less-than-effective when a crisis erupts and operators get overwhelmed.
Just one current day example of these immense losses includes the isomerization unit explosion at the Texas City Refinery, which resulted in the loss of fifteen lives and millions of dollars in damage. An analysis of the incident showed that faulty hard-wired alarms, improper acknowledgement of DCS alarms, improper start up procedures, and graphics giving misleading information all contributed to the incident.
Advanced Decision Support Addresses Operational Errors
Recognizing that operational error is the single largest contributor to plant operating losses; Yokogawa has introduced Advanced Decision Support to help operators make the right decisions the first time, without trial and error. Making good decisions involves assessing the problem, verifying information, identifying alternatives, anticipating consequences, and making a choice using sound and logical judgment. In a crisis situation, a human operator requires help to do so. Therefore, the ADS concept is designed to use best practices to assist operators in semistructured or unstructured decision-making processes and support, rather than replace, operator judgment.
Many automation suppliers have products and software to individually address HMI issues, procedural automation, and alarm management. However, Yokogawa appears to be the first supplier to integrate all three operations aspects into one cohesive package. This is a market-driven, standards-based approach to solving a longstanding problem. The alarm management piece is based upon the ISA 18.2 standard. The HMI Management and Procedural Management pieces are based upon the evolving ISA 101 and 106 standards, respectively.
Multi-Dimensional Consultative Approach
To support the unique requirements of different industries and different plants, Yokogawa uses a multi-dimensional consultative approach to link these pieces together. This involves two different types Yokogawa consultants:
- Knowledge engineering experts to analyze operations tasks (startup, shutdown, load changes, etc.) as performed by the most experienced plant experts and distill this knowledge into control procedures and tasks
- Human engineering experts to design an effective and ergonomic human machine interface between plant operators and the automation systems
In many cases, these Yokogawa consultants will be able to translate the plant's specific, pre-defined requirements into a standard Advanced Decision Support solution. In other cases, for example, in plants in which the plant management needs help identifying or clarifying issues, the Yokogawa consultants would first develop an ADS master plan for management review and approval prior to implementation.
While the industry has focused much thought and effort on automating procedures, alarm management, and human machine interface individually and is on a path toward finalizing standards and best practices within all three areas; ARC believes that insufficient attention has been focused on how they can all work together to help improve operator effectiveness.
In this, Yokogawa appears to be on the right track with its Advanced Decision Support approach. ARC will follow this development and report back to our clients on its progress in the future.
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