An Operator Staffing Assessment Requires a Detailed Analysis of Each Piece of Equipment and a Few Other Factors...

An Operator Staffing Assessment requires a detailed analysis of each piece of equipment that falls under the responsibility of the operator. It's no surprise that our method is primarily data driven. Our Automation Index Model (AIM Tool) measures every P&ID to capture all equipment under an operator’s responsibility. Each and every piece of equipment has a certain amount of workload based on how complex the asset may be. Some equipment may have a very low impact on workload and other assets are very complex and have a large impact on workload. This is why we measure and score every piece of equipment. The best way to measure equipment complexity is to have up to date and accurate P&ID's.

Data is key, but what other Factors can contribute to workload?

When we sit down to interview an operator, we are not just evaluating the level of their workload; we are also evaluating the efficacy of the support systems in place that help them manage that workload.

Alarm Factor:

Alarm management plays a large role in minimizing operator workload. Poor alarm management results in frequent alarm shelving, delays in alarm response times, and alarm floods, all of which can hinder an operator's ability to effectively manage and respond to critical situations.

The interview process is a good chance to get a finger on the pulse of alarm management. Perception is reality for console operators, and hitting KPIs does not always guarantee that the alarm system will not overwhelm them during upset conditions. On the other hand, it is possible that they have learned to cope with poor alarm management and simply do not know what good looks like until they see it. In most cases operators will ignore alarms and use their experience and training to do what they think needs to be done. This alarm culture has been linked directly to major incidents.

HMI Factor:

Many operators in the industry fall victim to tunnel vision during abnormal situations. As they work to resolve an upset in one unit, they miss an escalating problem in another area because of poor HMI design limiting their situational awareness. Most operators only have P&ID style graphics (Level 3 displays) and have never had a live system view of their most critical assets which allows them to see outside the box while they work on a problem.

A key takeaway from our interview process is how the operator approaches this tunnel vision problem. A properly designed overview display allows an operator to keep the ‘big picture’ in mind and is a key part of the high-performance HMI. Typically, we find that operators try to build their own overview using graphics that are too detailed to capture their entire span of control(P&ID view), which leads them to demand 8-12 screens at their console. Another workload contributor.

Screen Factor:

The number of DCS screens an operator requires has been a contested topic at many facilities. While onsite, we assess the operators' visual needs: Number of screens, screen size, screen layout for the console and if screens should be located on walls. In most cases when we find the traditional P&ID screens (Level 3 displays) we find operators require large rows of screens and sometimes even stack them up on top of each other. This is an ergonomic nightmare that causes many concerns. How an operator works through tasks, uses screens and data, and makes decisions will have an impact on workload. Workload will impact the amount of time it takes operators to work through complex problems.

Something many people don't think about is how the screens and lighting in the control room are related. Glare is a major issue and can slow down operator response and even contribute to human error. We often find low ceilings in most control rooms; this causes the lights to reflect directly onto the operator screens. Some operators turn the lights down or completely off which is another issue that has an impact on performance and vigilance. A major problem that may be making its way to your control room is "light sickness". When you expose night shift operators to LED light, which contains blue light, operators stop developing melatonin. Blue light at night has serious health related correlations. This is based on real science. When you get an opportunity to address the lighting in the control room, please use filters to reduce blue light for night shift workers.

Additional Factors:

Monitoring the DCS is only one part of maintaining safe and efficient operation of the plant. Many operators are expected to contribute in other ways that are not accounted for in traditional workload assessments. Some of those things may include inside / outside responsibilities where the operator leaves the console for a period of time. In many cases this routine practice is very relaxed and many times we see nobody is monitoring key processes for short periods of time.

Other operator activities that contribute to workload consist of alarm rationalization initiatives, permit approvals, and computer-based training (CBTs). These are just a few additional tasks that need to be accounted for. Our AIM model accounts for the additional workload that comes with these responsibilities, and our practice of interviewing multiple shifts for each position ensures that we receive consistent and accurate information from the operators.

In closing, an operator staffing study should be mostly data driven but must absolutely cover interviews, observations, and assessments of all the systems they use and the contributing factors that impact overall operator performance.

Written By: Jack Lluy and Stephen Maddox

www.mycontrolroom.com