Fitting the Workplace to the Worker

Figure 1. ISO 11064 ergonomic design standards

One of the most vivid examples of a need to consider HFEE is in the control rooms of many process plants worldwide.

How often do you see a press release, brochure or magazine article celebrating a successful start-up that includes a photo of an operator sitting at the operator console? Most likely, the photo showed a bunch of monitors and keyboards plopped down on some computer furniture. What you didn’t see was that the control room was built like a box, and then someone was tasked with fitting all the people, equipment, supplies and kitchen into it.

Operators need to be allowed to do what they are trained and paid to do and that requires that they be provided an environment that is void of as many unnecessary distractions and disruptions as possible—something akin to an air-traffic control center.

What’s the Goal?

“The goal in designing a control room is to create a work environment that promotes the operator’s ability to maintain high levels of vigilance and situation awareness,” says Ian Nimmo, founder and president of User Centered Design Services, and who one client describes as “the godfather of situation awareness and alarm management.”

Through the late 1970s, control rooms consisted of long panel boards with logically grouped recorders, controllers, indicators, switches, lights and alarm light boxes arranged to provide operators with a “big picture” of the process.

Beginning in the 1980s, the introduction of distributed control systems (DCS) shrunk those long panel boards into fifteen-inch monitors. To compensate for the operator’s loss of the big picture, additional monitors were added, along with lots and lots of DCS-based alarms. It was not uncommon for a process plant to evolve from 150 alarm light boxes to more than 2,000 DCS-based alarms.

The distributed architecture of the DCS also encouraged control room consolidation, thus replacing face-to-face conversations between the control room and field operator with sometimes less-than-reliable radio communication. Greater physical distance also changed how supervisors interacted with the control room and field operators. Combined, these changes resulted in the creation of an entirely different control room environment, and it was done with very little thought about its impact on operational performance. What’s truly sobering is that twenty-plus years later, many of those same problems continue to exist in control rooms worldwide.

Planning for the Worker

The ISO 11064 standard, “Ergonomic Design of Control Centers,” form an excellent foundation for control room design and address such topics as specifying ergonomic principles, recommendations and requirements; control room and adjoining room arrangements; control room layout; workstation recommendations and design guidelines; environmental considerations and much more.

ISO 11064 becomes most beneficial when supplemented with additional process-industry-related guidelines, such as EEMUA’s 191 guidelines document, “Alarm Systems: Guide to Design, Management and Procurement;” its 201 guideline document, “Process Plant Control Desks Utilizing Human-Computer Interfaces: A Guide to Design, Operational and Human Interface Issues;” Electric Power Research Institute’s (EPRI) “Alarm Management and Annunciator Applications Guidelines;” and best practices from organizations such as the Abnormal Situation Management (ASM) Consortium.

Assembling such a library of standards, guidelines and practices is one thing; feeling comfortable in interpreting and appropriately applying them is something quite different. When in doubt, seek council.

Figure 2. One of Acuite’s simple yet intuitive means of indicating furnace performance is shown here. Similar techniques can be implemented in most of today’s operator interface workstations.

 “Some companies incorrectly decide they want the control room to have a certain look and feel without really understanding the operator’s needs or how the control room and field operators work during various operational phases (i.e., start-up, normal, abnormal, critical, shutdown, etc.). A control room’s design should be based on improving operational performance, not a design for the sake of being different,” counsels Nimmo.

Control rooms designed per ISO 11064 generally end up with either a theater or functional style, however within each of these basic styles, there are numerous variations. Depending on the operator’s needs, one style is likely a better solution than the other, but until interviews are conducted, people are observed on the job, the interaction of operators is understood and unit and process complexities and interactions are collected, it is impossible to say which style and variation is best for a given installation.

Shrinking Head Count, Bigger Control Room?

The process industries’ “shrinking knowledge base,” caused by the retirement of older workers with their wealth of institutional knowledge, is old news at this point.  Some companies are addressing this problem by combining local unit control rooms into a centralized control room. Their rationale is that fewer operators will be required, and the close proximity of operators will help disseminate process knowledge and enhance collaboration among plant units.

To the casual observer that seems to make sense, but as Peter Yacoe, plant manager at Calgon Carbon Corp.’s Big Sandy plant in Catlettsburg, Ky., points out, “Ian [Nimmo] and his team provided valuable insight to Calgon Carbon in developing practical options and solutions to our control room consolidation efforts.”

It’s advisable that when considering a control room consolidation project, you start by developing a “how-people-work” packet that includes unit-operator communication interaction diagrams, process complexity diagrams, operator workload diagrams, alarm occurrence diagrams, and staffing and organization diagrams. With the how-people-work packet in hand, the next step is to develop such things as a console adjacency matrix, communication and collaboration paths that take place during different operational phases, a variety of theater and functional console layout possibilities, control room walkways, in-plant communication requirements, control room egress locations, adjacent room functions (i.e., kitchen, offices, conference room, etc.), location and size of plant overview video walls, operator workstation design, supporting equipment (i.e., printers, copiers, files, etc.) locations and much more. When all the documents, drawings, notes, etc. are finished, one best control room design solution will emerge, but you still aren’t finished.

Useful Graphics

Because of its broad industry coverage the ISO 11064 standard does not address alarm and graphic designs. For that, documents such as EEMUA 191 and 201 and ASM Consortium’s “Effective Operator Display Graphics” guideline become beneficial.

Simplicity is the basic rule of thumb here.

Lisa Garrison of Acuite, a company with extensive expertise in operator graphic designs says, “When it comes to designing useful process control graphics, we need to forget that we have 256 colors available; we need to forget what we’ve seen in video games and what we see on TV during an automobile race. The goal of every process control graphic should be to provide the operator readily usable information and near-instant recognition of abnormalities.”

Ever looked inside the cockpit of a modern jet fighter? You will see lots of analog gauges clustered together by function. The grouping and placement are the result of understanding the pilots’ (operators) needs. Now take a look at the graphics your operators are using. Were they designed with functionality in mind, or do they mimic the P&ID’s?

Most operators, especially experienced ones say P&ID-like graphics exist for the benefit of engineers and plant managers. They admit that such graphics aren’t that useful to them.

A senior operator at a major plastics manufacturer summoned it up nicely when she said, “We already know what the plant looks like, and we know exactly where things are located. Besides, a bunch of digital values up and down a multi-colored and highly detailed graphic aren’t much use to us because no one bothered to include a simple reference point.”

The message is loud and clear: Every control room operator’s ability to remain vigilant and rapidly respond to abnormal situations is the direct result of his or her working environment and how much needed information is presented to them.

Graphic Analysis

Acuite’s Nick Dinadis suggests evaluating existing operator graphics using the following criteria:

Content: Operators can only be effective if the operator interface provides them with the right information at the right time in a usable and logical manner. Often graphics are designed for normal operation and don’t support abnormal situations, such as start-up or shutdown. Documenting the different graphics and keystrokes/point-and-clicks required during different operational phases can provide valuable insight into what graphic modifications are warranted.

Format: Even the best information is of little help to operators if it is not communicated as efficiently and reliably as possible. Everything from the appearance of meters and equipment to the use of colors and text must be consistently tailored for optimum usability. Recommendations include the use of a gray-scale color palette; reserving specific colors—i.e, yellow and red—for alarms; use of deviation bars; the use of advanced analytical graphics, such as multi-point spider webs (polar stars) driven by thirty to forty data points; and other intuitive “health-at-a glance” graphic elements.

Structure: The types and organization of graphic pages is critical to overall operator effectiveness. Based on industry- acknowledged best practices, the consistent organization of a multi-tiered graphics hierarchy is an important first step to providing operators with usable information and near-instant recognition of abnormalities. For example, Level 1 = overviews; Level 2 = task-oriented, major system overview and primary operating graphics; Level 3 = additional detail, similar to today’s graphics; and Level 4 = non-control and help displays.
Processes, quality and production demands, and automation systems have changed dramatically during the past twenty years, so doesn’t it make sense that control rooms designs should also change?

If air-traffic controllers require a well-designed, functional environment in order to maintain high levels of vigilance and situation awareness, why is it so difficult to think that process control operators don’t require, in fact deserve, a similar working environment?

Dave Harrold is co-founder of the AFAB Group and a regular Control contributor.