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 EEMUAs 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 Institutes (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 Acuites simple yet intuitive means of indicating furnace performance is shown here. Similar techniques can be implemented in most of todays operator interface workstations.
Some companies incorrectly decide they want the control room to have a certain look and feel without really understanding the operators 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 rooms 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 operators 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.
Its 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 arent finished.
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 Consortiums 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 weve 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&IDs?
Most operators, especially experienced ones say P&ID-like graphics exist for the benefit of engineers and plant managers. They admit that such graphics arent that useful to them.