Guidance
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monitoring life or safety-critical operations then full or partial standby lighting will normally be needed evenly throughout the room. As this will be supplied from UPS and/ or standby generators, early discussion with the electrical designers over lighting loads and supply cable diversity is vital. And don’t forget, the standby power system will also need to supply the lighting control system. Once all building, electrical and display screen/user parameters are established, the design
'A constant minimum lighting level across the room and on the walls is needed to ensure operators remain alert'
September/ October 2022
of the lighting, and possibly daylight control, can be carried out. As well as selecting and positioning luminaires to make sure no bright images are visible to the users on any of their screens, the lighting designer needs to make sure that there is lighting on any information boards and tables where crisis documentation may be laid out – even today paper-based documentation, such as sign-off or tick-box sheets, may be in use. The guide has a large chapter describing many different lighting techniques that may be used to provide the right illumination in control rooms. The acceptability of each is often determined by the rooms and task characteristics. High rooms, for instance, allow uplighting and direct/indirect lighting schemes to be considered. One important issue often overlooked is the need for the room lighting to provide a constant minimum lighting level across the room and on surrounding walls to ensure the operators remain alert – this is most important during the night shift where there may be an increased risk of operators becoming sleepy if the room lighting is dim. For this reason, the lighting control system is often set to ensure this minimum level cannot be reduced by operator actions. Given the wide variety of contexts it considers, LG22 inevitably overlaps in its recommendations and refers to supporting information in other relevant SLL lighting guides including LG7: Office Lighting; LG1: The Industrial Environment, and LG19: Lighting for Extreme Conditions.
Lighting Guide 22 (LG22): Lighting for Control Rooms is free to CIBSE/SLL members in PDF format. It can now be downloaded at: www.cibse.org/getinvolved/societies/society-of-light-andlighting-sll/sll-publications-and-guidance. Authored by Paul Ruffles from an outline by Richard Caple and with human factors input from David Watts
Screen adjustability Each display screen at a workstation is typically mounted on either a bracket, rails or stands that may allow the users to achieve a range of adjustability. This might include:
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Adjusting the distance between each individual display screen and the front of the workstation Adjusting each screen’s angle, tilt and swivel Allowing the screen to be adjusted in height to allow for different user eye heights
But in many workstations the range of adjustment is limited to avoid complex adjustments between the various users from one shift at that workstation to another. Thus, adjustments are often a compromise.
p Because workstations may have screens in various orientations around a user they are more likely to be able to see an image of a bright luminaire or window reflected in one of the screens
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