• Lighting: Computer and video glass display screens are very susceptible to reflection from ceiling or wall-mounted lighting units, and this detracts from their optimum use. The location of light units should be carefully chosen with reference to the position and angle of the display screens. Indirect or reflected lighting is often the best solution. It is recommended that a lighting engineer be used to prepare, or at least check the design. Many monitoring and control operators prefer to work in a darkened room with little or no ambient lighting. While dimming surrounding lights can improve focus on the screens, it can also lead to eyestrain, and make more difficult other manual tasks, such as video display selection and keyboard data entry.
• Electrical Power: Since monitoring and control systems rely on power, it is important that its source be reliable and of good quality — thus, without surges or reduction in voltage. Both of these criteria can be met with the use of an Uninterruptable Power System (UPS). The UPS smoothes any ripples in the primary power and can come in two types: a small, stand-alone unit dedicated to the security monitoring and control equipment; or building/area-wide systems that also support critical business functions such as data processing and telecommunications applications. The UPS — particularly the small dedicated type — is not designed to provide support for long periods and it, in turn, should be supported by a building generator circuit if more than 20 minutes of back-up is required. In addition, if only minimal UPS power is available, it should be dedicated for the most critical security monitoring functions.
Ergonomics is the interaction between people and things. A good example of ergonomic design is the arrangement within an automobile that ensures that the driver can access all of the required controls while maintaining concentration on the road and other traffic. Security workstation layout is very important to the accuracy and effectiveness of the monitoring staff.
Using the earlier list of functions that need to be performed by the monitoring and control staff will greatly help with the layout of the workstation. Use that list to separate which functions require viewing, which require action and what the relative importance is for each function.
Display equipment is designed so that it is not required to be within easy reach once it has been set up and adjusted for brightness and contrast. Display views should be prioritized by importance — primary, secondary or tertiary. Primary viewing is located within a 30° field of view cone; secondary within 60°; and tertiary outside that field of view — as illustrated above in Figure 1.
Equipment that requires frequent manipulation, such as a keyboard, mouse, PTZ control, audio volume adjustment, and a telephone dial pad, must be reachable without undue strain. Figure 2 shows the typical limits of reach. Items that require the most frequent reach — keyboard and mouse, for example — should be located in the primary area.
If alarm monitoring is the workstation’s priority, the annunciation screen should be centralized in the primary field of view, and the keyboard for alarm acknowledgement and response logging should be within easy reach for typing. All regularly used control switches, such as those for door locks and gate operation, should be reachable without the operator having to bend and stretch. For example, a gooseneck microphone enables the operator to speak in a calm, clear voice without having to lean forward or shout.
If the priority is video surveillance monitoring, any pan, tilt and zoom controls should be close at hand. Camera views for alarm assessment can be relegated to secondary positions.
Nearly all of the previous tips have been related to individual monitoring and control stations. The overall SOC layout is a function of the number of workstations. In a large SOC, a video wall may provide common display of camera images for all workstations to see. A supervisor’s station is placed behind the others and, if possible, on a raised platform for the best overview of the monitoring and control functions.
There are other functions that may be included in the SOC for situational awareness — secondary fire alarm annunciation, elevator controls, weather status display, and news and traffic reports. SOC design should consider all potential information sources for the optimum operation of the security function.
David G. Aggleton, CPP, CSC, is president of Aggleton & Associates (www.aggleton.com). He is actively engaged in the design of SOCs as a component of security technology solutions to mitigate risk & vulnerability since 1978. He can be reached at firstname.lastname@example.org.