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6.13 Uninterruptible Power Systems

In some facilities computer room back-up systems may be designed by the tenant agency. If this is the case, shell space and utility rough-ins should be provided. In facilities where uninterruptible power supply (UPS) systems are to be provided as part of the building construction, they should be designed as described in this section. All UPS systems are considered to be above standard for GSA space. Tenant agencies with UPS requirements are advised that a maintenance contract is recommended.

Requirements for UPS systems must be evaluated on a case by case basis. If UPS is required, it may or may not require generator back-up. When generator back-up is unnecessary, sufficient battery capacity should be provided to allow for an orderly shut-down.

Electrical Service Size. A UPS system should be sized with 25 percent spare capacity.

Critical Technical Loads. The nature, size, and locations of critical loads to be supplied by the UPS will be provided in the program. The UPS system should serve critical loads only. Non-critical loads should be served by separate distribution systems supplied from either the normal or electronic distribution system. Section Site Distribution, Secondary Distribution, Secondary Distribution Systems Figure 6-2 of this chapter shows the integration of UPS into the building power distribution system.

Emergency Electrical Power Source Requirements. When the UPS is running on emergency power, the current to recharge the UPS batteries should be limited. This limited battery charging load should be added when sizing the emergency generator.

If the UPS system is backed up by a generator to provide for continuous operation, then the generator must also provide power to all necessary auxiliary equipment, i.e., the lighting, ventilation, and air conditioning supplying the UPS and serving the critical technical area.

System Status and Control Panel. The UPS should include all instruments and controls for proper system operation. The system status panel should have an appropriate audio/visual alarm to alert operators of potential problems. It should include the following monitoring and alarm functions: system on, system bypassed, system fault, out of phase utility fault, closed generator circuit breaker. It should have an audible alarm and alarm silencer button. Since UPS equipment rooms are usually unattended, an additional remote system status panel must be provided in the space served by the UPS. The alarms should also be transmitted to the BAS.

UPS and Battery Room Requirements. Provide emergency lighting in both spaces. Provide a telephone in or adjacent to the UPS room. Battery room design must accommodate: proper ventilation; hydrogen detection, spill containment; working clearances. See Chapter 3: Architectural and Interior Design, Space Planning, Spaces for Uninterruptible Power Systems (UPS) and Batteries for additional requirements for UPS and battery room. See NEC and Chapter 7: Fire Protection Engineering for additional requirements.


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