Which Systems Are On Emergency Power?
All facilities must have an emergency power system for lifetime protection, as specified by law. It needs to be designed in accordance with NFPA 110, Emergency and Standby Power Systems.
Self-contained battery units may be used in buildings for individual light fixtures where other devices do not need an emergency generator.
Fire alarm and surveillance devices will have their own back-up battery.
The system should consist of a central engine generator and separate distribution system with automatic transfer switches, distribution panels, and 480/277V light panel (if applicable) feeding 208/120V panels with dry-type transformers, as required.
Terms of Service. A suitable enclosure should be built if the unit is to be installed outdoors, and arrangements should be in place to ensure stable starting at cold weather. Starting aids such as jacket-water heaters can be identified to increase the reliable starting capability in cold weather.
When installed at high altitudes or above-rated ambient temperatures, the system shall be configured according to the manufacturers’ recommendations. Even the process of starting batteries and battery chargers has to be considered for sizing calculations. For humid areas heaters may reduce moisture accumulation in the generator windings. Each of the generators need silencers. Acoustic treatment shall be given to the generator room, if necessary.
Generators should be placed at least 30 m (100 feet) from the communications frame equipment to avoid radio frequency interference. Architectural and Interior Design, Spatial Planning, Building Support Spaces, Mechanical and Electrical Rooms, Emergency Generator Rooms for additional room generator needs.
Unit-mounted radiators should be installed where appropriate. If the ventilation is restricted to indoor applications, remote installation is acceptable. Allowing for heat recovery and load shedding is not advisable.
Capability. The engine generator should be configured to approximately 110 percent of the design load; ideally, after the impact of inrush current declines, it should operate at 50 percent to 80 percent of its rated power. Consider the inrush current of motors which are started automatically at the same time when sizing the generator. Due to starting load currents, the initial voltage drop on generator output must not exceed 15 percent.
Loads of emergency Power. The following roles will include emergency power:
- Lighting up and out
- Fire alert system
- Auxiliary Engine
- Systems for smoke control (if code is required)1
- Pump Fire
- Switching mobile
- Safety Systems
- Mechanical controls
- The Automation Building System (BAS)
- Ascenseurs (one per bank)1
- Pump sump valves
- Pumps with sewage ejector
- Exhaust fans extract toxic, explosive or flame retardant fumes
- Uninterrupted power systems that cover computer rooms1
- Computer- and UPS air conditioning systems1
- Exhaust ventilator in UPS battery chambers
- Power and lighting for Fire and Defense Control Center
- Main electrical room lighting, electrical wardrobes and communications closets
- Communications armchair air conditioning devices
- Receptacles for electricity emergencies
- Horizontal recessed doors
- Many similar tools identified by code
Unit Delivery. The distribution system should be configured so that emergency and auxiliary power sources can not flow back energy into the de-energized main voltage systems under regular, emergency, or malfunction conditions.
Alarms about derangement of generators. Alarms shall be provided in the generator room for generator derangement. Any malfunctions should be sent to BAS. In buildings without BAS a generator warning announcer will be installed inside the fire control centre.
Automatic Switches to Transfer. Dual motor operation of automatic shift switches serving motor loads (adjustable time delay neutral position) or in-phase control (shift when normal and emergency voltages are in phase) to mitigate possible motor damage resulting from out-of-phase transmission. For emergency motor control centers we can also have pre transfer contacts to suggest time delay relays.
Automatic transfer switches serving 3-phase, 4-wire loads should have 4-pole contacts with a neutral overlap to minimize potential interference of ground defect relays.
Automatic transfer switches should have an isolation bypass switch which allows to manually bypass the regular or emergency source to ensure continued power to emergency circuits in the event of a switch failure or maintenance required.