21ST CENTURY HIGH-RISE TRAINING SERIES During the major Northeast blackout in 2003, numerous emergency generators in the New York City area failed within the first 30 minutes, mostly due to lack of regular maintenance, failure to test generators under a full load, and fuel supplies...
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21ST CENTURY HIGH-RISE TRAINING SERIES
During the major Northeast blackout in 2003, numerous emergency generators in the New York City area failed within the first 30 minutes, mostly due to lack of regular maintenance, failure to test generators under a full load, and fuel supplies contaminated by old, jelled fuel that had sat in day tanks and other storage tanks too long. This issue is one that clearly is not addressed in most buildings possessing generators and seems too commonplace.
The following case study was prepared by Jack J. Smits, M.Eng., P.Eng., of Manulife Real Estate in Canada:
The scenario — The focus of this case study is a 40-plus-story, 1970s-era commercial high-rise building in downtown Toronto, Ontario. The building possessed several emergency generators. In case of electrical power failure, separate emergency power is dedicated to the ground-floor retail and banking facilities. The fire pumps were diesel driven. The gearless elevators in the low-rise, mid-rise and high-rise banks had been upgraded to computerized variable-speed AC drives, solid-state rectifiers hoist motors. The previous DC generators that drive the DC hoist motors had been replaced.
In a power outage, the relatively large No. 1 emergency generator in the penthouse would power the mandatory building life safety systems, such as stairwell and floor emergency lighting, exit lighting, fire panels and annunciators, PA system, smoke exhaust fans, stair pressurization fans, one elevator per bank for firefighter use, air compressor controls, basement sump pumps and the building's boiler. Several automatic transfer switches would automatically and sequentially switch the various life safety systems over to the emergency power generator in the event of an electrical power failure.
Some major tenants with continuous business operations (CBO), where business is conducted 24/7, were provided with 208-volt/three-phase/60-amp emergency power from a second generator for emergency operation of essential equipment such as selective lighting, power for computers and servers in air conditioned hub rooms that powered all tenant computerized telecommunications and Internet servers. Most, but not all, high-tech tenants with servers had installed an uninterruptible power supply (UPS) unit with battery backup to allow for continuous electrical power supply to avoid momentary power loss that would otherwise require rebooting of the computers and servers.
Emergency testing — The computerized and direct digital control of all building heating, ventilating and air conditioning (HVAC) and lighting systems was by a building automation system that upon power failure would lock out all equipment and allow an organized re-start to prevent overloading and surges when normal electric power was restored.
Reportedly, both building emergency generators were tested monthly under part-load conditions and yearly, in accordance with National Fire Protection Association (NFPA) testing criteria while using a load bank for minimum 75% generator capacity. Because some tenants with CBO requirements were connected to the spare capacity of the building emergency generator and some smaller tenants were without UPS protection, the monthly testing of the No. 1 emergency generator in the penthouse was limited to selective testing of automatic transfer switches for stairwell lighting and elevator operation only.