Building Design and Construction Handbook - Merritt - Ventech!

PROTECTION AGAINST HAZARDS 3.47
TABLE 3.7 Capacities, Persons per Unit of Width, for
Means of Egress
Level egress components, including doors 100
Stairway 60
Ramps 44 in or more wide, slope not more than 10% 100
Narrower or steeper ramps
Up 60
Down 100
3.5.12 Building Operation in Emergencies
For buildings that will be occupied by large numbers of persons, provision should
be made for continuation of services essential to safe, rapid evacuation of occupants
in event of fire or other emergencies and for assisting safe movement of fire fighters,
medical personnel, or other aides.
Standby electric power, for example, should be available in all buildings to
replace the basic power source if it should fail. The standby system should be
equipped with a generator that will start automatically when normal power is cut
off. The emergency power supply should be capable of operating all emergency
electric equipment at full power within 1 min of failure of normal service. Such
equipment includes lights for exits, elevators for fire fighters’ use, escalators and
moving walks designated as exits, exhaust fans and pressurizing blowers, communication
systems, fire detectors, and controls needed for fire fighting and life
safety during evacuation of occupants.
In high-rise buildings, at least one elevator should be available for control by
fire fighters and to give them access to any floor from the street-floor lobby. Also,
elevator controls should be designed to preclude elevators from stopping automatically
at floors affected by fire.
Supervision of emergency operations can be efficiently provided by personnel
at a control center placed in a protected area. This center may include a computer,
supplemented by personnel performing scheduled maintenance, and should be capable
of continuously monitoring alarms, gate valves on automatic fire sprinklers,
temperatures, air and water pressures, and perform other pertinent functions. Also,
the center should be capable in emergencies of holding two-way conversations with
occupants and notifying police and fire departments of the nature of the emergencies.
In addition, provision should be made for the control center to dispatch investigators
to sources of potential trouble or send maintenance personnel to make
emergency repairs when necessary. Standards for such installations are NFPA 72A,
‘‘Local Protective Signaling Systems,’’ NFPA 72B, ‘‘Auxiliary Protective Signaling
Systems,’’ NFPA 72C, ‘‘Remote Station Protective Signaling Systems,’’ and NFPA
72D. ‘‘Proprietary Protective Signaling Systems.’’ See also Art. 3.7.2.
For economical building operation, the emergency control center may be made
part of a control center used for normal building operation and maintenance. Thus,
the control center may normally control HVAC to conserve energy, turn lights on
and off, and schedule building maintenance and repair. When an emergency occurs,
emergency control should be activated in accordance with prepared plans for handling
each type of emergency.
The control center need not be located within the building to be supervised nor
operated by in-house personnel. Instead, an external central station may provide the