Principles Of Smoke Control - Kidde VM-1 Manual

Figure 5: Elevator piston effects
Automatic sprinkler systems:
nearly always dictated as a component of large space or
tall building fire protection.
In designing a smoke control system, the size of the
expected fire must be determined as a base for sizing
the air handling equipment for smoke control. Escape
routes must be kept usable for extended periods of time
and this means that the size of the fire must be limited to
ensure that the smoke control system will not be
overwhelmed by a growing fire.
Automatic sprinklers are essential in order to limit the
size of a possible fire. Sprinklers can affect smoke in two
ways:
• Sprinklers can, by the discharge of water spray
through the smoke layer, bring the smoke down to a
low level
• By cooling the smoke, automatic sprinklers can
reduce smoke buoyancy and slow down the
movement of smoke through roof or ceiling vents
VM-1 Smoke Management Application Guide
Automatic sprinklers are
Chapter 1: Fire geometry and smoke movement in buildings
Automatic suppression systems are an integral part of
many fire protection designs, and the efficacy of such
systems in controlling building fires is well documented.
Klote and Milke, in Design of Smoke Management
Systems, point out that:
"while it is important to recognize that while the functions
of fire suppression and smoke management are both
desirable fire safety features; they should not be readily
substituted for each other."
One of the best ways to address the smoke problem in a
fire is to prevent or reduce smoke production. To the
extent that a suppression system slows the burning rate,
it reduces the smoke problem. For fires that are
suppressed rather than extinguished, some smoke is
produced. This smoke can move through a building due
to varied driving forces as discussed in general in this
chapter. Well-designed smoke management systems
can maintain tenable conditions along critical escape
routes, but will have little effect on the fire.
Where automatic sprinklers are installed, the
determination of the fire size for smoke control
calculations is based upon a limited fire spread, typically
9.8 ft. x 9.8 ft. (3 m x 3 m).

Principles of smoke control

Fire protection approaches
Smoke management is only one component of an
overall building fire protection system. The two basic
approaches to fire protection are to prevent fire ignition
and to manage fire impact when a fire does occur.
Figure 6 shows a simplified decision tree for fire
protection. The building occupants and managers have
the primary role in preventing fire ignition. The building
design team may incorporate features into the building to
assist the occupants and managers in this effort.
Because it is impossible to completely prevent ignition,
managing fire impact has assumed a significant role in
fire protection design.
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