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pass/fail criteria for a completed system before detail
design work begins.
Smoke control systems
Systems for controlling smoke movement in a building
can be divided into two separate types: shaft protection
and floor protection.
The vertical transfer of smoke to the upper stories of a
building from a fire on a lower floor occurs mostly from
shafts versus leakage through openings in floor
construction. Vertical smoke spread accounts for
95 percent or more of the upward movement of smoke in
high-rise building fires. Shaft protection can be further
divided into stairwell pressurization systems and elevator
hoistway systems.
Floor protection encompasses several variations of
zoned smoke control. Use of a particular system or
combination of systems is dependent upon building and
fire code requirements, as well as specific occupancy
and life safety goals established by the system designer.
For either type of smoke control system, electrical and
mechanical equipment or components can be classified
as dedicated or nondedicated.
Smoke control components must be capable of
continuous use at the maximum temperatures expected
during a fire, based upon calculations performed by the
smoke control system designer. Most smoke control
systems will be designed with a primary goal of
maintaining a tenable environment for occupants outside
the fire area for zoned smoke control and within atriums
or large spaces. This goal is achieved by exhausting
smoke from a building, limiting fire growth, or for atrium
smoke control systems, preventing accumulations of
smoke below a six-foot height along egress paths.
Dedicated
Dedicated smoke control systems are independent
systems for air-movement and are not used for any other
purpose under normal building operating conditions.
Upon activation, dedicated systems operate specifically
to perform a smoke control function.
Dedicated systems have the following advantages:
•
System design and control functions are less likely
to be modified during maintenance
VM-1 Smoke Management Application Guide
Chapter 1: Fire geometry and smoke movement in buildings
•
Operation and control of the system is less complex
with system controls typically routed only to the
VM-1 SCS and the firefighter's smoke control station
(FSCS)
•
Independent of other building systems, dedicated
systems are less likely to be affected by changes in
other building systems
Dedicated systems have several recognized
disadvantages:
•
Dedicated systems are more costly
•
Component failures may go undetected for a long
time
•
Dedicated systems often require more building
space for installation
•
Automatic weekly self-testing of dedicated smoke
control systems must be programmed with
consideration for weather conditions
Nondedicated
Nondedicated smoke control systems share or use
components with other building systems including the
HVAC system for a floor, area, or zone. Smoke control
system activation suspends normal operation of HVAC
and other shared components for use in achieving
smoke control objectives.
Nondedicated systems have the following advantages:
•
Equipment costs are shared
•
Component failures of equipment needed for smoke
control are more apparent due to their use for daily
services
•
Smoke control system components do not require
additional building space
Nondedicated smoke control systems have three
recognized disadvantages:
•
System control may involve complex interlocks with
shared equipment used for HVAC or energy
management
•
Inadvertent modification of HVAC controls or
equipment affecting smoke control functionality is
more likely to occur
•
Other building system modification may interfere
with smoke control system operation
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