Designing A Dedicated Smoke Control System; Introduction; About Stairtowers - Simplex 4100U Application Manual

Designing a Dedicated Smoke Control System

Introduction

About Stairtowers

Most of the systems discussed so far have been non-dedicated systems. Even in a building where
the primary smoke control system is non-dedicated, special zones or functions may exist that
require a "dedicated" system. The most common example of a dedicated system is a dedicated
smoke control system for a stairtower.
A "stairtower" is a stairwell with a ventilation system that is isolated from the main building.
The only connection between the building and the stairtower are fire-rated doors on each floor.
Since the building occupants should use the stairtower to leave during an evacuation, keeping the
stairtower smoke-free is vital.
A stairtower has its own dedicated system that pressurizes the stairtower to keep smoke out.
This dedicated system can take several forms, from a fan mounted in the roof of the stairtower, to
a duct system that delivers air to each level.
You must pressurize a stairtower enough to keep smoke out. However, if the pressure in the
stairtower is too great, then opening the doors leading into the stairtower can be difficult.
(See the figure below.)
Too Much Pressure
Figure 1-4. The Effects of Too Much or Too Little Pressure
Too Little Pressure
Building
Stairtower
1-13
Building
Stairtower