Smoke Alarm User Manual

Installation, Operation and Maintenance Manual
Issue 1 Page 5-1
February 2001
5 SYSTEM DESIGN
5.1 Introduction
The chapter contains the necessary information to enable an engineer to determine the correct system
design. The majority of this chapter covers the pipe network design. It is important that this phase is
completed prior to the installation of any components comprising the High Sensitivity Smoke Detection
(HSSD) system.
5.2 Selecting the Correct Detector
Two types of Detector are available; Standard and Ultra sensitive versions. The following paragraphs
should be considered prior to selecting the type of Detector to be used in a particular application.
5.2.1 Ultra Detector
The Ultra sensitive Detector incorporates an avalanche photon detector and has a minimum dynamic
sensitivity range of 0.001 to 0.01 %/m (0.0003 to 0.03 %/Ft) obscuration and should be used in clean
environments. The air within the room being monitored by the detector should be filtered and the
humidity controlled. Typical applications are Low to Ultra high-grade clean.
Sensitivity Ranges Recommended Applications
%/Ft %/m
0.030 - 0.0076 0.10 - 0.025 Low Grade Clean Room
0.024 - 0.0048 0.08 - 0.016
0.018 - 0.0024 0.06 - 0.008
0.016 - 0.0016 0.055 - 0.0055
0.015 - 0.0015 0.050 - 0.005 High Grade Clean Room
0.013 - 0.0013 0.045 - 0.0045
0.012 - 0.0012 0.04 - 0.004
0.010 - 0.0010 0.035 - 0.0035
0.009 - 0.0009 0.03 - 0.003
0.0076 - 0.00076 0.025 - 0.0025 Ultra Grade Clean Room
0.006 - 0.0006 0.02 - 0.002
0.0045 - 0.00030 0.015 - 0.001
0.0038 - 0.00022 0.0125 - 0.00075
0.0030 - 0.00015 0.01 - 0.0005