A study of photoelectric type smoke detector response

Pao Yue-kong Library Electronic Theses Database

A study of photoelectric type smoke detector response

 

Author: Wong, Hing-yi Annie
Title: A study of photoelectric type smoke detector response
Degree: M.Eng.
Year: 2007
Subject: Hong Kong Polytechnic University -- Dissertations.
Fire detectors.
Optical detectors.
Department: Dept. of Building Services Engineering
Pages: viii, 94 leaves : ill. ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2117605
URI: http://theses.lib.polyu.edu.hk/handle/200/640
Abstract: This study investigates the fire safety problem of a smoke detection system in terms of the probable response time of photoelectric smoke detectors. Response influencing factors including fuel quantity, air velocity through the detector and detector configurations, which describe the smoke aerosol generation, bulk smoke transport with airflow and local smoke transport in a detector, are investigated. The response time of photoelectric light-scattering type detector in a test chamber as described in UL 268 were examined through cotton wick smoke flowing at design velocities of 0.5 ms-1, 0.8 ms-1, 1.4 ms-1, 2 ms-1 and 3 ms-1. Measurements of a 'base case' detector, i.e. a detector installed with a sensing chamber, a sensor screen and an outer casing, were compared with those of three other casing configurations: (1) a detector with the sensing element freely exposed; (2) a detector with a sensing chamber; and (3) a detector with a sensing chamber and a sensor screen. The results showed that the response time would be significantly affected by the airflow near the detector. A response time constant k for a photoelectric smoke detector was proposed and correlated with the airflow velocity. Detector casing configurations were proved to have significant influences on the constant. This smoke detector response time constant would be a design parameter for photoelectric type smoke detectors in the fire detection system.

Files in this item

Files Size Format
b2117605x.pdf 12.11Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information