Citation

Smithies JN, Burry PE, Spearpoint MJ. Fire Safety J. 1991; 17(6): 445-459.

Copyright

(Copyright © 1991, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A research programme has been running in excess of three years monitoring and recording the signals produced by individual heat and smoke sensors in a medium sized analogue addressable fire detector installation. The data has been recorded on 40 Mbyte Winchester discs which have been connected via electrically isolating circuitry to the same scanner interface as the Automatic Fire Detection Systems computer. One 40 Mbyte capacity disc is capable of collecting and recording all of the scan data continuously, at the system scan rate, for a period of 5 days. A second smaller analogue addressable system has been monitored by a microcomputer event logging system for a period of approximately 4 years.Various forms of statistical treatment analysis have been carried out on the data. The preferred form appears to be 'return period analysis'--a cumulative logarithmic frequency analysis showing the number of times threshold signal levels have been exceeded. The latter technique enables a relationship between threshold analogue signal levels and frequency of false alarms to be predicted. The measurement and analysis techniques developed are applicable to the commissioning of both new installations and extensions to existing installations. The techniques enable potentially troublesome sensor points to be identified before they can cause false alarms. The approach can reduce the number of false alarms and may thus enable the sensitivity of parts of the system to be enhanced.