NATIONAL FOREWORD

This Indian Standard (Part 23) which is identical with ISO 7240-23 : 2013 ‘Fire detection and alarm systems — Part 23: Visual alarm devices’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Fire Fighting Sectional Committee and approval of the Civil Engineering Division Council.

This standard is published in various parts. Other parts in this series are:

Part 2 Control and indicating equipment

Part 3 Audible alarm devices

Part 4 Power supply equipment

Part 5 Point-type heat detectors

Part 6 Carbon monoxide fire detectors using electro-chemical cells

Part 7 Point-type smoke detectors using scattered light, transmitted light or ionization

Part 11 Manual call points

Part 12 Line type smoke detectors using a transmitted optical beam

Part 15 Point type fire detectors using scattered light, transmitted light or ionization sensors in combination with a heat sensor1)

Part 16 Sound system control and indicating equipment

Part 17 Short-circuit isolators

Part 20 Aspirating smoke detectors

Part 22 Smoke-detection equipment for ducts

The purpose of a visual fire alarm device is to warn person(s) within, or in the vicinity of, a building of the occurrence of a fire emergency in order to enable such person(s) to take appropriate measures.

This standard allows manufacturers to specify visual alarm devices in terms of the range at which the required illumination is met. Three classes of device are defined, one for ceiling mounted devices, one for wall mounted devices and an open class. The maximum range of the visual alarm device is tested by measuring the light output in a part of the hemisphere surrounding it to determine its light distribution. As the light output of some visual alarm devices can change over time due, for example, to the effect of self-heating, a specific test checks that the variation of light output over time is within acceptable limits.