NATIONAL FOREWORD

This Indian Standard (Part 20) which is identical with ISO 7240-20 : 2010 ‘Fire detection and alarm systems — Part 20: Aspirating smoke detectors’ 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 22 Smoke-detection equipment for ducts

Part 23 Visual alarm devices

Aspirating smoke detectors differ from point-type smoke detectors (see IS/ISO 7240-7) in that air is drawn into the smoke-sensing chamber, rather than relying on convection.

This standard is not intended to place any other restriction on the design and construction of such detectors.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions and terminologies are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.