NATIONAL FOREWORD

This Indian Standard (Part 6) which is identical with ISO 7240-6 : 2011 ‘Fire detection and alarm systems — Part 6: Carbon monoxide fire detectors using electro-chemical cells’ 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 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

Part 23 Visual alarm devices

Carbon monoxide (CO) fire detectors can react promptly to slow, smouldering fires involving carbonaceous materials because CO does not depend solely on convection, but also moves by diffusion, and CO fire detectors can be better suited to applications where other fire detection techniques are prone to false alarms, that is, due to dust, steam and cooking vapours.

Whilst CO gas has greater mobility than smoke, it can be diluted by ventilation systems and can be affected by convection currents. Hence, it is necessary to take into account the same considerations as for point smoke detectors. Recirculating systems confined to a single room have little effect on dilution, as this is similar to the natural diffusion of the CO gas.

CO fire detectors can be less affected by stratification than other types of fire detectors.