13.0 General

COP-FSI defines: "Fire detection systems" as "Any system designed to detect automatically the presence of smoke, heat, combustion products or flames and give warning of same."

Loss Prevention Council, UK (LPC, UK) approves the follow items for fire detection and alarm systems:-

- Certificated fire detection and alarm system firms (in UK)
- Fire detection and alarm systems
- Control and indicating equipment
- Detectors
- Manual call points
- Line units
- Sounders
- Fire resistant cables
- UL910 cables (UL is Underwriters's Laboratories of USA)
- Central stations for fire alarm systems
- Signalling systems for central stations
- Control and indicating equipment to BS 3116: Part 4: 1974

Foreword
1. General information
2. Classification of installations
3. Protection
4. Equipment
5. Zones
6. Wiring
7. Certification, testing and maintenance
Appendix A     Listed companies certificate
Appendix B     Log book format

FSD is discussing actively with the industries and professionals to adapt LPC Rules for AFA for use in Hong Kong.  These rules comprise clauses written by LPC, adding to the basic BS5839: Part 1: 1988.

13.1     AFDA system description

The various components of fire detection and alarm systems are shown in a schematic diagram. (See figures at http://arch.hku.hk/teaching/project/301control.htm and http://arch.hku.hk/teaching/intgtech/111.htm)

There exits a variety of fire detectors:-

Heat Detectors

• Point type (fixed temperature) - The detector responds when the air temperature surrounding the detector rises to a certain level.
• Pont type (Rate-of-Rise, ROR) - The detector responds to a certain rate of rise of temperature of the surrounding air.
• Point type (fixed temperature and ROR) - The detector responds when either of the above conditions occurs.
• Beam type - A receiver mounted on one side of a large volume emits a light beam (normally laser) that reaches the receiver on the other end. The signal received will change if the air temperature or the rate of temperature rise of the air changes.  The control panel will compare the signal received with preset fire signal reference memory, to check if a fire really occurs.  To surveille a larger volume, some beam detectors employ reflecting mirrors interposed between the laser sender and receiver.
• Linear heat detector - 2 cables insulated from each other run around the surveilled space / object.  Heat generated will melt the insulation, causing cables coming into contact or giving different signals at the receiving panel.  The location of fire can also be reported, knowing the distance of the affected portion of the linear heat detector from the panel.

• Point type (optical) - Light is emitted inside the detection chamber into which smoke comes.  A receiver inside the detection chamber receives the light scattered by the smoke particles.  Traditional detectors decide from the received signal if a fire occurs.  Analogue addressable detectors let the fire control panel and its memorised fire reference library decide if a fire should be announced, or a warning signal, or a fault signal.
• Point type (Ionization) - The smoke particles / air particles inside the detection chamber of the detector are ionized by an ionization source which is normally Americium 241.  The amount of ionized particles reach the receiver will reflect the amount of smoke present.  Refer to point type - optical, for signal analysis.
• Beam type - This is similar to beam type heat detector except that the signal received by the analysing panel is calibrated to respond to smoke growth and presence characteristic of fire situations.
• Aspirating smoke detectors - Air is drawn by a tubing system to a sensor which is normally now a laser source and a receiver of the scattered laser (i.e. smoke scatters laser) for raising a warning / fault / false / fire alarm.

• Flame emits strong infrared radiation. Flame detectors respond to this to give alarms.

• Combustible gas detectors are normally point types.  One type makes use of catalytic effect of a chemical compound inside the detector to cause the combustible gas to change its chemical nature, at the same time inducing changes in electronic flow which are detected and analysed to give a signal of the presence of a dangerous concentration of the combustible gas.

• Zoned system - several detectors forming one fire detection zone, several zones in a building.
• Addressable system - each detector is giving an address showing at the fire detection control panel if the detector detects fire, a fault signal.
• Analogue addressable fire detection system - the magnitude of the detected signal can be continuously monitored and the threshold for giving out warning, and alarm can be set at the panel.

Look at this link for some installations.

The following LPC listed companies produce various types of smoke / heat detectors and systems, and their web sites contain a lot of updated product and related technology information:-

LPCB List of Approved Fire and Security Products and Services http://www.lpc.co.uk/lpcb/index.html
Underwriters Laboratories Inc. - search - http://www.ul.com./search.htm
FM Approval guide http://www.factorymutual.com/ag_fire.htm
 

Caradon Gent	http://www.apgate.com/elec/company/co_13633.htm
Apollo	http://www.crowcon.com/apollo.htm
Cerberus	http://www.cerberus.ch/
Edwards	http://www.edwardsinternational.com/product.htm
Hochiki	http://www2.hochiki.com/
Honeywell	http://207.88.216.196/Cfire.htm (of http://www.honeywell.com/) contains, among other information, an article called: Excel Fire Alarm System - The Essentials of Fire Detection Alarm
Kidde	http://www.kidde.co.uk/
Nittan	http://www.nittan.com
Notifier	http://www.notifier.com/
Thorn	http://www/bsdirectory.com/docs/24_4.htm
Reliable	http://www.reliablefire.com/firealarm/firealarms.html
Fireline	http://www.fireline.com/firealarmsystems/firealarmsystems.html

The following web sites contain information on aspirating smoke detectors:-
 

Cerbeurs	http://www.cerberus.ch/
Stratos	http://www.dialspace.dial.pipex.com/town/square/hu07/stratos.htm
Hygood	http://www.hygood.co.uk/
VERDA	http://www.vsl.com.au/vesda/
Kidde	http://www.kidde.co.uk/
Reliable	http://www.reliablefire.com/vesdafolder/vesda.html

13.2   Reference

RULES OF THE FIRE OFFICES' COMMITTEE AND FIRE OFFICES' COMMITTEE OF IRELAND FOR AUTOMATIC FIRE ALARM INSTALLATIONS FOR THE PROTECTION OF PROPERTY, 12th EDITION, February 1985

The Loss Prevention Certificate Board. List of Approved Fire and Security Products and Services, Annual Publication.  Loss Prevention Council, UK.

BS5839: Fire detection and alarm systems for buildings.  BS5839: Part 1: 1988 Code of Practice for system design installation and servicing.

Look at the relevant parts of the following web sites for the layout and schematic diagrams of the related system :-
http://arch.hku.hk/teaching/case.htm#Studies on Building Services
The Graduate House, HKU, http://ug.arch.hku.hk/course/intgtech3/grad_hs/cindex.html
Tsui Tsin Tong Building, HKU, http://arch.hku.hk/teaching/intgtech/