AS 1670 6 1997 fire detection, warning, control and intercom

Australian Standard Fire detection, warning, control and intercom systems— System design, installation and commissioning Part 6: Smoke alarms... Australian Standard Fire detection, war

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AS 1670.6-1997 Fire detection, warning, control and intercom systems - System

design, installation and commissioning - Smoke alarms

Licensed to LUU MINH LUAN on 25 Feb 2002

Australian Standard 

Fire detection, warning, control and intercom systems— System design, installation and

commissioning Part 6: Smoke alarms

The following interests are represented on Committee FP/2:

Audio Engineering SocietyAustralian Building Codes BoardAustralian Chamber of Commerce and IndustryAustralian Chamber of Manufactures

Australian Construction Services — Department of Administrative ServicesAustralian Electrical and Electronic Manufacturers Association

Australian Fire Authorities CouncilAustralian Fire Protection AssociationBuilding Owners and Managers Association of AustraliaCommonwealth Fire Board

CSIRO — Division of Building, Construction and EngineeringDeafness Forum of Australia

Department of DefenceFire Protection Industry Association of AustraliaInsurance Council of Australia

National Electrical Contractors Association of AustraliaNew Zealand Fire Equipment Association

New Zealand Fire Protection AssociationNew Zealand Fire Protection Industry Contractors AssociationTelstra Corporation

Review of Australian Standards To keep abreast of progress in industry, Australian Standards are

subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary It is important therefore that Standards users ensure that they are in possession of the latest editi on, and any amendments thereto.

Full details of all Australian Standards and related publi cations will be found in the Standards Australi a Catalogue of Publi cations; this information is supplemented each month by the magazine ‘The Australian Standard’, which subscribing members receive, and which gives detail s of new publications, new editions and amendments, and of wit hdrawn Standards.

Suggestions for improvements to Australi an Standards, addressed to the head off ice of Standards Australia, are welcomed Notif ication of any inaccuracy or ambiguity found in an Australian Standard should be made wit hout delay in order that the matt er may be investigated and appropriate acti on taken.

This Standard was issued in draft form for comment as DR 96002.

Australian Standard 

Fire detection, warning, control and intercom systems—System design, installation and commissioning

Part 6: Smoke alarms

PUBLISHED BY STANDARDS AUSTRALIA(STANDARDS ASSOCIATION OF AUSTRALIA)

1 THE CRESCENT, HOMEBUSH, NSW 2140

ISBN 0 7337 0814 5

This Standard was prepared by the Joint Standards Australia/Standards New ZealandCommittee FP/2 on Fire Detection, Warning, Control and Intercom Systems, to facilitatethe installation and commissioning of smoke alarms in domestic residential situations and

is the result of a consensus among the representatives on the Joint Committee to produce

it as an Australian Standard

The term ‘informative’ has been used in this Standard to define the application of theappendix to which it applies An ‘informative’ appendix is only for information andguidance

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Page

SECTION 1 SCOPE AND GENERAL

1.1 SCOPE 4

1.2 APPLICATION 4

1.3 REFERENCED DOCUMENTS 4

1.4 DEFINITIONS 4

1.5 COMPLIANCE WITH OTHER STANDARDS 4

1.6 INTERPRETATION OF SPECIFIED LIMITING VALUES 4

SECTION 2 INSTALLATION AND COMMISSIONING 2.1 LOCATION OF SMOKE ALARMS 5

2.2 ALARM SIGNALS 5

2.3 INTERCONNECTION 6

2.4 WIRING 6

2.5 MOUNTING 6

2.6 COMMISSIONING 6

APPENDICES A FIRE AND DETECTION CHARACTERISTICS 8

B INSTALLATION GUIDE 10

C MAINTENANCE 18

First published as AS 1670.6 — 1997.

STANDARDS AUSTRALIA

Australian Standard Fire detection, warning, control and intercom systems—

System design, installation and commissioning

Part 6: Smoke alarms

2706 Numerical values — Rounding and interpretation of limiting values

3000 Electrical installations — Buildings, structures and premises (known as the SAA

Wiring Rules)

3786 Smoke alarms

SAA

HB46 Guide to residential fire safety

1.4 DEFINITIONS For the purpose of this Standard, the definitions given belowapply

1.4.1 Multiple station smoke alarm — a smoke alarm with interconnection facilities for

common alarm communication

1.4.2 Single station smoke alarm — a smoke alarm not intended to be interconnected

with other units for common alarm purposes

1.4.3 Smoke alarm — a device containing a smoke detector and an alarm sounding

device

1.5 COMPLIANCE WITH OTHER STANDARDS The smoke alarm installation

shall comply with the appropriate electrical safety requirements specified in AS 3000.NOTE: To minimize false alarms caused by electrical interference and for ease of maintenance,

it is recommended that smoke alarms connected to low voltage are wired to a dedicated circuit

1.6 INTERPRETATION OF SPECIFIED LIMITING VALUES For the purpose ofassessing compliance with this Standard, the specified values herein shall be interpreted inaccordance with the ‘rounding method’ described in AS 2706, i.e the observed orcalculated value shall be rounded to the same number of figures as in the specifiedlimiting value and then compared with the specified limiting value For example, forspecified limiting values of 2.5, 2.50 and 2.500, the observed or calculated value would

be rounded to the nearest 0.1, 0.01 and 0.001 respectively

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S E C T I O N 2 I N S T A L L A T I O N A N D

C O M M I S S I O N I N G

2.1.1 General Smoke alarms shall be located on or near the ceiling On levelscontaining bedrooms a smoke alarm shall be located between each area containingbedrooms and the remainder of the dwelling Where the bedroom area is served by ahallway, the smoke alarm shall be located in that hallway

NOTE: For information on fire and detection characteristics, see Appendix A

2.1.2 Multi-level Where the dwelling is multi-level, at least one smoke alarm shall belocated on each level such that the egress path from each level is protected All smokealarms shall be interconnected

2.1.3 Sloping ceilings Smoke alarms in rooms with ceiling slopes greater than 1 in 8shall be located at the high side of the ceiling

2.1.4 Dead air spaces Smoke alarms shall not be located in the following areas:

(a) Within 300 mm of a light fitting

(b) In dead air spaces as shown in Figure 2.2

2.1.5 Joists and beams On ceilings with exposed joists or beams with a depth notexceeding 300 mm, smoke alarms may be located on the underside of the joist or beam

2.1.6 Stairwells Smoke alarms installed in stairwells shall be located to ensure thatsmoke rising in the stairwell is not prevented from reaching the smoke alarm by a door orother obstruction

2.1.7 Forced air circulation In areas provided with airconditioning or forced airventilation, smoke alarms shall not be installed closer than 400 mm to any supply airopening Smoke alarm locations shall be chosen to take account of the airflow towardsreturn air openings Where ceiling fans are installed smoke alarms shall not be installedwithin 400 mm of the blades of the fan

2.1.8 Environmental conditions Smoke alarms shall not be located in areas where theenvironmental conditions exceed the manufacturer’s operating parameters

2.2 ALARM SIGNALS

2.2.1 Aural alarm signals Smoke alarms shall be installed to ensure that the auralsignal is clearly audible in all bedrooms of the dwelling over the background noisenormally encountered, with all intervening doors closed For audible signals intended toarouse sleeping occupants, the sound pressure level of the signals shall be not less than

75 dBA when measured at the sleeping position

NOTES:

1 A sound pressure level of not less than 75 dBA and 15 dB above expected ambient noiselevels (air conditioners and the like) at the bed should be sufficient to awaken an averagesleeping person (see Paragraph B5 of Appendix B)

2 Appendix B provides a step-by-step guide to the selection of smoke alarms, and to thelocation in which they will achieve adequate performance

2.2.2 Visual alarm signals Visual alarm signals shall be installed where it is required

to alert persons who are hearing impaired or in areas of high ambient noise levels

2.2.3 Other sensory alarm signals Where the alarm signals specified in Clauses 2.2.1and 2.2.2 are not adequate, other types of sensory stimulating alarm devices may be used

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devices in accordance to the manufacturer’s requirements.

Typical field wiring with interconnections are shown in Figure 2.1

FIGURE 2.1 TYPICAL FIELD WIRING

2.4 WIRING Field wiring for smoke alarms on dedicated circuits shall generally becarried out in 16/0.20 stranded wire for externally d.c powered units and 1.0 mm2 cablefor 240 V a.c powered units Where connected to existing circuits the cable size shall bethe same as the circuit to which the connection is made

2.5 MOUNTING Smoke alarms shall be mounted in accordance with themanufacturer’s instructions, with the aperture for smoke entry not less than 25 mm belowthe ceiling surface when mounted on the ceiling

2.6 COMMISSIONING Smoke alarms shall be commissioned in accordance with the

manufacturer’s instructions

The correct operation and adequacy of the sound intensity of each smoke alarm shall bechecked

Where the smoke alarm system performs additional functions such as the alarm operation

of interconnected devices and the operation of escape lights, the additional functions shallnot adversely affect the operation of the system

NOTES:

1 To enhance fire safety in the home refer to Handbook SAA HB46

2 Appendix C provides information on the maintenance of smoke alarms

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or smoulder for several hours before breaking out in flames Some types of detectors aremore appropriate than others for specific types of fires and consideration should be given

to smoke alarm selection

A2 FIRE GROWTH During the smouldering stage, a fire will release a small amount

of heat, possibly toxic gases, and airborne matter in a variety of particle sizes Particulatematter and toxic fume inhalation is the most common cause of death in house fires.Following the onset of flaming, the fire will grow in size and spread rapidly, fuelled bythe surrounding combustible material and the heat produced by the fire The rate of firespread in any specific case will depend on the flammability of interior contents, includingfurnishings, the surface materials of ceilings, walls and floors, and the oxygen supply.During the flaming stage, with adequate air supply various gases and particulate matterreleased will be approximately proportional to the fire size Where the air supply isrestricted, as may be the case in a closed living unit, oxygen depletion will occur andcarbon monoxide production will increase as the fire grows

A3 FIRE BY-PRODUCTS The most threatening by-product of a fire and one ofspecial consideration where fire deaths are concerned is carbon monoxide All materials,when burned, release carbon monoxide — some synthetic materials at much higher rates.Test fires of simulated living rooms show that furniture upholstered with polyurethanefoam is capable of producing lethal concentrations of carbon monoxide within one or twominutes of ignition Carbon monoxide interferes with the ability of blood to carry oxygen

to the brain, causing confusion, disorientation and unconsciousness A person exposed tohigh levels of carbon monoxide would be unconscious after a few breaths and deathwould follow in one to three minutes The carbon monoxide given off from a fire could

be likened to pumping a car exhaust into the home

At a certain stage of the fire, the cumulative effects of overheated air, toxic gases andoxygen deficiency will overcome any occupants Since the time available for escape isdependent on the stage at which the fire is detected and on the rate of fire spread,maximum protection is achieved by detection of the fire at its earliest stage

A4.1 General The object of any smoke alarm is to provide early warning of a fire inorder to maximize escape time Whilst attempting to reach the same objective, differentdetection principles, such as ionization or photoelectric, behave differently In decidingwhich type to install, consideration needs to be given to the likely type of fire(smouldering or fast flaming) and therefore the type of particulate matter and gases to bedetected The ambient conditions and the likelihood of the installation creating anunacceptable level of nuisance alarms should also be considered A mixture of alarm typesmay be required to optimize detection results

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by detecting the airborne particulate matter from the fire before significant heat build-upoccurs Results of full-scale fire tests in actual dwellings indicate that smoke alarmsprovided sufficient time for evacuation from the dwelling For these reasons, theinstallation of smoke alarms in the vicinity of sleeping areas is recommended as theprimary means of providing an alarm signal (see Appendix B).

A4.3 Ionization smoke alarms Ionization smoke alarms respond to a sufficiently widerange of fires to be of general use and are particularly responsive to fast flaming fireswhere little visible smoke may occur They are generally less troubled by dust or insectcontamination, are generally more prone to nuisance alarms due to fumes from cookingand portable gas or oil heaters, which may lead to the alarm being disconnected by theuser, and are slower to respond to smoke produced by slow smouldering fires than arephotoelectric types

A4.4 Photoelectric smoke alarms Photoelectric smoke alarms sense visible smokeparticles They respond to a sufficiently wide range of fires to be of general use and areparticularly responsive to smouldering fires and the dense smoke given off by foam-filledfurnishings or overheated PVC wiring Photoelectric smoke alarms are generally lessprone to nuisance alarms from cooking but may be more prone to nuisance alarms caused

by airborne condensate, dust or insect contamination They contain no radioactivematerial Mesh screens may reduce insect ingress, but it is impossible to make the alarmsdust proof, as they would then be unable to sample the air For this reason it is importantthat photoelectric smoke alarms are kept clean

A4.5 Heat alarms and heat detectors As an addition to the installation of smokealarms, heat alarms or detectors provide a method of fire detection in locations wheredetection is considered advisable, yet the installation of a smoke alarm is inappropriate orwould cause an unacceptable level of nuisance alarms Examples may include enclosedlaundries or kitchens

Heat alarms or detectors are not a substitute for smoke alarms; they are not sensitive tosmoke, but in a closed room with a vigorous fire they may respond faster than a remotelylocated smoke alarm A heat alarm or detector must be interconnected to any smokealarms so that the alarm can be heard throughout the building Heat alarms or detectorsrequire the least maintenance of any alarm and are less affected by contamination

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