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Handbook for Fire Detection Systems and Emergency Warning and Intercommunication Systems
Iceweb thanks and acknowledges AMPAC INDUSTRIES PTY LTD permission to publish this handbook.
The purpose of this handbook is to provide information on the various configurations available for Fire Detection Systems. Appendixes on AS1668 controls and emergency warning systems have been included as they form part of the modern day requirements for fire control.
Although Ampac has created the handbook, it does not relate specifically to our products and it is intended to be used as a guide for all manufacturers equipment and systems.
It should be noted that the information is to be used as a reference only and that when specifying equipment for a project, it is best to consult with the end user and the manufacturer to ensure the most appropriate equipment is selected.
Additional copies of the handbook are available on request, as are in house presentations, or just call one of our customer service offices for more information.
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2.0 FIRE DETECTION SYSTEMS
There are two types of fire detection systems currently available. The first is referred to as conventional, the second addressable.
2.1 CONVENTIONAL SYSTEMS
Conventional systems have been around for many years. Although the appearance of the system components has changed dramatically over the years, the system operation has not. Typically a building is sectioned into fire compartments (zones). Each zone will be protected by "conventional" detectors (smoke or thermal). Conventional detectors have two states, normal and alarm. Each zone is wired back to the fire indicator panel (FIP) separately.
Australian Standard 1670 states that zones have the following limitations:
No more than 40 detectors.
Protect an area no more than 2000m2.
Protect no more than one floor.
The FIP has one appropriately labeled indicator per zone. When a detector is in the alarm state, the indicator illuminates. When the fire brigade observe the FIP, they can determine which zone the fire is in, but not which detector caused the alarm. This can mean a lengthy search within the zone, to determine the fires exact location.
Conventional systems have provided adequate protection for a long time. Even now these systems can be the most appropriate choice when factors like building services interfaces, life safety, risk, budget and end client requirements are taken into consideration.
2.2 ADDRESSABLE SYSTEMS
Addressable systems differ from conventional systems in the following ways:
1. FIP has a LCD display so that plain English messages can identify detector location, instead of an LED indicator identifying zone location.
2. Each detector has a unique address.
3. Detectors are wired in a loop instead of terminating with an end of line device.
4. Zones are sometimes used for convenience, but are not required.
5. Keypads are used for control instead of discrete switches.
6. High level interfaces can be used to communicate with other building services. Eg: Security System.
2.2.1. WHY HAVE A LOOP?
1. Detectors are continually polled to ensure system integrity.
2. If one open circuit occurs, no detection is lost, as the loop is bi-directional.
3. The loop allows data to be transmitted. This means additional devices can be used to control outputs. Eg Mechanical services, shutdowns and input devices to connect to flow switches, fire pumps etc.
NOTE: If a short circuit occurs on an addressable loop, all devices on that loop cease to work! This can be over come by placing short circuit isolators in strategic locations.
2.2.2. WHAT ARE THE ADVANTAGES?
1. Faster response time - each device displays individually at the FIP.
2. Reduced installation costs - far less cable and labour is required.
3. Greater flexibility - additional devices can be added easily. FIP can be connected to other FIPs, graphics stations, mimic panels etc, at any time. Conventional zones can be mixed with addressable devices.
2.2.3. WHAT IS AN ANALOGUE DETECTOR?
Before we answer this, lets define the other types of detectors.
1. Conventional detectors - are detectors without address identification and will only relay an alarm in a zone as indicated by the FIP. Their sensitivity is factory set and can not be altered.
2. Addressable detectors - are detectors with an address identification and will relay the exact location of the alarm to the FIP. Their sensitivity is factory set and can not be altered.
Both conventional and addressable detectors will only report a fault to the FIP when they are removed from their bases.
The definition of an analogue detector is - detectors with address identification relaying exact location of alarm, but will also provide the FIP with constant data as to the condition of the detector. This means that apart from the standard alarm and fault conditions being reported to the FIP, additional conditions can be sent such as:
Dirty detector - When contamination in the detector reaches a pre-set level, a maintenance fault is reported at the FIP. This reduces the number of false alarms to the Fire Brigade.
2.Pre-alarm - when the smoke/heat level increases towards the full alarm set point, an intermediate set point can be used to give a "pre-alarm" signal at the FIP. This allows an investigation of the fire to take place before the brigade is called and evacuation procedures take place. This is most beneficial at high security sites and sites that have a high concentration of people.
2.2.4. WHAT IS A COMMUNICATION LOOP?
A communication loop is a serial loop consisting of a screen cable originating from the FIP extending to the required location/s and back to the FIP.
Required locations generally consist of one or more of the following:
LCD Mimic- compact unit that displays alarms, faults and isolates on a device basis using a liquid crystal display.
LED Mimic- usually only displays alarms on a zone basis (can be per device). Typically the LEDs are on a facia that represents the building layout
Addressable Loop - typically 126 devices can connect to the loop. The remote location does not have control or indication of the devices, it is purely a termination point.
Remote Conventional Zones - usually provided in modules of 4 or 8 zones. The remote location does not have control or indication of the zones, it is purely a termination point.
Graphics Package - used to display alarm, fault, isolate on a zone or device basis using graphic presentations of the building floor plan. Control of the system is also available on most units.
Mechanical Control Interface - used when there is a multiple number of mechanical control panels, each with a large number of fans.
Sub Fire Indicator Panels - have control and indication of a specific area within a large site. They can connect to conventional or addressable devices or a combination of both.
SFIPs do not report directly to the Fire Brigade, instead they report to the sites main fire indicator panel.
BMS Module - this module provides an RS232 interface to a sites building management system. The module reports a change of state for alarm, fault and isolate conditions. This can be done on an individual detector basis or by zones.
3.0 SYSTEM CONFIGURATIONS
Now that the building blocks have been explained, we can look at how they can be interconnected to create the most cost-effective solution for your client. When deciding on which system to use factors such as; budget, level of risk, size of site and life safety must be taken into account. Depending on the manufacturer, there may be a limit on the number of zones/loops that can be fitted in the FIPs.
The following configurations are by no means exhaustive. System components can be mixed and matched further than the seven examples shown. However, the seven examples cover most situations and are intended to give a general overview
Please note that there are a number of drawings related to the configurations which are not suitable for Internet deployment. Should you require these please email :firstname.lastname@example.org
The system is made up of conventional detectors (heat/smoke) arranged to cover the site in zones. A conventional FIP is used to indicate the location of a fire on a zone basis. Any ancillary outputs required such as airconditioning shutdowns, EWIS signals etc, are. "hard wired" from the FIP to the relevant equipment.
Typically used in low rise, building sites eg nursing homes, small offices.
The system comprises of addressable detectors (heat/smoke) reporting back individually to an addressable FIP. Auxiliary outputs can be hard wired or addressable devices can be placed on the loop (saving cabling costs).
Typically used in low or high risk, large area buildings eg warehouses, hospitals.
The system comprises of a combination of conventional and addressable detectors. An addressable FIP capable of connecting to both types of detectors must be used. Auxiliary outputs can be hard wired or addressable devices can be .used.
Typically used where there is a combination of low and high risk areas. This is also a very good option where a site is being extended and the existing conventional panel does not have enough room to accommodate the expansion. This allows addressable detectors to be used in the extension without upgrading the whole site (which can be done over time).
3.4 DISTRIBUTED CONVENTIONAL - OPTION 1
The system comprises of zones of conventional detectors connected to an individual addressable device. An addressable FIP is used, but will only display alarms on a zone basis, not per detector. Auxiliary outputs can be hard wired or addressable devices can be used.
Typically used in low risk, high rise or large area buildings eg office towers.
3.5 DISTRIBUTED CONVENTIONAL - OPTION 2
The system comprises of data gathering panels placed in strategic locations. Each DGP would be fitted with the required number of conventional zones to protect a defined area. DGPs do not have any controls or indicators, they are purely a termination point. As well as the zone connections, auxiliary outputs can be fitted in the DGPs. Power is normally provided by dedicated supplies and batteries, however, it can be obtained from the main FIP. As the DGPs communicate via a high level interface, the main FIP must be microprocessor based, but not necessarily addressable. The main panel is capable of running the DGPs as well as its own conventional zones.
Typically used on low risk, multiple building sites where central control is required. eg army barracks.
3.6 DISTRIBUTED ADDRESSABLE
The system comprises of data gathering panels placed in strategic locations. Each DGP would be fitted with the required number of addressable loops, to protect a defined area. DGPs do not have any controls or indicators, they are purely a termination point. Auxiliary outputs can be fitted in the DGP or on its addressable loops. The main FIP will be addressable, capable of running the DGPs and its own addressable loop/s.
Typically used in high risk, multiple building sites eg shopping centres, large hotels etc.
The system comprises of sub fire indicator panels (conventional or addressable) connected to the main FIP via high level interface. Each SIP has control and indication of the detectors connected to it. Auxiliary outputs can be either in the SIP or addressable devices. The main panel can have its own addressable loop/s as well as communicating to the SIPs. In a network system, the main FIP has facility to interrogate any detector/device on the whole site. As an example, the main panel can alarm test a detector connected to SIP No 2, loop No 3.
Typically used in high risk, multiple building sites eg prisons, airport terminals, etc.
4.0 TYPICAL CABLING REQUIREMENTS
CONVENTIONAL DETECTOR CIRCUIT
Two core TPS originating from panel to end of circuit fitted with 3.3K E.O.L.
Two core cable originating from FIP or remote addressable module, extending through the protected areas and returning to the FIP or remote addressable module.
Maximum loop resistance 50 OHMS.
The following refer to TPS, or RADOX cables.
|Cross Section Area||Loop Res per km||Rec Dist|
Two core screened twisted pair cable originating from FIP extending through the protected areas and returning to the FIP.
|Capacitance||100 picofarads per metre or less|
|Resistance||100 ohms per kilometre or less|
|Impedance of loop||typical 120 ohms|
|Maximum distances between modules||1.2K providing cable meets above specifications.|
|Recommended cable type||
(non fire rated)
5.0 AUSTRALIAN STANDARD 1668 FAN CONTROLS
If you live in a country other than Australia you will have to refer to appropriate National Standards
The requirements for AS1668 controls vary widely from state to state, within states and within individual buildings. It is therefore difficult to generalise on mode of operation.
We would like to cover this subject by providing some options when wiring a system that has an addressable fire indicator panel.
The options are not exhaustive, however, the options cover most situations and are intended to give a general overview.
OPTION NO 1
Conventional wiring, a multicore cable (usually 5 core), is run from the FIP to the mechanical control panel/s for each fan.
Typically used when there is a small number of controls required, or when the mechanical control panel is in close proximity.
OPTION NO 2
Addressable wiring, a dedicated addressable loop is run from the FIP, to each mechanical control panel, then back to the FIP. Addressable devices are placed along side the mechanical control panels to transfer the relevant data.
Typically used when there is a multiple number of mechanical control panels, each with a small number of fans.
OPTION NO 3
High level communication wiring, a dedicated communication loop is run from the FIP to each mechanical control panel, then back to the FIP. Data gathering panels are placed along side the mechanical control panel or in strategic locations. Wiring from the DGP to the mechanical panels would be either in conventional wiring or addressable.
Typically used when there is a large site with multiple mechanical control panels, each with a large number of fans.
6.0 EMERGENCY WARNING AND INTERCOMMUNICATION SYSTEMS
Emergency Warning and Intercommunication systems can be broken into two specific areas. 1. Single zone evacuation, 2. Multi zone evacuation that incorporates an intercommunication system.
The following descriptions are not exhaustive, however, they provide a guide as to what is currently available.
1. SINGLE ZONE EVACUATION
Self contained tone generator and speaker. They provide alert evacuation tones only. Typically used as a substitute for internal fire alarm bells.
Combined tone generator and small wattage amplifier. They provide alert and evacuation tones as well as the option of public address. Suitable 100 volt line speakers are to be used with this system. They are generally fitted into the sites FIP and are used on small sites.
Stand alone system. They provide alert and evacuation tones as well as public address. Other characteristics are, large wattage amplifier, number of auxiliary inputs available, visual alarm output available, battery back up provided. Used on small to medium sites.
2. MULTIZONE EVACUATION
Generally a large site will be split into evacuation zones. Fire compartments, floor levels or manageable areas, usually define a zone. Each zone is fitted with its own speaker system capable of providing background music, alert and evacuation tones as well as public address. Visual alarms are used to supplement the speaker warning in high ambient noise areas eg plantrooms. Each zone is individually controlled at the master emergency control panel (MECP).
As well as the speakers, warden intercom point/s are generally provided in each zone. The WIPs are used to communicate information to the head warden via the MECP in an emergency situation. This is known as the emergency intercom system.
Optional equipment available to help your client utilise the system to its fullest are secondary emergency control panels (SECP) and remote paging consoles (RPC). SECPs can be located in one or many locations and give the operator full control and indication of the system. RPCs can also be located in one or many locations. They allow the operator to page (public address) one zone, a group of zones or all zones.
The next progression in evacuation systems is to distribute the main equipment. In a conventional system, the amplifiers, speaker terminations, WIP terminations, etc, are housed in one central location, the MECP. With a distributed system, data gathering panel/s are placed in strategic locations. The DGPs house the necessary equipment to run the apparatus (speakers, visual alarms, WIPs) in its local area - the only control and indication is at the MECP (unless SECPs are provided), as is the case with standard systems. Distributed systems are used in sites such as hotel resorts and large hospitals.