The Rafiki Twinflex plus is a patented, 2 wire intelligent fire alarm system suitable for the majority of fire alarm installations. The Twinflex plus also has the option of the added feature of  ‘checkpoint’ alarm confirmation.

Checkpoint alarm confirmation drastically reduces the disruption and cost associated with false alarms, particularly during the settling-in-period following installation. Introduction of mandatory licensing of HMO’s of three stories or more was introduced in April 2006.

Licensing of HMO’s is mandatory for all local authorities and all buildings that are registered must comply, amongst other things, with fire regulations contained within BS5839 part 6, the main code of practice for installations within HMO’s and in some cases BS5839 Part 1 may also be applicable in communal areas.

False alarms are a huge problem in within these types of buildings and installers are constantly looking for an early warning fire alarm system without the disruption of false alarms.

There are over 485,000 false alarms attended by the Fire Services each year and hundreds of thousands more that are not recorded, sixty-five per-cent of which are attributed to equipment. In the main, detecting fire when no real fire is present, e.g. cooking fumes, steam etc. Even though these fire detectors are doing what they are designed to do they obviously can’t differentiate between a real fire and a false alarm, but the disruption caused and cost to the community is enormous. To tackle this problem Rafiki Protection has developed the Twinflex plus system incorporating ‘checkpoint’ alarm confirmation.

Extract from BS5839 Part 6 (Clause 12. Limitation of false alarms)

In some (usually larger) houses in multiple occupation, high levels of false alarms sometimes occur, simply as a result of the number different occupants, each of whom carry out activities, such as cooking, that can lead to false alarms. In such circumstances, occupiers have been known to compromise or even cause damage to, the fire detection and alarm system, or to ignore fire alarm signals. This makes it important to minimise, as far as practicable, the extent to which occupiers are disrupted by false alarms in other occupiers’ accommodation. This might, for example, be achieved by use of a mixed system (see 9.1.5)*. Alternatively, other measures might be adopted; for example, in the event of a fire signal in one dwelling unit, a short time delay might be incorporated for the occupier to investigate the cause and, if appropriate, reset the system before a fire alarm signal in other dwelling units.
* Mixed system BS5839 part 6 and BS5839 Part 1

Rafiki Checkpoint – Definition

Alarm selection, the main feature of the Rafiki Twinflex plus is the ability to set a pre-alarm in individual rooms or apartments but at the same time initiate full alarm should fire be detected in any communal area. This is made possible by a detector sounder ‘logical link’ feature. This is the first time that this feature has been made available on a conventional system and is beneficial where two stage alarms are required.

At the planning stage of installation fire zones are designated as ‘dwelling’ or ‘communal’. Detectors in dwelling zones (e.g. apartments, hotel rooms etc.) are enabled with the ‘logical link’ feature by way of a dil switch in the detector. This then allows the control panel to be, simply, programmed with a variable time alarm confirmation period (1-5 minutes at one minute increments). In the event of a fire being detected in a dwelling only the local (room) sounder will operate to alarm occupants of that particular dwelling.

The control panel will then carry out a number of checks over this period (which may be 2 minutes, for example ) to confirm the detector is still in alarm and is a genuine fire, not a false alarm generated by cooking fumes, steam etc. If at the end of this checking period the detector ceases to signal alarm the control panel will automatically reset the detector/sounder and the system will revert to its normal state.

If, however, at the end of the confirmation check the detector is still generating an alarm signal the control panel will instantly sound all alarms in the building for full evacuation. Detectors sensing fire, or, call point activation (in any zone) in communal areas instantly generate a full alarm throughout the building.

• The control panel meets all the requirements of EN54-2 and EN54-4:1997.
• The detector meets the requirements of EN54-5 and EN54-7 :2000.
• The sounder meets the requirements of EN54-3:2001.

NOTE: Twinflex Plus panels are configured to have ‘Dwelling’ or ‘Communal’ zones at the time of commissioning. Dwelling zones are then set with the ‘checking’ period – between 1 and 5 minutes. Rafiki advises that this panel should only be installed and configured by qualified fire alarm installers or equivalent personnel.

Using the Twinflex Plus system in an installation

At the planning stage, fire zones are designated as either ‘Dwelling’ or ‘Communal’. Multipoint detectors in the dwelling zones have the facility to use ‘checkpoint’ technology. By simply enabling the logical link dil switch in the detector. The ‘Checkpoint’ technology is the ability to select a checking period for individual detectors to confirm the smoke/heat detected as a genuine fire not an false alarm. This checking period can be selected between 1 – 5 minutes at commissioning stage after consultation with fire officers or other authorized bodies.

Communal Zone
Communal area, e.g. hall/stairway; kitchen; lounge. When a detector alarm is activated on this type of zone, the control panel enters the fire state and the alarms are activated immediately in all zones throughout the installation.

Single Dwelling per Zone (Zonal confirmation alarm) e.g. flats with more than one room

When a detector alarm is activated on this type of zone, all sounders on the zone are activated and then the control panel carries out the configured number of confirmation checks.If the detector alarm is confirmed, the control panel enters the fire state and the alarms are activated throughout the installation; if the detector alarm is rejected, the sounders on the zone are silenced, and the detector in alarm is reset.

Multiple Dwellings per Zone (Local confirmation alarm)
Dwellings requiring a single detector/sounder, e.g. hostel; hall of residence; hotel rooms; bedsits.

When a detector alarm is detected on this type of zone, the integral sounder in the detector that generated the alarm signal is activated and then the control panel carries out the configured number of confirmation checks. If the detector alarm is confirmed, the control panel enters the fire state and the alarms are activated throughout the installation; if the detector alarm is rejected, the sounder is silenced, and the detector reset.

Note: Activation of any manual call point will override alarm confirmation

Read more about the generally accepted guidelines by Rafiki, Aico, and other Fire Alarms manufacturers, (they are also commonly accepted for all the domestic, commercial and industrial properties in UK); the Rafiki advices for Fire Alarms, some of the guidelines provided by Rafiki(intelligent fire technology) – check out the Rafiki series of industrial/commercial fire alarm systems (like the Rafiki Twinflex), found at The Conventional and Analogue Fire Alarms. For more details about the fire alarms, visit the Fire-Detect website(see a list of articles about the fire alarms here and here).

A fire risk assessment should identify:

• Possible hazards;
• Sources of ignition;
• Persons at risk of fire;
• Means of escape;
• Fire detection and alarm systems;
• Fire fighting facilities;
• Routing procedure in the event of fire;
• Any difficulties with the above – and plans to put them right.

Fire Detection & Alarm Systems BS5839 – Risk Assessment

• The ‘Fire precautions (Workplace) Regulations’ require any business employing five or more persons to hold a written ‘Fire Risk Assessment’ and ‘Emergency Plan’.  This must be periodically reviewed.
• The local fire brigade can enforce compliance, and close any building that does not meet this act.
• In the event of a fire in a building without a written ‘Fire Risk Assessment’, those responsible may face fines and imprisonment, and/or private litigation.

The Law requires you to

• Complete a fire risk assessment for your work place (considering all employees, the public, disabled people and people with special needs).
• Identify and record any significant findings or persons at risk.
• Provide and maintain fire precautions.
• Provide information, instruction and training.
• Nominat e persons responsible to implement your emergency plan.
• Consult employees about the above nominations and your proposals to improve fire precautions.
• Inform other employees who may have work places in the building about any significant risks which may affect their safety and co-operate with them to reduce/control these risks.
• If you are not an employer, but control premises which contain more than one workplace, you are responsible for complying with fire regulations.
• You must establish a suitable means of contacting the emergency services.
• Your employees must co-operate to ensure the workplace is safe from fire and its effects.

Fire Risk Assessment – System Zoning Information

In order to aid identification of the source of a possible fire, the protected building should be divided into ‘zones’.  When deciding on a suitable zoning scheme for a building, consideration should be given to the size, any existing fire routines, escape routes, zone accessibility, and structural fire compartmentation.

The following guide lines should be observed:

• If the total floor area of the building is less than 300sqm then the building needs only one zone, regardless of the number of storeys.
  If the total floor area is greater than 300 sqm:
• The maximum area for a zone is 2000sqm.
• If a stairwell (or similar) extends beyond one floor it should be a separate zone.
• If a zone covers more than one fire compartment then the zone boundaries should follow the compartment boundaries.
• The search distance within the zone in order to ascertain the position of the fire should not exceed 60m.  Remember that the use of Remote Indicator lamps may help to reduce the distance traveled.
• If a building is divided between occupiers, zones must not be shared between them.

These are some of the guidelines provided by Rafiki(intelligent fire technology) – check out the Rafiki series of industrial/commercial fire alarm systems (like the Rafiki Twinflex), found at The Conventional and Analogue Fire Alarms. For more details about the fire alarms, visit the Fire-Detect website(see a list of articles about the fire alarms here and here).

There are many options open to the specifier and installer. In properties where a simple system is required, this can be achieved using either RadioLINK RF or hardwired technology. Where there is a need for a more comprehensive system, just choose the particular control and/or signalling devices that you need and install the system that meets your requirements.

Below you can see a list of the 3 possible components of an Aico System – Hard wired devices(switches, call points, relay bases), Ancillary system devices(beacons, sounders, door holders), and RadioLINK system devices(bases, manual call points, remote control switch, repeater, etc).

Hard-Wired System Devices

MCP401RC Manual Call Point

• Mains powered with built-in 10 year+ rechargeable lithium cell back-up
• Non-breakable operating element with reset key
• For use with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms

Ei1529RC Remote Control Switch

• Allows the user to locate the source of an alarm when all units are sounding, hush any false alarms and also test the system
• Mains powered
• For use with Ei2110 Multi-Sensor, Ei160RC Series and Ei260RC Series alarms

Ei159 Alarm Locator Switch

• Allows the user to locate the source of an alarm when all units are sounding
• Pressing the locate switch silences all alarms apart from the one that is the source of the alarm
• Automatically resets after 10 minutes
• For use with Ei2110 Multi-Sensor, Ei160RC, Ei140 and Ei260RC Series alarms

Ei128R Relay Base

• Contains set of relay contacts that are switched on receipt of an alarm interconnect signal
• Volt-free relay contacts, rated at 240V 5A
• Pulse or Constant switching option
• Mains powered
• For use with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms

Ei128RBU Relay Base

• As Ei128R but with built-in 10 year+ rechargeable lithium cell back-up
• For use with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms

Ei128COV Cover

• Available separately for Ei128R and Ei128RBU

Ancillary System Devices

SAB300 Xenon Beacon/Strobe

• For switching via an Ei428/128R/128RBU relay
• Flash energy of 3 Watts and flash frequency of 0.9Hz
• For internal or external use (IP65)
• Clear(C) or Red(R) lens options

SABV4 High Intensity Xenon Beacon/Strobe

• For switching via an Ei428/128R/128RBU relay
• 5 Joule high intensity flash
• For internal or external use (IP65)
• Opal(O) or Red(R) lens options

Ei167RC Remote Sounder

• Interconnects with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms
• Also compatible with Ei168RC RadioLINK base
• Mains powered with 10 year+ rechargeable lithium cell back-up
• Minimum sound output of 85dB(A) at 3m Y03 Remote Sounder
• For switching via an Ei428/128R/128RBU relay
• Switchable sound output frequency 500-2900Hz
• Sound output level 97-100dB(A)
• For internal or external use (IP54)

MDH230 Magnetic Door Holder

• For switching via an Ei428/Ei128R/ Ei128RBU relay
• Supplied with metal door plate
• Magnet de-activates when relay switches and releases door plate

RadioLINK System Devices

Ei168RC Base

• Wireless (radio-frequency) communication
• For use with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms
• Mains powered with 10 year+ rechargeable lithium cell back-up
• Unique ‘House Coding’ feature prevents interference from neighbouring systems

Ei407 Manual Call Point

• Completely wire-free
• Powered by built-in 10 year lithium cells
• For use with Ei2110 Multi-Sensor, Ei160RC and Ei140 Series alarms on Ei168RC bases
• Non-breakable operating element with reset key

Ei408 Switched Input Module

• Triggers RadioLINK devices from a set of Volt-free closing contacts (e.g. sprinkler flow switch)
• Designed to be remotely sited
• Powered by built-in 10 year lithium cells

Ei411H Remote Control Switch

• Allows alarm Locate, Hush and Test functions to be performed
• Completely wire-free
• Powered by built-in 10 year lithium cells
• For use only with Ei2110 Multi-Sensor and Ei160RC Series alarms on Ei168RC bases

Ei420 Repeater & CO Alarm Interface

• Repeats RadioLINK signals to strengthen signal paths
• Allows Ei260RC Series Carbon Monoxide (CO) alarms to be linked into a RadioLINK system
• Mains powered with 10 year+ rechargeable lithium cell back-up

Ei428 Remote Relay Module

• Contains set of relay contacts that are switched on receipt of a RadioLINK signal
• Volt-free relay contacts, rated at 240V 5A
• Mains powered with 10 year+ rechargeable lithium cell back-up
• Pulse or Constant switching option

To purchase Aico fire alarms, sounders, remote control switches, manual call points, bases, repeaters, CO alarms, remote sounders, relay bases, or covers – visit the Domestic Fire Alarms section under the Fire Alarms, Fire and security. Also, to help you in your choice of the domestic fire alarms, we also recommend the Domestic alarm selector, choosing what alarms to fit and where, based on BS 5839-6:2004.

These fire alarms are designed for applications where the budget is a key consideration and where maintenance is in the hands of the owner occupier or there is no requirement for lithium power cell back-up. The 140 Series provides an alkaline battery back-up instead of rechargeable cells. Further cost savings are possible through the innovative and totally unique Easi-fit technology, as there is no need to purchase additional wiring enclosures, mounting kits, leads or connectors. In a field where time is money, the fact that Easi-fit alarms are simpler and quicker to install ensures even greater savings. Now with Easi-fit fixing pack, suitable for use on plasterboard, concrete or wood surfaces.

Features and benefits

• The easi-fit installation system – saves time and trouble on-site
• No additional base to buy and fit – saves time, cost and trouble
• Removable trunking door on mounting plate – simple to fit trunking if required
• No plug and socket to fiddle with to slow the job down
• Quality alkaline battery already fitted – slide alarm on to base to connect it
• Useful fixing screws supplied – suitable for plaster, wood and concrete surfaces
• Alkaline battery designed to last up to 4 years in stand-by
• Multiple cable entries and surface wiring knockouts
• Large, clearly marked wiring connections
• The test/hush button provides false alarm control and also allows the alarm to be manually tested
• Ei’s unique large volume optical smoke chamber and sophisticated electronics have a proven track record of reliability and high efficiency detection

Ei141 Ionisation Alarm

• Responds quickly to fast flaming fires
• Unique and proven long life ionisation smoke chamber
• Alkaline battery supplied already connected to reduce installation errors (does not draw power until alarm is fitted to the mounting plate)
• Hush button for false alarm control
• Interconnects with other Ei mains powered smoke and heat alarms
• Separate mains and warning LEDs
• Time and money saving Easi-fit design
• 5 year guarantee
• Kitemarked to BS EN 14604: 2005
• Buy online this ionisation alarm, Aico Ei141

Ei144 Heat Alarm

• Ideal for protecting kitchens and garages
• Fixed temperature fast response thermistor sensor, 58° ± 4°C
• Alkaline battery supplied already connected to reduce installation errors (does not draw power until alarm is fitted to the mounting plate)
• Hush button for false alarm control
• Interconnects with other Ei mains powered smoke and heat alarms
• Separate mains and warning LEDs
• Time and money saving Easi-fit design
• 5 year guarantee
• Kitemarked to BS 5446: Pt.2: 2003 Class A1
• Buy online this heat alarm, Aico Ei144

Ei146 Optical Alarm

• More responsive to slow smouldering fires
• Advanced optical chamber with proven extended life capability
• Fine mesh insect screen
• Alkaline battery supplied already connected to reduce installation errors (does not draw power until alarm is fitted to the mounting plate)
• Hush button for false alarm control
• Interconnects with other Ei mains powered smoke and heat alarms
• Separate mains and warning LEDs
• Time and money saving Easi-fit design
• 5 year guarantee
• Kitemarked to BS EN 14604: 2005
• Buy online this optical alarm, Aico Ei146

Easi-Fit, installation guide

1. Step 1 – Screw the mounting plate supplied with the alarm to the ceiling during first fix. No separate enclosure is required.
2. Step 2 - Wire up terminals on the mounting plate and clip on the protective cover.
3. Step 3 - Slide the alarm into place. There’s no need to wire up a separate lead and connector.

These info can also be found in the Fire, Smoke, Heat and CO Alarms, and they complement and explain the section of Fire Alarms: Conventional/analogue and Domestic systems. To buy these models of fire alarms beloging to the Aico 140 Series, visit the Domestic Fire Alarms. Do you need any more info/have a question? Ask Mr. Sparks – leave us a comment here. Also, to help you in your choice of the domestic fire alarms, we also recommend the Domestic alarm selector, choosing what alarms to fit and where, based on BS 5839-6:2004.

The 160RC Series Easi-fit mains powered smoke and heat alarms are our highest specification range, especially so when coupled to the RadioLINK system. Designed for the specifier, installer and end user demanding the very highest standards of safety, performance and reliability you’d expect from Europe’s leading manufacturer of mains powered fire detection products.

Almost all practical duty of care provisions are catered for. With no risk of casual back-up cell removal, the power supply is virtually guaranteed against any external threat to the energy supply. Risks of false alarms are minimised and installation costs are lower due to ease of installation and the all round quality of the outstanding 160RC Series.

Features and benefits

• Tamper-proof rechargeable Lithium battery back-up
• Low power cell warning
• Built-in Test/Hush button on all models
• easi-fit mounting base
• Interconnectable to other Ei mains powered alarms
• Compatible with Ei168RC RadioLINK base
• Comprehensive Indicating LEDs
• Remote Control functionality
• 5 year guarantee

Why rechargeable Vanadium Pentoxide Lithium Cells? The 10 year+ technology used in the 160RC Series provides the most effective and reliable back-up power available. Maintenance requirements are negligible. The cells used are the only rechargeable cells with a realistic ten year life expectancy confirmed by manufacturer Panasonic. Constantly ‘topped up’ by the mains, they out-perform lithium primary batteries, capacitors or rechargeable cells currently in use in other smoke alarms.

• Environmentally friendly – no special disposal requirements
• A precision charging circuit ensures peak efficiency at all times
• 6 month back-up without mains power
• Cells supplied fully charged
• Proven 10 year+ life
• Cells are soldered for reliable long term connection
• Terminals are laser welded for reliability
• No battery replacement requirement

Ei161RC Ionisation Alarm

• Responds quickly to fast flaming fires
• Unique and proven long life ionisation smoke chamber
• Kitemarked to BS EN 14604: 2005
• Hush button for false alarm control

Ei164RC Heat Alarm

• Ideal for protecting kitchens and garages and other areas prone to false alarms
• Fixed temperature fast response thermistor sensor, 58° ± 4°C
• Kitemarked to BS 5446: Pt.2: 2003 Class A1
• Hush button for false alarm control

Ei166RC Optical Alarm

• More responsive to slow smouldering fires
• Large volume high performance optical chamber with proven extended life capability
• Fine mesh insect resistant screen
• Kitemarked to BS EN 14604: 2005
• Hush button for false alarm control

Control Switch Ei1529RC

When used in conjunction with RC alarms, this switch offers three vital remote control functions.

• TEST – Test all alarms from one convenient switch
• HUSH – Any nuisance alarm can be quickly and easily silenced
• LOCATE – Allows the source of the alarm to be identified
• MAINS CHECK – The Test function will not operate without mains power, providing a simple way to test the mains supply

Manual Call Point MCP401RC

Manual Call Point Surface Mount for use with all Ei mains powered alarms

These info can also be found in the Fire, Smoke, Heat and CO Alarms, and they complement and explain the section of Fire Alarms: Conventional/analogue and Domestic systems. To buy these models of fire alarms from the Specifier Range 160RC series, visit the Domestic Fire Alarms. Do you need any more info/have a question? Ask Mr. Sparks – leave us a comment here. To help you in your choice of the domestic fire alarms, we also recommend the Domestic alarm selector, choosing what alarms to fit and where, based on BS 5839-6:2004.

How do the fire alarms integrate/function together with the control switch and the manual call point? It is illustrated in the picture below.

Fire Safety Design stage 5 – the choice and siting of alarm devices

For systems protecting property alarms must do no more than alert fire fighters, while those used for life protection it is essential that alarm signals are sufficient to warn all people that the systems is designed to protect, especially if you have to rouse those who are sleeping.

Annex B within the standard shows some typical ambient occupational noise levels, which may help in selection of quantity and siting of alarm devices. It is also generally accepted that a good fire door will attenuate sound by around 30dBA, while a typical office partition door will attenuate by approximately 20 dBA.

Alarm sounders

• General sound levels should be 65dBA or 5 dBA above ambient noise levels, although 60dBA is acceptable in:
  - specific areas where the rest of the area is 65dBA;
  - in stairwells;
  - in rooms of less than 60 sqm;
  - 75 dBA at the bedhead to wake sleeping persons;
• dBA levels should not be considered if taken closer than 0.5m of a wall or partition;
• Maximum sound level provided should not exceed 120 dBA;
• Frequency of sounder should range between 500 to 1000 Hertz;
• A common tone throughout a building;
• A minimum one sounder per fire compartment;
• For small systems, a minimum of two sounders are required (connected on separate circuits);
• If ambient sound levels exceed 90 dBA, then Visual Alarms must be provided;
• In premises used for entertainment, where music is greater than 80 dBA, the music should automatically be silenced.

Visual Alarm Devices

• Should be readily visible within the total area being protected;
• Preferably  coloured RED;
• Flash rate of between 30 to 130 flashes per minute;
• Should be mounted at minimum height 2.1m or within 150mm of ceiling;
• Recommended in areas where people have impaired hearing in order to comply with requirements of the Disability Discrimination Act.

Fire Safety design stage 6 – zoning of the building

The purpose of splitting a building into fire zones is to enable the safe and accurate identification of a fire condition within the protected premises. The general rules in determining the number of zones for a particular building is as follows:

• If the total floor area is greater than 300 sqm, the you must use more than one zone;
• A detection zone should not extend beyond a particular floor;
• If you have to walk more than 60m withing a zone before seeing the location of the fire, then you must create another zone;
• Automatic detectors within a stairwell or another vertical flue-like structure should be considered a separate zone;
• The total floor area should not exceed 2000 sqm unless using MCP’s only, then the zone can be extended up to 10.000 sqm.

Other points applicable to detection zones:

• Any call point mounted on the stairwell must be considered as part of the zone for the particular floor, and ideally the MCP should be mounted on the inside of the final exit door to that stairwell;
• For analogue/addressable systems, the control equipment may give specific text information; however, it is still necessary to provide simple LED indication of a particular zone;
• Remote indicators for particular detectors can be used to reduce the search distance, however they should be clearly labelled to which detector it is referring to.

Alarm zones

Alarm zones are required when parties have agreed to a “staged” evacuation whereby only parts of the building evacuate immediately. The general rules for alarm zones are as follows:

• An alarm zone should coincide with the fire compartments of the building;
• An alarm zone may cover more than one detection zone but not visa-versa;
• The extent of overlap between alarm zones should not confuse the occupants;
• An Alert signal must operate at a frequency of 1 second on 1 second off and the sounders should all be synchronized.;

Zone integrity

The integrity of Alarm and Detection zones is important. The decision to install a conventional or addressable system(see the previous diagrams) will determine which of the following points apply:

• A fault on one circuit albeit alarm or detection should not affect any other circuit;
• A cross connection between an alarm and detection circuit should not affect any other circuit other than those affected;
• A short circuit S/C or open circuit O/C on a detection circuit should not disable more than 2000 sqm nor a maximum of 5 devices on floors immediately above and below;
• Removal of a device should not affect operation of a MCP;
• In the event of a single O/C or S/C on an alarm circuit it should not prevent at least one sounder, normally mounted adjacent the CIE, from operating.

Design stage 7 – Selection of control and indication equipment

It is now possible to obtain both Conventional and Analogue/addressable control panels(CIE) to suit a wide variety of building sizes. The chart below is designed to help with the selection of a panel best suited to your needs.

These panels have “in built” power to maintain the system for 24h in the event of mains failure, with additional capacity to operate the alarms for 30 minutes. Should it be necessary to have a longer standby period, an additional remote power supply unit should be added.

Siting of the control and indicating equipment

Ideally, the control and indicating equipment should be sited:

• In an area of low risk;
• On the ground floor in the vicinity of the entrance used by the Fire Brigade;
• In an area common to all building users;
• Where automatic detectors are in use;
• Where ambient light levels are sufficient to clearly see the zonal information;
• Adjacent to an alarm sounder.

Thank you for consulting us in your fire design needs. Was this series of articles useful to you? Let us know. To purchase fire alarms, consult our online offer of:

• heat alarms, fire alarms, ionisation alarms, smoke alarms,
• domestic alarms,
  
• conventional or analogue alarms,
  
• disabled toilet alarms,
  
• any emergency lighting

and purchase online the preferred or needed alarm system for your home/office.

What does the British Standard BS 5839: Part 6: 2004 recommend?This is the definitive Code Of Practice to which architects, building professionals, enforcing authorities, landlords and installers should refer for recommendations on the design, installation and use of smoke and heat alarms in the majority of domestic dwellings. Landlords in both the public and private sector are considered to have a Duty of Care to fit compliant smoke and heat alarm systems.

System Grades

Six different grades of fire detection systems are defined and – generally speaking – the greater the fire risk the more sophisticated the system should be. Briefly, these grades are as follows:

• Grade A – A full system with control and indicating equipment installed to BS 5839: Part 1
• Grade B – Detectors and sounders using simpler specified equipment
• Grade C – Detectors and sounders or alarms with central control
• Grade D – Mains powered alarms with an integral stand-by power supply
• Grade E – Mains powered alarms with no stand-by power supply
• Grade F – Battery powered alarms

System Categories

Three different categories of life protection systems are defined. Briefly, these categories are (starting at the highest):

• LD1- Alarms in all circulation spaces that form part of escape routes and all areas where a fire might start, but not bathrooms, shower rooms or toilets
• LD2 – Alarms in all circulation spaces that form part of escape routes and rooms or areas that present a high fire risk
• LD3 – Alarms in circulation spaces that form part of escape routes

BS 5839: Part 6: 2004 emphasises that no one type of alarm is most suitable for all applications. Consideration must be given to the most suitable type of detection – optical, ionisation and heat.

New build properties & materially altered dwellings one to three storeys – Grade D, LD2

• Mains alarms with battery back-up
• Optical smoke alarms in circulation spaces – hallways and landings e.g. Ei166RC with or without RadioLINK
• Heat alarm in the kitchen e.g. Ei144 or Ei164RC with or without RadioLINK
• Smoke alarm or heat alarm as best suited for the particular circumstance in the main living room
• All alarms must be interconnected
• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A)

Existing tenanted properties two and three storey – Grade D, LD3

• Mains alarms with battery back-up
• Optical alarms in circulation spaces – hallways and landings e.g.  Ei166RC with or without RadioLINK
• If a fire risk assessment shows the property or occupier to be a high fire risk, increase the number of alarms installed to meet the risk – e.g. follow recommendations for an LD2 installation
• All alarms must be interconnected
• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A)

Existing tenanted properties single storey – Grade F, LD3

• Battery powered with a minimum battery life of 5 years e.g. Ei 10 year alarm
• Optical smoke alarm in circulation spaces – hallway
• If a fire risk assessment identifies a concern that the occupier cannot or may not replace a battery, use mains alarms or mains with battery back-up
• If a fire risk assessment shows the property or occupier to be a high fire risk, increase the number of alarms installed to meet the risk – e.g. follow recommendations for an LD2 installation

What do Building Regulations Demand in New Build & Materially Altered Dwellings?

Architects, builders and installers must comply with Building Regulations and install mains powered alarms in new and materially altered dwellings.

In England & Wales

Building regulations approved document B (Fire Safety) minimum requirements are currently Grade D, LD3, but it also defines that installation should be to BS 5839 Pt. 6 and therefore Grade D, LD2 is recommended.

Grade D, LD3

• Mains alarms with battery back-up with the mains supply taken from a lighting circuit or a dedicated circuit from the distribution board
• Smoke alarms are required in the circulation spaces such as hallways and landings. In general optical alarms are recommended e.g. Ei146, Ei166RC
• Heat alarm to be installed in the kitchen where there is no door separating the kitchen from the circulation space, e.g. Ei144, Ei164RC
• Smoke and heat alarms must be interconnected
• Alarms may be interconnected using radio-links

Northern Ireland

Building Regulations (Northern Ireland) Technical Booklet E (Fire Safety) requirements were amended in June 2005 to:

Grade D, LD2

• Mains alarms with a battery back-up
• Smoke alarms are required in the circulation spaces, hallways and landings
• A smoke alarm is required in the ‘principal habitable room’ e.g. living room
• A heat alarm is required in every kitchen
• Loft conversions require all the above to be installed
• Smoke and heat alarms must be interconnected
• Alarms may be interconnected using radio-links

Scotland

Building Standards Technical Handbook No 2 (Fire) requirements are currently:

Grade D, LD3

• Mains smoke alarms with battery back-up
• Smoke alarms are required in the circulation spaces, hallways and landings
• Smoke alarms must be interconnected
• Alarms may be interconnected using radio-links

This article was taken from the Fire, Smoke, Heat & CO Alarms guide of our supplier, Aico.

Fire Safety Design stage 2 – Siting of Manual Call Points

All manual call points, whatever the system, should be RED in colour and comply toBS EN 54-11Type A, and should be located as follows:

• Onall storey existsandall exitsto open air irrespective whether they are designated fire exits;
• So that nobody has to travel more than45 metresto reach one except if the exit routes are undefined, in which casethe direct line distance should not exceed 30 metres;
• The above distances need to bereducedto 25 and 16 metres respectively, if there are persons with limited mobility or there is a likelihood of rapid fire development;
• Onescape routes and exitsto the open air, so that no one has to travel more than 45 metres on a defined route and 30 metres on an undefined route;
• In all areas withpotential high fire risk, such as kitchens, etc;
• Wherephased evacuation is planned, call points will need siting on all exits from a particular zone;
• 1.4 metres + or – 200mm above the floor;
• Call pointsfitted with protective hinged covers for whatever reason should be listed as a Variation;

Fire Safety Design stage 3 – Select automatic detectors

In is very important to:

• Havean adequate number ofdetectorsto fully cover the area requiring protection;
• Selectthe correct type of detectorto match the potential fire type;
• Tosite the detectorsto give the best chance of detecting the fire quickly;
• To take into accountthe potential threat of false alarms.

We would strongly recommend that the designer reads Section 2&3 ofBS 5389-1:2002, for further advice on the selection and siting ofautomatic detectors.
Optical detectorsare generally used for detecting slow smouldering fires while ionisation detectors are better suited to free burning high energy fires.

How to avoid false alarms

Within the standard, a strong case is made to avoid false alarms. There are some areas where the placement of automatic smoke detectors should be avoided.

Irrespective of the type of smoke detector, the areas to be avoided are steamy, dusty or smoky enviroments such as kitchens, showers or bathrooms.

Other areas where care should be taken when using optical detectos are: enviroments with large amounts of dust, areas where steam occurs or where there are likely to be infestations of small insects such as grain thrip flies.

Other forms of detectors – some advices

• Fixed temperature heat detectors
  The fixed temperature heat detectors can be used in areas where smoke detectors are unsuitable; however, they are not advisable for use in corridors or where production of smoke may be a threat to people’s escape;
• Rate of rise heat detectors
  Rate of rise heat detectors, which have a combined fixed temperature and rate of rise sensing element, may offer improved reaction times. However, they should not be used within kitchens or where there is likely to be a rapid fluctuation in temperature, like the loading bays, boiler rooms, lantern lights, etc.
• Duct detectors
  This device incorporates anoptical smoke detectorwhich samples the air extracted from the duct via a sampling tube. While this may appear to be an ideal solution for a wide range of applications, it is strongly recommended that before its use, you consult a professional design team for further information. Air velocity and dilution of the air will greatly affect the expected sensitivity of such a device;
• Beam detectors
  Unlike a point type detector, beam detectors provide detection over a much greater area as well as being suitable for siting at much higher mounting heights. Generally, one beam detector can protect an area of up to 100m in length with a width dependant on the roof construction(flat or apex).
  Ideal for use in shopping malls, warehousing, aircraft hangers or buildings with high atria.

These are the 2nd and 3rd stages ofour recommendation of fire design/fire safety design(seestage 1). To be continued with the next steps.