Smoke Alarms in Bungalows – The Alarms to Fit in the Bungalows

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarms to Fit dependant upon risk assessment:
  - in the bedrooms: multi-sensor alarms or ionisation alarms;
  - in the garage: heat alarms;
• Alarm Types: Grade D, Category LD2
• Alarm series you can use in bungalows:
  - the Aico Ei2100 series(multi-sensor Aico Alarms);
  - the Aico Ei160RC series(optical and ionisation alarms);
  - the Aico Ei140 series(smoke and heat alarms).

Smoke Alarms in Houses 2-3 storey – The Alarms to Fit in a 2-3 storey house

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the landing area: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarms to Fit dependantupon risk assessment:
  - in the bedrooms: multi-sensor alarms or ionisation alarms;
  - in the garage: heat alarms;
• Alarm Types: Grade D, Category LD2
• Alarm series you can use in a house with 2-3 storey:
  - the Aico Ei2100 series(multi-sensor Aico Alarms);
  - the Aico Ei160RC series(optical and ionisation alarms);
  - the Aico Ei140 series(smoke and heat alarms).

Smoke Alarms in Houses 4+ storey – The Alarms to Fit in 4+ storey houses

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the landing area: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarms to Fit dependant upon risk assessment:
  - in the bedrooms: multi-sensor alarms or ionisation alarms;
  - in the garage: heat alarms;
• Alarm Types: Grade B, Category LD2

Smoke Alarms in HMO 1-2 Storey – The Alarms to Fit in the 1-2 Storey HMOs

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the landing area: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarms to Fit dependant upon risk assessment:
  - in the bedrooms: multi-sensor alarms or ionisation alarms;
• Alarm Types: Grade D, Category LD2
• Alarms Series you can use in the HMO 1-2 Storey:
  - the Aico Ei2100 series(multi-sensor Aico Alarms);
  - the Aico Ei160RC series(optical and ionisation alarms);
  - the Aico Ei140 series(smoke and heat alarms).

Smoke Alarms in HMO 3+ storey – The Alarms to Fit in the communal areas

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the landing area: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarm Types: Grade A, Category LD2

Smoke Alarms in HMO 3+ Storey – The Alarms to Fit in the individual units

• Rooms in which smoke alarms must be fitted:
  - in the hallway: multi-sensor alarms or optical alarms;
  - in the landing area: multi-sensor alarms or optical alarms;
  - in the living room: multi-sensor alarms or optical alarms;
  - in the kitchen: heat alarms.
• Alarms to Fit dependant upon risk assessment:
  - in the bedrooms: multi-sensor alarms or ionisation alarms;
• Alarm Types: Grade D, Category LD2
• Alarms Series you can use in the HMO 3+ Storey individual units:
  - the Aico Ei2100 series(multi-sensor Aico Alarms);
  - the Aico Ei160RC series(optical and ionisation alarms);
  - the Aico Ei140 series(smoke and heat alarms).

Please note: this information is provided as a guide based on BS 5839-6:2004 recommendations for standard dwellings with no floor greater than 200 square m in area. ther standards and regulations exist that they may be applicable to the installation.
A Fire Risk Assessment may demand a higher Grade/Category of system than that shown. Please refer to BS 5839-6:2004 for full information.

What is an HMO? What is a House in Multiple Occupation?

Under the changes in the Housing Act 2004, if a landlord lets a property which is one of the following types it is a House in Multiple Occupation:

• an entire house or flat which is let to three or more tenants who form two or more households and who share a kitchen, bathroom or toilet (for a definition of household please see the frequently asked questions);
• a house which has been converted entirely into bedsits or other non-self-contained accommodation and which is let to three or more tenants who form two or more households and who share kitchen, bathroom or toilet facilities;
• a converted house which contains one or more flats which are not wholly self contained  (ie the flat does not contain within it a kitchen, bathroom and toilet) and which is occupied by three or more tenants who form two or more households;
• a building which is converted entirely into self-contained flats if the conversion did not meet the standards of the 1991 Building Regulations and more than one-third of the flats are let on short-term tenancies;
• in order to be an HMO the property must be used as the tenants’ only or main residence and it should be used solely or mainly to house tenants. Properties let to students and migrant workers will be treated as their only or main residence and the same will apply to properties which are used as domestic refuges;
• More details about the HMOs and their licensing.

For Smoke alarms and Heat Alarms – for domestic use – check out the Fire & Security section.

1. The Optical Smoke Chamber

Ei’s unique large volume optical smoke chamber and sophisticated electronics have a proven track record of reliability and high efficiency detection. Longevity and resistance to false alarms as well as reliable protection from electromagnetic interference has also been proven over many years.

2. The Insect Screen

Smoke Alarms are sophisticated electronic devices. Protection from external contamination is vital to maintain the fire detecting sensitivity of the product and to minimise false alarms. A fine mesh insect screen reduces false alarms caused by insect contamination and fibres, while allowing free access of smoke to the sensor chamber. A dust cover is also provided for protection on site and prior to occupancy.

3. Test and Hush Button

The test and hush button provides false alarm control on all Easi-fit models. It also provides a manual test function.

4. The Rechargeable Cells

Ultra high performance vanadium pentoxide lithium rechargeable cells are used in the Ei2110 Multi-Sensor, 160RC Series(EI161, EI164, EI166, EI168), 150 Series and RadioLINK bases. These cells offer the best back-up possible and are proven to last a minimum of 10 years.

• A precision charging circuit ensures peak cell efficiency at all times.
• Cells provide up to six months back-up without mains power.

5. The Indicating LEDs

Self monitoring and indicating LEDs and audible warning signals. Each alarm self tests every 40 seconds. Two separate LED indicators are used to indicate healthy mains supply, battery fault, alarm status and low cell/battery warning.

6. The Sounder

At 85dB(A) at 3 metres, our alarms are loud. Unique encased horn assembly has the piezo disc securely held with silicone mastic to prevent creepage and premature horn failure. Additionally soldered contacts prevent failures due to corrosion and arcing associated with more commonly used pressure contacts

More features and details:

• Heat alarms feature a fixed temperature fast response thermistor sensor, making them ideal for protecting kitchens and garages.
• Computer analysis of smoke flow results in a precision casing design that allows fast access of smoke to the sensor.
• Ionisation alarms feature a high performance ionisation chamber that responds quickly to flaming fires. Proven in millions of applications.
• The Ei2110 Multi-Sensor and 160RC Series alarms allow Test, Hush and Fire Locate functions to be performed from an optional control switch mounted at an easily accessible height.
• Alkaline battery back-up in the 140 Series(EI141, EI144, EI146) designed to last up to 4 years in stand-by.

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. 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.

Types of alarm sensor

Multi-Sensor Alarms – where should they be used?

The Multi-Sensor alarms combines the best features of an optical alarm – quick response to slow smouldering fires and  immunity to kitchen fumes, with the best features of a heat alarm – quick response to a fast flaming fire and immunity from contamination. This makes it the ideal choice for all rooms in a dwelling except a kitchen. The Multi-Sensor is less prone to contamination and effectively eliminates the problems of nuisance alarm associated with the ionisation and the optical type alarms.

1. A custom algorithm written into the integrated circuit monitors and interprets the signal from…
   a. An ultra fast temperature sensor and …
   b. A high performance optical sensor.
2. This combination allows detection of both fast flaming and slow smouldering fires.
3. This means the alarm will respond quickly to a wider range of fire types than any of the other individual sensor types.

Optical Alarms – where should they be used?

Optical sensors are more responsive to smouldering fires producing large particle smoke typical of fires involving furniture and bedding. They are more immune to invisible smoke produced by ‘burning the toast’ and similar cooking fumes. This makes them ideal for siting in hallways close to kitchens where false alarms from ionisation alarms may be a particular problem. The BS 5839: Pt.6: 2004 Standard recommends the use of optical alarms in circulation spaces of a dwelling, such as hallways and landings. Optical alarms are prone to false alarm if exposed to steam and should not be located too close to poorly ventilated bathrooms or shower rooms.

1. A light beam is pulsed in the sensor chamber every 10 seconds to ‘look’ for smoke. Any smoke present has to be visible to the naked eye so that the receptor can ‘see’ it. If no smoke is detected, the alarm will remain in a standby state.
2. When large particle smoke is detected, the light beam will be scattered onto the light receptor.
3. This will then send an electrical signal to the IC (Integrated Circuit).
4. This causes the alarm to sound.

Ionisation Alarms – where should they be used?

Ionisation type sensors are particularly sensitive to the almost invisible smoke produced by fast flaming fires. This makes them more liable to false alarm due to cooking fumes if sited in a hallway close to a kitchen. Ionisation alarms are less vulnerable to false alarms caused by dense tobacco smoke, excessive dust and insect ingress.  The BS 5839: Pt.6: 2004 Standard recommends that ionisation alarms should not be used in hallways and landings, where there is a risk of false alarms caused by cooking fumes.

1. Inside the sensor chamber is a minute (safe) radioactive element that ionises the air within. This causes a small current to flow in the chamber and this will remain constant for the life of the alarm unless smoke particles enter.
2. When smoke enters the sensor chamber, the balance of the current is disturbed.
3. This is detected by the electronics in the alarm circuitry and a signal is sent to the Integrated Circuit (IC).
4. This causes the alarm to sound.

Heat Alarms – where should they be used?

Heat alarms are less likely to cause false alarm problems as they are not responsive to any type of smoke or fumes, only heat. Because of the potential for a slower response than smoke alarms, they should only be used in a fire alarm system that also includes smoke alarms, and all of the alarms must be interconnected. BS 5839: Pt.6: 2004 recommends that heat alarms should be used in kitchens. It goes on to suggest that they may also have a role to play in the main living room but they should not be installed in circulation spaces or areas where fast response to fire is required.

1. A thermistor (a heat sensitive resistor) is sited in the sensor chamber of the alarm.
2. When the temperature rises the resistance of the thermistor reduces.
3. The IC continuously monitors the resistance of the thermistor. When this indicates the temperature is 58ºC or over, the IC sends a signal to the sounder circuit.
4. The alarm then sounds.

Which Alarms to Fit Where?

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 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.

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.

Spacing of detectors in normal applications

Under flat horizontal ceilings – smoke and heat detectors:

• Area covered by one detector:
  - smoke detector – 100sqm;
  - heat detector – 50sqm;
• Distance between any part of the wall and the nearest detector:
  - smoke detector – 7.5m;
  - heat detector – 5.3m;
• Distance between detectors:
  - smoke detector – 10.6m;
  - heat detector – 7.5m;
• Ceiling heights – general:
  - smoke detector – 10.5m;
  - heat class 1 – 9.0m;
  - heat(other classes) – 7.5m;

Design stage 4.1: Detector spacing for pitched roofs

Generally mount the first row of detectors in apex except where woof rise is less than 150mm for heat or 600mm for smoke, in which case consider as flat ceiling. Coverage increases by 1% for every degree of angle of pitch to a maximum of 25%. If slope differs either side, so will coverage of detectors in apex.

Design stage 4.2: Siting detectors near obstructions or unusual ceilings

Detectors should be sited no nearer than twice the depth of the obstruction.

• If greater than 250mm, do not site the detector nearer than 500mm.
• If the obstruction is greater than 10% of floor to ceiling height, treat it as a wall.
• If the gap between partition or top of racking is less than 300mm, treat as wall.
• Remember to keep a clear space of greater than 500mm from any detector.
• Low beams or rafters – refer to table 2 of BS 5839-1:2002, detectors may not be required between each one depending on their construction.
• For ceiling of floor voids – mount detector in top 10% or 125mm, whichever is the greater.
• More info – consult section 22.3 of BS 5839-1:2002

Design stage 4.3: siting optical beam detectors

Like “Point Detectors” the furthest distance between the wall and line of detector should be more than 7.5m.

• If used under a pitched ceiling, you may increase coverage by 1% for every degree of angle of pitch up to 25%. If pitch varies either side, so will the coverage.
• If used below 600mm of ceiling height in order to provide supplementary detection of a rising smoke plume, for ex. the width of the area protected on each side of the beam should be regarded as 12.5% of the height of the beam, and the nearest likely seat of fire.

Notes:

• Transmitters and receivers should be mounted on a solid construction, not something that will move with temperature or wind;
• Avoid mounting beams where high probability of people or equipment may obstruct the beam;
• Do not hire beam less than 500mm from along side any wall/obstruction;
• Additional beam detectors can be sited at lower levels if smoke is unlikely to reach the apex due to a natural heat barrier.

Design stage 4.4: further considerations

• For a type P1 system, every part of the building should be suitably protected. For this purpose each enclosed space should be considered separately.
• Areas covered by a Type P2 system should be separated from unprotected areas by a fire resisting construction.
• Voids which are not more than 800mm deep need to be protected unless fire can spread through them from one to the other or it is identified in a Fire Risk Assessment, as a potential High Risk;
• Where rooms are divided by partitions or storage racks reaching to within 300mm of the ceiling each section should be protected separately.
• Shafts for elevators, lifts, hoists, escalators and enclosed chutes through floors and stairways should be protected by detectors at the top of the shaft and within 1.5m of openings of each floor.
• Enclosed staircases should be protected by detectors on each main landing within the staircase.
• Lantern lights should be protected by a detector unless they are less than 800mm in height above the ceiling and are not used as ventilation.
• Extra detectors may be needed to cope with structural features within a room.
• Consideration must be given to possible adverse air flows when air conditioning and ventilation systems are in use.
• If a detector is concealed, it may be desirable to provide a remote visible indication of its operation.
• Care should be taken when siting to ensure that adverse conditions such as high levels of shock or vibration are not encountered.

To be continued with the next steps in Fire Safety and Fire Design.