Fire Alarm System Installation and Maintenance for Houses of Multiple Occupation (HMO's) and other domestic properties.

The legislation and requirements for Fire Alarm Systems installed in HMO's will vary depending on your geographical area and local authority.  In most cases, the system will have to comply with BS5839 Part 6 and the type of system will depend on your local authority's recommendation dependant on the property type. 

Abbion Fire and Security Systems will always aim to comply with the relevant Standards and requirements set by your local authority.  If you are unaware of what is required under your local authority licensing scheme, please use the links below to visit their website.  If your local authority website is not listed, please contact us and we will update it as appropriate while also helping you establish your needs. 


  • Cardiff City Council
  • Newport City Council
  • Swansea Council
  • Rhondda Cynon Taf Council
  • Bristol City Council
  • Torfaen County Borough Council
  • Monmouthshire Council


The requirements for fire alarm maintenance vary from system to system.  Abbion Fire and Security already offer maintenance packages for Fire Alarm Systems installed to BS5839 Part 1, please visit our Commercial Fire Alarm Systems or System Maintenance pages for more details.  Mains powered systems as detailed below do not have such specific requirements and as such can often be left unchecked or serviced.  If you are in any doubt as to whether your fire alarm system requires a maintenance contract, please do not hesitate to contact us.

Abbion Fire and Security Systems run an Annual Inspection Test facility where, for a fixed fee, we can attend your property and test all of your detection, identifying any issues with the fire alarm system.  On completion, we provide a detailed report of areas requiring action and an Annual Inspection Test Document for your records.  Contact us for further details on this facility. 

Fire Alarm Systems Overview

Risk Analysis

Risk analysis is identified as critical and the design of a fire detection system installation should take into account the level of protection and type of system best suited for the particular type of property.

In assessing the fire risk, the following should be considered:-

  • The presence of smoke in escape routes is the greatest impediment to safe escape in the event of fire and therefore smoke alarms should be installed in the circulation areas.
  • Approximately 46% of domestic fires start in kitchens and it is essential that a smoke alarm be sited in any adjacent circulation space.
  • Fires started by smokers' materials are the most common cause of fatalities, therefore, occupants known to smoke should have smoke alarms fitted in living rooms, dining rooms and bedrooms.
  • Heating appliances are the second most common cause of fire deaths and particular consideration should be given to installing smoke alarms in the relevant rooms.
  • Fires caused by electrical appliances and faulty wiring account for about 14% of fires and the use of electric blankets, by high risk groups such as the elderly justify fitting smoke alarms in bedrooms.
  • Arson is a growing problem and if a significant possibility, the level of protection should be high, especially around the vicinity of entrance doors if malicious ignition is considered a significant threat.
  • The elderly, over 80 years and children under 5 years are at greater risk and should be protected to an appropriately high level.
  • Socially deprived and low income occupants have an increased risk from fire and replacement of smoke alarm batteries can be a low priority - in these cases mains power is essential.
  • People with impaired mobility require more time to escape and special consideration should be given.
  • Occupants in HMO's are also a high risk group.

Design Considerations

Battery-operated smoke alarms
These are low cost and simple to install but the battery is vulnerable to removal and therefore the ability of these smoke alarms to detect a fire some years after initial installation is not considered to be high.

Mains-powered smoke alarms
Potentially more reliable than battery-operated ones, because they require less attention by the user, they are more costly themselves to install. Also, they suffer the disadvantage that there is no protection when the supply is interrupted. In view of this they should be supplied from a dedicated circuit and not a lighting circuit as this could be at risk from fire damage.

Mains-powered smoke alarms with back up
This is the best option especially if reliability of the mains supply is not high or disconnection is likely. Also, this type of alarm can be connected to a lighting circuit. RCDs are not recommended unless on a lighting circuit already.

Consideration should be given to the difficulty of disabling when permanently in alarm due to fault, without isolating the lighting.

Relative frequency of fires in rooms within dwellings

 Room Proportion Of Fires
 Kitchen 46%
 Bedroom/Bedsit 15%
 Living Room/Dining Room 14%
 Access Area  5%
 Ashpit, Refuse Area 4%
 Store 2%
 Bathroom, Cloakroom, WC 2%
 Roof Space 1%
 Laundry 1%
 Airing Cupboard 1%
 Misc & Unknown 9%
Deaths in Fires  
 Room Proportion of Fires
 Living Room/Dining Room 50%
 Bedroom 30%
 Kitchens 15%


Grades of System

This covers many types of alarms, differing widely in cost, complexity and reliability, and groups system into 6 grades.

Grade A: BS 5839 Part 1 and Part 4 System.
Grade B: Detectors other than smoke detectors but complying to BS 5839 Part 4.
Grade C: System of detectors from mains supply with some central control.
Grade D: One or more mains smoke alarms with standby supply.
Grade E: One or more mains smoke alarms with no standby supply.
Grade F: One or more battery-operated smoke alarms.

Recommended grade and type of system in typical dwellings

Level of Protection

System is usually installed to protect life and the level of protection should be related to the fire risk.
Systems for the protection of life (type LD) have detectors installed in the following subdivisions:
LD1: Throughout the dwelling.
LD2: Escape routes and high risk rooms.
LD3: Escape routes only.
Systems for the protection of property (type PD) are subdivided into:
PD1: Throughout the dwelling.
PD2: Defined rooms or areas.

Choice of System

The grade of system considered depends on the nature of the dwelling, the level of fire risk and characteristics of the occupants.
Two examples, the Standard states:
Grade F systems, comprising one or more battery-operated smoke alarms, are the least reliable in the long term because of the need for battery replacement.
With occupants at risk due to being deprived of power through non payment of bills, mains powered smoke alarms with standby should be installed.
Because of the greater fire risk in HMO's these are considered separately from single family dwellings.
With regard to sheltered housing, smoke alarms should normally form part of a social system. Where this is not possible, mains smoke alarms should be installed and any fire signal relayed to the warden.

Types of Detector

There are two types of smoke detectors commonly used:

Ionisation Detector: Operates on the principle that electrical current flowing between electrodes in an ionization chamber is reduced when smoke particles enter.
They are particularly sensitive to the smoke from fast flaming fires containing small particles.
Optical Detector:  Operates by detecting the scattering of light by smoke particles and are sensitive to optically dense smoke.
Where the Standard recommends the use of smoke alarms, either type is generally suitable, but the type of fire that may be expected and the need to avoid false alarms, should be taken into account.
Heat Only fixed temperature type (point) is recommended for most dwellings. They should be installed where ambient temperatures are likely to fluctuate rapidly over short periods, e.g. kitchens.

Location/Siting/False Alarms

For most single-family dwellings a type LD3 system will provide a reasonable standard of protection, i.e. smoke alarms sited in the circulation areas ( hallways and staircases).  In houses of four or more storeys, a LD2 system with heat detector in each kitchen is recommended.
•one detector between bedroom and kitchen/living room.
•in circulation areas, no door should be further than 7.5m from nearest detector.
•in a single storey dwelling, with one detector, it should be as close as possible to the living accommodation.

False alarms are common in domestic fire systems, and accordingly, installation design should aim to minimize false alarms.
•most common cause is fumes from the kitchen, therefore, fit optical type nearest kitchen.
•if people smoke in living and dining rooms, then fit ionisation type.
heat detectors should be fitted in kitchens, laundry rooms and boiler rooms.


Smoke alarms only work if they are capable of arousing the sleeping occupants and a sound level of 85 dB should be achieved at the open doorway to each bedroom and 75 dB at the bedhead in each bedroom with the door shut.
In single-family dwellings, a lower sound level is acceptable in other areas of the house, with no minmium sound level recommended.
For people with severe impaired hearing, a visual alarm and underpillow vibrating disc linked to a smoke alarm is recommended.


                                                                                               "Installing Confidence....Maintaining Quality"                                                                                                                  

                  Areas Covered: Cardiff, Newport, Swansea, Bristol, Rhondda Cynon Taff, Torfaen, Monmouth, South Wales, West Wales, West of England