HOW TO – Quick Overview – Best practice for positioning Smoke, Heat and CO alarms

Fire Safety 

Fire safety is one of the key sections within the Building Regulations, which outlines the requirements needed to provide an early warning of fire, escape routes, preventing the spread of fire, and providing access to firefighting facilities for the Fire and Rescue Services.

BS 5839-6

Fire Building Regulations in the UK point towards BS 5839 as they key code of practice for the planning, design, installation, commissioning and maintenance of fire detection. (BS 5836-6 for domestic, and BS5839-1 for non domestic).

BS 5839-6:2019 categorises different grades and categories of fire detection systems for different types of building. Part 6 of BS 5839, outlines the code of practice for the design, installation, commissioning and maintenance of fire detection and fire alarm systems in domestic properties. Generally, the greater the fire risk and the more demanding the application required, the more comprehensive the fire safety system needs to be.

Here is a quick overview for specifying a fire detection and fire alarm system:

    1. There are 6 Grades of system, from ‘A’ to ‘F’, with ‘A’ being the most comprehensive fire detection system. (e.g. what the system comprises)

For further detail on system grading for fire detection and fire alarm systems, click here.

    1. Fire detection systems are divided into different Categories (LD1, LD2, LD3) that relate to the level of protection the system provides (e.g. where the detectors are fitted)

For further detail on categories for fire detection and fire alarm systems, click here.

Smoke alarm positioning to meet Building Regulations  

Building Regulations vary throughout the UK, and so specify different levels of fire safety when installing fire alarm systems. Please refer to our standards and regulations section within the Professional knowledge base for latest guidance.

All latest Building Regulations recommend:

  1. Fire detection systems should be provided in accordance with the relevant recommendations of BS 5839-6.
  2. All alarms should be interlinked to ensure audibility throughout property
  3. (As outlined in BS 5839-6) smoke alarms positioned in circulation areas should be of optical type (or multi-sensor type incorporating an optical sensor).

As fire safety technology continues to advance, multi-sensor alarms (those monitoring for more than one indication of fire e.g. smoke and heat) are becoming increasingly available and affordable. These provide a quicker, more reliable, response to fire – so giving occupants more time to escape – and also reduce the risks of false alarms.


Locations of smoke and heat alarms must be compliant with either BS 5839:6 or relevant Building Regulations if in any doubt. Our smoke and heat alarms are not intended for any non-residential, commercial or industrial application, nor for any other purpose other than described in the above. For the maximum protection, we recommend you fit to meet LD1 category standards, which includes a heat alarms. Latest standards and UK Fire and Rescuse services strongly advise that a heat alarm is always installed in a kitchen as part of a complete fire protection system that includes smoke alarms.


Smoke Alarms should be fitted in all rooms especially principal habitable rooms where the temperature is normally between 4°C (40°F) and 38°C (100°F). Smoke alarms can be fitted in hallway, landing, living room(s), bedroom, airing/meter cupboards.

Heat alarms are best suited to areas where dust, fumes and moisture can cause nuisance alarms in smoke alarms. Designed for use in for a kitchen, laundry/boiler room, loft, garage.

The latest British Standards recommend that smoke and heat alarms are installed:

  • On the ceiling, as central as possible in the room
  • Sited 300mm from walls and light fittings – this ensures the alarm is out of any ‘dead air’ spaces where the airflow may be blocked
  • Placed within 3m of every escape door and bedroom door to ensure audibility
  • Positioned between high risk rooms and bedrooms
  • For peaked and sloped ceilings – make sure there is a maximum of 600mm vertically down from the apex for smoke alarms, and 150mm vertically down for heat alarms

Some additional do’s and don’ts for when positioning smoke and heat alarms:

Do’s – make sure you:

  • Install smoke alarms in circulation areas at a distance no greater than 7.5 m from the farthest wall, no greater than 7.5 m from a door to any room in which a fire might start and no greater than 7.5 m from the next smoke alarm.
  • Install heat alarms on the ceiling, ideally in the centre of the room/space e.g kitchen, garage and loft.
  • Install sufficient alarms to compensate for closed doors and obstacles.
  • Install your heat alarm at a distance no greater than 5.3 m from the farthest wall, no greater than 5.3 m from a door to any room in which a fire might start and no greater than 5.3 m from the next heat or smoke alarm.

Don’ts – make sure you:

  • Do not install the alarms within 1500 mm (1.5 m) of a fluorescent light fitting and keep wiring at least 1000 mm (1 m) from these fittings.
  • Do not install alarms on circuits containing fluorescent light fittings or dimmer switches.
  • Do not install alarms within 300 mm (12”) of light fittings or room corners.
  • Do not install smoke alarms in wall positions that are less than 100 mm (4”) or more than 300 mm (12”) away from the ceiling.
  • Do not Locate the smoke alarm close to bathrooms or showers as it can be susceptible to nuisance alarms from steam.
  • Do not install heat alarms on a wall.
  • You should never hardwire or wireless interlink FireAngel alarms with non-FireAngel branded systems.


The British Standard EN 50292 standard recommends that a CO alarm should be installed:

  • Between 1m–3m from all potential sources of carbon monoxide (fuel burning appliances)
  • Sited 300mm from walls and light fittings – this is to ensure that they are outside of
    any ‘dead air’ spaces that occur in corners and spaces where the airflow may be
  • If the fuel burning appliance is in a confined space (e.g. a boiler room) then the
    alarm should be sited on the ceiling just outside the room
  • If there is no fuel-burning appliance, then place the alarm at breathing height e.g. bed’s head height in bedroom

Recommended: In all rooms with fuel burning appliance, e.g kitchens, living rooms, bedrooms. 

The standard also recommends that CO alarms should not be installed:

  • In an enclosed space
  • Where it can be obstructed
  • Directly above a sink
  • Next to a door, window, extractor fan, air vent or similar ventilation opening
  • Where the temperature may drop below –5 ºC or exceed 40 ºC.