Where Should Smoke Alarms Be Positioned?

A smoke alarm can be fully operational and still provide inadequate protection if it is installed in the wrong location. Correct positioning helps ensure fires are detected early enough to warn residents and support a safe escape.

Landlords, housing associations and managing agents need to consider more than whether smoke alarms are installed and working. They also need to ensure alarms are positioned appropriately for the property, its escape routes, potential fire risks and the type of detection system in place.

This guide explains where smoke alarms should be positioned, common installation mistakes and the key standards and guidance that influence alarm locations.

What Determines Smoke Alarm Positioning? 

There is no single alarm layout that works for every residential property. The right positioning depends on the building, the risks within it and how residents would escape if a fire occurred. 

Factors that influence alarm positioning include:

• The number of storeys
• Escape routes and circulation spaces
• The location of higher-risk rooms
• The location of fixed combustion appliances
• The type of fire alarm system installed
• The recommendations of the relevant British Standards
• The findings of the Fire Risk Assessment

The appropriate positioning will vary between houses, flats, HMOs, and larger residential buildings.

Where Should Smoke Alarms Be Installed?

Smoke alarms are commonly positioned on ceilings in circulation spaces and other areas where they can provide early warning of fire. Typical locations include:

• Hallways
• Landings
• Escape routes between bedrooms and final exits
• Living rooms, where appropriate
• Communal areas within residential buildings
• Shared circulation areas within HMOs

Kitchens will often require heat detection rather than smoke detection to reduce unwanted alarms caused by cooking fumes and steam.

Landlords and those responsible for residential buildings should choose alarm locations based on the property layout, escape routes and level of detection required rather than applying the same layout to every building. The manufacturer’s installation instructions and the recommendations of BS 5839-6 should also inform the final position of each alarm.

Different legal requirements can then affect the level of provision required. In England, rented homes must have at least one smoke alarm on every storey used as living accommodation. New homes and certain building work are also subject to Building Regulations and supporting technical guidance.

Requirements differ across the UK, so organisations managing properties in more than one nation should check the applicable national guidance.

To learn more about landlords’ legal responsibilities, read our guide to Smoke Alarm Regulations for Landlords.

How BS 5839-6 Determines Smoke Alarm Positioning 

BS 5839-6 classifies domestic fire detection systems according to both their grade (the type of system installed) and their category (the level of detector coverage provided). Together, these classifications influence where smoke and heat alarms should be positioned throughout a property.

Fire Alarm Grades

Grade	Typical Application
Grade A	Separate fire alarm control and indicating equipment, typically used in larger or more complex residential buildings, including many HMOs.
Grade D1	Mains-powered alarms with a tamper-proof standby power supply, commonly installed in new homes and many HMOs.
Grade D2	Mains-powered alarms with a replaceable or rechargeable standby power supply.
Grades E–F	Simpler battery-powered systems generally used in lower-risk domestic properties where appropriate.

Fire Alarm Categories

Category	Typical Detector Coverage
LD1	Detection throughout the dwelling, including circulation spaces, bedrooms, living areas and high-risk rooms where appropriate.
LD2	Detection within circulation spaces forming escape routes together with specified high-risk rooms, such as kitchens and principal living rooms.
LD3	Detection within circulation spaces forming the escape route only.

The appropriate grade and category should always reflect the property’s layout, occupancy, fire risks, and the findings of the Fire Risk Assessment.

Properties occupied by people who may require additional time to evacuate, including older people, occupants with disabilities, or other vulnerable residents, may require a higher standard of protection. 

In these situations, a Person-Centred Fire Risk Assessment may identify that more comprehensive detector coverage, such as an LD1 system, is appropriate. 

Typical Smoke Alarm Positioning

The table below outlines the alarm types commonly used in different areas of a residential property and the positioning guidance typically followed under BS 5839-6. 

Room / Area	Recommended Alarm Type	Typical Positioning Guidance
Hallways and landings	Optical or multi-sensor smoke alarm	Ceiling-mounted to protect escape routes and circulation spaces.
Living rooms	Optical or multi-sensor smoke alarm	Installed where required by the fire alarm category or Fire Risk Assessment.
Kitchens	Heat alarm	Ceiling-mounted to reduce unwanted activations caused by cooking fumes and steam.
Bedrooms	Smoke alarm where required	May be provided as part of an LD1 system or where identified by the Fire Risk Assessment.
Rooms containing fixed combustion appliances	Carbon monoxide alarm	Installed in accordance with the manufacturer’s instructions and applicable legislation.

BS 5839-6 and the relevant building regulations also provide recommendations on matters such as detector spacing, coverage, and the maximum travel distance to the nearest alarm. These technical requirements vary depending on the type of property, the fire alarm category, and the applicable guidance. 

Designers and installers should always refer to the current editions of the relevant standards and the manufacturer’s installation instructions when determining the precise location of each detector. 

Where Should Smoke Alarms Not Be Installed?

Correct positioning is just as important as selecting the appropriate smoke alarm. Installing alarms in unsuitable locations can delay smoke detection, increase the likelihood of false activations, or reduce the overall effectiveness of the fire detection system.

Smoke alarms should generally not be installed:

• Immediately outside bathrooms, where steam may trigger unwanted activations
• Within kitchens, unless specifically recommended as part of the fire detection system
• Close to extractor fans, ventilation grilles, or air conditioning outlets that may disperse smoke
• Immediately beside windows or external doors where air movement may affect performance
• Within dead air spaces close to ceilings or corners where smoke may not reach the detector quickly

The manufacturer’s installation instructions and the recommendations of BS 5839-6 should always be followed when determining the most appropriate location for each smoke alarm.

Optical or multi-sensor smoke alarms are commonly used within circulation spaces because they provide reliable fire detection while helping to reduce unwanted activations. Heat alarms are generally recommended within kitchens, where smoke alarms are more likely to activate due to cooking fumes or steam rather than fire. 

Similar principles apply to carbon monoxide alarms, which should be installed in accordance with the manufacturer’s instructions and should not be positioned where ventilation, moisture, or airflow may affect their performance. 

Smoke Alarm Positioning in HMOs

Houses in Multiple Occupation (HMOs) often require more comprehensive fire detection than standard residential properties due to the increased number of occupants, shared accommodation, and more complex escape routes. 

The positioning of smoke alarms should support the building’s means of escape while reflecting the findings of the Fire Risk Assessment, the recommendations of BS 5839-6, and any applicable local authority licensing conditions.

Smoke alarms are commonly positioned to protect:

• Shared hallways
• Landings
• Escape routes
• Other circulation spaces identified by the Fire Risk Assessment

Where required by the Smoke and Carbon Monoxide Alarm (England) Regulations 2015, carbon monoxide alarms should also be installed in rooms containing fixed combustion appliances, in accordance with the manufacturer’s instructions. 

For more detailed guidance on HMO fire alarm systems, read our article on Smoke Alarm Requirements for HMOs.

Smoke Alarm Positioning and Ongoing Maintenance

Smoke alarms should continue to be inspected, tested, and maintained throughout their service life to ensure they operate as intended and remain capable of providing reliable fire detection and occupant protection.

Good practice includes:

• Testing smoke alarms regularly
• Maintaining alarms in accordance with the manufacturer’s recommendations
• Replacing alarms at the end of their recommended service life
• Including smoke alarms within planned testing and inspection programmes where appropriate

Correct positioning is only effective if smoke alarms continue to operate as intended throughout their service life. Routine smoke alarm testing help confirm alarms remain operational, identify faults before they affect fire detection, and provide confidence that the system will respond when it is needed most.

Maintaining Effective Smoke Alarm Coverage

Correct positioning of smoke alarms plays an important role in achieving reliable fire detection and protecting occupants. Installing alarms in appropriate locations, carrying out routine testing and maintenance, and reviewing alarm provision following changes to a building all help support effective fire safety management and ongoing compliance with the relevant legislation and British Standards.

Osterna supports housing associations, managing agents, local authorities, freeholders, employers, and large private landlords across the UK with professional smoke alarm testing, Fire Risk Assessments, fire safety testing and inspections, fire door inspections, and wider building compliance services.

Speak to the Osterna team today to discuss your smoke alarm testing and compliance requirements.