Requirements for Fire Detection Systems in HMOs

What is an HMO?

HMOs are typically large houses that have been converted into flats or bedsits, such as student housing. ‘Houses in multiple occupation’ are defined by gov.uk as follows:

Your home is a house in multiple occupation (HMO) if both of the following apply:

  • at least 3 tenants live there, forming more than 1 household
  • you share toilet, bathroom or kitchen facilities with other tenants

It is important to note that the requirements for sheltered housing, such as supported living facilities, and self-catered rentals, such as holiday cottages are different, and not covered in this blog.

Kitchen facilities are often shared in HMOs
Shared kitchen spaces are a fire risk in HMOs

What grade of smoke alarm system is required for HMOs?

Within most HMOs, there are several acceptable options available for compliance with the Standard, depending on its size and configuration. 

The first option is to have Grade A fire alarm system installed throughout the building. This type of system consists of a conventional or addressable fire alarm panel, and then fire alarm detectors, call points, sounders and beacons are specified according to the layout and requirements of the property and manufactured to BS EN 54. It also requires a power supply to BS EN 54-4, and installation to BS 5839 Part 1.

However, in most cases, this level of coverage is not a requirement. In some small HMOs, for example, it may be acceptable to install a Grade D1 system. This is defined as a system incorporating one or more interlinked mains-powered smoke alarms (and heat alarms if required), each with an integral stand-by supply. They can be hardwire-interlinked or radio-interlinked, meaning that fire alarm panels are not required. The stand-by supply must be tamper-proof and last the full life of the alarm.

The final option, suitable for many medium and even large HMOs, is a mixed system. This involves the installation of Grade A components in communal areas, and any other high-risk areas identified by the risk assessment. Elsewhere in the premises, a separate Grade D1 system can be installed. This has become the preference, as it is likely to reduce the impact of nuisance alarms from individual flats on other occupants.

Ei Electronics and Kidde offer both RF and wired mains powered alarm systems as well as a range of accessories that can help you to test, locate and hush alarms easily. For more guidance about the alarm grade system, visit our help guide.

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Fire detection categories

The coverage within the building by the detection system is divided into three distinct categories. These are described with the following codes:

LD1 (highest level of coverage): Covers all circulation spaces that form part of escape routes plus all rooms in which a fire could start

LD2 (middle level of coverage): Covers all circulation spaces that form part of escape routes plus all rooms and areas that present a high fire risk to occupants

LD3 (lowest level of coverage): Covers circulation spaces that form part of the escape routes

Diagram showing levels of fire detection systems in HMOs

Any room which a building user must pass through, from another, in order to exit the premises would need detectors installed to satisfy these Categories. For example, if all rooms in a bungalow open onto a hallway which leads outside, only the hallway is considered a circulation space forming part of the escape route; if the only exit from the kitchen is into the dining room which then opens onto a hallway, the dining room would also need a detector under LD3 minimum protection as it is part of the escape route.

What category of fire detection is required within my HMO?

Different levels of coverage are needed in different areas of the building due to the risk of fire. This includes different Grades of fire detection system, as well as different configurations of components. For example, communal areas in HMOs are required to have Grade A systems, as they have particularly high levels of risk. This is due to the shared, and therefore often neglected responsibility for safety and housekeeping in HMOs. Moreover, the exact installation requirements within your HMO will depend upon the configuration and size of the premises. For more advice for landlords about fire safety in HMO’s, visit our help guide.

Messy kitchens are a health risk, and a fire hazard.
Responsibility for housekeeping can be neglected in HMOs. This is a fire risk,

Minimum levels of requirements for fire detection systems in HMOs:

The following is general guidance on the minimum levels of installation required in different scenarios.

One or two storey HMOs, where the area of each floor is less than 200sqm:

A Grade D1, category LD1 configuration should be installed in a new, or materially altered HMO. In an existing premises of this size, category LD2 is acceptable if it is already installed, but an LD3 system must be upgraded to comply with the Standard.

Areas within HMOs with more than 3 floors, or where the area of at least one floor is greater than 200sqm

Individual, one-room dwellings, with or without cooking facilities:

A Grade D1, category LD1 configuration should be installed. This is required in a new and existing HMO premises.

Individual dwellings comprising two or more rooms:

A Grade D1, category LD2 configuration should be installed. This is required in a new and existing HMO premises.

Communal areas

A Grade A, category LD2 configuration should be installed. This is required in a new and existing HMO premises.

Suitable Fire Detection Systems in HMOs

Always ensure that a comprehensive fire risk assessment has been carried out in your property by a competent person, to determine the risks specific to your premises. This is essential to protect the occupants, particularly as many tenants of HMOs are young and / or vulnerable renters. The Responsible Person for the building may be prosecuted if they cannot demonstrate that they have made every reasonable effort to comply with fire safety requirements enforced by their local council, particularly if a fire breaks out. Compliance with the Standards is the best way to ensure that this compliance can be achieved and evidenced.  

For additional guidance, please visit our Smoke Alarm Help and Information and BS 5839 summary page.

Managing False Alarms

Managing false alarms is a public safety issue. As reported by the BBC, in 2020 the Chief Fire Officer (CFO) at Lincolnshire Fire and Rescue – Les Britzman – asked business owners to take more care and responsibility in managing false alarms. Provided that there are no hazardous materials in the premises and there is no immediate risk to life or the community, the CFO stated that organisations should “have systems in place to go and check those buildings themselves” before calling 999 if a fire is discovered.

Despite this, a National Statistics report shows that FRSs in the UK attended 246,529 fire false alarms in 2023. This was a 3.1% increase on the previous year, and a 6.3% increase on figures 5 years ago. Last year (2023) saw the largest number of false alarms attended since 2011. This diverts essential resources from real emergencies and puts people at risk due to avoidable blue light journeys.

Islington Fire Station, London.
Islington Fire Station, London. The station is part of the London Fire Brigade network of emergency responders.

Further to wasting public resources, management and mitigation of false alarms ensures that time is not wasted by needless evacuations. Unnecessary evacuations may cause downtime of machinery, and potentially a loss of earnings. If false alarms are allowed to persist, there occupants may become desensitized to the sound. This puts lives at risk, as in a real emergency, occupants may fail to react properly.

The importance of managing false alarms

BS 5839 Part 1, the Code of Practice for design, installation, commissioning and maintenance of fire alarm systems in non-domestic premises, has a focus on managing false alarms. Therefore, managing fire alarms is recommended for organisations to demonstrate that they are acting responsibly to prevent fires.  To achieve this, the Responsible Person must ensure that all false alarms on a system are logged. Each false alarm must also be investigated for a root cause, which must be addressed. Mitigating work must be undertaken as necessary to prevent the same incident occurring again. To learn more about this Standard, see our summary of BS 5839-1: 2017.

Should a real fire occur, documentation including a record of, and mitigation work following past false alarms will be required during the investigation. The maintenance of these records is not a legal requirement. However, correct documentation can prevent prosecutions of negligence. It is also highly likely that insurers will require these records when processing a claim.

How to prevent false alarms

Preventing false alarms can be as simple as fitting flip covers to manual call points to prevent accidental activations. Indeed, this is now a recommendation in the Standard, though not a requirement. However, if a false alarm occurred because a manual call point was accidently triggered, the need to mitigate against repeat occurrences may necessitate their installation.

Fire Alarm System Testing & Maintenance
Functional testing of point smoke detectors with a Solo aerosol dispenser and access pole.

Another fundamental part of managing false alarms in existing fire alarm systems is to ensure they are maintained. This includes regular testing, inspections, and servicing. This will reduce the risks of false alarms caused by faulty or improperly installed equipment, as well as ensuring that the system is effective in an emergency.

Premises with a change of use should be professionally inspected to identify whether the existing fire alarm system remains suitable. For example, replacing optical beam detectors with a system of point heat detectors would prevent false alarms in a storage warehouse that has been converted into a factory with machinery that creates a lot of dust.

Optimising new fire alarm systems

For new fire alarm systems, during the design stage the full details of the Fire Risk Assessment, the building, and its intended / current use should be made available. This ensures that the most suitable types of detector can be selected, and positioned in the correct way. Suitable detectors in the correct locations are one of the easiest methods for managing false alarms. For example, installing an optical smoke detector near kitchens or bathrooms could result in false alarms due to steam from cooking or baths and showers.

Identifying design shortcomings is not generally the responsibility of an installer. However, the Standard does state that any issues noticed during installation – particularly those arising from features of the building that might not have been known to the designer – should be brought to the attention of the designer or Responsible Person.

Fire Risk Assessments must be kept up to date and carried out by a competent person.
Fire alarm systems should be tailored to the building. It should account for the risks identified in the building’s fire risk assessment.

False alarms put unnecessary strain on UK fire services, diverting essential resources away from real fires, and putting lives at risk. Managing false alarms is in the interest of organisations as it prevents disruption.

Safelincs provide nationwide fire alarm system servicing and maintenance contracts at competitive pricing. View our Servicing and Maintenance page or call our Servicing team on 0800 612 4827 for more information.

Daniel Bennett

Senior Product Manager

Daniel is our Senior Product Manager. He has a wealth of knowledge when it comes to emergency lighting, fire alarms, smart products, and fire extinguishers.

Latest Posts by Daniel Bennett

Managing False Alarms19th March 2024

BS 5839-1 fire alarm system standard explained

fire-alarm-panel-kitsBS 5839 Part 1 ‘Fire detection and fire alarm systems for buildings. Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises‘  is the key Standard for commercial fire alarm systems with central control panels. It helps customers and installers to specify, design, install and maintain fire alarm systems.

It is a substantial document and to help our customers find their way through it we have created a summary of the Standard. The summary covers:

  • Why might I need a fire detection / fire alarm system for my premises?
  • What are fire detection and fire alarm systems?
  • What is meant by ‘category of system’?
  • What are the main design considerations for an appropriate fire detection / fire alarm system?
  • What are the main installation issues?
  • What happens once the installation is complete?
  • Commissioning, documentation, and certification
  • Maintaining the system: what is involved?
  • User’s responsibilities and premises management: who does what?

Safelincs, the UK’s most progressive and customer friendly fire safety company offers its customers nationwide maintenance of fire alarm systems as well as a range of fire alarm system components:

For quotations for a new fire alarm system, please ring our friendly customer care team on 0800 612 6537.

To arrange your fire alarm system maintenance visit, please ring 0800 612 4827.