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.

Mains Powered Smoke Alarms with Lithium Back-up Ei3000 Series
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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.

Hushing Interlinked Smoke Alarms

Interlinked smoke alarms are becoming more and more popular as they quickly alert you to the event of a fire across larger houses, where there is a risk that you might not hear an alarm going off in the kitchen when you are, for example, in a bedroom upstairs.

Whether connected to each other with wire or wirelessly interlinked through radio frequency, interlinked smoke alarms allow you to connect multiple units – including different types of detectors – which will all sound at the same time when a single alarm detects a potential fire. The heat alarm in the kitchen, the ionisation alarm in your home office, and the specialist strobe and vibration alarm in your elderly parents’ bedroom, for example, will all go off at the same time, if just one alarm is triggered by fire.

Most of us are familiar with the test button on smoke alarms which allows residents to test their alarms regularly, to ensure the components are working and the power supply, whether battery or mains power, is working. On top of this, however, many alarms have a “hush” button which allows you to silence an alarm that has gone off, for example, due to burnt toast.

So how do hush buttons work when you have several interlinked alarms?

It’s easy to assume that, as they are all connected, hushing one alarm will silence all of them, but it is equally logical that only the unit on which you pressed the hush button should be silenced – after all, you don’t want people to assume it was a false alarm if there really is a fire raging downstairs.

Interestingly, not all interconnecting smoke alarms hush in the same way. Here is an overview explaining the different approaches employed by the three main smoke alarm manufacturers in the UK.

Kidde Slick Wireless Smoke and Heat AlarmsFor Kidde smoke alarms, the originating alarm (the unit which detected a potential fire and triggered all of your units) will have its warning light flash faster than all other units while the alarm is sounding – enabling you to identify the smoke alarm that caused the alarm. Pressing the hush button on ANY unit will silence the ENTIRE network.

Ei160e Series Smoke and Heat AlarmsIf you have interlinking Ei Electronics smoke alarms, only the originating unit’s hush button will be able to silence the ENTIRE network. The other units in the circuit can be individually silenced. To identify the originating unit you need to look for the alarm whose warning light is flashing every second, compared to every 40 or so seconds on the other units.

FireAngel WST600 Series Radio-Interlinked Smoke and Heat AlarmsFireAngel smoke alarms, however, deploy an improved silencing protocol. If you hush the originating smoke alarm then, as with the other brands, ALL connected units will be silenced. However, if you hush any other unit, the ORIGINATING alarm will continue to sound but ALL OTHER units will be silenced. This allows you to quickly identify the originating alarm which is very helpful both in case of a false alarm or a real emergency.

If you require support selecting the best smoke alarm system for yourself, please contact the friendly Safelincs support team either by emailing support@safelincs.co.uk or by ringing 0800 612 6537