The Scope of BS 5839: Pt. 1

Fire alarm systems in non-domestic premises are generally designed and installed in accordance with the guidance given in BS 5939 Part 1.There are many types of fire alarm systems each suited to different building types and applications. A fire alarm system can vary dramatically in both price and complexity, from a single panel with a detector and sounder in a small commercial property to an addressable fire alarm system in a multi-occupancy building.

BS 5939 Part 1 categorizes fire alarm systems as:

• "M" manual system (no automatic fire detectors so the building is fitted with call points and sounders),
• "L" automatic systems intended for the protection of life, and
• "P" automatic systems intended for the protection of property.

Categories for automatic systems are further subdivided into L1 to L5, and P1 to P2.

• "L5" - systems designed to satisfy a specific fire safety objective (other than that of a Category L1, L2, L3 or L4 system).
• "L4" - installed within escape routes comprising, such as corridors and stairways.
• "L3" - as "L4", plus automatic detection to rooms which open onto an escape route.
• "L2" - as "L3, plus automatic detection installed in defined parts of the building.
• "L1" - systems installed throughout all areas of the building.
• "P2" - systems installed only in defined parts of the premises.
• "P1" - systems installed throughout the premises.

The Scope of BS 5839: Pt. 6

This Code of Practice covers fire alarm systems starting from a simple self-contained battery smoke alarm right through to major systems with central panel(s) in accordance to BS 5839-pt1.

BS 5839: Pt.6 covers the following domestic building types:
Bungalows
Multi-storey houses
Individual flats
Individual maisonettes
Mobile homes
Individual sheltered accommodation as well as their common parts
Houses in multiple occupation (HMOs)
Certain NHS housing in the community
Mansions
Shared houses
Houses divided into several self-contained single-family dwelling units


Not included are hostels, caravans, boats (other than permanently moored) and communal parts of blocks or flats or maisonettes.

BS 5839: Pt.6 is primarily concerned with saving lives and reducing injuries. However, it does contain within it recommendations for helping to reduce property damage too. Good fire safety practice and adherence to the Code can give the best possible early warning of fire and so reduce the financial impact as well as human suffering.

The Grade System

Relates to system engineering, not level of protection.

BS 5839: Pt.6 grades fire detection systems from Grade F up to Grade A. Generally speaking, the greater the fire risk and the more demanding the application, the more comprehensive the system needs to be.

• Grade F - System of one or more battery powered smoke alarms (and heat alarms if required)
• Grade E - System of interlinked mains powered smoke alarms (and heat alarms if required) with NO stand-by supply. The interlink can be hardwired or radio-interlinked. Please note that Safelincs Ltd will not sell Grade E alarms, as we only recommend alarms with backup batteries.
• Grade D - System incorporating one or more interlinked mains powered smoke alarms (and heat alarms if required), each with an integral stand-by supply. The interlink can be hardwired or radio-interlinked.
• Grade C - System consisting of fire detectors and alarm sounders (which may be smoke alarms) connected to a common power supply, comprising normal mains and stand-by supply, with central control equipment
• Grade B - Fire detection and alarm system comprising fire detectors (other than smoke alarms), fire alarm sounders and control and indicating equipment to either BS EN 54-2 (and power supply to BS EN 54-4), or to Annex C of BS 5839: Pt.6
• Grade A - Fire detection system incorporating control and indicating equipment to BS EN 54-2, and power supply to BS EN 54-4, installed to BS 5839: Pt.1 with some very minor exceptions

As the overwhelming number of residential applications in the UK will fall into the D to F categories, this is the area on which this guide will naturally focus. If you are particularly interested in unusual grades of protection, you are invited to look further at the relevant clauses of the Code.

Of course, installers and specifiers may install a system with greater safety features than laid down in the letter of the Code. For example, rather than a Grade E system landlords might consider it prudent to install a Grade D system instead. This is especially true considering the many restrictions that apply to the use of Grade E systems.

Battery Powered Smoke Alarms - Grade F

BS 5839: Pt.6 acknowledges the advantages of the single, battery powered smoke alarm. They are simple to install and offer protection at very low cost. Battery powered smoke alarms conforming to BS EN 14604:2005 are recommended. Battery powered smoke alarms are typically suitable for owner-occupied buildings (existing buildings) with up to two storeys. Please note: if your property has multiple levels, it is recommended to have interlinked alarms. This is to ensure you receive the earliest possible warning of fire.

Single story tenanted properties were allowed in the last version (2004) of this standard to be fitted with Grade F alarms. This has now been changed to a grade D requirement. As an aside, landlords have now been found liable in cases where tenants themselves have disabled an alarm. For this reason, it is unlikely that landlords will be able to trust tenants to adequately look after a smoke alarm. The Code highlights the fact that battery powered smoke alarms are also only suitable for owner-occupied properties if the likelihood is, that batteries will be replaced within five days of a low battery signal.

Mains Powered Smoke Alarms without Back-up Battery - Grade E

The Code does not recommend an application for alarms without back-up power source any longer. Grade E systems have serious drawbacks: power cuts or the termination of supply for whatever reason disables them totally. They can also be rendered useless by the tripping of a protective device, or even - in some cases - by the fire itself. Householders may also disable them at the mains all too easily if false alarms are a problem.

Mains Powered Smoke Alarms with Back-up Battery - Grade D

The problems outlined above can be overcome by using mains powered alarms that incorporate, within each alarm, a stand-by supply such as a primary or rechargeable battery. The alarms have to be interconnected either through wiring or radio-interlink. The mains power supply can come from a dedicated power supply directly from the fuse box or from the nearest permanently powered light fitting, as long as the smoke alarm heads can be removed without removing the base as well.

Grade D is required for new, owner-occupied buildings of up to three storeys, two storey rented properties and existing, owner-occupied buildings of more than two storeys. Very large storeys (>200m2) might require Grade B alarm system.

A question remains for landlords - can they be sure that their tenants are paying their electricity bills? Given that many tenants may have low incomes (in many local authorities, 70% or more of all tenants are on subsidised incomes), they may well experience periods of disconnection - and yet the landlord could well be liable if the alarm fails to sound because the tenant has not paid his or her bills! Unfair or not, as the law stands, it obviously makes good commercial sense to ensure that a reliable, ideally re-chargeable and sealed-in backup battery is in place.

The minimum back-up duration recommended is 72 hours, and the Code acknowledges that there could well be circumstances where a longer stand-by period is justified e.g. tenants' inability to pay their electricity bill.

Fire Detectors supplied with Power from a common Power Supply Unit - Grade A, B, C

More expensive high specification systems can offer connection of all fire detection devices to a common power supply via low voltage transformers, or interlinked fire and security systems. Again, a minimum 72 hour back-up is recommended by the Code. Due to the complexity of A, B and C Grades, we have omitted the descriptions from this short guide.

Levels of Protection - Categories of System

This relates to the level of protection afforded by the system.

Within the A - F grades defined earlier, the standard identifies three different categories of protection:

• LD1 - A system installed throughout the dwelling, incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling, and in all rooms and areas in which fire might start, other than toilets, bathrooms and shower rooms
• LD2 - A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises, and in all rooms or areas that present a high risk of fire to occupants
• LD3 - A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises

It is noted that an LD3 type system is intended to protect escape routes for those not directly involved in the fire and may not save the life of anyone in the immediate vicinity of the fire.

Only by quoting Grade and Category can a meaningful and effective alarm system be specified, e.g. Grade D, Category LD2.

You can buy the full BS 5839-6:2013 standard online.

History of BS 5839-part 6

When first introduced in 1995, the BS 5839: Pt.6 Code of Practice became the most important set of recommendations ever made on fire safety in the home.

It had an immediate impact on architects, system designers, installers and landlords in the private or public sector, all of whom were required to familiarise themselves with these important recommendations. Landlords in particular needed to abide by these recommendations, as legal liability with regard to 'duty of care' would undoubtedly become a serious issue should a fire occur in an inadequately protected property.

In short, BS 5839: Pt.6 became the essential guide to providing adequate fire protection in all dwelling types.

In September 2004, the Code of Practice was extensively revised and updated by the publication of BS 5839: Pt.6: 2004 which superseded BS 5839: Pt.6: 1995, which is now withdrawn. The changes therein are important and need to be fully understood and appreciated by all those with responsibility for fire safety in domestic dwellings.

An updated standard came out in 2013 and included for the first time common areas in sheltered housing. Carbon monoxide detectors were also permitted as fire alarm sensors and the requirement for rented accommodations were tightened.

Please contact us by email info@ggfire.co.uk or use our contact form.