‘Dr Zzeus’ Tom Brookes, MD of Zzeus Training and Chairman of the FSA, answers your questions related to fire safety compliance.
Q. I am getting a little confused with the BS 5839-6 grades and categories. The Client has asked for a Grade D1 LD1 system?
BS 5839-6:2019+A1:2020 is the latest version of the Part 6: Code of practice for the design, installation, commissioning and maintenance of fire detection and fire alarm systems in domestic premises. In Part 6 Grade and Category are split into two parts and this is the first thing to understand. If you think of Grades as types of system, and Category as areas to be covered, it makes it easier.
Clause 7 in the document deals with the Grades of system.
Grade A: A fire detection and fire alarm system, which incorporates Control Indicating Equipment (CIE) conforming to BS EN 54 2 and power supply equipment conforming to BS EN 54 4, and which is designed and installed in accordance with all the recommendations of BS 5839 1:2017, Section 1 to Section 4 (generally speaking, a full part 1 fire alarm with a few differences such as sound levels, deaf and hard of hearing sections etc.)
Grade B: Not currently defined.
Grade C: A system of fire detectors and alarm sounders which may be combined units connected to a common power supply, comprising the normal mains and a standby supply, with central control equipment.
Grade D1: A system of one or more mains-powered detectors, each with a tamper-proof standby battery.
Grade D2: A system of one or more mains-powered detectors, each with an integral standby supply consisting of a user-replaceable battery or batteries.
Grade E: Not currently defined.
Grade F1: A system of one or more battery-powered detectors powered by a tamper-proof primary battery.
Grade F2: A system of one or more battery-powered detectors powered by a user-replaceable primary battery.
Clause 8 lists the Categories of system (areas to have detection)
Category LD1: The system detection should be installed throughout the premises, in all areas that are part of the escape routes, and in all rooms and areas, other than those with insignificant causes of ignition, such as toilets, bathrooms and shower rooms.
Category LD2: The system detection should be installed throughout the premises, in all areas that are part of the escape routes, and in all rooms or areas that present a high fire risk, including any kitchen and the primary habitable room such as the lounge.
Category LD3: The system detectors should be installed in all areas that form part of the escape routes from the premises, such as hallways and landings.
Types of buildings covered by BS 5839-6:2019
Applies to configurations of domestic premises, such as bungalows, multi-storey houses, individual flats and maisonettes, mobile homes, holiday homes, sheltered housing, mansions, shared houses and houses divided into several self contained single family dwelling units.
Types of buildings not covered by BS 5839-6: 2019
It does not apply to hostels, caravans or boats (other than permanently moored boats used solely as residential premises), or to the communal parts of blocks of flats or maisonettes. It does not apply to any premises used for purposes other than as domestic premises (e.g. small shops, factories or similar premises used solely as places of work). Aico has some superb guides on its website to help you better understand BS 5839-6 systems. So, to answer the original question, the D1 LD1 system asked for is mains powered detectors with tamper-proof batteries, installed in all areas except the bathrooms and shower rooms.
Do you have a question you’d like answered? Email your queries to Tom@Zzeus.org.uk
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