Fire Alarm Grades for London Landlords: Grade D, Grade A and LD Categories

Councils, letting agents and fire risk assessors often talk about fire alarms in terms of a "grade" and a "category", such as "Grade D1, LD2". Many landlords nod along without knowing what that means. This guide explains the grades and categories used in British Standard BS 5839-6, which covers fire alarms in homes, and what is usually expected for different kinds of London rental.

Grades: how the system is built

• Grade F: battery-only alarms. F1 has a sealed long-life battery, F2 has a battery you can replace. The minimum legal standard in many single-household lets, but not usually enough for HMOs.
• Grade D2: mains powered alarms with a battery backup that the user can replace, usually interlinked so they all sound together.
• Grade D1: mains powered alarms with a sealed, tamper-proof backup battery. The usual choice for new installations and many smaller HMOs.
• Grade A: a full system with a control panel, detectors and manual call points, typical in larger HMOs, bedsit buildings and blocks with shared escape routes.

Categories: where the detectors go

• LD3: detectors on the escape route only, such as hallways and landings.
• LD2: the escape route plus rooms where fires are more likely to start, such as the kitchen and living room.
• LD1: detectors in almost every room where a fire could start.

What is usually expected

For a typical single-household let, landlords must by law have a smoke alarm on every storey used as living space, and a carbon monoxide alarm in rooms with a fixed combustion appliance, such as a gas boiler. For HMOs, councils usually expect more: often interlinked mains alarms to Grade D with LD2 or LD3 coverage in smaller shared houses, and a Grade A system in larger or taller HMOs. The exact standard depends on the property and the council's fire risk assessment, so always check your licence conditions. Our guide to HMO licence electrical requirements covers the wider picture.

Smoke or heat?

Kitchens normally get heat detectors rather than smoke detectors, to avoid false alarms from cooking. Our guide to smoke detectors and heat detectors explains which goes where.

Certificates and testing

Mains wired systems should be installed and commissioned by a competent person, with a certificate you can show the council or your agent. Alarms should be tested regularly and replaced at the end of their life. Our guide to smoke alarms and fire alarm certificates covers the paperwork.

Book a survey

Energy North Ltd installs and tests mains wired alarms for landlords across North, East and West London with City & Guilds certified electricians. See our EICR service.