British Standards

At Q-Mech Scotland Ltd protecting people and property is our number one priority and we strictly adhere to all British Standards.

BS 9251, first published in 2005 and revised in 2014 with input from the fire service and industry professionals, sets out standards for residential sprinkler systems across a wide range of premises. These include individual dwellings, HMOs, blocks of flats, residential care premises, hostels, dormitories, and similar accommodation.

Properties are grouped into risk Categories 1–3, based on building size and occupant vulnerability:

        •       Category 1: Individual dwellings and small blocks of flats under 18 m.

        •       Category 2: Blocks of flats over 18 m and small residential care homes (up to 10 residents).

        •       Category 3: Large residential care homes (over 10 residents) and hostels.

Each category has minimum design requirements, including sprinkler head spacing (typically one head per 25 m², with defined distance limits) and system performance criteria:

        •       Category 1: 10-minute minimum run time, based on 1–2 heads.

        •       Category 2: 30-minute minimum run time, based on 1–2 heads.

        •       Category 3: 30-minute minimum run time, based on 2–4 heads.

The BS 9251:2021 update introduced a fourth category to address taller residential buildings (over 18 m) and higher-risk scenarios. Key changes include improved alignment with Fire and Rescue Service guidance and BS EN 16925, enhanced resilience for higher-risk buildings, increased water supply and reliability requirements (such as duplicate pumps), clearer guidance for mixed-use buildings, improved fire service interaction, and clearer requirements for alarms, fault signalling, and defined roles and responsibilities

BS9251:2021 update

Introduction of a fourth category of system to cater for taller residential buildings (greater than 18 m) and higher risk scenarios. The rationale for this is for the following:

  • Alignment with Fire and Rescue Service national operational guidance e.g. access and response time.

    • consistency with BS EN 16925 (Fixed firefighting systems – Automatic residential sprinkler systems – Design, installation, and maintenance)

    • greater risk profile in higher-rise buildings, including the need for improved resilience.

  • Additional recommendations for large capacity minimum water suppliers for taller buildings and higher risk scenarios. 

  • Further recommendations for duplicate pumps and other reliability enhancements in certain scenarios.

  • Further recommendations for non-residential occupancies in protected buildings. 

  • Additional measures and information for the fire service to interact with the installation

  • Clarification of alarm and fault signalling requirements 

  • Clarification of roles and responsibilities. 

BS EN 12845 – Automatic Sprinkler Systems - is the British and European Standard that sets out the requirements for the design, installation, and maintenance of automatic sprinkler systems in commercial and industrial buildings. Its primary objective is to control or suppress fires in their early stages, protecting life, property, and business continuity.

The standard defines:

Hazard classifications (Light, Ordinary Hazard Groups OH1–OH4, and High Hazard HH) based on building use, fire load, and occupancy.

Design criteria including sprinkler spacing, discharge densities, operating areas, and water supplies.

System components such as sprinkler heads, pipework, valves, pumps, tanks, alarms, and control arrangements.

Water supply requirements, including duration, flow rates, and reliability (town main, tanks, pumps, or combinations).

Installation and acceptance testing procedures to ensure systems operate as intended.

Inspection, testing, and maintenance (ITM) obligations to maintain long-term reliability.

In the UK, BS EN 12845 is commonly used alongside LPC Rules (Loss Prevention Certification Board), which add further insurer-driven requirements. The standard applies to most non-domestic buildings, including retail, industrial, warehouses, hotels, and large mixed-use developments, and is not intended for domestic dwellings, which are instead covered by BS 9251.