Residential Sprinklers Design

We'll guide you through every step of the way

Residential Sprinkler Design

To begin the sprinkler design process; consideration and consultation with the Authority having jurisdiction (AHJ) will need to have taken place in order to evaluate the risks to be protected; including fire loading and the type of occupancy. It is important to establish the system category in the early stages of design as this will have an effect on various design criteria, e.g. Water supplies.
Category of system Description of Building/Occupancy
1Single family dwellings such as: individual dwelling house, flat, maisonette or transportable home
Houses of multiple occupation (HMOs)
Bed and Breakfast accommodation
Boarding houses
Blocks of flats 18m or less in height and with a maximum total floor area of 2400 m2
2Blocks of flats greater than 18m in height
Small residential care premises with ten residents or fewer
Sheltered and extra care housing
3Residential care premises with more than ten residents
Dormitiores (e.g. attached to educational establishments)


A) If any buildings permanently house vulnerable people this should be taken into account in determining the building category.
B) A building with more than two floors and 5 or more lettable bedrooms should be treated as Category 2.
C) Where the total floor area is greater than 2400m2 then the building should be treated as Category 2.
D) Where the fire strategy requires the communal rooms and corridors to be sprinkler protected, then the building should be treated as Category 3.
Category of system Minimum Design Parameters
 Minimum design discharge density [mm/min.]Number of design sprinklers Minimum duration of supply [min]
12.041 [or] 210
22.81 [or] 230
32.82 [to] 430
Please note: If the sprinkler system is required as a compensatory feature, consultation will be required with the AHJ to determine if the system characteristics need to be enhanced to meet its requirement which can then be documented on the certificate of compliance accordingly.

Examples of when the sprinkler system is installed as a compensatory feature:

• Attic Conversions where adequate secure escape is not practical or possible
• Buildings that cannot meet the access requirements for fire appliances
• Building where the minimum fire resistance cannot be achieved
Design Parameters (compensatory feature)
Category of system Minimum design discharge density [mm/min.]   Number of design sprinklers Minimum duration of supply [min]
24 130
2.8 2
34 130
2.8 4
Once the Category of system has been confirmed (this is usually identified at quotation stage) we can begin producing sprinkler drawings. We will create drawings with sprinkler head locations which have been positioned to provide full protection, it is important that we work with the latest reflected ceiling plans to coordinate and keep compliance. These sprinkler layouts will then be sent over for your approval; once they have been approved we will carry out hydraulic calculations to determine the pipe sizes and system demand.

Extent of sprinkler protection:

Sprinkler protection should be provided in all parts of the premises. However, unless required by a fire strategy or risk assessment, the following may be excluded:
  • Bathrooms with a floor area of less than 5m2
  • Cupboards or pantries with a floor area of less than 2m2 or where the least dimension does not exceed 1m
  • Attached buildings such as garages and boiler houses without direct access from within the protected building
  • Crawl spaces
  • Ceiling voids
  • External balconies permanently open to the outside
  • Uninhabited loft/roof voids

Sprinkler coverage and positioning:

  • The maximum area 25m2 or manufacturers recommendation, whichever is the lesser
  • Not be more than 5.5m apart and less than half the spacing from any wall
  • The distance between sprinklers should not be less than 2.4m
  • Not more than 100mm below the ceiling
  • The whole of the floor area and the walls up to 0.7m below the ceiling should be wetted
  • Sprinklers should not be adversely affected by obstructions (smoke detectors, lights etc.)
  • Sprinklers should be positioned a sufficient distance from any heat sources


To begin the design process; consideration and consultation with the AHJ will need to have taken place.


Once a design has been agreed upon, we can then supply sprinkler heads, pipework and sprinkler control sets.


Once sprinkler positions have been approved by the client, we can begin the installation of the sprinkler system.


Fire sprinkler systems need to be serviced annually to ensure that they continue to operate correctly in line with BS9251:2014.

Want to find out more?

Contact Us to enquire or get a free quotation