Mandatory Fire Suppression for Wales - A Technical Guide
The Welsh Government has amended Approved Document B volumes 1 and 2, with new regulations and guidance to be implemented on 1st January 2016.
The amendments to the documents arise from the Domestic Fire Safety (Wales) Regulations, resulting in a new Section 7A ‘Automatic Fire Suppression Systems’ in the Building Regulations 2010 Statutory Instrument. Section 7A introduces regulations 37A and 37B, requiring all new ‘domestic premises’ to have a fire suppression system installed.
A fire suppression system is defined as an automatic system that controls and extinguishes fires without human intervention. Typically these are sprinkler systems, although other types are available.
This guide refers mainly to fire sprinkler systems.
Where and when
The requirements apply throughout Wales from 1st January 2016 and apply to new build and change of use applications forming:
- New houses and flats
- Care homes
- Rooms for residential purposes (other than in a hotel, hospital, prison or short stay leisure hostel)
- Registered group homes and sheltered housing
The transitional provisions are as usual – applications deposited after 1st January 2016 and applications already submitted but commenced after 1st January 2017 must include fire suppression.
The new Approved Documents
Note that the requirement to provide fire suppression is statutory. This means that sprinklers are mandatory, compensatory features cannot be added to the building to avoid their inclusion.
The new Approved Documents for Part B (Wales) contain guidance as follows:
- Both documents contain a new Section 2 in B1 ‘Residential Automatic Fire Suppression Systems’
- Section 2 requires suppression systems to be designed and installed to BS 9251 and 9252 or other ‘equivalent standard’, neither specifically including or precluding other suppression systems such as water mist: innovative systems must be ‘designed and tested for use in domestic buildings and be fit for their intended purpose’
- The system should cover the whole dwelling, except fire separated garages etc. The common parts or ancillary areas within blocks of flats are not included. Neither are bathrooms under 5m2, cupboards under 2m2 and concealed voids.
- Where a building with an existing suppression system is altered or extended the system should be revised as necessary to ensure cover of all areas (not applicable to those without suppression).
- Guidance is given on means of water supply to the system.
- An appendix outlines requirements for maintenance of suppression systems and the information to be given to property owners to maintain their systems.
Sprinkler myths exploded
- Sprinkler heads do not all activate in the event of a fire. This only happens in the movies. In the event of a fire individual sprinkler heads will activate once the air around the head reaches a certain temperature.
- Sprinklers create significantly less water damage than fire service firefighting operations.
- Sprinklers do not ‘false alarm’ as they only operate on elevated air temperature, not in response to smoke particles. Burning the toast will not result in activation of the sprinkler system.
Some of the guidance in Approved Document B has been amended due to the fire safety benefits of having a fire suppression system installed. This includes:
- Houses over 4.5m can be served by a single protected stair
- Guidance on fire service access is amended to increase the maximum distance for pump appliances from the building from 45m to 60m
- Boundary distances for external fire spread are halved
- Flats over 4.5m can be served by a single protected stair without the need for an alternative exit or increased smoke detection coverage
- Self-closers are not required to bedroom doors in care homes, and more than 10 beds are allowed per compartment
Reference is also made in both documents to BS9991 – this code of practice for fire safety includes many alternative solutions where suppression systems are installed, including open plan flats. However BS 9991 requires comprehensive fire safety management strategies to be adopted as part of a design solution.
There are two main British Standards for the design of sprinkler systems. BS 9251:2014 covers domestic and residential systems and BS EN 12845 covers all buildings. In most instances covered by the new regulations the domestic standard is the most appropriate and cost effective.
An alternative type of fire suppression to sprinklers is a ‘watermist’ system. Mist systems release tiny droplets of water that absorb the heat from a fire and generate a steam that interrupts the combustion process. Watermist systems do not have an approved technical standard to be designed against, although there is a British Standard Draft for Development DD 8458:2010 which is at this time an un-adopted standard. Watermist systems will be considered on a case specific basis based on the manufacturers design which is in accordance with DD8458:2010.
Where town mains are to be used, the designer must consult with the water undertaker to establish the typical operating water pressure range and flow capacities available. At this time the water undertakers in Wales will not guarantee a mains pressure suitable for a mains-fed suppression system. Therefore the 2 available system types remaining are:
- Mains fed with in-line booster pump
- Tank fed and pumped
There is a limited market availability of in-line booster pumps at this time, meaning that tank fed systems will be the most common solution. Where tank fed systems are used they require a low-water alarm, and dedicated sprinkler pumps also require a fault alarm. The tank must be sized in accordance with BS 9251:2014 depending on system category.
There are 3 categories of system defined by BS 9251:2014, depending on building type, size, and number of sprinklers per room.
Category 1: Suitable for single family dwellings such as individual houses and flats, including small houses in multiple occupations (up to 2 floors and 5 lettable bedrooms). Also for systems serving all residences in blocks of flats up to 18m in height and less than 2400m2.
- Maximum number of sprinklers per room is 2
- Typical volume of stored water 1m3 to 1.5m3
Category 2: Suitable for blocks of flats over 18m in height, larger houses in multiple occupation, sheltered accommodation and small residential care premises (10 residents or less).
- Maximum number of sprinklers per room is 2
- Typical volume of stored water 3m3 to 4.5m3
Category 3: Hostels and larger residential care premises.
- Maximum number of sprinklers per room is 4
- Typical volume of stored water 6m3 to 9m3
Where coverage is provided to the communal areas of flats, the category will usually be adjusted upwards. Additionally, increased flow rates will be required where the system is designed as a compensatory feature, for example in the design of open plan flats in accordance with BS 9991:2015. Where the building is of a size that these parameters cannot be achieved, the system should be designed in accordance with BS EN 12845.
BS 9251 contains detailed clauses on sprinkler spacing and coverage, and should be referenced by the system designer. Here are some of the basic requirements for system coverage:
- Maximum area protected by a single sprinkler head is as per the manufacturer’s listed performance or 25m2, whichever is the lesser
- Sprinklers should be no more than 5.5m apart
- The minimum distance between sprinkler heads is 2.4m
- The system should be designed to cover the whole room and the walls up to 0.7m below the ceiling
- Where the room size demands more than two sprinklers the system must be designed as a category 3 system to cope with simultaneous activation of more than two heads.
Competency of designers and installers
Design, installation and commissioning must be carried out by competent persons, defined as: ‘a person, suitably trained and qualified by knowledge, understanding and practical experience’. A compliance certificate should be provided by the competent installer to demonstrate compliance with the British Standard.