BS 9990:2015 Dry Riser Requirements, Installation and Maintenance Standard
BS 9990:2015
Across the UK, dry risers form an essential part of building fire safety systems, providing firefighters with a reliable way to deliver water rapidly to higher floors during an emergency.
All installation, testing, and maintenance should be carried out to the BS 9990:2015 standards, with every legal obligation fully met.
So what does BS 9990:2015 include and what guidance does it provide?
The British Standard includes guidance on work on site as well as important provisions for the protection of buildings during construction.
In this article we will cover the most important aspects of the BS 9990:2015 from the legal perspective to installation, maintenance and servicing and we will conclude the article with some essential requirements of the British Standard.
Do I Need a Dry Riser and Why?
Dry riser systems are typically required in buildings where the highest occupied floor is under 50 metres tall, as outlined in Approved Document B (Fire Safety) of the Building Regulations for England and Wales. If you are building a new property or refurbishing an old one, you should have a fire strategy report in place. You may be exempt, however, the report should still be carried out to ensure compliance, as some buildings below 18 metres in height may be located in areas with limited access, where a dry riser could still be required. Your local fire officer and Building Control will decide what fire suppression systems you will require and whether a dry riser will be needed. Once this is confirmed, you will receive a report on where and how the dry riser should be installed. Remember, if you are refurbishing an old building, you will most likely be required to have some form of fire suppression. Once the design is produced and the building is ready for installation, the appropriate person visits site to carry out a survey prior to installation. For the full cycle of the installation, please see our Installation page.
Dry Riser Maintenance BS9990:2015
According to BS 9990:2015, dry riser systems should operate at a pressure of 12 bar, be visually inspected every six months, and pressure tested annually to ensure they remain fully operational.
Dry Riser Inlet
A dry riser should be equipped with a 2-way breeching inlet for a 4 inch system (6 inch dry risers will have a 4-way breeching inlet). Each breeching inlet must comply with BS 5041-3 and be installed within an inlet cabinet that meets BS 5041-5 requirements. The bottom edge of the door should be positioned between 400 mm and 600 mm above ground level. Dry Riser Inlets should be installed in an external wall or in a boundary wall of a building and as close as possible to the fire appliance (within 18-metres).
Dry Riser Inlet Standard:
CONFORMS TO BS5041 PART 3
Dry Riser Outlet Valve
An Outlet Valve should be installed at each floor level, including the ground floor. The valve should be positioned so that its lowest point is approximately 750 mm above floor level. Outlet valves for fire mains should ideally be protected within a cabinet or enclosure that complies with BS 5041-4. For dry riser systems, outlet valves must conform to BS 5041-2. The outlets should be flanged rather than directly threaded, allowing for easier maintenance and servicing, however screwed valves are now generally accepted in the industry by the authorities.
Dry Riser Outlet Valve Standard:
CONFORMS TO BS5041 PART 2
Air Release Valve
Automatic air release valves are installed at the top of each system. The air release valve is manufactured from solid brass, ensuring durability and long-term reliability. It features a male screwed connection. The valve is designed to operate under demanding conditions, with a maximum hydraulic test pressure of 300 PSI and a recommended working pressure of 175 PSI, providing consistent and efficient air release across a range of fire protection applications.
Note: There is no specific BS 5041 section for air release valves; however, they must comply with the functional requirements set out in BS 9990:2015.
Drain Valves
For the testing purposes, there is 25mm drain valves installed in accordance with BS 5041-3 to facilitate effective drainage.
Note: There is no dedicated BS 5041 section specifically for drain valves; however, they must meet the overall performance requirements of BS 9990:2015.
Pipework
Galvanised steel pipework should be installed throughout as it is designed to meet the required operating pressure, durability, and long-term robustness of the system. Pipework comes in 3-metre lengths and is rated at 70-bar pressure.
Signage
Fire mains and associated equipment clearly identified with appropriate dry riser inlet and outlet signage.
Horizontal Run
Any run of connecting pipe between the inlet and the vertical run of the main should be kept to a minimum and should be given a fall towards the drain valve. NOTE: For typical building applications, the run of horizontal connecting pipe is a maximum of 18 m in length.
Positioning
Ensure that the inlet cabinet is unobstructed and within the 18 metres from the fire applicance. Inlet and outlet valves should be positioned 750mm to its centre point from the finished floor. All cabinets should be positoned between 400mm - 600mm from finished floor.
Fixing
Cabinets must be securely fixed to the wall. This is typically done by using screws. For recessed units, the wall opening should be correctly sized to allow the architrave to sit flush.
Fire Stopping
If a cabinet is installed in a fire-rated wall any gaps around the cabinet or pipe penetrations must be sealed with appropriate fire-stopping material to maintain the wall’s integrity. Dry riser cabinets are not fire rated.
Additional Notes for Dry Riser Systems
All materials used within the system should provide excellent flow characteristics and high-quality casting finishes. Components should offer effective sealing, corrosion resistance, and long-term durability to ensure reliable system performance.
Here is the BS9990:2015 updated version with all the latest information, link: https://knowledge.bsigroup.com/
Have more Questions?
Should you have any questions regarding your system, our team is always available to provide clear guidance and support, whether you speak with our contracts manager or one of our qualified engineers. We can provide precise guidance in accordance with BS 9990:2015. If you need to connect with us, please give us a call on +44 (0) 161 706 1232.
Dry Riser One Ltd has in-house knowledge and expertise across all aspects of dry riser systems, ensuring you can use our services with complete peace of mind. All installation, testing, and maintenance are carried out to the BS 9990:2015 standard and supported by additional accreditations such as CHAS.
Our job is to raise awareness and help communities nationwide stay safe in their homes, including new properties that are soon to be occupied.
Sources:
UK Building Regulations – Approved Document B
BS 9990:2015 – Non-automatic firefighting systems in buildings
The Regulatory Reform (Fire Safety) Order 2005