A dry riser is a supply system that enables the distribution of water to multiple levels or compartments of a building, as a component of its fire-fighting systems.
Dry risers are a building regulations requirement in occupied buildings over 18M tall. Wet risers are a building regulations requirement in buildings over 50M.
Dry risers may also be found in environments where access is limited or compartmentation is an issue (i.e. multilevel basements, car-parks or hospital corridors).
Dry Risers are designed and installed in accordance with BS 9990 and Building Approval Regulations.
Inlets enable connection of Fire Service water supplies. This is conventionally in an external cupboard or enclosure marked “DRY RISER INLET”. Within this enclosure is a breeching inlet with at least 2 BS instantaneous male couplings. Also in this cupboard is a drain valve to enable the dry riser to be emptied of water following fire service operations or testing.
These enclosures should be secure from vandalism but immediately accessible. They usually have a breakable area in the door to facilitate urgent fire service connection.
Outlets (or Landing Valves) are connection points to enable the fire service to attach and advance its hose lines within a building. Each outlet consists of a single BS instantaneous female outlet, operated by a gate valve.
The annual testing and maintenance of both Dry and Wet Risers is the responsibility of the property owners or managing agents.
British Standard 5306: Part 1 1976 (Revised by BS9990) recommends that the system is visually inspected every 6 months and serviced annually to ensure that the equipment is ready for immediate use in an emergency. In addition, it is recommended that a ‘full wet test’ be carried out annually, comprising of a wet pressure test to 150 PSI or 10 Bar subjecting the mains to a full working test.
benefits of Fire Protection Systems
If you own or operate a commercial building, then the safety of the property and its occupants is of paramount importance. When you consider that there are over 100 commercial building fires in the UK every day, getting appropriate fire protection systems in place, before the worst happens, is essential.
Fire Protection Systems
Below are some of the different types of fire sprinkler system which we are pleased to offer our customers. We are specialists in the design, installation, and also the service and maintenance of various fire protection systems, and are happy to advise you on the system best designed to suit your needs.
Wet Sprinkler System
These are the most common fire sprinklers and are installed to protect premises where there is no risk of freezing. The systems are permanently charged with water and as such the systems are very quick to react, as there is water permanently in the pipework above the sprinkler heads. Wet fire sprinkler systems are required for multi-storey or high rise and for life safety systems.
Alternate Sprinkler Systems
This type of sprinkler system is used in buildings where there is a chance of freezing during the winter months. The systems have pipes full of water during the summer and when the weather starts getting colder, they are drained down and filled with air under pressure for the winter. When there is a fire whilst the system is on air, the air pressure in the system drops on operation of a sprinkler head and water is then discharged from the system onto the fire.
Dry Pipe Sprinkler Systems
The pipework in the system is permanently filled with air under pressure and the system operates in the same way as the alternate system when on air. Dry pipe systems are used in buildings or parts of buildings where there is a permanent risk of freezing, such as chiller rooms and cold stores.
Pre-Action Sprinkler Systems
These types of systems are specifically designed for the protection of high value ‘business critical’ areas, such as computer rooms and server rooms to prevent discharge of the system due to accidental damage.
The systems are permanently charged with air which will drop and trigger a low air signal should a sprinkler head be accidentally broken. The system will only be charged with water once a signal has been received from two independent detection devices. These signals will cause an actuation valve to open and release water into the pipes. Activation of the system would then occur in the normal way of a sprinkler head being triggered by heat.