This is about the fire sprinkler riser
The shape of fire sprinkler riser components depends on the preferences of designers and changes in system requirements. However, the use of prefabricated manifolds can make many of them easier to assemble.
For this series, Part 1 discusses how to use the key components of the fire riser to simplify maintenance and check the adequacy of the fire sprinkler system. This article explains how different components can be combined to create a specific fire sprinkler riser component for a wet pipe system. An important question for contractors is when should they use prefabricated manifolds to build risers instead of completely assembling them on site- We will answer the questions along the way.
The riser may or may not be equipped with a check valve
This paper quotes the National Fire Protection Association (NFPA) standards. These include NFPA 13 for commercial sprinkler systems, NFPA 13R for multi-family residential systems, and NFPA 13D for domestic fire sprinkler systems. Many jurisdictions have adopted these documents and their provisions into law.
The check valve and alarm check valve at the fire riser can meet the requirements of NFPA 13. The fire sprinkler riser is usually equipped with a check valve, but it does not always exist. The riser and connected pipe of the sprinkler system can prevent its contents from flowing out of the sprinkler pipe and flowing into the municipal water supply, water tank or other water sources. In wet piping systems, they can also maintain stable pressure downstream.
The alarm gate valve or alarm check valve is almost always located at the fire sprinkler riser with a check valve. When the fire sprinkler in the wet piping system is started, the port of the alarm check valve will be filled with water.
The alarm bell or fire alarm control panel can be powered by water or activated by the pressure switch connected to it. According to Section 16.9.5.5 of NFPA 13, 2019, if fire department connection and alarm valve are equipped at the same time, no additional check valve is required for a single wet pipe system.
When drinking water and non-potable water sources may be mixed, the commercial fire riser may not have a check valve – NFPA 13R or 13D systems do not need a check valve.
Fire check valve
The check valve prevents backflow. Backflow preventers can use multiple check valves, vents and other mechanisms to more effectively prevent cross contamination. According to NFPA 13, multiple risers connected as a single manifold can be equipped with backflow preventers (16.9.5.2) as check valves. NFPA 13 recommends but does not require the installation of these devices in two cases in Section A.5.1.8.
1. The system directly connected to the public water supply system meets the conditions, including at least one water tank or covered reservoir with safe drinking water and regular maintenance.
2. Systems containing antifreeze or other solutions, as well as systems supplied by public water pipes and non-potable water sources (such as ponds or polluted rivers), must be treated.
Fire sprinkler system
If the fire sprinkler system uses both drinking and non-potable water sources, or if the water department is concerned about backflow, backflow preventers may be installed. In these cases, the check valve may not be located at the system riser.
The residential fire sprinkler system conforming to NFPA 13R and NFPA 13D does not need a check valve or a backflow preventer. Local laws may require the use of backflow preventers. If they are included in the fire service and listed in the list, they can be used as control valves and check valves of the system, so that there is no need to install any additional equipment at the riser.
If necessary and convenient, the fire sprinkler riser assembly can include pressure reducing valve and pressure relief valve.
Summary of fire-fighting equipment
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