Fire riser is a component of the fire suppression system. It is a pipe connected to a pressurized water source which supplies water to the sprinkler system in the building.
It is where the gauges, valves, and alarm devices are located. The fire risers typically have a waterflow switch that will activate the fire alarm system when a sprinkler head fuses.
Component of a Fire Riser
Riser clamps:
A fire riser bleeder valve is a component in fire sprinkler systems designed to release excess water pressure. It helps maintain optimal pressure levels, preventing damage to the system.
Elbows
A fire riser elbow is a pipe fitting with a bent shape, typically at a 90-degree angle, used in fire sprinkler systems. It facilitates changes in direction, allowing pipes to navigate obstacles.
Fire riser sprinkler heads are devices attached to a fire sprinkler system. Activated by heat, they release water to suppress or extinguish fires. Different types are designed for specific applications, ensuring effective fire protection.
Auxiliary Systems
Fire riser auxiliary systems are additional components integrated into fire protection systems. These may include pumps, alarms, and backup power sources, enhancing the overall functionality and reliability of the system in emergencies.
READ: 9 Fire Prevention And Fire Fighting Devices And How To Buy Them
Types of Fire Riser
We have majorly two (2) types of fire riser:
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Dry Fire Riser:
Dry risers do not contain water when they are not being used, but are charged with water by fire service pumping appliances when necessary.
The dry fire riser system typically includes pipes that are pressurized with air or nitrogen instead of water. The pipes are connected to a water supply, but a valve, known as a dry pipe valve, keeps the water from entering the pipes.
In the event of a fire, when a fire sprinkler head is activated by heat, the air pressure in the pipes is released., the drop in air pressure triggers the dry pipe valve to open. Once the valve opens, water flows into the pipes and reaches the open sprinkler head and the water then discharges through the activated sprinkler head, suppressing or extinguishing the fire.
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Wet Fire Riser:
The wet risers are permanently charged with water.
In a wet fire riser system, water is always present in the pipes, ready to be discharged in case of a fire emergency. The system is connected to a pressurized water supply, often from the municipal water mains or a dedicated water tank.
Sprinkler heads are strategically placed throughout the building. Each sprinkler head is equipped with a heat-sensitive element.
When a fire occurs, the heat generated raises the temperature in the vicinity of a sprinkler head. The heat-sensitive element in the sprinkler head is designed to respond to a specific temperature threshold. Only the sprinkler heads directly affected by the fire’s heat reach the activation temperature and release.
Once activated, the sprinkler head opens, allowing pressurized water from the pipes to discharge onto the fire. The water helps suppress or extinguish the fire, limiting its spread and protecting life and property.
The entire process is automatic and does not require human intervention. The wet fire riser system responds rapidly to the localized heat, ensuring a quick and targeted water discharge.
Fire Riser Requirements
Some codes to look out for:
Design Requirement
A. System designer qualifications shall comply with Chapter 212-80 WAC, Chapter 18.160 RCW, and Chapter 18.270 RCW as administered by the WSP (http://www.wsp.wa.gov/fire-sprinklers/).
B. All plans and calculations shall be stamped with a valid Washington State certificate seal identifying the appropriate level of competency.
C. Submittals will be sent out for engineering review at the applicant’s expense.
Special design requirements
For IFC Section 903 Automatic Sprinkler Systems, the definition of FIRE AREA shall be as follows: The aggregate floor area enclosed and bounded by exterior walls of a building (MMC 9.04.902). An area or occupancy separation wall or fire wall shall not constitute a separation between two areas within a structure for sprinkler requirement purposes.
IFC Section 903.2 is amended by adding these items:
A. Existing buildings altered such that the total fire area square footage exceeds the threshold square footage for each occupancy group listed in this section shall be provided with an automatic sprinkler system. Where there is a change-of occupancy classification in an existing building, the sprinkler requirements for the
new occupancy classification shall apply.
B. An automatic sprinkler system shall be provided throughout buildings where the combined area of all fire areas on all floors, including any mezzanines, exceeds the threshold square footage for each occupancy group listed in this section. See MMC 9.04.903 for reduced fire sprinkler thresholds that apply in the city.
READ: Passive Fire Protection
Water Supplies
Hydraulic calculations are required for alterations involving more than five sprinklers. Available flow information shall be obtained from the Marysville Water Utilities Division. Fire pumps shall be diesel driven, or electric motor with diesel driven standby power, with 24-hour fuel diesel supply.
Underground Piping
A. All underground sprinkler supply piping shall be included on civil drawings and shall be approved by the water supplier and the Marysville Fire District (MFD).
B. All NFPA 13 and 13R fire sprinkler systems serving commercial or multi-family structures shall be fed by a minimum of 6” ductile iron underground fire main supply line, unless hydraulic calculations by a sprinkler designer prove a different size is acceptable to the AHJ and as shown on approved plans.
C. All pipe joints shall be triple restrained.
Fire Department Connection (FDC)
A. FDCs shall be installed in a location as shown on approved civil plans.
B. FDC signage shall comply with city EDDS standard plan 2-050-001.
C. FDCs shall be located at least 40 feet from buildings and within 3-10 feet of a hydrant. Exception: When approved by the AHJ, wall mounted FDCs may be used on existing buildings with retrofit sprinkler systems. If a wall mounted FDC is allowed, it should be installed on the side of the building adjacent to the approved fire access and be located within 50 feet of a hydrant.
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