Aug 27, ’14 | Written by Adam Levine

Fire Sprinkler Parts & Inspection Terms

Picture this, you’ve just had your building’s fire sprinkler system inspected and later receive a report from your fire sprinkler company. As you read through the report, you notice there are several deficiencies listed and repairs needed to be fixed in order to keep your building up to code. But there’s a problem – you have absolutely no idea what any of these parts are or the essential roles they play in a functioning fire sprinkler system..

You’re in luck! Here, we’re going to explain the most common components of your sprinkler system and why they are important for you to know. Whether you’re a property manager or building owner trying to understand the work that needs to be done on your system, or just starting out in the fire sprinkler industry, we’ve got you covered.

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Fire System Vocabulary List

#1 Alarm Check Valve: A common type of fire sprinkler system alarm apparatus. When water flows in an alarm valve, the valve’s clapper will lift off of the seat, and water will flow through the alarm line. The alarm line will be connected to either a mechanical water motor gong, or an electric bell. When water flows through the line, either the gong or electric bell will ring, which will alert passer-byers to contact emergency services..

#2 Butterfly Valve: A common type of control valve used to regulate flow in a system. It is an indicating type, since you can see whether it’s open or closed by looking at the orientation of the “flag” on the valve.

#3 Check Valve: A valve that allows in only one direction to prevent backflow. For example, this device is used to prevent water in the fire sprinkler system from returning to the public water supply.

#4 Concealed Sprinkler Head: A sprinkler head that is installed slightly above a ceiling, with a cover plate that conceals the actual sprinkler head. This plate will drop down in the event of a fire, which will allow the sprinkler head to activate.

#5 Control Valve: Controls the flow of water to the sprinkler system. In other words, closing this valve will prevent water from flowing out of the fire sprinklers. The control valve should always be in the open position, although there are some unique exceptions (i.e. the control valve for a fire pump test header). Otherwise, the valves may be closed to do system repairs, testing, or maintenance.

Standpipe and Sprinkler Control Valve

#6 Dry Pipe Sprinkler System: A sprinkler system employing automatic sprinklers that are attached to a piping system containing air or nitrogen under pressure, the release of which (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve, and the water then flows into the piping system and out the opened sprinklers.


#7 Fire Department Caps: Caps that are installed on the threaded inlets of the fire department connection. These caps prevent people from sticking objects into the fire department connection.


#8 Fire Department Connection: Connection used by the fire department to pump water into the fire sprinkler or standpipe system to supplement the building’s water supply. Otherwise known as an FDC, or siamese connection (since there are two inlets on the connection), this connection is located on the exterior of the building.

#9 Fire Pump: A pump that is used to provide additional pressure to the water supply in order to meet the hydraulic design requirements of the system. They are commonly used on standpipe and sprinkler systems in high rise buildings, as well as for warehouses that contain high hazard storage.

Fire Pump Installation

#10 Fire Sprinkler Head: In general, a device that, in the event of a fire, will open automatically, and discharge water. The sprinkler head opens automatically when the activating link (either a glass bulk or pieces of soldered metal) reaches a certain temperature. When the link disengages, the orifice cap is released, and water will flow out of the sprinkler head. There are many different types of sprinkler heads, including quick response, standard response, extended coverage, extended coverage fast response, and open sprinklers. They can be installed in either the upright, pendent, or sidewall orientations.

Fire Sprinkler Head

#11 Gauge: Measures the water or air pressure in the sprinkler or standpipe system. According to NFPA25, the gauge must be replaced every five years.

Capitol Fire Gauge

#12 Hangers:Component that holds the sprinkler pipe in the air. The hanger itself needs to be attached to the building structure (i.e. joists, beams, concrete slab) with parts known as inserts, flanges, and clamps

#13 Inspectors Test: A device used to test the alarm that must activate when water flows through the sprinkler system.

#14 Jockey Pump:Small pump, used in conjunction with a fire pump, that is connected to the sprinkler system. It is used to make up small pressure fluctuations in the system.

#15 Main Drain:Primary drain connection located on the riser. This drain allows you to empty the water out of the system. It is also used to determine the static and residual pressures of the building’s water supply.

#16 OS&Y Gate Valve: A common type of control valve used to regulate flow in a system. When the stem rises, the gate in the valve lifts, and water can flow through the valve.

#17 Pendant Fire Sprinkler: A sprinkler designed to be installed so that the water stream is directed downward against the deflector

#18 Post Indicator Valve (PIV): A valve that controls the water that is flowing into the building in the event of a fire. It also provides a visual indication if a gate valve is open or closed.

#19 Retard Chamber:A device used to reduce the possibility of false alarms due to changes in the water supply pressure (i.e. water surges).

#20 Spare Head Box: A small box that contains a set of spare sprinkler heads and a sprinkler head wrench. In the event of a fire, the heads in the spare box can be used to quickly replace an activated sprinkler head, which would allow the sprinkler system to be returned back into service.

#21 Sprinkler Head Wrench: A special wrench designed to install and remove sprinkler heads.

#22 Tamper Switch: A switch that detects when a sprinkler valve has been partially or fully closed. This is important, since we always need to know when a sprinkler system has been impaired and will therefore not operate properly in the event of a fire.

#23 Upright Fire Sprinkler: A sprinkler designed to be installed so that the water spray is directed upwards against the deflector.

#24 Water Motor Gong:A mechanical water-driven alarm device typically installed on the outside wall of the sprinkler riser room. In the event of a fire, the bell will ring, which will alert passer-byers to contact emergency services.

#25 Wet Pipe Sprinkler System:A sprinkler system employing automatic sprinklers attached to a piping system containing water and connected to a water supply so that water discharges immediately from sprinklers opened by heat from a fire.

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