Have you ever wondered if one of your fire sprinkler head goes off, do all of them go off as well? This is a common, and important, question building owners/business owners ask their fire protection companies. The short answer to this question is, it depends on the type of fire sprinkler system you have.

Types of fire sprinkler systems

There are four main types of fire sprinkler systems. The type of fire sprinkler system you have is determined by a few factors like hazard type and size and building type and size. It depends on the type of sprinkler system you have when addressing the question of sprinkler head activation.

The main system types are:

  • Wet pipe systems that contain water in the piping network.
  • Dry pipe systems that contain pressurized air/nitrogen in the piping network and hold water back with a valve.
  • Pre-action systems that are dry systems but hold water back with an electronically activated valve.
  • Deluge systems that are a type of dry system where water is held back by a valve with sprinkler heads always open.

All of these sprinkler types, with the exception of a deluge system, are closed head systems. This means that each sprinkler head is held closed by either a heat-sensitive glass bulb or a two-part metal link held together with fusible alloy. The glass bulb/link applies pressure to a pipe cap which prevents eater from flowing though the piping system. When the ambient temperature around a sprinkler head or nozzle reaches the activation temperature, water flows out of that sprinkler head.

This is the reason that, for most sprinkler systems, in the event of a fire emergency only one sprinkler will off, not all. Each sprinkler activates independently when the predetermined heat level is reached (typically 135-165 degrees Fahrenheit) so only sprinklers near the fire will operate. In the event of a larger fire, several sprinklers may operate but only those in the vicinity of the fire.

Deluge systems explained

A deluge fire sprinkler system is the only sprinkler system wherein all sprinkler heads will activate if one is activated. All sprinkler heads are open in this type of system, with a direct connection to a water supply. So if your building is equipped with a deluge system, you would in fact have all sprinklers go off if one does.

The reason for this design is to extinguish large scale fires like chemical or mechanical fires. These fires can rapidly spread and are challenging to extinguish, hence the deluge sprinkler design. These systems are typically only found in high hazard industrial and commercial applications like chemical processing facilities or aircraft hangars.

Sprinkler malfunctions

 The only instance where multiple sprinkler heads would operate if one does would be if there were problems with your sprinkler system. Some common reasons for sprinkler system malfunctions are:

  • Corrosion
  • Human error
  • Frozen pipes
  • Mechanical damage
  • Overheating

As a note, a sprinkler head cannot be activated by force (i.e., someone hitting it). The only way a sprinkler will operate is by heat.

To prevent any of these malfunctions from occurring, maintain regular inspections of your fire sprinkler system.

Fire sprinkler system inspections

Fire sprinkler systems should be inspected on an annual basis. NFPA 25 dictates varying frequency by state and system type. Inspections should only be conducted by a licensed contractor. If you have a sprinkler system that you suspect may be malfunctioning, contact a local, licensed fire protection company immediately.

The trained technicians at Fire Systems, Inc. are fully certified and licensed to install, inspect, modify, and repair all types of fire sprinkler system. All technicians are Fire Systems’ employees, with no sub-contracting, so we can guarantee the quality of service we are able to provide.

Fire Systems also offers an advanced software system that keeps track of when inspections are due, so you never have to worry about being late on required inspections. We can also provide training in the proper use and maintenance of your system.

Call us today at 770-333-7979 or visit our website for more information.