How do fire sprinkler systems work?

Fire sprinkler systems are a necessary component of any commercial or residential establishment, protecting not only the lives of you and those around you but also your valuable assets. It’s likely that if you look up in any modern building you will see those automatic sprinklers poking out of the ceiling.

While most are aware of what they are, there are many misconceptions about how sprinkler systems actually work and the various parts that make these systems so effective in firefighting. Here we’ll debunk those myths to get a better understanding of how fire sprinkler systems work to protect you and your company.


Automatic Sprinklers Are Heat Activated, Not Smoke Activated

Contrary to popular belief and most movie scripts, fire sprinklers are triggered by high heat- not smoke. As a fire ignites, the air above it heats quickly and spreads along the ceiling. An automatic sprinkler is typically activated when the temperature reaches within the range of 135-165 degrees Fahrenheit, saturating the fire below it.

Sprinkler heads have a small glass plug containing a glycerin-based, colored liquid that expands with temperature. The color of the liquid correlates to the temperature required to activate the sprinkler, ranging from 135-440 degrees Fahrenheit and varying based on the building setting. When the liquid heats, the glass bursts and opens the pipe releasing pressurized water.

Fire Sprinkler Heads Activate Individually

fire sprinkler head

 Many people think once a fire is detected, all sprinkler heads simultaneously go off. This is usually not the case- only the sprinkler head experiencing high temperatures will activate. By activating individually, sprinkler heads actually minimize water damage while using an average of six times less water than a fire hose. In most cases, only one or two sprinklers are needed to either control the fire until the fire department arrives or stop the fire altogether.

There are numerous pipe systems that vary in the way that water is stored and delivered to sprinkler heads once activated. In a wet pipe system, pressurized water is stored in the pipes and released immediately through the sprinkler. A dry pipe system keeps pressurized air in the pipes instead of water, releasing the air when a sprinkler is activated and allowing the water to flow through. A pre-action system is similar to a dry pipe system in that it stores air instead of water until a sprinkler is activated, except there’s an additional system that must be triggered in order to release any water. A deluge system is one that is used in settings where the risk of a fire spreading is high, in which case all sprinklers release water at the same time once a fire alarm goes off.

Sprinklers Are Turned Off Manually Post Fire

fire riser room sign

It is yet another myth that fire sprinklers automatically shut off after a fire has been extinguished. Once a fire is under control, the system has to be manually shut off in order to stop the water flow and replace any sprinklers that were activated.

Sprinkler system risers are the pipes that connect the fire sprinkler system to the building’s water supply. The main riser will have water control valves that allow you to turn the water flow on and off. While it is likely the fire department will do this step for you, knowing how to manually shut off your fire sprinkler system’s water supply may come in handy in the event of a malfunctioning sprinkler.

When is a fire sprinkler system required?

As with many other preventative systems, you never realize how necessary they are until it is too late. Fires can not only jeopardize the lives of your employees and customers but can also do irreparable damage to a company.

Luckily, the NFPA issues national standards for meeting fire safety requirements so you and your business are never left at risk. Along with any local or state regulations, the following are some guidelines to help better understand fire sprinkler system requirements:

  • Automatic fire sprinkler systems are required throughout buildings that are 55 feet high or more, in new buildings with a fire area exceeding 5,000 square feet, and in old buildings that have been remodeled.
  • Water supply control valves must be easily accessible, protected if in exposed areas, and marked to indicate which sprinkler locations they control.
  • Fire pumps should be installed to get the necessary amount of water pressure to the sprinklers, and fire pump room entrances should be clearly marked.

How much does a fire sprinkler system cost?

While some business owners may hesitate to install a sprinkler system if it isn’t required by law, the cost of repairing any property destroyed in the event of a fire is far greater than the price of any fire sprinkler system installation. This alone should be reason enough as to why a fire suppression system is worthwhile.

There are many different factors that affect the cost of a fire sprinkler system, ranging from the area being covered to the features added. So, how can you determine how much a fire sprinkler system may cost you?

Building Type

While the average fire sprinkler installation cost is around $1.35 per square foot, this price can vary depending on the area being covered and parts being used. The easiest and least expensive way of installing a system is when a building is still under construction, so the team can have direct access to everything they need. Fire sprinkler system costs for new construction are usually between $1 to $2 per square foot, while fully finished buildings and high rises may increase the price to $2 to $7. Historic buildings can range up to $10 per square foot due to their stricter policies.

Pipe Design

Another factor that determines the price of a sprinkler system is the design of the piping system. Plastic pipes are the most budget-friendly option and are also the most versatile, while metal piping is more expensive but can be beneficial to unfinished areas such as attics and basements.

There are two main types of piping systems you can choose from: standalone or multipurpose. A standalone system is designed with pipes that are solely dedicated to a sprinkler, and while it is the most common it is also more costly. A multipurpose system allows for the sprinklers to be connected to the main water supply pipes and is a more affordable option.

Sprinkler System Features

The more features you wish to install can also affect the price of your fire sprinkler system. A water storage tank and booster pump can be a critical component if you are using a well as your source of water, but can also spike up your installation costs. Backflow preventers are another feature to consider, which prevents pressurized sprinkler water from contaminating the main water supply that your system is linked with. Features such as these can drive up the installation costs by quite a bit.