How Does a Fire Sprinkler System Work?

Posted by Lucas Kirn, P.E. on Jan 3, 2019 1:33:09 PM

A fire sprinkler system is an active type of fire protection system that discharges water in the event of a fire.

Contrary to popular belief, most fire sprinkler systems are only designed to control a fire to provide time for fire service personnel to respond to the event. Fire sprinkler systems that are designed to fully suppress a fire are known as early suppression fast response (ESFR) systems and are used primarily in special high hazard applications.

In this post we will take a closer look at how these fire sprinkler systems work — and why it's vital to keep them well-maintained and corrosion-free.

Sprinkler System Components

All fire sprinkler systems consist of a water supply, a network of supply piping, and fire sprinklers. Most fire sprinkler systems are supplied from a municipal water source, but water supplies can also be provided by water storage tanks or natural sources such as lakes or ponds. The piping network is typically constructed of metallic pipe, but it can also use plastic materials in lighter hazard applications such as single or multi-family homes. Fire sprinklers are installed throughout the piping network and are designed to discharge water from the sprinkler system when a specific temperature is reached.

Most fire sprinklers utilize liquid-filled glass bulbs. As the temperature surrounding the sprinkler rises, the liquid inside the glass bulb expands and eventually ruptures the bulb which releases water from the sprinkler orifice. An ordinary temperature rating for a fire sprinkler is 155°F.

For fire sprinkler systems to operate properly the water supply must be pressurized. If the water supply is not pressurized, then the proper amount of water will not be discharged when the fire sprinkler actuates. The pressure supplied by the municipal water supply is typically sufficient to operate the fire sprinkler system. When additional pressure is needed a booster pump is installed between the water supply and the fire sprinkler system piping.

Fire Sprinkler System Design

Despite the typical Hollywood portrayal, most fire sprinkler systems are designed so that sprinklers only operate individually. In other words, all sprinklers on the same system will not operate at the same time. This design allows the fire sprinkler system to discharge only the amount of water necessary to control (or suppress) a fire, and not an excessive amount that may cause significant water damage and unnecessarily stress the water supply.

While there are multiple variables that impact system activation response time, fire sprinklers can activate in as little as 1 minute, which is much faster than average fire department response times. Fire sprinkler systems are widely recognized as the single most effective method for fighting the spread of fires in their early stages before they can cause severe injury to people and damage to property. In buildings completely protected by fire sprinkler systems, over 96% of fires are controlled by fire sprinklers alone.

Maintaining a Corrosion-Free Sprinkler System

As is the case with all mechanical systems, fire sprinkler systems will degrade over time from continued corrosion activity related to system modification, maintenance, and testing. There are many variables that determine how quickly a system degrades, but ultimately system performance will be affected.

As a sprinkler system degrades it can lead to excessive build-up of debris inside the piping network that can partially or fully obstruct supply piping or completely block water flow from a fire sprinkler. This prevents the fire sprinkler system from providing the required water pressure and flow needed to control a fire should one occur.

Corrosion can also cause pipe failures and leaks that result in water damage and extensive repair costs. It requires a collaborative effort between building owners, property managers, fire officials, and fire sprinkler contractors to work together to ensure fire sprinkler systems are inspected and maintained properly and that corrective action is taken immediately when deficiencies are found.

With this information in mind, you can see how important it is to maintain a functional and corrosion-free fire sprinkler system. Contact our team of experts today to learn how to protect your own industrial sprinkler system.

Submit Your Corrosion Question

Lucas Kirn, P.E.

Written by Lucas Kirn, P.E.

Director of Engineering