How Does A Fire Sprinkler Work?

How Does A Fire Sprinkler Work and How do Fire Sprinkler Systems Save Lives and Property

How Does a Fire Sprinkler Work?
How Do Fire Sprinkler Systems Save Lives and Property?

It is a proven fact that fire sprinkler systems are very important when it comes to fighting fires. They are actually so effective that death and property loss is 65% less in a building with fire sprinkler systems. But the question is how does a fire sprinkler work and how come they are so effective in firefighting?
Their effectiveness is one of the many reasons why we should have fire sprinklers in all commercial buildings. And not only. We should also have fire sprinkler systems in our homes. Imagine if all homes that caught on fire lately had fire sprinkler systems in place. People, property, and fire fighters would be safer.

And this brings us back to our questions: how does a fire sprinkler work? And how does the sprinkler system contain the fire? Does heat trigger a fire sprinkler? Or is smoke the trigger?

We are going to look at the picture of a fire sprinkler to understand what it's made of and what sets it off.

How Does A Fire Sprinkler Work

A fire sprinkler consists of:

  • Connecting Pipe Thread - connection to the water supply
  • Plug - upon activation, this plug frees the water
  • Glass Bulb filled with liquid - this bulb bursts at rated temperatures. The actual temperature depends on the sprinkler head type.
  • Sprinkler Deflector

How does a fire sprinkler work?

In order for a fire sprinkler to work as intended, it has to be part of a fire sprinkler system. To form a system, individual sprinklers are placed on a network of piping filled with water. Because the water is under pressure, we can say the fire sprinklers are always on standby.

Let's examine how fire sprinklers work step by step:

  1. Fire breaks out
  2. The air temperature above the fire raises
  3. When the temperature is high enough, the liquid-filled bulb bursts
  4. The sprinkler plug frees the water
  5. The sprinkler sprays water on the fire. Sometimes the fire is completely extinguished. Sometimes the sprinkler contains the fire, meaning it controls the heat and minimizes the amount of toxic smoke that develops.

Since the air temperature raises fast in a fire, the fire sprinkler is also activated fast. This is why fire sprinkler systems are so effective in controlling a fire. Or assisting fire fighters in combating fires.

Key Takeaways from our review of how a fire sprinkler works

  • Smoke does not activate fire sprinklers
  • Heat from a fire activates a fire sprinkler
  • Only the fire sprinkler closest to the fire activates and sprays water
  • The amount of water discharged by a fire sprinkler is minimal (10-15 gallons per minute). If this was not the case, we'd be trading fire damage with water damage. But that is not how a fire sprinkler works.
  • Fire sprinklers almost always extinguish the fire. If the fire is not extinguished, it is contained until the fire department arrives
  • Unlike what you've seen in movies, fire sprinklers don't all activate at once
  • Fire sprinklers are a great addition in residential buildings as well, not only commercial ones

In Conclusion

Fire sprinklers are effective in extinguishing or containing fire because they react fast after a fire breaks out. They reduce the risk of injury and death because they reduce the flames, heat and smoke of a fire. Fire sprinkler systems give people the time needed to evacuate the building. They reduce property damage because they contain or extinguish the fire before the fire department arrives. Fire sprinklers are one of the best tools we have to fight fires.

5-year Fire Sprinkler System Inspection

5-Year Fire Sprinkler System Inspection, Testing, and Maintenance

Under NFPA 25 guidelines, there are several frequencies for a fire sprinkler system inspection, testing and maintenance. One of the most important and overlooked inspections is the 5-year fire sprinkler system inspection. This article will touch on key points about the 5-year inspection and why it’s so important. So let’s dive right into the 5-year fire sprinkler system inspection, test and maintenance.

We must first note who is responsible for the 5-year fire sprinkler system inspection. The building owner or the owner's representative have the responsibility for the inspection. They are also responsible for accessibility to the building and fire sprinkler components.

There are several different types of fire sprinkler system. Each type of system has different requirements for inspection, testing, and maintenance. What we need to determine first is what type of system is in the building. A qualified fire sprinkler contractor can do that for you. Once you know what type of sprinkler system you have, the inspection requirements can be laid out.

We must also note that the building owner must keep all records of fire sprinkler inspection, testing, and maintenance. These records will inform the qualified fire sprinkler contractor of the type of inspection and services needed.

Fire Sprinkler System Components. How They Relate to the 5-Year Fire Sprinkler System Inspection

There are 4 types of fire sprinkler systems: wet, dry, pre-action and deluge systems. These system have several similar components that need a 5-year fire sprinkler system inspection, testing and maintenance.


You should replace gauges every 5 years or test them in comparison to a calibrated gauge. In general, it is more cost effective to change the gauges every five years.

Fire Sprinklers

Another common component are the sprinklers. In a fire sprinkler system inspection, we test the sprinklers exposed to harsh conditions and replace them where needed. A qualified contractor can determine these environments.

Sprinklers that need testing and sometimes replacing:

  • Solder-type sprinklers with a temperature rating of 325 exposed to ambient temperatures. Test a sample sprinkler to determine if they still function as they should.
  • Sprinklers in service for more than 75 years. Test a sample sprinkler to determine whether they need replacing or not. In general it is more cost effective to replace such old fire sprinklers.

Private Service Water Main

A private service water main provides water for your fire sprinkler system. It can be underground or exposed piping. Every 5 years, you should perform a flow test on your water main. This test will determine the condition of the piping. A licensed contractor will perform a flow test on a hydrant. They will check the a main drain and the hose and fire department connection condition. They will compare results to previous testing and the original one. This way they'll investigate deterioration of water demand. This testing will determine if the private service water main provides the correct amount of water for your system.

Water Storage Tank

If a storage tank provides water for your system, the 5 year requirements are as follows.

  • Unless you have a non-corrosive protection tank in which case a 3 year internal inspection is required by the standard.
  • Every 5 years you should inspect the interior of the water storage tank.
  • It is not necessary to drain the entire tank
  • NFPA 25 allows certified commercial divers or remote video as an alternative means. D

During this 5 year inspection, the inspector will look for signs of pitting and corrosion. He will also check the tank coating, pin holes, cracks and wall thickness. The tanks that are ring type foundation sand in the middle are inspected for voids beneath the floor.

The inspector will check the heating system piping and components. He will also inspect the anti-vortex plate for deterioration or blockage. This inspection identifies failure points or weakened areas of the tank. The level indicators are also tested every 5 years. This test ensures this component works as intended and your tank has the correct water levels. Failure of this can cause a tank to over flow or you may have an empty tank at some point.

Mainline Strainer

(if applicable)
If your system has one, the inspection team will remove and inspect it for damage and corroded parts. This can affect the flow of demanding water for your water protection system.

The neglect of these items can be damaging and costly. But most of all, it causes your fire protection system to be completely compromised.


All systems equipped with alarm valves need a 5-year inspection. The inspector will verify the operation of the clapper and the valve seat. He will also look for corrosion or obstruction materials. Any foreign materials can clog up the system, not allowing to function as it should. The inspector will also make sure there is no re-pressurizing of areas where it is not needed. Or the system doesn't release pressure where it is needed.

The inspector will also test pressure reducing, pressure relief, and fire hose valves. This test ensures the system is not over pressurized or under pressurized. This testing information shows if the system is receiving the designed pressure.

Obstruction Investigation

One of the most important parts of a 5 year inspection is the obstruction investigation. This investigation consist of the piping and branch line. The inspector will open a flushing connection at the end of one main. He will also remove a sprinkler towards the end of one branch line. The reason for this inspection is to detect the presence of foreign materials.

MIC (Microbiologically Influenced Corrosion)

The presence of MIC in piping is a serious problem. MIC creates leaks, pin-hole leaks and spreads throughout the entire system. Other common foreign materials are zebra mussels, rust, work gloves and scales. Zebra mussels are present in systems with a natural water supply such as lakes and rivers.

To Conclude
The 5-year fire sprinkler s ystem inspection is important for the performance of your fire protection system. Sprinklermatic inspectors know the importance of the NFPA 25 standard. We also know how neglected components of a system can impair its performance. If a 5-year inspection is not performed correctly, it can cost loss of lives and property damage.
Future Articles:
In future articles we will look at the 5 year inspection of standpipe and fire hose.

Fire Protection Supply Chain Management

Supply Chain Management in Fire Protection - 7 Steps to Success

Supply Chain Management in Fire Protection - 7 Steps to Success


SPRINKLERMATIC has created a unique Supply Chain Management system that utilizes a Single Source for all our material. Our Supplier manufactures the CPVC pipe, fittings and glue. They distribute through their own supply houses. They fabricate and deliver both steel and CPVC.
SPRINKLERMATIC emphasizes training trough our annual Best Practice training day. All of our team members receive proprietary CPVC training and certification. We are the only Fire Sprinkler contractor to have CPVC glue ASME Bonder qualification.

Supply Chain Managment-REV6-02

Supply Chain Management involves the handling and oversight of material, from the time it is manufactured to time of install. Here at Sprinklermatic we take pride in the SCM process we have implemented. Sprinklermatic works directly with our Trade Partners, a global leader in fire protection and life safety systems, to bring the highest quality product to every project in the most efficient manner possible.


Through the observations and investigation of field installations, and with laboratory analysis, it has been shown that the exposure of certain chemicals and chemical combinations can affect the overall performance of CPVC products. This has become a noteworthy issue in regards to the reliability of fire sprinkler systems over the past several years. Laboratories and manufacturers have addressed this issue by releasing literature identifying products that are compatible with CPVC products, as well as literature listing specific products that are not compatible with these CPVC products. For a product to be considered “compatible” with CPVC it must be identified as suitable by CPVC manufacturers, or suppliers, for use with all CPVC products and combination (or hybrid) systems and/or it must be deemed suitable for use in such systems by a third party when tested to a generally accepted protocol. There are a number of these protocols available for the purpose of evaluating suitability.


1-MIC - Microbiologically Influenced Corrosion (Whatch this video to find out what MIC is)

The first area of concern is the presence of internal antimicrobial coatings for steel pipe, when used in combination with CPVC products (i.e. hybrid systems). Our trade partners Fabrication shop has been audited and is responsible to provide a Blazemaster CPVC compatible fabrication facility; using only products that are Blazemaster CPVC compatible.

2-The second area involves ANCILLARY PRODUCTS used with CPVC such as cutting oils, thread sealants, and antifreeze.
By eliminating multiple vendors and working directly with a single source who Manufacturers – Distributes – Fabricates Steel and CPVC – Delivers – Trains and Certifies the installers; we feel like we have gone through great lengths to prevent CPVC contamination. As a sole source provider; we have eliminated the finger pointing as to the responsible party for contamination due to ancillary products. Our trade partner has audited the manufacturing, fabrication and distribution facilities and has documented that no incompatible products are present in either facilities.

3-The third area is the non-ancillary chemicals and products used by other trades and building owners. Non-ancillary products are those that are not directly associated with sprinkler system installations and include products such as lubricants, paints, and pesticides. Sprinklermatic and it’s trade partner offer a One Hour Lunch & Learn for all key subcontractors on the job, prior to construction, and discuss the general Do’s and Don’ts of CPVC use on the job. Our trade partner will provide the appropriate ongoing observations and ongoing training, as needed, for the duration of the project.

Inspecting. Testing. Maintenance.

Inspecting. Testing. Maintenance.

What's wrong with the picture above?

Don’t lose control of the situation when your fire protection system is impaired. Sprinklermatic has a 24 Hour Emergency Response TEAM that can get your system back in Service.

One Call Does It All (954.327.3686)

INSPECTING – TESTING – MAINTENANCE for fire protection systems and equipment

1. Fire Sprinklers

2. Fire Alarms:

3. Fire Extinguishers

4. Emergency Exit Lights

5. Fire Hydrants: Compliance with FS 633.082

6. Live Hands On Training: On site or at our Training facility- Sprinklermatic University

7. Fire Pumps:

8. Standpipes – Fire Hose valves – Fire Hoses

9. Engineered Life Safety System: Compliance with High Rise Retrofit Requirements FS 718.112(I)

10. Microbiologically Influenced Corrosion (MIC)

11. Temporary Fire Pump Trailer