Fire Prevention & Protection

Fighting Fire in Sprinklered Buildings


By Michael Spaziani

During the past 30 years, automatic sprinkler systems have come a long way. With better testing and research and new and improved technologies, protection designs are more versatile at controlling fires. Unfortunately, during that same time frame, many sprinklered buildings have still burned, costing millions in unnecessary property damage and causing business interruption.

Understanding the basic concepts of fighting fire in sprinklered buildings can be challenging. Firefighters need to understand that the building’s construction and occupancy, along with its fire protection systems, should be part of preincident planning, not only part of size-up activities during an emergency.


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A properly designed and installed fire protection system can protect the building and its contents. The fire service can best understand how to interact with the sprinkler system in a fire event by being involved in the implementation of the system at the design stage and throughout the life of the building.

In the best-case scenario, firefighting operations that involve a sprinklered building should consist of completing final extinguishment of the fire, managing the sprinkler system, and performing salvage and overhaul operations. Letting the sprinkler system work as designed may greatly reduce property damage.

Automatic Sprinkler System Design and Function

Sprinkler systems are designed based on the construction and occupancy of a building. It is critical that the local fire department work with the building owner during the initial stages to properly design the sprinkler system to protect the facility. This is also a great opportunity for the fire service to understand the building and occupancy the system is intended to protect in a fire.

Sprinklers make a difference in both fire suppression success and firefighter safety by doing the following:

  • Providing an available fire suppression system 24/7/365.
  • Activating promptly on  detecting a rise in temperature.
  • Operating directly over the fire, putting water only where it is needed.
  • Continually operating, even during a large fire and in thick smoke.
  • Reducing the chance of fire spread by wetting combustible surfaces near the active fire.
  • Controlling and containing fire by cooling hot gases and burning surfaces and reducing flame height.
  • Controlling radiant heat.
  • Using less water than a fire hose; sprinklers deliver as little as 20 gallons of water per minute, whereas a hose delivers hundreds of gallons per minute.
  • Sending an automatic alarm to a central station, security guard, or fire department.

An automatic sprinkler system is a network of pipes, valves, and sprinklers that deliver water from one or more sources to one or more sprinklers that have been activated in response to an increase in ambient temperature beyond a preset threshold. When the system is activated, water flows from the water sources into the pipes and valves and through the sprinklers onto the fire. In most systems, only the sprinklers directly over the fire operate; therefore, water is not sprayed throughout the building. It is directed only where it is needed. This application minimizes water usage and water damage to the contents of the building. FM Global has found that the fire was controlled by nine or fewer sprinklers in 75 percent of the fires it has investigated.

The sprinklers are designed to activate at a particular temperature and deliver a specific volume of water per minute. The temperature rating and volume of water are based on the burning characteristics of the building’s contents and construction. Therefore, a sprinkler designed to control a fire in which the primary fuel is wood releases a lower volume of water than a sprinkler designed to control a fire in which the primary fuel is plastic, because plastics release much more energy than wood when they burn.

When a local fire department responds to a sprinkler system activation, the most important job is to ensure that sufficient water is flowing to all parts of the system, so the sprinklers can do their job. That necessitates that fire personnel complete the following tasks:

·       Check the alarm panel to determine which area(s) have been activated.

·       Check that water is flowing from the source to the system.

·       Ensure the fire pump (if applicable) is operating.

·       Ensure all valves are wide open so the water flow is not restricted.

·       Supplement the water flow through the fire department connection (FDC), tapping into a water source that is not used to supply the sprinkler system.

A preincident plan will ensure these steps are executed efficiently and prevent uncertainty during an active fire. If preincident planning has been done correctly, fire personnel will know where the alarm panel is and how to read it, the location of the water source for the sprinkler system, what FDC to tie into, and what water supply to use for that FDC. In addition, fire personnel will know where the fire pump and sprinkler valves are to confirm that they are wide open and functioning properly.

Why Sprinklered Buildings Burn

Even with a perfectly designed system, sprinklered buildings can still burn for the following reasons:

• The occupancy of a building changes, but the sprinkler system does not change with it.

• The sprinkler system is impaired before a fire.

• The sprinkler system is impaired during a fire.

Automatic sprinklers are designed to control a fire within a specific occupancy. If the occupancy increases or is modified (e.g., the occupancy changing from an office to a storage area), the existing sprinkler system may no longer be effective. Lack of proper testing and inspection of sprinkler control valves can increase the chance of an impairment during a fire. Lastly, situations can occur in which the fire is believed to be controlled and so, the sprinkler control valves are turned off, when in reality the fire is still burning.

Preventing Design Deficiency or System Impairment

The following are five key elements that can dramatically reduce the chances of a design deficiency or system impairment occurring:

1.     A cooperative partnership between the facility owner and/or occupant and the fire department is the cornerstone of effective fire protection. A positive working relationship will make the preincident plan better, the response stronger, and will minimize misunderstandings and errors. Further, it will ensure that if something within the facility changes, the fire department knows about it and reacts accordingly.

2.      Good communication between the fire department and facility personnel means that you are both on the same side regarding protecting the property. All parties have an interest in preventing property loss. The business doesn’t want to lose money, the employees don’t want to lose their jobs, and the fire department doesn’t want its personnel exposed to unnecessary danger. Strong communication means that problems are identified and addressed, changes to the building are noted and incorporated into the preincident plan, and everyone is on the same page.

3.     Regular inspections and routine maintenance are vital to discovering system problems before a fire, so they can be remedied. Something as simple as a rock in a pipe can spell disaster for the entire building if it goes undetected.

4.      Periodically updated preincident plans allow the fire department to stay abreast of changes in ownership, building design, and occupancy. The department can then update the preincident plan accordingly and identify any issues that need to be addressed. This cuts down on the potential for ugly surprises during a fire response.

5.      Training can minimize the chance of incorrect human interaction with the sprinkler system. The wrong action could render a properly functioning system useless against a fire. Fire department personnel and facilities management staff should be properly trained to interact with the alarm panel and the automatic sprinkler system to correctly identify the cause of an activation and respond appropriately.

Sprinkler systems are most effective if they are in working order and are permitted to operate as designed. If the system is not in working order, the valves are not open, sufficient water is not available to meet the demand from the sprinklers, or the system is not properly matched to the occupancy of the structure, the system may not work as intended and may not effectively control the fire.

Preincident Planning

In general, fire departments do not respond to a high number of commercial or industrial fires—on average, only 0.5 percent of responses are for these types of fires. Thus, fire departments may be less comfortable entering an unfamiliar commercial structure. Preincident planning can alleviate this anxiety.

The property survey necessary to complete a preincident plan gives department personnel the opportunity to do the following:

·     Meet the people at the facility with whom the department will interact during an emergency.

·     Observe the structure and occupancy to understand its fire protection systems, building usage, building contents, and normal daily activities.

·     Observe any potential hazards and have the opportunity to work with the facility to rectify them and improve safety.

Conducting these surveys and using the information gained to create a preincident plan for that property are cornerstones of community risk reduction because of the opportunity to recognize and fix potential problems.

For all the advantages of preincident plans, it is important to bear in mind that something in the facility may have changed since the property was last surveyed. The plan is merely a place to start; responders may need to modify their tactics based on the conditions found at the time of an incident. Strive to keep the lines of communication open with facility personnel so that if there is a change to the structure or occupancy, they will reach out to the fire department with that information and the preincident plan can be updated accordingly.

Engine Company Operations in Sprinklered Buildings

It is prudent for fire personnel to respond to a fire or an automatic sprinkler alarm activation with the proper mindset. Do not assume that you are responding to a false alarm. Yes, false alarms happen, but you cannot not know in advance which automatic sprinkler alarm activations are fires and which are not. If you assume a false alarm and let your guard down, a tragedy could happen.

Work the same protocol every time. Perform the same actions you do at every response, even if you were just there. Each alarm needs to be cleared properly in accordance with the department’s standard operating procedures.

Fire personnel should bring the preincident plan to the location and consult it to formulate a plan of action. If the preincident plans are well-executed and regularly updated, they will be of significant assistance. The preincident plan should include a building plan that will help determine they key places to deploy firefighters (at the alarm panel, at the fire pump, at the FDC, and at the sprinkler control valve). However, remember that the property may have changed since the last preincident plan update. Always confirm details like construction and occupancy while on scene.

Be ready to answer key initial questions on arrival:

·     Which system(s) have activated?

·     Where is the activation within the building?

·     What is causing the flow of water to the automatic sprinkler system? (Fire? Mechanical damage? Malfunction?)

·     If fire is showing, how much is there? Is it what you would expect in a building with this protection system?

With mental preparations complete, fire personnel should be ready to assess the activation. As stated before, the main tasks are to locate the fire, deploy the team, locate the water sources, and control the sprinklers.

All activations need to be verified to determine what caused the activation and, if water is flowing, what caused that water flow. Activations can be caused by situations other than an active fire. For example, a water flow only activation could be caused by a water surge from the utility or by a forklift hitting and damaging a sprinkler.

Once you have confirmed the activation and located the fire, it is time to implement the preincident plan to deploy your team. During every incident, a team member should be assigned to monitor the fire pump operation and stand by the sprinkler control valve.

Remember, if the sprinkler system is activated and is controlling the fire, your best option may be to let the sprinkler system do its work. While the sprinkler system is working, fire departments should monitor the situation and intervene only if necessary. Often, sprinkler valves are closed too soon in the belief that this action will improve visibility for firefighters or reduce water damage. However, closing the valves too soon can render a properly functioning system useless against a fire.


Michael Spaziani is assistant vice president, a senior staff engineering specialist, and the manager of Fire Service Programs for FM Global. He has worked in the fire service for more than 25 years as a firefighter, an officer, a fire marshal, and an instructor. He manages the FM Global Fire Prevention Grant Program as well as training and relationships for the fire service.