What the Fire Protection Engineer Didn’t Tell You


Many firefighters’ experience with fire sprinklers is limited to the residential setting with fires in apartments. We respond to a report of a fire in the kitchen only to arrive and find it has been extinguished by the small white sprinkler in the ceiling (photo 1). However, this may not be the experience in every building protected by a fire protection system (sprinklers). When we walk into a commercial occupancy during a preplan and discover that it is protected by sprinklers, the experience of that extinguished kitchen fire comes to our mind. We say, “It has sprinklers,” and our tactical minds shut off. “It won’t burn.” Right?

(1) Typical residential light-hazard fire sprinkler head. (Photos by author.)
(1) Typical residential light-hazard fire sprinkler head. (Photos by author.)

The presence of a fire protection system cannot be an excuse for us to not think tactically about the buildings in our response areas. I think we can all agree that the likelihood of a major fire in a protected building is low; however, there are still issues that should be addressed before the fire. The fire protection engineer or designer who designed the system has expectations of how that system will operate. Our expectations need to be similar; often, they are not. We must look at a building protected by sprinklers and have a game plan on how to operate in it. Some of the issues we will discuss are fire attack, search, water supply, ventilation, and high-rise operations. Let’s take a look at some of these issues and develop some realistic strategies to deal with them based on the designed function of the systems.


When it comes to fire attack, we must base our line selection on the building and size-up, not on the presence or absence of sprinklers. The problem with the complacency of “it has sprinklers” is that sometimes they are not working as designed. A number of things can prevent a system from working as designed. All it takes is one valve being closed, and you can have a major fire on your hands. Base your line selection on what you see. Keep in mind that the smoke conditions at a single-family dwelling mean something very different than the same conditions at a large retail occupancy.

The late Lieutenant Andrew A. Fredericks from the Fire Department of New York used the ADULTS acronym to teach us about when to use the 2½-inch handline: Advanced fire on arrival; Defensive operations; Unable to determine extent (size) of fire area; Large, uncompartmented areas; Tons of water; and Standpipe system operations.1 The “U,” undetermined size or location of the fire, would apply to most storage occupancies with or without sprinklers. Not knowing for sure means we must set ourselves up for success. These buildings would certainly fall in the large, uncompartmented category as well. The last thing we want is to get 150 feet into a big-box retail store only to find out that we need the reach and flow of a 2½-inch line and the 1¾-inch line we have is not enough. These are situations where we must use the 2½-inch initially. Only after verifying the location and extent of the fire should we drop down to a 1¾-inch for overhaul operations. Plan for the worst and hope for the best.

In some storage occupancies, you may find what the designer would call small hose connections.2 Do not use them for initial attack. They are installed by the designers as an overhaul hose connection, and there are no design requirements for their minimum flow or pressure. The calculated water needed to supply the system does include an extra 50 gpm for each hose connection on the most demanding riser. There is also a provision for outside hose streams in NFPA 13 that is typically 250 to 500 gpm, depending on the type of system and what it is protecting. While the extra water has been added to the required flow, there is no provision in the code for this flow to be verified for the inside connections. As additional sprinklers are opened, the residual pressure and consequently the flow will be reduced. NFPA 13E provides recommendations for operating in buildings equipped with standpipes and sprinklers. The code does limit the maximum static and residual pressure, and you may find pressure-reducing devices, but that is not an indication that they are reliable for initial attack lines. They are intended to be used for overhaul, and their use should be limited to that intended function. Another compelling reason to let them be is that it could put firefighters at risk if things go bad. We are all trained to follow our hoseline out of the building. If you have hooked up to an interior hose connection, following your hose out would no longer be an option.

Along with selecting the proper hose size, we must consider the point of entry and length of the hose stretch. Often, the main entrance is not going to provide the best access to the fire. Good recon is needed to determine which entry point is the most appropriate. Larger buildings also necessitate that we look at the length of our hoseline. These are situations where preconnected hoselines may not be enough. Good preincident planning and size-up will provide the needed information to estimate the stretch properly so we do not end up stretching short.


When you look at the issue of search, consider several factors. The operation of the sprinkler system is going to cool the smoke and cause it to behave differently. You may find floor-to-ceiling smoke conditions in areas remote from the fire. For the larger buildings, you cannot operate as in a single-family dwelling. The search must be more planned and specific. Adequate resources must be available and assigned to the search function based on the size or square footage of the occupancy.

The smoke condition is going to determine if you can make a successful search or not. If the sprinkler system is operating, you can plan to have some visibility remote from the fire. You may be able to see 12 feet in front of you, but you will not be able to see across the building. In his book Searching Smarter, John F. “Skip” Coleman talks about searching in big-box stores.3 He goes into detail with the types of searches that are the most effective. I agree with his take on search in these buildings. Team search with a search rope is the most safe and efficient use of the fire department’s resources. Keep in mind that if the conditions begin to deteriorate, you must exit the building immediately.

The other tactic to consider is the access/removal of the victim through an exterior wall. The victim removed from the 2007 Charleston (SC) Sofa Super Store was located and removed this way.4 However, it requires good information and the appropriate forcible entry tools given the building construction. You may encounter several types of wall construction, from steel/sheet metal to prefab tilt-up concrete. This type of operation may require the use of specialized breaking and breaching techniques and may be difficult. The best time to determine the needed resources for this task is during the preplanning process.

The search that will be the most effective in these types of occupancies is going to be a “strategic search.” Crews are assigned to search specific areas based on, again, preplanning and size-up factors. If an occupant says that Jane from Accounting is not outside, we may then assign a crew to search her office area.

In these commercial searches, a search rope is invaluable. Firefighters may encounter maze-like conditions and smoke conditions that limit visibility that require the search crews to use a search rope. Know what you are looking for, and have a way out. Have a specific, limited area to search, and use a search rope so that if the conditions begin to change, you can find your way out of the building. Also, continually be aware of your surroundings, identifying any other exits or escape paths such as doors and windows.

The use of thermal imaging cameras (TICs) will also assist in the search process. In a building with a functioning sprinkler system, the TIC will allow us to more clearly navigate through the “cold smoke” conditions. It will also allow crews to identify operating sprinkler heads, as the discharging water will produce a visible spray pattern. The TIC cannot take the place, however, of a search rope or other means of securing a safe exit from the building.


The residential kitchen fire we respond to that has been handled by a single sprinkler may not require support of the fire department connection (FDC) for a successful operation. Some residential systems may not even have an FDC. On the other hand, a fire in a large storage occupancy can have sprinklers with up to a one-inch orifice (photo 2). Having three or four sprinklers activated means the system could be flowing hundreds of gallons per minute. Support of the FDC in the early stages of the incident will be a vital part of a successful operation. Knowing the location or locations of the FDCs and identifying what buildings or portions of a building are supplied by a given FDC is part of the preplanning process.

(2) Residential sprinkler (left) vs. sprinklers used to protect storage and retail with a ¾-inch and one-inch orifice.
(2) Residential sprinkler (left) vs. sprinklers used to protect storage and retail with a ¾-inch and one-inch orifice.

The presence of a water tank or pump should serve as a red flag and will require greater attention to water supply issues. These components signal that the municipal water supply is not adequate to provide the needed pressure or volume to the fire protection system. National Fire Protection Association 13, Standard for the Installation of Sprinkler Systems, 2010 edition, requires that the tank must provide for a two-hour water supply. (4)If the fire department is operating on the scene for an extended period of time, you must consider alternative sources of water. Fires deep seated in storage occupancies can take hours to extinguish completely. Be sure you identify alternate water supplies during the preplanning process.


Ventilation is always a challenging topic; that is no different in buildings with sprinklers. The cooling action of an activated sprinkler can be a factor in the challenges we can expect to encounter. It is difficult at best to move this cool smoke. It is neutrally buoyant and does not move like the smoke in a typical house fire. Storage buildings may have smoke and heat vents on the roof, but if the smoke is not going to rise, the vents will provide limited benefits. The positive-pressure ventilation (PPV) fan will provide limited benefits as well, depending on the size of the building. Our experience with the fan is, again, with a single-family dwelling. If you look at the difference in the volume between a home and a warehouse, you can see why a few fans at the door will have little effect (Table 1). The volume of a typical big-box retail store is more than 185 times that of an average single-family dwelling. The use of fans won’t hurt, but we cannot expect them to work as well as we are accustomed to. The limitations of fans in large-volume structures will require alternate means of ventilating the building such as using up all available openings and letting the building vent naturally. To get the maximum effectiveness out of your PPV fans, arrange them as recommended by the National Institute of Standards and Technology PPV study, in a “V” pattern.5

table 1

An example of the challenges in ventilating a building of this type is a fire we have had several times in our department in the past couple of years. The building is a 180,000-square-foot recycling facility with an approximately 25-foot roof. We have had fires in different areas of the building, but the ventilation issue has been consistent. After trying several options, the one we found to be the most effective was to open the existing openings and skylights on the roof in the fire area and all of the roll-up doors at ground level. Although more effective than PPV, it still took longer than expected to ventilate the building.


Modern high-rise buildings are required to be protected with automatic sprinklers and standpipe systems. Depending on the height of the building, these systems can be quite complex. Fire departments must rely on preplanning information and the expertise of the building engineers to understand the capabilities and limitations of these systems. Are there some alternatives to the FDC if it is damaged? You can pump into the fire pump test header if you open the correct valves in the building. Using a standpipe outlet on the ground level can work as well. If an outlet is equipped with pressure-reducing valves, however, this option for supplying the system is no longer available (photos 3 and 4).

(3) Fireground adjustable pressure-reducing valve.
(3) Fireground adjustable pressure-reducing valve.
(4) Factory set pressure-reducing valve.
(4) Factory set pressure-reducing valve.

Preparations must also include locating the sprinkler isolation valves on each floor. These valves allow you to shut down the sprinkler system in a particular area of the building without affecting the other floors or the standpipe system. Each system is going to be a little different, and understanding the parts and locations of critical valves will ensure that the fire department’s operations are the safest and most efficient. Learning and documenting the systems in your buildings are the responsibilities of a professional firefighter.


The key to operating successfully in buildings equipped with fire sprinklers is to know the system, its capabilities, and its limitations. Fire departments must operate in concert with the installed fixed fire protection systems in all buildings. A part of that preparation is having a plan should the system not be operating as it was designed. During your prefire plans, gather as much information as possible about the fire protection systems and their operation. If you are unsure, consult your fire marshal, building official, building engineer, or local sprinkler contractor to have your questions answered about a given system. In large-area buildings with a significant smoke condition, the need for a hoseline or a lifeline cannot be understated; it is a must for safe operations. Fire departments must understand the capabilities and limitations of each system. You must have realistic expectations of how to operate in these types of buildings.


1. Andrew A. Fredericks. “The 2½-Inch Handline,” Fire Engineering, December 1996, 40.

2. National Fire Protection Association 13, Standard for the Installation of Sprinkler Systems, 2010. Quincy, MA: National Fire Protection Association.

3. John F. “Skip” Coleman. Searching Smarter. Tulsa, Okla: Fire Engineering. 2011. 236-238.

4. “Nine Career Fire Fighters Die in Rapid Fire Progression at Commercial Furniture Showroom – South Carolina,” FA CE report #F2007-18. National Institute for Occupational Safety and Health, 2009.

5. Technical Note 1629, “Firefighting Tactics Under Wind Driven Fire Conditions: 7-Story Building Experiments.” S. Kerber and D. Madrzykowski. National Institute of Standards and Technology, Gaithersburg, MD, April 2009.

KYLE SMITH is a lieutenant with Cobb County (GA) Fire & Emergency Services, where he is assigned to Engine Company 19. He has been in the fire service for 19 years and worked in career and volunteer departments. He also works as a consultant for a fire protection engineering firm specializing in big-box retail, where he has obtained fire protection certification from the National Fire Protection Association (NFPA) and the National Institute for Certification in Engineering Technologies. He is a member of the NFPA 14 technical committee.

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