We all pass large or complex buildings in our coverage area and look at them from the perspective of a firefighter, imagining what could go wrong. But then we also might think, “That building has a sprinkler system; should be no big deal.” Although that line of thinking is generally accurate, because sprinkler systems are usually designed to control a fire, in many cases, they can only do so much; it’s assumed that the fire department will arrive and finish the job.
Sprinklers may be installed for other reasons, including exposure protection, but this should be determined during the preplanning process so that firefighters can work effectively in conjunction with the system’s intended design.
Firefighters can be confused, however, about sprinkler systems, the water supplies that feed them and how much water they can or cannot use from a given supply, particularly if they haven’t spent time up front understanding how the system was designed to work. To help clear things up, fire departments must be familiar with standards and recommended practices that apply to their operations. In the case of sprinklers and standpipe systems, firefighters must be familiar with NFPA 13E: Recommended Practice for Fire Department Operations in Properties Protected by Sprinkler and Standpipe Systems (2010 ed.).
Valve Access
Although not necessarily found in all building codes, some codes and many insurance companies have recommended that sprinkler risers/control valves be readily accessible by firefighters from the exterior of the building. This can be accomplished in several ways: via post indicator valves (PIVs), wall valves or an exterior door leading directly into the sprinkler valve room, all of which allow firefighters (or facility emergency team members) to access the valves with minimal risk to ensure that they’re fully open in an emergency situation.
Firefighters may also access these valves in a collapse situation, when the water supply must be shut down to a section of a building where fire has consumed that section and the incident commander has determined that the system is no longer effective. In other scenarios, interior crews may report that the fire is out and request that the system be shut down, which can be accomplished by someone who may not need to don full PPE/SCBA to safely access the valve.
FDCs & Hose Stream Allowances
Sprinkler systems work best when fire departments operate effectively in conjunction with them. With that in mind, one of the most important things fire departments can do on the fireground is locate and connect to the fire department connection(s) (FDC) immediately upon arrival.
There are both “inside” and “outside” hose stream allowances provided for in a sprinkler system design, and the calculated flow for each depends upon the hazard. For buildings with no standpipe connections in them, no inside hose stream allowances should have been calculated. But if there is an inside standpipe connection, allowances of up to 100 gpm may have been included, which can allow for a small fire department hose stream connected to the combined sprinkler/standpipe system to complete extinguishment and mop up at a fire in the building without robbing water from the sprinkler system.
Outside hose streams should also have been accounted for in the design, taking into account fire apparatus tying into a hydrant on the water supply to the sprinkler system to allow for a flow of 100, 250 or 500 gpm from the hydrant concurrently with the sprinkler flow. The quantity depends on the hazard, and must be obtained from the designer or the hydraulic design plate at the sprinkler riser in the building. Many older sprinkler systems, however, were never provided with these plates, or they’re now missing or difficult to read.
Although it’s preferable (and recommended by NFPA 13E) that firefighters use a water supply other than the one that supplies the sprinkler system, the reality is that there’s usually no other easily accessible choice. Even hooking into a hydrant that’s “off property” at the entrance may be on the line that supports the property’s sprinkler system, and depending on the water supply arrangement, may directly reduce the available supply to the sprinkler system. This is why it’s critical to hook to the FDC and supplement the system from a fire department pumper.
Can You Share the Supply?
The question that’s often asked is, can firefighters hook into a hydrant that’s on the same water supply as the sprinkler system to use the water to fight the fire? The answer is a strong maybe. As we’ve already discussed, building sprinkler systems should’ve been designed with an allowance for hose streams, depending on the building’s design and purpose:
- Offices, residential buildings, churches, classrooms and similar light-hazard occupancies may have only been designed for a 100-gpm hose stream allowance for the fire department.
- Other hazards–such as those stemming from manufacturing, general storage, mercantile, etc.–may have been designed for a 250-gpm hose stream allowance.
- High-hazard occupancies, such as flammable liquid manufacturing, plastics manufacturing, and similar hazard occupancies may have been designed for a 500-gpm hose stream allowance.
Essentially, the design will determine how much water the fire department may draw from the water supply system for firefighting purposes supplemental to the sprinkler system operation.
Changes & Challenges
In most cases, firefighters are able to flow the hose stream allowance for a given building from the water supply, and the sprinkler system should still have adequate supply to do what it was designed to do. However, if there are any problems with the sprinkler system’s water supply (partially closed valves, pipe deterioration over time, etc.), if the occupancy has changed to include more hazardous materials/processes than what it was originally designed for, or if other changes have occurred, it’s possible that the sprinkler system may not be getting the supply it needs to be effective.
Additionally, many fire apparatus are not equipped with flow meters and may not be able to accurately estimate how much water they’re taking from the sprinkler supply for hoselines (although good pump operators should be able to accurately estimate this even without flow meters). This is another reason why it’s so critical for crews operating at a sprinklered building to pump the FDC supplying the sprinkler system.
What to Do Prior to an Incident
Firefighters should preplan the pressures that the connections should be pumped at, but if you haven’t preplanned, pump at 150 psi, adding pressure for multi-story buildings when supplying sprinklers to upper floors. But most systems aren’t designed to operate at pressures greater than 200 psi and should not be pumped at pressures greater than this. Tip: Identify the maximum hose stream allowance you can take off, and clearly list this on your preplans.
Important: In general, if firefighters expect the sprinkler system to work properly, they can’t flow large/master stream appliances from the same water supply that’s supplying building sprinklers. An alternative water supply should be identified and used for this.
Issues such as these are best identified and addressed prior to an incident occurring at the protected property via proper preplan inspections. Inspections will allow fire crews to discover the locations of valves, how they operate, their required fire flow, your department’s ability to provide that flow and the maximum occupancy that the sprinkler system is designed to protect. It will likely be necessary to view the sprinkler plans to determine some of this information. Inspections must also ensure that there haven’t been any changes made that threaten the system’s design.
Notes on Ventilation, Salvage & Resources
Good ventilation and salvage work is key to any successful firefighting operation, but particularly at fires where sprinklers are flowing. Quick application of salvage covers in areas where sprinklers are activated can result in saving a lot of stock. Effective ventilation will allow hoseline teams to quickly locate the seat of the fire and finish extinguishment. Remember: Only after extinguishment is complete should sprinkler valves be shut down. If valves are shut down prematurely, a fire can quickly grow out of control. More than one building has burned to the ground due to early closure of valves that are assisting on-scene firefighters.
Additionally, don’t skimp on first-alarm companies just because the building is sprinklered. You’ll still need to perform all the same functions that you would on an unsprinklered building, so ensure your response includes at least 3—4 engines, 1—2 ladders and other support apparatus to initiate your water supply, fire attack, ventilation, search and rescue, and other functions. You’ll need 15—20 (or more) firefighters to accomplish all fireground tasks; the general number of occupants will be determined by the type of occupancy and time of day. Make sure you’ve got the staffing levels on hand when the call comes in for these types of buildings.
Standard Differences
In a previous article (“Firefighting Tactics for Sprinklered Buildings,” November 2012 issue), we addressed fighting fires in sprinklered residential buildings up to four stories. These buildings are normally protected by sprinkler systems designed to NFPA 13R: Standard for the Installation of Sprinkler Systems in Residential Occupancies Up To and Including Four Stories in Height. There are a few differences in the design of systems included in that standard, such as:
- The design intent, which focuses on life safety and fires originating in living spaces. There are a number of areas in buildings with these designs that are permitted to be unprotected, while a building designed to NFPA 13 will typically have sprinklers throughout.
- A building protected by an NFPA 13 system will generally be designed to provide water to flow 10 or more sprinklers, while an NFPA 13R system generally requires a design for only four sprinklers to activate. In either case, if the fire is not contained within the design area, and the fire grows large enough to activate more than the designed number of sprinklers, the system may not be able to contain the fire. Boosting the system flow/pressure via pumping the FDC can help to overcome this.
Conclusion
Fire departments must have SOPs/SOGs on how they’re going to handle fires at sprinklered buildings. In addition, every sprinklered building should be preplanned to determine the available water supplies, designed hose stream flows and any special procedures that should be utilized when handling a fire in these buildings. Remember: Feed the FDC first, and carefully plan your attack in sprinklered buildings to ensure incidents in them remain “no big deal.”
