By BILL GUSTIN
Charging and flowing additional hoselines from a standpipe when the initial hoseline is already in operation require close coordination because the additional flow of the second hoseline will result in an increase in friction loss in the standpipe and hoselines supplying the fire department connection. Consequently, the additional hoselines can “steal” water from the initial hoseline and endanger its crew. Situations that can require operating more than one hoseline from a standpipe include large areas with little or no compartmentation, such as office suites in commercial high-rise buildings; large, luxury apartments; and hotel suites.
In Florida, the State Legislature passed a law giving condominium owner associations until 2019 to retrofit their buildings with sprinklers. Consequently, the state has dozens of luxury high-rise condominium buildings on the Atlantic Ocean and the Gulf of Mexico with no sprinkler protection, many with units of more than 3,000 square feet. Fire departments should identify and extensively preplan all buildings in their jurisdiction that have the potential for a volume of fire that exceeds the suppression capability of a single hoseline.
Additionally, these departments must train on deploying more than one hoseline from a standpipe, ideally in the buildings where it may be required. When a fire department is granted permission to train in a building, perhaps in conjunction with a fire drill for occupants, it should seize the opportunity-especially if it is permitted to connect hoselines to its standpipe system and flow water out of windows or from balconies or the roof. Although it is infrequent, firefighters permitted to flow water from a building’s standpipe system have a unique opportunity to learn some of its capabilities and limitations in terms of flow and pressure. When it is not possible to flow water from a building’s standpipe system, do not expect it to provide any more flow and pressure than the minimum required by National Fire Protection Association (NFPA) 14, Standard for the Installation of Standpipe and Hose Systems. In buildings constructed after 1993, NFPA 14 requires one of the standpipes in a building to flow a minimum of 500 gallons per minute (gpm) from the two most hydraulically remote 2½-inch standpipe hose outlets, with each outlet flowing 250 gpm at a minimum pressure of 100 pounds per square inch (psi) and a maximum pressure of 175 psi. Additionally, the standard requires additional standpipes to flow 250 gpm at 100 psi. Prior to 1993, NFPA 14 required these flows at a minimum pressure of just 65 psi, which is a compelling reason to use only 2½-inch hose in buildings constructed before 1993.
|(1) The inline gauge is labeled for standpipe stretches of 2½-inch hose: 70 psi for three lengths and 80 psi for four lengths. Note how the gauge is protected. (Photo by Edwin Barbosa.)|
What does NFPA 14 tell fire officers about the capability of a standpipe system to flow more than one hoseline? First, don’t expect a 2½-inch hose outlet to flow more than 250 gpm. Second, don’t expect to flow more than 500 gpm from a single standpipe. Any additional flow is a gift you cannot count on. In some jurisdictions, standpipe systems have never been flow tested in accordance with NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. (http://bit.ly/1byHoxO) Consequently, firefighters have no way of knowing if a buildup of corrosion in piping over the years has progressively reduced flow or if pressure-reducing hose outlet valves will function properly.
Fire officers who encounter a volume of fire that has the potential to exceed the suppression capability of one hoseline should consider “softening the target”-that is, take some of the thermal energy away from the fire by applying water directed from exterior streams or below-the-floor nozzles before committing personnel with hoselines. Additionally, consider operating portable master stream devices from just outside the refuge of enclosed stairwells. A word of caution here: Opening a stairwell door to a fire floor with a heavy fire condition can turn the stairwell into a chimney, endangering occupants and firefighters. Do not open a stairwell to the fire floor before ensuring that firefighters and occupants have been evacuated from the stairwell on all floors above the fire floor. When conditions permit, stretch the initial hoseline before deploying additional lines; team up engine companies, if necessary, to get the first line in operation.
Say you stretch 200 feet of 2½-inch hose with a 11⁄8-inch smooth bore nozzle connected to a standpipe outlet on a stair landing on the floor below the fire floor. With my department’s hose, this would require a pressure of 80 psi at the standpipe outlet to achieve a nozzle pressure of 50 psi, overcome the friction loss of 25 psi in 200 feet of 2½-inch hose flowing 265 gpm, and an elevation loss of five psi because it is connected one floor below the fire. This pressure may be significantly different for other departments because of differences in the friction loss of their particular brand and grade of hose. Fire departments must determine standpipe outlet pressures based on flow testing their hose at their desired flow and nozzle pressure.
|(2) The three-inch hose “pigtail” facilitates connecting a wye to standpipe hose cabinets in older buildings that do not have outlets in stairwells. Here, it is connected to an outlet on a stair landing and is in position to supply two 2½-inch hoselines. Note the inline gauges connected to each of the wye’s outlets. (Photo by Alex St. Joy.)|
In photo 1, this inline gauge has been labeled for stretches of three and four lengths of 2½-inch hose. Similarly, some departments mark pressures on the face of their inline gauges with pin striping tape or a grease pencil. It is very important that pressures on an inline gauge be read with the nozzle fully opened and flowing; otherwise it is reading static pressure, which can drop significantly when the hoseline is flowing. Flowing the nozzle also gives firefighters on the hoseline an opportunity to judge the quality of its stream before they advance into a hostile environment. My department issued inline gauges to fire companies about 10 years ago. Before that, we managed to determine and control standpipe outlet pressures by opening the outlet with the nozzle open until we had, in our judgment, a good stream. We would do this before leaving the refuge of an enclosed stairwell when the fire floor hallway was untenable or at the door to the fire apartment if it was closed, keeping the public hallway clear of smoke. Acquiring the inline gauges did not change the way we operate; we always flow the hoseline to assess the stream before entering a hostile environment.
Maintaining Pressure in the Initial Attack Line
Although an inline gauge is useful for determining standpipe outlet pressure when operating with a single hoseline, it is an absolute necessity when deploying additional hoselines when the initial hoseline is in operation in the fire area. Consider the following scenario when companies are not equipped with inline gauges.
You encounter a heavy fire condition in an office suite of a commercial high-rise building. First-alarm companies connect four lengths of 2½-inch hose to a standpipe outlet in the stairwell on the floor below the fire and flow the line to assess the quality of their stream before advancing on the fire floor.
Now, the crew members on the initial hoseline advise that they cannot advance further toward the fire, and they call for an additional 2½-inch hoseline. Companies connect a second 2½-inch hoseline to a standpipe outlet two floors below the fire floor and begin flowing it without any consideration of the effect the additional flow will have on the initial hoseline. Consequently, the outlet pressure for the initial line can drop to 40 psi. This significantly reduces the flow to the initial hoseline at a time when its crew is calling for more water and could result in their being seriously burned.
Let’s consider the same scenario, but this time firefighters use inline gauges and pay close attention to the pressure of the first hoseline when deploying the second line. The initial hoseline is again connected and charged on the floor below the fire. With the nozzle open, firefighters gradually open the valve wheel of the standpipe outlet until the inline gauge reads 80 psi, and they assess the quality of their stream. When the crew on the initial hoseline calls for another 2½-inch line, they are directed to fully open their nozzle so that their inline gauge can be read accurately by a firefighter assigned to the standpipe outlet. The second hoseline is connected to an outlet two floors below the fire and is slowly charged with the nozzle open. This is a critical stage of the operation because the firefighters assigned to each outlet must communicate and closely monitor their respective inline gauges. As the second hoseline is charged, the firefighter on the first hoseline further opens the outlet in response to a drop in pressure, maintaining 80 psi. If the 80 psi cannot be achieved with the outlet valve fully open, the engine supplying the system’s fire department connection must be directed to raise its pressure before fully charging the second hoseline. As much as flowing an additional hoseline can drop the pressure in the initial line, shutting it down will have the opposite effect. When operating with two or more hoselines from the same water source, close the nozzle slowly because it will raise the pressure in the other line, possibly requiring the nozzle firefighter to gate back the nozzle to avoid excessive nozzle reaction.
Other Methods for Charging the Second Hoseline
Following are two methods for charging a second hoseline from a standpipe that do not require firefighters at two outlets to monitor inline gauges and adjust pressures: First, many fire departments, including mine, use a wye or a “water thief” appliance. My department connects a 2½-inch × 2½-inch × 2½-inch wye to a five- or six-foot “pigtail” of three-inch hose to facilitate connecting to standpipe outlets located in hose cabinets, not in the stairwells, in older buildings (photo 2). One advantage of using a wye is that it simplifies connecting a second hoseline because it does not have to be connected to an outlet two floors below the fire floor. Another advantage is that when inline gauges are connected to both outlets of a wye, one firefighter can monitor and adjust pressure on both hoselines, which will be the same for each hoseline if it is the same length and diameter and operating at the same nozzle pressure (photos 3-5). When using a water thief or a wye, fully open the standpipe outlet valve and control pressure to each hoseline with its ball valves. Once the wye’s ball valves are adjusted to the proper pressure, lock their valve handles so they can’t be accidentally kicked out of position.
There is, however, a significant disadvantage of using a wye or water thief for standpipe operations that makes it ineffective when used with some systems. As stated previously in this article, NFPA 14 requires a minimum flow of only 250 gpm from a standpipe outlet-again, anything more than that is a gift fire officers cannot count on. It is not unusual to find that standpipe outlets are capable of flowing more than 500 gpm, but you can never take this for granted. Fire departments that use wyes or water thieves for standpipe operations must plan and practice for the day when they encounter a standpipe system with outlets that are not capable of supplying two hoselines. Another disadvantage of using a wye for standpipe operations is its weight, which seems to increase in proportion to the number of flights of stairs you must carry it.
My company has devised a method for supplying a second hoseline from a standpipe when its outlets are not capable of supplying two hoselines. The initial hoseline is connected to a standpipe outlet on the floor below the fire. Pressure is adjusted at the valve’s hand wheel with the nozzle flowing and the reading on an inline gauge. If a second line is called for, firefighters connect a section of 2½-inch hose to the outlet two floors below the fire and stretch it up to the landing below the fire floor. There, they connect a 2½-inch hydrant gate valve, an inline gauge, and the second hoseline. When the outlet two floors below is fully opened, one firefighter can charge the second hoseline from the gate valve while monitoring and adjusting the pressure on both lines. This method has the effect of moving the outlet to the stair landing on the floor below the fire (photo 6). Although, NFPA 14 limits maximum standpipe outlet pressure to 175 psi, fire departments that use appliances such as wyes or gate valves for standpipe operations should refer to the manufacturer’s specifications to determine their maximum operating pressure.
BILL GUSTIN is a 42-year veteran of the fire service and a captain with the Miami-Dade (FL) Fire Rescue Department. He began his fire service career in the Chicago area and conducts firefighting training programs in the United States, Canada, and the Caribbean. He is a lead instructor in his department’s officer training program, is a marine firefighting instructor, and has conducted forcible entry training for local and federal law enforcement agencies. He is an editorial advisory board member of Fire Engineering and an advisory board member for FDIC. He was a keynote speaker for FDIC 2011.
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