TEMPORARY FIRE HYDRANTS

BY CHARLES RIELAGE AND ANDREW REGISTER

Starting in 2004, the Spiniello Company began repairing water mains in the village of Mariemont, Ohio, located just outside Cincinnati. The company was contracted by Cincinnati Water Works to rehabilitate the existing water mains in sections of the village. The technology the company uses allows it to clean the existing mains, most of which are 70 years old, and apply a high-tensile strength concrete spray to the inside of the mains, a less expensive alternative to excavating the mains completely and replacing large sections of pipe. Although this sounds like an easy task, it was very time-consuming and does affect department operations to a degree. The project started its second phase during the spring of 2005 and completed it by late summer.


(1) An existing fire hydrant with a pressure-reducing valve supplying water to temporary water mains. Two to three fire hydrants are used to supply firefighting and domestic water to each loop of temporary water mains. (Photos by authors, unless otherwise noted.)

During the repair process, temporary water mains were laid above-ground using four-inch-diameter pipe. Temporary “fire hydrants” were located near the existing hydrants, which were tied into the aboveground water mains (photo 1). This community is fortunate to have 145- to 165-psi static hydrant pressure with gpm flows averaging between 1,300 and 1,500 gpm. On completion of the project, hydrant water flows of between 2,000 and 3,100 gpm were obtained, supplied from the rehabilitated water mains. With these temporary mains and hydrants, the pressure on the system was limited to between 60 and 80 psi, and total volume out of these hydrants was approximately 1,140 gpm. These hydrants were activated by a stop-cock type valve.


(2) Temporary fire hydrant attached to the water main. Note the stop cock nut to control water flow from the hydrant.

Since these mains were located next to the curb, they were vulnerable to being run over by vehicles, which could also easily strike the hydrants (photo 2). The temporary mains were made of PVC with a plastic joint every 12 feet, which easily comes apart when struck by a vehicle tire. Neoprene hose was used wherever the water main needed to make a turn.

The company conducting the repair work has performed this type of repair in more than 22 states. In these temporary systems, fire flow is a significant problem, as are colder temperatures and plumbing failures. With the temporary system, six- and eight-inch mains are reduced to four inches, making friction loss much more significant and greatly reducing the volume.

However, we found that the deteriorated existing mains were producing the same gpm as the temporary hydrants when only one hydrant was in use. The temporary mains encompassed a one-quarter- square-mile area. The company uses at least two existing hydrants to feed the temporary mains. When flowing two temporary hydrants, the volume of available water was limited to 900 gpm at the test hydrant. Keep in mind that this particular area typically has consistent hydrant flows of between 1,300 and 1,500 gpm.

The distance to a secondary water source can be more than 2,000 feet from a standard hydrant because of the size of the area where the water mains were being rehabilitated. A relay pumping operation would be required to provide an adequate secondary water supply from the permanent water supply system located outside the temporary water supply system.


(3) A temporary water main supplying water to an orange hose that supplies water to the buildings affected by the water main rehabilitation project.

We have encountered the following problems with the temporary hydrants: vehicles that strike or park in front of these hydrants, plumbing failures in the pipe section connecting joints, and supply line feeds to buildings breaking loose (photo 3). Temporary water main pipe break repairs are performed strictly by the contractors, whose response time to calls is longer than that of the local water department.

During flow testing, the contractor-supplied lightweight metal hydrant wrenches warped, delaying the start in water flow. We corrected this problem by carrying 12-inch adjustable wrenches with fire hydrant wrenches and the temporary hydrant wrenches (photo 4).


(4) Left to right: A contractor-supplied hydrant wrench, 12-inch adjustable wrench, and regular spanner wrench can all be used to operate temporary fire hydrants.

Cooler temperatures and plumbing failures raise additional questions regarding the performance reliability of the temporary water mains and hydrants. As freezing temperatures occurred in December 2004, several mains froze up and failed, not only affecting basic water service but also disabling the loop supplying the temporary hydrants protecting the area.

Plumbing failures occurred regularly. The temporary system’s joints were PVC with plastic ties that created a watertight seal. These joints will fail if run over by a car tire. While conducting a pitot reading on one of the temporary hydrants, a nearby joint failed. We were able to obtain with these temporary hydrants gpm similar to what was obtainable with our existing hydrants, but only if the entire temporary system is intact and operational. Any time these joints failed, a significant pressure reduction resulted.


(5) Temporary fire hydrant used on a structure fire that fell over from the weight of the five-inch supply line. Temporary fire hydrants and mains should be monitored for system failures during the duration of an incident. (Photo by Steve Ashbrock.)

These temporary mains were installed in the curbs and laid across driveway entrances, making them easily susceptible to damage. The hydrants themselves run vertically about three feet above the temporary four-inch main. When charged, the hydrant can twist, causing a joint in the temporary main to fail, thus compromising the gpm flow for the temporary main (photo 5).

Through preplanning and innovation, our department adapted to the situation and was prepared for incidents involving these temporary hydrants. We mapped out these temporary hydrants on preplans, locating the nearest secondary source of water available from the existing permanent mains outside the temporary water main system area. Temporary hydrants were painted fluorescent orange, and all apparatus carried wrenches to fit these hydrants as well as 12-inch adjustable wrenches.

All personnel were trained on the proper use of these hydrants as well as what to expect if a temporary water main failure occurred. We also provided mutual-aid companies and local citizens information on these temporary hydrants and water mains.

As water mains across the country age, you will find this type of repair more common as a means to improve the water supply system at a reduced cost. These temporary hydrant/water main systems may be coming to your community; be prepared to deal with the associated problems that may arise while using them.

The temporary hydrants do have flows comparable to those of existing hydrants, but only under certain conditions: You can use only one hydrant at a time, and the temporary system cannot have any leaks.

Do not place all your trust in a temporary fire hydrant/water main system. Work with your water department to limit the area affected by repairs at any one time so that only a small segment of your community is solely dependent on these temporary water systems.

Train your personnel in the operation of these hydrants, and plan to use other responding engine companies to provide a secondary water supply from a separate source, if needed. As long as you plan for contingencies, your department will be prepared to respond to fire emergencies requiring the use of temporary fire hydrants.

SUCCESSFUL FIREGROUND OPERATION

On May 31, 2005, at 0643 hours, Mariemont Fire Department Station 67 was dispatched to a possible structure fire in an area that was protected by the temporary fire hydrants. The first-arriving engine and medic on-scene found a two-story house with smoke showing from the first and second floors.


(6) The engine was supplied by a five-inch supply line from a temporary fire hydrant during a structure fire. An 800-foot secondary supply line provided a backup water supply in case the temporary water main failed. (Photo by Steve Ashbrock.)

A temporary hydrant was located within 50 feet of the house. The engineer stretched a five-inch supply line to the temporary hydrant as the engine and medic crews advanced the first hoseline, a 134-inch preconnect (photo 6). The temporary water supply system supplied two preconnect lines for approximately the first 20 minutes of the incident when a mutual-aid engine from Little Miami Fire Rescue was requested to lay a secondary water supply from a permanent fire hydrant. Fortunately, the fire was on the outer perimeter of the temporary water main system area. The five-inch hoselay for the secondary water supply was approximately 800 feet.

Prior to the establishment of a secondary water supply, the two handlines were flowing 350 gpm between the two hoselines. Mariemont’s standard fireground flows for attack lines are 160 gpm for automatic nozzle lines and 190 gpm for a 1516-inch smoothbore nozzle line. The engineer encountered no problems during the initial 20 minutes of the operation, when the handlines were fed solely by the temporary system.

Because of the time of day, the secondary water supply from a permanent fire hydrant was disconnected when the fire was declared under control, since the secondary water supply was from a hydrant on Wooster Pike (U.S. Route 50), a major east-west thoroughfare into downtown Cincinnati, and caused major traffic problems.

The command staff determined that the water supply was adequate for the incident and that the three lines operating for overhaul could be properly supplied by the temporary fire hydrant alone. Crews operated handlines for another hour and a half during overhaul and encountered no water supply issues.

The only problem we encountered with the temporary hydrant was when operations were concluded: The hydrant could not be shut down because the shutoff valve was stripped. A temporary water main in-line valve was shut down just feet away from the hydrant to cut the water supply to that hydrant. Contractors arrived before the fire department left the scene and replaced the broken hydrant within 10 minutes.

CHARLES RIELAGE, a 15-year fire service veteran, is a firefighter, paramedic, and fire instructor for the Evendale (OH) Fire Department. He also is a part-time shift supervisor for the village of Mariemont, Ohio. Rielage has a bachelor’s degree in fire safety engineering and serves as an outreach instructor for the National Fire Academy.

ANDY REGISTER, a 13-year fire service veteran, is a member of the Springfield Township (OH) Fire Department, where he is a firefighter, paramedic, and member of the Training Division. He also is a part-time shift supervisor for the village of Mariemont, Ohio. He was Mariemont’s fire marshal during the water main rehabilitation project.

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