AUTHOR’S NOTE: Although my two-part article on large-diameter hose published in the January and February 2000 editions of Fire Engineering is still accurate and relevant, I felt it is time to take an updated look at large-diameter hose.
SOME FIRE DEPARTMENTS DEPLOY THEIR LARGE- diameter hose (LDH) the same way at every fire. That’s fine if all of their fires are the same. Fire departments that protect a variety of residential, commercial, and industrial properties must deploy their LDH by more than one method if they are to take full advantage of its capabilities. Engine companies should train on various LDH evolutions and choose the one that will be most effective for the size of fire encountered, the demand for water, and the strength of the water supply system. This article examines various LDH evolutions and the conditions for which they would be indicated. Further, we will look at LDH appliances (i.e., valves and manifolds) that increase the capability and versatility of LDH.
OVERRELIANCE ON LDH
Since LDH can deliver large flows over long distances, one large-diameter hoseline can often supply all the water needed at a fire. Many fire departments, including mine, lay a single large-diameter supply line and seldom establish a second redundant water supply. This has gotten us into trouble when a vehicle, usually a small car, punctures our LDH and we lose our water supply. When a car with low ground clearance drives over LDH, it usually gets stuck. The driver, attempting to get off the hose, will usually end up spinning the wheels, which can rapidly wear a hole in the LDH. Additionally, the vehicle’s extremely hot catalytic converter will melt through LDH. Most fires demand that a backup hoseline be employed to protect firefighters operating the attack hoseline. This is an excellent safety practice that can save firefighters’ lives if they lose water on the attack hoseline. But, consider this: What good is a backup hoseline if it is pumped from the same engine that is pumping the attack hoseline and that engine breaks down?
SUPPLY LINE FROM SECOND WATER SOURCE
I began my career in the fire service 34 years ago in the suburbs of Chicago-years before LDH. Back then, the first two engines to arrive at a working fire would drop 2½- and three-inch hose at the fire and “lead out” to different hydrants. There, each engine would connect to its hydrant with a short soft-suction hose and pump the hoselines. If water was lost because of a burst line or an engine breakdown, water was still available from the other engine at the second source of water.
Today, in many suburban communities, the first-arriving engine or quint responds directly to the fire scene and pumps preconnected hoselines from its booster tank. Then, LDH is hand-stretched to a close-by hydrant, or a second company forward lays an LDH supply line from a more distant hydrant and connects it to the pump intake of the first-arriving apparatus. This is a common way to operate at residential fires, but it can be dangerous, because it depends on a single source of water. All it takes is one impatient driver of a small car to shut down the operation. The lesson here is clear: A fire of any significance must have a supply hoseline from a second source of water, even if one large-diameter supply line can provide sufficient gallons per minute (gpm). Don’t put all your eggs in one basket.
MAINTENANCE AND PREPARATION
Every few months, companies in my department receive notice that the training division will time and evaluate them as they perform an LDH evolution. This “benchmarking” evaluation program has been a great success, resulting in a departmentwide improvement in efficiency, speed, and safety when deploying LDH. Companies are motivated to get out and practice the evolutions before they are evaluated.
 (2) LDH with locking couplings should not necessitate spanner wrenches. If they are needed, be sure to align the locks. |
We have found that the benchmarking program improves performance in another way. Companies scheduled for evaluation will meticulously inspect, clean, and lubricate their LDH couplings and appliances to ensure that one person can rapidly connect and disconnect them without the need for spanner wrenches. This attention to detail is an effort to shave time off the evolution.
 (3) The thick layer of calcium and lime deposits behind this gasket makes it difficult to operate the couplings without spanner wrenches. (Photo by Ray Bell.) |
Companies in a spare apparatus will carefully check its large-diameter hose load to make sure that “Dutchmen” are properly positioned so that couplings can clear the hosebed. This is especially important for companies in a quint apparatus with a rear-mount aerial device, because misplaced couplings can “hang up” against the turntable or jam inside chutes through which hose must pass to clear the turntable.
 (4) Frequently lubricate LDH couplings with silicone spray or other recommended lubricant, and “exercise” them until they can be operated by one person without using spanner wrenches. |
LDH storz couplings equipped with locks should not necessitate the use of spanner wrenches. Stiff LDH couplings may have been run over by a vehicle but most likely are hard to operate because of age, corrosion, or lack of lubrication. Gaskets in LDH tend to swell and lose their resiliency after a few years. I believe this deterioration is hastened by South Florida’s hot weather. Additionally, we found that water in our area forms calcium and lime deposits in the soft aluminum large-diameter couplings and appliances. This corrosion can be hidden under a coupling’s gasket and build up to a point where it can reduce the clearance between couplings and necessitate the use of spanner wrenches. Pry up a gasket in an older storz coupling that is hard to couple or uncouple. You’ll usually find corrosion. You can easily remove it with CLR® or a similar cleaner. Replace stiff, swollen, or deformed gaskets, and lubricate each storz coupling and appliance with a silicone spray. One manufacturer of LDH recommends a lithium-based, water-soluble grease to lubricate its LDH gaskets. “Exercise” couplings frequently-that is, lubricate them and then repeatedly couple and uncouple them until one person can perform these actions easily. Finally, when coupling LDH, make sure to align the locks so they are close to each other. This makes one-person operations easier, especially if spanners must be used.
CHECK FOR WATER
An engine should never lay hose to or from a hydrant without first flowing it to ensure that it works and to remove any debris that otherwise would end up in the intake or the pump. As I teach around the country, I’m amazed at how many firefighters consider this a waste of time because they have never had a problem with a hydrant. I wish I could have that much confidence in my district’s water supply system! Certainly, any fire department that contends with freezing weather has encountered a frozen hydrant (photo 5). Hydrants in my company’s district seem to be a “magnet” for vehicles. A hydrant that has been struck by a vehicle may not appear to be inoperative at first glance. A broken operating stem can be detected only by attempting to flow the hydrant.
Hydrants in urban areas that are missing caps may become depositories for beverage containers, cigarettes, and food wrappers. These objects must be flushed out by gently flowing a hydrant before making a connection. Opening a hydrant rapidly and allowing it to flow wide open can cause the water to raise debris up into the bonnet, above the level of the outlets. Later, as residual pressure drops with an increased demand for water, the objects are likely to flow out of the hydrant into a pump intake.
 (6) Flowing a hydrant removes debris that otherwise would end up in the pump. |
Engines in urban areas should carry a large pipe wrench to open hydrants that have rounded off pentagon operating nuts-the result of youngsters’ repeatedly opening the hydrant to cool off using whatever tool they can find.
FORWARD HOSELAY
A forward lay begins with a pumper stopping at a hydrant and checking it for water before reaching the fire scene. Then, the company will lay supply hoselines from the hydrant to the fire. At the fire, the hose is connected to the apparatus that laid the supply line or to another apparatus already on the scene pumping from its booster tank. LDH is ideal for this evolution because it can flow a significant amount of water with minimal friction loss. Often, hydrant pressure alone is sufficient to supply adequate water for an apparatus pumping at the fire because of its capabilities. Some fire departments use LDH only, as if it were a very long soft-suction hose, connected directly to a hydrant and the pump’s intake.
A forward lay allows an apparatus to operate at the fire scene instead of pumping at a hydrant that can be hundreds of feet from the fire. This facilitates the use of preconnected hoselines and apparatus-mounted master streams. It allows a quint to operate its aerial device and elevated master stream, and all lights, ground ladders, tools, and equipment are readily available at the fire scene.
 (7) A company begins a forward lay by pulling slightly past the hydrant and flowing it. The hydrant man heels the hose and signals to the engineer to lay out to the fire. |
A forward hoselay is great for fires in detached private dwellings, but it can create problems at large fires, because the fire scene can become congested with too many pumpers that can be exposed to falling walls or electric wires. Additionally, engines that lay in their supply lines may crowd later-arriving ladder apparatus and interfere with the aerial device’s reaching the fire building. Also, engines that rely entirely on hydrant pressure may reach the point of cavitation [“running away” at excessive revolutions per minute (rpm)] as the demand for water decreases the residual pressure in the water supply system. These are some reasons a fire department should not perform a forward lay with every engine on every fire. Later, we will look at reverse and split hoselays as well as pumping LDH when hydrant pressure is insufficient.
When performing a forward-lay evolution, begin by pulling 10 to 20 feet past the hydrant. This will allow the hose to be pulled from the hosebed in a fairly straight line and reduce the chances of its catching on ladders, grab rails, or spotlights. After checking for water, pull enough hose to reach the hydrant plus an extra three feet. This will allow for a smooth connection without a kink.
 (8) The pumper is connected to a four-way valve, thereby boosting pressure in the supply line without interrupting the flow of water. |
Pulling too much hose at the hydrant is a common mistake; it is usually caused by haste or excitement. Excess hose laid out at a hydrant can end up in a mess of kinks or result in a big loop that obstructs the street. Before the apparatus lays hose to the fire, the hydrant man should “heel,” or anchor, the supply line by folding the hose so that the coupling is in front of him, step or kneel on the fold with one foot or knee, and hold on to the hose so that it will pull out of the hosebed as the apparatus drives to the fire. The hydrant man should heel in view of the driver engineer so that he can see the hydrant man signal him when it is time to drive the apparatus toward the fire. He should take a stance so that he will not lose his balance if the hose gives him some resistance. It is critical, however, for the hydrant man to immediately realize when he is on the losing end of the hose and to let go of it. He should not get into a “tug of war” with hose that hangs up in a hosebed or catches on a grab rail, a folding step, or some other projection on the apparatus, because it will drag him down the street.
LDH can also be secured to a hydrant by a strap. The strap should have a weak plastic buckle that will break and release the hose if it should hang up. Similarly, it’s not a good idea to secure LDH by wrapping it around a hydrant. Hose that hangs up can snap violently or unwrap from the hydrant with tremendous force. A firefighter struck by a flying LDH coupling can suffer a career-ending injury.
 (9) Details of connecting to a four-way valve: “S”= supply line to fire; “I”= short section of LDH to intake of pumper boosting pressure; and “D”= discharge from pumper boosting pressure. |
Often, companies performing a forward lay take too long at the hydrant and delay getting water to the fire. Two common mistakes are taking time to close the hydrant after flow checking it for water (leave it flowing!) and taking the time to connect the supply line to the hydrant before the apparatus lays out. When performing a forward lay, quickly flow the hydrant, lay out the necessary tools and appliances, pull and heel the hose, and get going. The hydrant man will have plenty of time to shut off the hydrant and make his connection while the engine is laying out to the fire.
 (10) Pumping to a four-way valve from a large-diameter discharge, located on the right side of the apparatus for the safety of the pump operator. |
A lack of communication can result in a delay in charging the supply line or, worse, charging it prematurely. A hydrant man must recognize his company’s hand or air horn signal or listen to his radio for the order to “send the water.” A hydrant man who misinterprets a signal to charge the line may charge the line prematurely. This can result in “charging” the hosebed-much to the entertainment and delight of other companies watching the evolution at a drill. It’s no joke, however, when it occurs at a fire. Charging the hose too soon can also cause a “wild line”-water flows uncontrollably from the hose before it is connected to an apparatus. A hydrant man with a portable radio must receive clear and specific orders when to charge the supply line, such as, “Engine 2, pump to Engine 2 hydrant; charge the line.” The hydrant man should then transmit, “Engine 2 hydrant, charging the line,” to verify that the order was received and understood.
LDH APPLIANCES
There are three appliances that can enhance the capabilities of LDH when it is laid from hydrant to fire: the four-way hydrant valve, the large-diameter intake valve, and the large-diameter water thief manifold. A four-way hydrant valve enables an engine to lay a supply line from a hydrant to the fire and receive water with hydrant pressure. Then, if more water is needed, another pumper can go to the hydrant, connect its suction hose and a discharge line to the four-way valve, and use its pump to boost pressure in the supply line. (Later, we will look at different ways to connect and pump LDH from discharge outlets of apparatus.)
 (11) A large-diameter intake valve connected to the pump’s “steamer” connection: the valve wheel is at the top, the air bleed is at the side, and the relief valve is at the bottom. |
Ball and clapper valves in the four-way valve allow an engine to receive water and increase pressure without interrupting the flow to the supply line. Fire departments that operate with four-inch LDH will realize the benefit of a four-way valve more often than those with five-inch LDH. This is simply because four-inch LDH has more friction loss than five-inch LDH and, hence, requires higher pressure to flow the same volume of water.
A large-diameter intake valve serves as an adapter from the LDH storz couplings to a threaded “steamer” pump intake. A piston raises and lowers to open and close the waterway, or a rotating ball controls the flow of water, allowing an engine to pump from its booster tank before it receives a supply line. Then, once a supply line is connected and charged, the valve is opened to allow water to flow into the pump. The intake valve facilitates a smooth transition from booster tank to LDH supply line without interrupting the flow of water. The piston or ball in a large-diameter intake valve operates by a worm gear that fully opens or closes with several rotations of the valve wheel crank. This is to comply with a National Fire Protection Association (NFPA) requirement that the intake and discharge valves for LDH must open and close in no less than three seconds. This requirement is intended to prevent a water hammer, which will occur if you operate large-diameter valves too quickly. Additionally, an adjustable relief valve on the device protects the LDH and pump from water hammer and dangerously high pressures.
The intake valve has an air-bleed outlet that provides an exhaust for air trapped in the supply line that would otherwise end up in the pump. When LDH is charged, water filling the hose displaces a substantial amount of air. This air, trapped ahead of the water, must be expelled before it rushes into the pump, because it will interrupt the flow of water. A pump deprived of water will cavitate. Apparatus with electronic pressure control governors may automatically throttle back to idle, because the device senses that the pump has lost its water supply.
My company recently received a new apparatus, a 1,500-gpm pumper with a 60-foot aerial ladder. This apparatus does not require the connection of large-diameter intake valves to its pump’s steamer intakes because it is equipped with large-diameter master intake valves (MIV).
 (13) The toggle switch control to the master intake valve. Lights indicate the position of the butterfly. |
The MIVs are bolted directly to the pump’s intake flange on each side of the apparatus behind the pump panel. The MIV functions basically the same as an externally connected large-diameter intake valve. A butterfly valve in the valve’s six-inch-diameter waterway slowly opens and closes in compliance with NFPA requirements. An electric motor controlled by a toggle switch on the pump panel operates the valve. Additionally, it can be operated manually. “Innovative” company members have already replaced the standard knob with a handwheel crank for easier manual operation. The MIV is also equipped with air bleeds and adjustable relief valves.
A large-diameter water thief, also known as a “portable hydrant manifold,” functions as a large in-line gate valve when it is used in a forward hoselay. The water thief is connected to the supply line at the fire, controlling the flow of water from the hydrant. Then the apparatus is connected to the outlet of the water thief with a short (10-, 15-, 25-, or 50-foot) section of LDH. A large-diameter water thief increases a company’s efficiency when performing a forward lay in the following ways.
 (14) The large-diameter water thief is connected to the supply line. The engineer rolls out a short section of LDH to connect the water thief to the pump intake. |
- Connecting the water thief allows the supply line to be charged before it is connected to the apparatus. This frees the hydrant man the same way a hose clamp would. Since LDH usually comes in 100-foot sections, an engine company without a water thief may have to pull as much as 80 feet of hose from the hosebed to reach a pump intake-that’s a lot of hose that can develop kinks and block the street. A large-diameter water thief is connected at the first coupling behind the apparatus. The company then orders the hydrant man to charge the supply line. Then, a short section of LDH is used to connect the water thief to a pump intake.
- A large-diameter water thief is equipped with an adjustable pressure relief valve that protects the LDH and the apparatus (photo 15).
- A large-diameter water thief enables firefighters to control the flow of water in the supply line at the fire scene instead of having to shut off the hydrant, which can be hundreds of feet away. This is a definite advantage if an apparatus must be rapidly disconnected from its supply line and repositioned to avoid falling walls, power lines, or exposure to fire. We used our large-diameter water thief to reposition our apparatus twice at a serious anhydrous ammonia leak. A massive white cloud of ammonia gas refrigerant, leaking from a cold storage warehouse, threatened a densely populated residential neighborhood. We laid several hundred feet of five-inch supply line and directed an elevated master fog stream into the vapor cloud. The fog stream had the desired effect of absorbing the ammonia and washing the vapor cloud out of the air. Twice during the operation, we shut off our supply line at the water thief, disconnected it from our pump, and reconnected hose from our hosebed to the outlet of the water thief. We then forward laid from the water thief to reposition our apparatus closer to the leak source.
- Since a large-diameter water thief controls the flow of water at the fire scene, it facilitates switching a supply line from one apparatus to another. Consider this scenario: An engine pumping at a fire scene breaks down. Suddenly, its hoselines’ pressures are reduced to hydrant pressure. Firefighters rapidly shut off the water supply to the disabled engine by closing the water thief and reconnect to another engine. This engine connects a hoseline from a discharge to the intake of the disabled engine and uses its pump to restore pressure to the hoselines. In this operation, the disabled engine becomes in effect a big manifold pressurized by the second engine.
 (15) The relief valve on the large-diameter water thief opens at a preadjusted pressure. This one was set at 150 psi. |
A critical factor in this operation is the setting of the disabled engine’s intake relief valves. If the intake relief valves are set too low, say less than 150 psi, they will open and dump water, which could prevent restoring adequate pressure to its hoselines.
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TAPPING INTO A TEMPORARY WATER SUPPLY
There is no shortage of strong opinions on the practice of a first-arriving engine’s operating from its booster tank and relying on the second-due engine to lay in a supply line from a hydrant. The argument against the practice is indisputable: There is no guarantee that the second engine will arrive in time to establish a continuous supply of water before the first-due engine has an empty booster tank. (For that matter, the second engine may never arrive because of an accident or a mechanical breakdown.)
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 (18) |
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 (18-19) Connecting to the discharge of the second engine to receive its tank water. |
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There is a way to reduce the chances of running out of water before the supply line is connected and flowing: The engineer of the first-due engine connects a section of 2½- or three-inch hose to an intake and rolls it out in the direction from which the second engine is expected to arrive. Now, when the second engine lays in to the fire scene, the engineer of the first engine connects the hose to a discharge of the second engine. The second engine pumps its tank water to the first engine. Tapping into the tank of the second engine provides additional water to the first engine in seconds. This buys time to carefully break and make LDH connections and charge the supply line s-l-o-w-l-y. Haste makes waste with LDH: Charging a line too fast will cause a heavy appliance such as a large-diameter water thief to violently whip and twist with enough force to break an ankle or the appliance.
 (20) |
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 21. |
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 (20-22) This buys time so the LDH supply line can be carefully connected to the first apparatus, laid out without kinks, and charged slowly. |
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Carefully lay out LDH before it is charged. This is especially important where it is connected to a pump intake. Excess hose at the pump can roll itself into a big kink that ends up under the apparatus (photo 23). Again, mistakes like this may be amusing to other companies watching it at a drill, but they can have terrible consequences when they occur at a fire.
 (23) Haste makes waste with LDH. Here, failure to carefully lay out the hose at the pump results in a kink under the apparatus. |
Training is the key to efficient LDH operations. You will not become or remain proficient in working with LDH unless you drill on it frequently. As mentioned, a forward hoselay has some advantages, but LDH cannot be used to its full potential if it is forward laid by every engine at every fire.
 (24-32) Pressurizing a disabled pumper: (24) The engine pumping preconnect breaks down. |
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 (25) The pressure is reduced to the hydrant pressure. |
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 (26) The supply line to the disabled pumper is shut down at the large-diameter water thief, |
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 (27) disconnected from the disabled pumper, and |
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 (28) reconnected and charged to another pumper. |
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 (29) The second pumper pumps the three-inch hose to pressurize the disabled pumper. LDH can be used between apparatus if necessary. |
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 30. |
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 (30, 31) The pressure to the disabled pumper and its hoseline is restored. |
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 (32) If the intake relief valve of the disabled pumper is set too low, it will dump water, preventing restoration of adequate pressure. |
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In Part 2, we will look at using LDH in reverse and split hoselays, as well as various ways to connect and pump LDH to take full advantage of its flow potential.
I wish to acknowledge the assistance of the following in the preparation of this article: Battalion Chief Bill Peters, apparatus supervisor (ret.), Jersey City (NJ) Fire Department; Richard Avallone, training officer, Pompano Beach (FL) Fire Rescue; Captain Ray Bell, Miami Dade (FL) Fire Rescue; and “Mac” McGarry, engineer (ret.), Glenview (IL) Fire Department.
BILL GUSTIN, a 34-year veteran of the fire service, is a captain with Miami-Dade (FL) Fire Rescue and lead instructor in his department’s officer training program. He began his fire service career in the Chicago area and teaches fire training programs in Florida and other states. He is a marine firefighting instructor and has taught fire tactics to ship crews and firefighters in Caribbean countries. He also teaches forcible entry tactics to fire departments and SWAT teams of local and federal law enforcement agencies. Gustin is an editorial advisory board member of Fire Engineering and FDIC.
