Hi, I'm John McGuire, a Past Fire Chief for 12 consecutive years. I also served as Captain for 3 years, Assistant Chief for 5 years, and as department Fire Inspector and Fire Instructor. I have been a volunteer firefighter since 1957, and have numerous awards including a life saving award. I am also a Chauffer/Pump Operator in my department as well as a neighboring department. I have also gone through many air pak bottles in fires and utilized an aerial in our department. Also, co-authored the Town of Rhinebeck and the Town of Hyde Park Fire Code, co-authored the Dutchess County Fire Mutual Aid Plan, and co-founded the Dutchess County Fire Chiefs Council and served as it's President.
When I first joined, our department had a 1941 "6 wheeler" U.S. Army Fire Truck on a Chevrolet 4 wheel drive chassis which the Fire District had purchased through the government surplus program. The overall appearance looked just like every Army truck one sees in the old war movies except that it had a fire truck body, ladders, a hose bed and a front mounted pump. Our fire district, founded in 1931, bought this rig through the Army Surplus program in 1941.
The pump was a Darley 300 gallon per minute pump driven by a shaft connected to the front of the engine which extended forward under the radiator directly to a gear box at the rear of the pump. The engine turned the shaft and there was a clutch lever, on the gear box, which when the lever was moved 180 degrees, engaged this gear box. This in turn caused the internal pump impellers to turn and pump the water out of the discharges at a pressure determined by the pump operator. The water tank contained 400 gallons.
Our fire department also had a 1953 1200 gallon tanker with a 500 gallon per minute (gpm) front mounted pump. This rig was the first tanker in the Hudson Valley of New York and was requested many times to assist many other departments where more water was needed at a fire. The body style was not like a typical fire truck body with a large area for hose, but rather it had an oil truck type of body, rounded, with a shelf on each side of the tank body for some hose. In the rear there was a large door that opened overhead. Inside this area there was a 3/4" hose on a reel that could be unreeled and used for fighting brush fires, car and truck fires and other small fires.
The front mounted pumps could receive water from their own tanks, or from another pumper, or from a hydrant. The pumps could also draw water from a water source such as a pond, lake, stream, river or a swimmimg pool. This last process was called "drafting". Each of these processes will be discussed.
With the front pump, like the midship pump, when one wants to pump water and use the water in the truck's tank, a valve has to be opened to allow the water to gravity flow from the tank on the fire truck to the pump where the engine speed can be increased by a hand throttle at the pump panel which causes the internal pump impellers to turn faster which increases the water pressure of the water flowing through the hose. The hose can be connected to one of the usual 2 1/2" discharge nozzles on the pump which provides water through the hose to the nozzle at the end of the hose which applies the water to the fire in a straight stream or in a fog pattern which is a wide angle spread of the water, similar to an umbrella only in reverse. The 2 1/2" discharge nozzles on the pump can be altered by placing a 2 1/2" to 1 1/2" reducer on the outlet, and/or by placing a 2 1/2" x 1 1/2" x 1 1/2" wye on the pump. One can then utilze an 1 /3/4" line, or lines, off these reduced discharge nozzles.
1 3/4" hose uses 1 1/2" couplings just like 3" hose uses 2 1/2" couplings.We can can also use the same principle and reduce the size from 2 1/2" to 1" hose couplings for forest fire use.
To receive water from another pumper, a hose from their pump is connected to the intake of your pump and that water travels through your pump to whatever discharge outlet the operator chooses. The pressure of the water arriving can be increased in your pump by increasing your engine rpm's which makes the internal pump impellers spin faster resulting in increased flows and pressure for your firefighting operation through the hose(s) connected to your pump.
We mentioned "drafting" earlier which is the use of a larger diameter hard suction hose which can be various sizes in diameter depending upon the capacity of one's pump. Pumps that can pump 500 gallons per minute (gpm) usually have a 4 1/2" suction hose where larger pumps can have 5", 6" and up depending on the gpm.
The hard suction hose, usually at least 2-10' lengths, is connected to the larger diameter opening on the lower part of the pump and the other end is placed in the water, whether it is a lake, pond, stream, river, a portable tank, or a swimming pool. A unit on the pump called a primer is acuated which creates a partial vacuum inside the pump and the atmospheric pressure forces the water up through the hard suction into the pump where it can be directed to hoselines or to it's own tank. The pressure of the water flow can be adjusted as previously mentioned.
On a midship pump, where the pump panel is on the driver's side, the left side usually, the pump is engaged by a lever switch in the cab, with the driving transmission in neutral, which disengages the truck transmission from the driveline. After engaging this lever, the regular truck transmission is placed in "D" on automatic transmissions or in the highest direct gear in a standard tranny. The driver then goes to the pump panel wherever it is located on the apparatus, and directs the flow of water using the valves and discharges as discussed earlier. Some rigs have the pump panel on the right side, or the curb side, so the pump operator doesn't have to stand out on the traffic side.
Some fire trucks have the pump panel mounted up on top behind the cab and the operator would stand up there to operate the pump. Some like this type better than having the pump panel on the lower left side because they maintain that they can see the fire ground better.
Having run all three, I prefer the ground position, front mount or side mount, as once one has the pumps running, one can give a quick helping hand in doling out equipment, helping with air paks, starting generators, etc., while keeping a close eye on the pumps and lines that the firefighters are depending upon for safety and extinguishment. The midship provides more opportunity than the front mount for the pump operator to assist his colleagues with equipment while he can stay in close proximity to his pump operation duties. When one is up on top running the pump, it takes time to descend to the ground & perform tasks and then time to ascend the steps again, which could create an unsafe situation with one being away from the pump too long as well as the possibility of slipping on the steps.
I haven't discussed the rear mounted pumps as I have not operated one and in our travels around the U.S., Canada, Iceland, Denmark, Ireland, Scotland, Holland and France, I have not seen one, except in photos, but I believe they were used in areas of London quite extensively. (Since I originally wrote this piece, rear mounted pumps have proliferated & I will discuss them later on)
Back to our original thoughts- The advantages of a front mount pump are that the fire truck can be nosed into a water source, getting quite close, and still keep it's rear drive wheels on solid ground for an easy backing up situation when finished. This is also advantageous where the water source has to be approached and accessed on a downward grade with the front of the truck lower than the rear wheels.
This was the case for us back in the 1970's when we pumped for over 8 hours, through 2 1/2" hose, 2300', then up a 50' foot aerial with our 750 gpm front mount pump at a large fire in Hyde Park, NY. A midship pump rig could not have accessed the water as we did without calling another rig there to borrow additional sections of suction hose which would have taken more time. Also, a midship rig would have been tipped to one side and it would have put one side of the rig too close to the water. Of course, some rigs do have a front suction intake that can be used to assist in a situation like this, but not very many.
Another benefit of the front mount is the ability to "pump on the run", meaning water can be supplied through a hose, or hoses, and applied to a fire while the truck is moving, which is particularly useful for field, prairie and brush fires. Midship mounted apparatus also have the ability to pump and roll .
The benefit of a midship pump is the versatility in placing lines to the rear of the truck to the sides, to the rear, and to the front. I've already mentioned the benefit of the midship pump operator to assist fellow firefighters with tools and equipment as he is close to all of the compartments. At the same time he can keep a close eye on the pump, pressures and engine gauges.
Again, in my experience of operating both midship and front mount many times, the ability to assist one's colleagues plays a large role in a fire attack so I feel that the midship has the advantage as well as the mechanical advantages of piping, installation and versatility.
Since I wrote the above, rear mounted pumps,and rear side mounted pumps have become popular for many reasons.
One of the reasons stated in one manufacturers manual states that it is more efficient for the pump drive system and the installation of the piping for the outlets. Others state that it puts the pump operator closer to the compartments where he can help colleagues & if on the right side, away from traffic.
Our neighboring department jsut received a rear mounted pump on a brush truck and I'm a driver there as well as my own dept. so after I operate it an incident, I'll report however I am sure it will be fine.
Oh, another big move is the narrowing of the pump panels by some pump makers, some down to 28", which frees up more space for compartments. This is the case with the Hale Qmax-XS pump with capacities up to 2,250 gpm. The 28"wide panel is with electric valves or one can have manual valves which makes the panel 34" wide. Either way, twelve four inch discharge ports are standard, each able to flow 1,500 gpm.
In the Fire Apparatus & Emergency Equipment magazine, Dec./12, Hale reps also spoke about a 500- 1,250 gpm pump model, the Sidekick, that hangs under & outside the the frame rail on the driver's side. This creates space so the tank can be moved forward which allows a shorter wheelbase, a shorter rig and some weight taken off the rear axle which may allow a larger tank or some extra equipment.
In the same article, Darley Co. reps say they have pumps capable of 3,000 gpm and numerous combinations of pumps in combination with the compressed air foam (caf) that is becoming very popular.
Reps at the Waterous Pump Co. see a trend in FDs considering pumps at the 1,250 gpm size in order to cut costs in purchase (larger engines & transmissions), operation and maintenance.
According to the article, the 1,500 gpm pump is still the most popular size in the U.S.
We'll discuss the foam systems available in another article in the near future.
Best wishes, John
I'll pick up here next time. Thanks.
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