The whole tanker traffic jam can be further complicated if a tanker gets stuck as it attempts to back out the lane, trapping all the other trucks at the scene. Some departments have a water supply pumper pull in the end of the lane and set a dump tank behind the pumper. This allows room for tankers to pass by the dump tank to side dump or rear dump thus keeping all tankers out on the road. The downfall of this setup is that the lane is blocked. No other vehicles can go back down the lane to the fire scene. In an attempt to keep all water supply operations out on the roadway, a dump tank can be set next to the water supply pumper. Now both lanes of the road are blocked causing all tankers to turn around in narrow private drives and back long distances to rear dump in the dump tank.
(Photo #2) When using the Single Lane Water Supply Setup the pumper and dump tanks are set up in the same traffic lane.
What if there was a simple standardized water supply setup in which:
- All water supply vehicles stay on the roadway,
- The lane to the fire remains open,
- Tankers can drive past the fire scene and side dump or rear dump with no turning required?
The Single Lane
Water Supply Setup
The single lane water supply setup features the use of rectangular dump tanks that sit in a single traffic lane in line with a pumper (see photo #1 and diagram #1). This allows traffic to pass by in the other traffic lane. Tankers can either side dump or rear dump. A pumper can easily draft from both sides of the truck at the same time. This makes it possible to draft from dump tanks in front of and behind the pumper. We’ve seen four dump tanks in the single lane setup easily handle a fire flow of 1,200 GPM. Only one pumper is needed to run the dump site including operating jet siphons — if you use efficient jet siphons. This same water supply set up can be used with the attack pumper when it’s setting out on the roadway.
Rectangular Dump Tanks
These can be custom built by dump tank manufacturers. We recommend that you specify eight feet width on your dump tanks. Our dump tanks are 8 feet wide by 14 feet long by 29 inches deep (2,000 gallons). We tried 3,000-gallon dump tanks — 10 feet wide by 16 feet long by 29 inches — for greater storage capacity but found that the extra two feet in width was just too wide for the typical roadway. Most dump tank racks on tankers are built for square dump tanks and are approximately 12 feet long. Contact dump tank manufacturers for single lane tanks that can fit on your truck. For example: Fold-a-Tank’s Type II single lane dump tank holds about 2,000 gallons and is eight feet wide and folds up so the total length is only 11 feet, three inches.
(Photo #3) When the dump tank is full the water level is within two to three feet of the pumper’s suction inlet.
Dump Tank Drafting Flanges
You want to be sure that you specify a through the dump tank wall drafting flange (see picture #2). This saves running suction hose up over the side of the dump tank. You only need one suction flange per dump tank. When the dump tank is filled with water the suction hose is filled to within two to three feet of the pumper’s suction inlet (see picture #3). This makes priming the pump very easy. Dump tank flanges can easily be retrofitted on existing dump tanks. It usually takes two sections of suction hose to reach the dump tanks in the single lane set up. With the suction strainer firmly supported in a corner of the 14 feet long dump tank it is well protected from turbulence of jet siphons and dumping tankers (see picture #4). You’ll learn to dump in the drafting tank(s) first.
A 90-Degree Suction Elbow
This elbow (see picture #5) helps turn the suction hose right down along the running boards on your pumper. This makes it easy to stand up next to a midship side mount pump panel. You want to be sure to specify that the elbow use two 45-degree angles to complete the 90-degree turn. An abrupt 90-degree turn severely impedes water flow when drafting through the elbow.
A Suction Butterfly Valve
A suction butterfly valve — if no inline suction shut off valve — can be used to allow you to draw water from the on board water tank while you hook up the suction hose. A critical benefit of the butterfly valve is that it extends your suction inlet out to within five inches of clearing the running boards. This is important to allow the 90-degree suction elbowroom to guide the suction hose down past the running boards.
(Photo #4) Low-level strainer is attached to dump tank flange in the corner of dump tank. It is well protected from turbulence of tanker dumping and jet siphons.
The single lane concept is difficult to thoroughly explain in a magazine article. There are currently three power point presentations available online. These power points can fill in more details on the finer points on how the single lane water supply setup works. You can either Google “single lane water supply set up” or go to the www.gotbigwater.com website — under “Big Water Information” look under “Operations” and “Data.” If you haven’t viewed the Got Big Water website you’ll find it to be a treasure trove of information about supplying water to a fire scene.
Trucking water to a fire scene is all about efficiency. The single lane water supply setup is one of several tools that can increase your water supply efficiency at the fire scene.