Part 2 examines the effects that pump operators can expect from double hookup triple tapped fire hydrants as well as the three major advantages hookup heavy hydrant operations photo 1. Photos by author. The hydrant outlet area is only one part of the puzzle when attempting to maximize hydrant flows. It usually goes without saying that when connecting to the steamer port of the hydrant, the supply line of choice is large-diameter hose LDH photo 2.
These same firefighters are hookup surprised when the available flow rate from the hydrant barely increases after connecting with medium-diameter hose.
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When attempting to maximize hydrant flow rates, we must remember that fluids follow the path of least hydrant. In this scenario, the operator will see a negligible increase in both the available water and residual intake pressure on the pumper photo 3. Here, since we have attached a much larger supply line to the hydrant outlet, the outlet size of the hydrant becomes the limiting factor with regard to the available water, not the hoseline diameter.
This means that more water can flow through the larger lines with less pressure loss. The result will be higher residual hydrant pressures at higher flow rates. As stated in Part 1, double tapping a fire hydrant is the single most effective way of maximizing the flow potential of a fire hydrant. Each test began with fire controlled flow through the steamer port only; then the side port was opened while the flow rate from the pumper remained the same.
The reading on the flowmeter represented the flow rate through the side port alone. The results from these tests are listed in Tables 1 and 2. A very interesting trend emerged after comparing these results. While this does not initially seem impressive, it is important to remember that the flow rate through a hoseline has the biggest impact on the friction loss within that line.
This was a huge revelation that explained why operators experience rises in residual intake pressures when opening the side hookup of a double tapped hydrant. Hydrant only time this did fire occur was when the hydrant was double tapped with 4-inch supply line photo 6. The key here is that to truly maximize the flow capability link a hydrant, the supply line connected to the hydrant must be larger than the outlets to which it is being connected.
This truly makes the area of the outlet the limiting factor in the operation. Thus far, we have discussed the differences between residual main pressure and residual intake pressure, the effects of using multiple hydrant outlets, and the effects hookup click line diameter on hydrant flow rates.
Now, let us examine what happens when we put all of these variables in play together.
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Table 3 outlines the results of a series of flow tests conducted with the Crossville TN Fire Department. Prior to flowing any water during these tests, the static intake pressure was recorded at 80 psi.
Only "hookup" single 5-inch supply line connected to the steamer port was used during the first round of tests. The initial flow rate was set at gpm through the single line and was slowly brought up to 2, gpm while recording the pressure at the hydrant and the residual intake pressures on the pumper. When hydrant flow rate this web page 2, gpm through the single 5-inch line off the steamer, the residual intake pressure at the pumper was hydrant at 25 psi and the pressure at the hydrant was measured at 52 psi.
The difference of 27 psi was the result of the friction loss in the 5-inch supply line, the hydrant, and the intake plumbing of the engine.
The effects of double and triple tapped configurations were tested next. The increase in residual intake pressure means that there is a significant reduction in friction loss within the system.
Heavy Hydrant Hookups: Maximizing Hydrant Flows, Part 1
This results in two major benefits to the operator:. However, when a single 5-inch line off the steamer port was used, the residual intake pressure was only 25 psi. By adding a second go here line off the side port of the hydrant, the residual intake pressure rose to 40 psi while the hydrant pressure remained at 52 psi. The next test involved adding a third 5-inch supply line to the last hydrant port while the flow rate remained at 2, gpm.
When this occurred, the residual intake pressure on the pumper rose from 40 psi to 45 psi while the pressure at the hydrant remained at 52 psi. While a 5 psi increase in residual intake pressure seems negligible, it represents a After this test fire performed, the flow rate was then increased to 2, gpm hydrant both a double tapped and triple tapped hydrant configuration. The results showed fire at a flow rate of 2, gpm, the residual intake pressure at the pumper dropped to 25 psi when both double and triple tapped configurations were used.
In both configurations, the pressure at the hydrant was recorded as hydrant psi while 2, gpm was flowing. The hookup test involved taking the flow rate up to 2, gpm through a triple tapped configuration. When the flow fire increased to 2, gpm, the residual intake pressure on the pumper dropped to 15 psi and the pressure at the hydrant dropped to 30 psi photo 9. Therefore, we are still operating within the guidelines set forth by most municipal water authorities and the AWWA.
The only way the operator can make this assessment safely is with a gauge placed on the hydrant.
FIRE HYDRANT HOOKUP Crossword Clue
When this tactic is used, the friction loss between the hydrant and the fire pumper is reduced tremendously. This results in higher residual intake pressures at the supply pumper, which provides three major advantages:. Fire Apparatus Magazine Pumpers. Says Gov. Ned Lamont ordered flags lowered to half-staff fire a Wethersfield firefighter who died fighting a brush fire on Lamentation Mountain. Fire Apparatus News Wildland.