Sunday, January 31, 2010

AFD Supply Line Debate Continues


My fellow hose jockeys, through scientific studies, equations, and diagrams I will show you why smaller supply lines are in our favor rather than large diameter hose. Thank you to Walt the plumber and Kiwi Army Blackie & Nicole for their valued assistance.

To determine how much a hose line weighs we will complete the simple math equations to find out the specific weight of each hose diameter in question. In order to find the amount of water in a charged hose line we will use the Volume of a Cylinder Equation,
V = π x r² x h

V = Volume π = 3.14 r = Radius h = Height

First we must identity the characteristics of the hose in question.

5in Large Diameter Hose (LDH): π = 3.14 r = 2.5in h = 100ft

4in LDH: π = 3.14 r = 2in h = 100ft

3in: π = 3.14 r = 1.5in h = 100ft

All measurements must be converted to the same units to equate. Convert feet to inches.

Set up the problem for each hose diameter and solve.

V = 3.14 x 2.5² x 1200 = 23550in³

Using the cancellation table to cancel out all units, except the desired gallons.

V = 3.14 x 2² x 1200 = 15072in³

V = 3.14 x 1.5² x 1200 = 8478in³

Now water weighs roughly 8.33lbs/US Gallon. Figuring this and the weight of the hose will give us the total weight of the hose when full of water.

8.33 x 102 + 84 = 934 lbs for 5”
8.33 x 65 + 68 = 610 lbs for 4”
8.33 x 38 + 38 = 355 lbs for 3”

With temperatures regularly being below 32ºF/0ºC, the freezing point of water, it is common for hose lines in Antarctica to build ice accumulation. The ultimate question is this: would you rather try and maneuver the frozen 5” hose weighing 934 pounds or the 3” hose weighing only 355 pounds?

Conclusion: Frozen 3” is less than frozen 5” or 4” supply lines. Thank you.

(Courtesy of Lt Hardrick)

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