TM 10-4320-345-13
2-11. ASSEMBLY AND PREPARATION FOR USE - cont.
(h)
Using formula provided below, determine total feet of friction loss:
Vertical feet of friction loss in hoseline + Feet of elevation between pumping
station and hill crest = Total feet of friction loss
(i)
Using formula provided below, convert total feet of friction loss into psi:
Total feet of friction loss = fiction loss in psi
2.31
(2.31 = psi conversion factor)
(j)
Using formula provided below, determine existing psi at hill crest
150 psi - psi of friction loss = psi at hill crest
(150 psi = pumping station discharge pressure)
(k)
Using formula provided below, determine allowed additional psi before safety limit is reached:
225 psi - psi at hill crest = Allowed additional psi before reaching safety limit
(225 psi = safety limit of pressure)
(I)
Using formula provided below, convert allowed additional psi into vertical feet:
Allowed additional psi x 2.31 = Allowed additional vertical footage before reaching
safety limit.
(2.31 = vertical footage conversion factor)
(m)
Using formula provided below, determine point at which pressure reducing valve must be
installed in hoseline:
Altitude at hill crest - Allowed additional vertical footage = Pressure reducing
valve installation point
(13)
If elevation continues to drop excessively beyond first pressure reducing valve installation point, a
second pressure reducing valve must be installed in hoseline. Using formula provided below,
determine point at which second pressure reducing valve must be installed in hoseline:
Altitude at first pressure reducing valve installation point - 346.5 = Second
pressure reducing valve installation point
(346.5 = allowed additional vertical footage before reaching safety limit)
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