TM 10-4320-303-13
2.3.1.9 Determine Location of Pressure-Reducing Valve Assembly. (Continued)
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 pressure)
l. 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 psi = vertical footage conversion factor)
m. Using formula provided below, determine point at which pressure-reducing valve assembly must be
installed in hoseline:
Altitude at
-
Allowed additional
=
Pressure-reducing valve
hill crest
vertical footage
assembly installation
point
if elevation continues to drop excessively beyond first pressure-reducing valve assembly installation point, a
second pressure-reducing valve assembly must be installed in hoseline. Using formula provided below,
determine point at which next pressure-reducing valve assembly must be installed in hoseline:
altitude at first pressure-
Second pressure-
reducing valve assembly
-346.5 = reducing valve assembly
installation point
installation point
(346.5 = allowed additional vertical footage before reaching safety limit)
2.3.2 Grooved Pipe Coupling Removal and Installation . Remove and install grooved pipe coupling (Figure
2-12) as follows:
Tools
Used To
1-1/4, 1-1/16 inch wrench sockets and
Install 6 inch and 4 inch grooved
Handle (Items 85, 86, and 146,
pipe couplings.
Appendix C)
Personnel
Two required
NOTE
This is a general procedure for removal and installation of bolt secured model
grooved pipe couplings. Follow this procedure when using a bolt secured model
grooved pipe coupling to connect two TWDS components.
2-36
