Install Instructions

IM-PR 566442 1114 (Design Manual)
108
0.1
1.0
10.0
100.0
0.01 0.10 1.00
10.00
Flow Rate (GPM)
Pressure Drop, 30% Propylene Glycol (FT OF HEAD PER FT OF TUBING)
0.5
5.0
50.0
0.02 0.03
0.04 0.05 0.06 0.08
0.20
0.30 0.40 0.50 0.60 0.80 3.00
2.00
4.00 5.00 6.00 8.00
ViegaPEX Barrier Tubing
Table 5-9 Thirty percent propylene glycol pressure drop table for ViegaPEX Barrier tubing
1½"
1¼"
¾"
⅝"
½"
⅜"
5
⁄
16
"
Continue calculating the pressure drop in the
primary piping:
• Determine the length of the primary piping.
Be sure to include all piping between the
heating source and secondary piping. For
each pipe size in the primary piping system,
use the pressure drop tables that correspond
to the system’s glycol content and ow
rate, and multiply the pressure drop per foot
(obtained from the table) by the equivalent
length of each corresponding piping size.
• Add the pressure drop of all valves, ttings,
heating source and other piping accessories
(expansion tanks, air separators, etc.) located
in the primary piping system.
The primary piping circulator should be sized to
accommodate the primary system flow rate at the
total pressure drop of the primary piping system
(calculated above).
Example of how to use a pressure drop chart:
Determine the pressure drop associated with 200
feet of ¾" tubing at a maximum flow rate of 5 gpm
for a 40% glycol solution:
1. Locate desired 5 gpm flow rate for the tubing
on the left vertical axis of Table 5-9
2. Follow to the right until you reach the
diagonal line corresponding to ¾" tubing
3. Move down to the horizontal axis and read
the pressure drop in feet of head per foot of
tubing (0.2 feet of head per foot of tubing)
4. Multiply the pressure drop per foot by the
length of tubing to find the feet of head for
the circuit (0.2*200=40 feet of head)