Install Instructions

IM-PR 566442 1114 (Design Manual)
34
Figure 1-26 Pressure drop of ViegaPEX Barrier tubing based on flow rate and diameter
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 flow
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, fittings,
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:
Determine the pressure drop associated with 200
feet of ½" tubing at a maximum flow rate of 1 gpm:
1. Locate desired 1 gpm flow rate for the tubing
on the left vertical axis of Figure 1-26
2. Follow to the right until you reach the
diagonal line corresponding to 0.5" tubing
3. Move down to the horizontal axis and read
the pressure drop in feet of head per foot of
tubing (~0.05 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 (0.05*200=10 feet of head)
0.1
1.0
10.0
100.0
0.01 0.10 1.00
10.00
Flow Rate (GPM)
Pressure Drop, 100% Water (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