Install Instructions

Viega PureFlow System Design Considerations
35 of 88
IM-PF 724596 1021 PureFlow Water System (EN)
6.5.3.2 Pressure Loss
Viega recommends the following velocities for hot and cold PEX water
distribution systems:
■ Domestic cold water — 10 fps
■ Domestic hot water — 8 fps
The 󶈶ow velocity through Viega’s PEX 󶈵ttings does not fall under these
limitations. The equivalent length of PEX tube for Viega PureFlow 󶈵ttings
is available from Viega to assist in system sizing where applicable (refer to
"6.5.2 Viega PureFlow Fittings Sizing" on page 33).
Flow
Rate
GPM
60° F (16° C) Water
Pressure Loss PSI/ 100 ft of Pipe
⅜ ½ ¾ 1 1¼ 1½ 2
0.5 2.0
0.75 4.1
1.0 7.0 1.6
Pressure Loss <1 psi
1.5 14.9 3.4
2.0 25.4 5.8 1.1
2.5 38.5 8.7 1.6
3.0 53.9 12.2 2.3
3.5 16.2 3.0
4.0 20.8 3.9 1.1
4.5 25.8 4.8 1.4
5.0 31.4 5.9 1.7
6.0 44.0 8.2 2.4
7.0 10.9 3.2 1.2
8.0 14.0 4.1 1.6
9.0 17.4 5.1 1.9
10.0 21.1 6.2 2.3 1.0
11.0 25.2 7.4 2.8 1.2
12.0 29.6 8.8 3.3 1.5
13.0 34.3 10.1 3.8 1.7
14.0 11.6 4.4 2.0
15.0 13.2 5.0 2.2
16.0 14.9 5.6 2.5
17.0 16.7 6.3 2.8
18.0 18.5 7.0 3.1
19.0 20.5 7.7 3.4
20.0 22.5 8.5 3.8 1.0
25.0 12.8 5.7 1.5
30.0 Pressure Loss
Excessive as Flow
velocity is > 12 ft/sec
18.0 8.0 2.2
35.0 10.7 2.9
40.0 13.7 3.7
45.0 17.0 4.6
50.0 5.6
55.0 6.6
60.0 7.8
65.0 9.0
70.0 10.4
75.0 11.8
Pressure Loss based on Hazen-Williams Formula (C = 150)
Pressure Loss for Actual Length can be calculated by following formula:
Actual Length / 100 ft x Value from chart above