Product Overview

Hydraulic characteristics
- Reference
conditions:
Upstream pressure =
8 bar
Downstream pressure
= 3 bar
Sizing procedure
Maximum flow velocity is recommended to be kept within 3 to 6 feet
per second when calculating the correct pressure reducing valve size.
This will prevent noise in the pipes and rapid wear of appliances.
Minimum flow velocity to prevent excessive wear on the valve and to
reduce the chance of noise due to low flow is 1 foot per second.
The correct size of the pressure reducing valve is taken from graph
1 on the basis of the design flow rate taking into account an ideal
maximum flow velocity in the valve body of between 3 and 6 f/s (blue band).
Example:
For 8 gpm, select the 3/4” size valve (see arrow on graph 1).
The pressure drop is taken from graph 2 also on the basis of
where the design flow rate intersects the curve for the valve size
already selected (the downstream pressure falls by an amount
equal to the pressure drop, with respect to the set pressure at no
flow condition). Make sure the falloff pressure (pressure drop) of
the chosen valve, at the specifed flow rate, will result in the valve
supplying the required pressure to the system fixtures
Example: For 8 gpm the Dp = 7.3 psi (see arrow on graph 2).
∆p (bar)
0,5
1
0,2
0,1
1,5
0,3
0,4
0,6
0,8
1,2
0,9
0,7
∆p (m w.g.)
5
10
2
1
15
3
4
6
8
12
9
7
5351
1/2" 3/4"
5350
1/2" 3/4" 1" 1" 1 1/4" 1 1/2" 2"
0.45
5
V (m/s)
0.1
4
3
0.3
1 1/4"
(535074/5)
1” 1 1
/
4”1
/
2” 3
/
4”
1 2 5
0,2
10 20
20 50
100
Flow rate
(l/min) (m
3
/h)
200
5
10
1.5
V (f/s)
0.3
15
10
1
8
20
90
Flow rate
(/s)
(gpm)
30 40 10 5 2 1
0.9
5
50 60 70
1 2
0.5 0.2 0.1
0.05
3 4 6
1.5 0.3 0.4
2.5
80 3 4
0.150.5
2 0.6
3 0.9
6 1.8
5
4 1.2
1
/
2”1
2”
Graph 1 (Maximum velocity for sizing)
48
103
20
10
150
28
35
62
117
90
68
5
10
2
1.5
20
3
15
7
1 in 1 1/4 in
3/4 in
1/2 in
FALL OFF PRESSURE
Reference values: Upstream pressure = 116 psi (800 kPa)
Downstream presssure = 43 psi (300 kPa)
14
∆ p (psi)
∆ p (kPa)
1 1/2 in
2 in
20
90
Flow rate
(/s)
(gpm)
30 40 10 5 2 1
0.9
5
50 60 70
1 2
0.5 0.2 0.1
0.05
3 4 6
1.5 0.3 0.4
2.5
80 3 4
Design Flow Rate
Size ½" ¾" 1" 1¼" 1½" 2"
gpm 4 to 7.3 7 to 12.5 10 to 19 17 to 34 24 to 44 37 to 70
Graph 2 (Pressure drop)