Straight Pipe Requirements
Sufficient straight-pipe runs are required at the
detector inlet and outlet for optimum meter accuracy
and performance . An equivalent of three diameters of
straight pipe is required on the inlet (upstream) side . Two
diameters are required on the outlet (downstream) side .
FORWARD FLOW
MINIMUM STRAIGHT PIPE
MINIMUM STRAIGHT PIPE
ELBOW
TEE
GATE VALVE
(FULLY OPEN)
MINIMUM STRAIGHT PIPE
CHECK VALVE
GLOBE VALVE
BUTTERFLY VALVE
PUMP
ELBOW
TEE
ANY VALVE
FLOWMETER
3 x D
7 x D
2 x D
D (Pipe Size)
D (Pipe Size)
MINIMUM PIPING REQUIREMENT
STANDARD CONCENTRIC
REDUCERS
(NO DISTANCE REQUIRED)
Figure 8: Straight pipe requirements
Pipe Reducer Requirements
With pipe reducers, a smaller meter can be mounted in larger pipelines . This arrangement may increase low-flow accuracy .
There are no special requirements for standard, concentric, pipe reducers .
Custom fabricated pipe reducers must have an approximate slope angle of 15 degrees to minimize flow disturbances and
excessive loss of head . If this is not possible, install the custom pipe reducers as if they were fittings and install the required
amount of straight pipe
Figure 9: Pipe reducer requirements
Chemical Injection Applications
For water line applications with a chemical injection point, install the meter upstream of the injection point . This eliminates
any meter performance issues .
Figure 10: Chemical injection point upstream of meter
If a meter must be installed downstream of a chemical injection connection, the distance between the meter and the
injection point should be between 50 and 100 feet (15 and 30 meters) . The distance must be long enough to allow the water
or chemical solution to reach the meter in a complete, homogeneous mixture .
Figure 11: Chemical injection point upstream of meter
If the injection point is too close, the meter senses the two different conductivities for each liquid . This will likely result in
inaccurate measurements . The injection method—spaced bursts, continuous stream of drips or liquid or gas—can also affect
downstream readings by the meter .
Meter Location, Orientation and Applications
Page 10
January 2018
MAG-UM-00379-EN-04