What’s a reliable margin of error for a flowmeter?
asked 14 December 2016 asked by Florent (360 points)
Hello, For portable devices measuring level and velocity, I would go with a 10% error margin.
Hello, In general, a flow meter is accurate to about 10%, and it is designed to measure clear water. But the geometry of a wastewater network is different. Surface velocity of fluids is not uniform, and therefore difficult to ascertain with precision. Also because the treatment of wastewater implies that fluids are charged, this further distorts readings. With wastewater, it's common to see a margin of error of up to 13 or 14%. NB. Depending on the configuration, make sure there is no hydraulic jump in the zone being measured.
Instead of assuming, because 10 - 15 percent is quite a large number! I would ask what model it is because meters are designed very reliable if he application is correct.
Here in South Florida we have used a combination Doppler/Ultrasonic flow meter to measure flow in a gravity wastewater system. The accuracy is +/- 5%.