| 1 | Confirm electrical conductivity | Clean water: approximately 0.05–2,000 mS/m | Magnetic-inductive meter for conductive liquids | Measures volumetric flow without moving parts and does not require an obstruction in the flow path. | The liquid normally needs conductivity above the meter's minimum specification. Very low-conductivity liquids, such as some demineralized waters, may require another technology. |
| 2 | Handle low or changing conductivity | Low-conductivity water, condensate, or treated water; often below 50–100 µS/cm | Ultrasonic transit-time meter or carefully selected mechanical meter | Ultrasonic measurement does not depend on liquid conductivity and can be installed without cutting the pipe when using a clamp-on design. | Check pipe material, wall thickness, lining, air bubbles, and straight-run requirements. Verify performance with the actual water quality and flow profile. |
| 3 | Match pressure rating to the system | Common industrial systems: 6, 10, 16, or 25 bar nominal pressure classes | Flanged magnetic, ultrasonic, vortex, or turbine meter with a suitable pressure class | A correctly rated body, flange, gasket, and connection protects the meter during normal operation and pressure transients. | Select for maximum operating pressure, not average pressure. Include surge, pump start-up, water hammer, vacuum conditions, and the pressure rating of adjacent piping. |
| 4 | Check process temperature | Typical water service: 0–80 °C; heated water may reach 120–180 °C | Meter with temperature-rated liner, electrodes, seals, sensor body, and electronics | Temperature affects wetted materials, seal life, electronics location, and the accuracy or reliability of some measurement principles. | Specify continuous and maximum peak temperature separately. Consider ambient temperature, insulation, steam cleaning, and whether a remote transmitter is needed. |
| 5 | Evaluate suspended solids and abrasives | Low solids: below 1%; abrasive slurries can exceed 10% by mass | Magnetic-inductive meter for conductive slurry; ultrasonic meter for compatible solids service | Magnetic meters have no impeller to clog and tolerate many suspended solids when the lining and electrodes are correctly selected. | Assess particle size, hardness, settling velocity, air entrainment, and lining wear. Avoid turbine or paddle-wheel designs where solids can jam or damage moving parts. |
| 6 | Size for the actual flow range | Design around the normal flow; verify minimum, maximum, and turndown requirements | Magnetic or ultrasonic meter with a suitable velocity range; reduced-bore installation where permitted | Correct sizing helps maintain measurable velocity at low flow while avoiding excessive pressure loss and over-range operation at peak flow. | Record minimum, normal, maximum, and emergency flow. Avoid sizing only from the pipe diameter. Check Reynolds number, velocity limits, accuracy class, and required turndown. |
| 7 | Plan installation and maintenance | Full pipe required for most inline meters; site conditions vary | Inline or clamp-on ultrasonic; magnetic meter with appropriate grounding and straight runs | Installation quality strongly affects repeatability, especially where flow is disturbed by pumps, valves, elbows, or partially filled pipes. | Provide grounding where required, keep the sensor full, avoid high points that collect air, follow straight-run guidance, and select outputs such as pulse, 4–20 mA, or digital communication. |