Flowmeter should be accurate to a tolerance of blank percent.

• A. +/- 1%
• B. +/- 2%
• C. +/- 3%
• D. +/- 5%

Answer: (C)

Flowmeter accuracy is about how close the indicated flow is to the actual flow during a test. A tolerance of plus or minus 3% means the meter’s reading will be within 3% of the true discharge across the range you’re measuring. This level of precision is practical for evaluating pump performance without requiring extremely pricey instrumentation or ultra-tight calibration.

If the tolerance were tighter, like plus or minus 1% or 2%, you’d need higher-precision meters and stricter setup, which isn’t usually necessary for standard testing and would raise costs. If it were looser, like plus or minus 5%, the readings could be too far from actual flow, leading to less reliable assessments of the pump’s capacity.

So, the typical, appropriate tolerance used in this context is plus or minus 3%. For example, at an actual flow of 1,000 gpm, the reading would be expected to fall roughly between 970 and 1030 gpm.