When selecting a flow meter for oil or diesel applications, accuracy is often the first factor that comes to mind. But there's another critical specification that can make or break performance in real-world conditions — turndown ratio . Also known as rangeability, turndown ratio defines the range over which a flow meter can maintain accurate measurements, from its highest to lowest detectable flow rate . In demanding environments like oil and gas operations, where flow rates fluctuate dramatically, this metric becomes even more important than raw accuracy. For example, in flare monitoring systems, flow can vary from a small pilot flame to a full emergency blowdown event. A meter with poor turndown might miss low-level leaks or fail during peak flows. That's why engineers are increasingly looking beyond basic accuracy and focusing on how well a meter performs across its entire operating range . Take thermal mass flow meters, commonly used in gas flow applications such as n...