How to Avoid Flow Measurement Pitfalls

Life is full of bumps and ripples. To smooth out the ride, it helps to have some warning signs when such obstacles may be approaching. When I identify a

Life is full of bumps and ripples. To smooth out the ride, it helps to have some warning signs when such obstacles may be approaching. When I identify a quick fix on an application, the customer will invariably ask, "How did you know that?" I normally reply along the line of, "Well, I made the same mistake in 1972." I have so many tire tracks on my back it looks like a freeway.

While it would be a tall task for me to relay all of my lessons learned here – perhaps someday direct brain transfer will be possible – I can provide some insight on major flow measurement application pitfalls and provide a few potential solutions. As such, below I’ve highlighted key pieces of advice in the areas of flowmeter installation, maintenance and specification in the hope that this information can help you avoid some of the most common pitfalls that confront flowmeter users in real-world application environments.


  • Don’t Come Up Short: Talk to a specialist about cost. Many projects founder at purchase date when the cost is much higher than estimates made early in the game.

  • Tell All & Sleep Peacefully: Include all information on the application, and let a specialist make the application and compatibility decisions. A layman in a specific technical field will often make assumptions, which could throw flags up for a specialist.

  • Knowledge Is King: Make sure you really know what you need and want. For instance, a flowmeter might be specified for 100 GPM, but what minimum flow is necessary? What accuracy level is realistic for your process?

  • Don’t Let the Tail Wag the Dog: If a flowmeter is to interface with a control system, don’t let the control dictate the input that forces the use of a less-efficient flowmeter. For example, I’ve often had the computer folks ask for an analog input on a batching system, which would completely skew accuracy.

  • A Grain of Salt: Beware of selecting equipment by browsing Web sites. Much of the information you encounter is marketing material written by the manufacturer and is intended to convince you to select their meter. To ensure proper flowmeter specification, you must perform a thorough and complete evaluation of all of the viable solutions for your application. There are no shortcuts to proper flowmeter specification.


  • Check Your Parameters: Make certain the person installing the flowmeter understands the installation parameters and have them check with the vendor regarding specific piping, power, and classification requirements.

  • Don’t Push the Envelope: Straight-run before and/or after the flowmeter is a common problem. Many times problems arise because the specifier has not done the necessary homework and/or the piping plans have changed due to "as built" requirements. Also, it is important to remember that stated straight-runs required are most often minimums and must be expanded in some cases.

  • Be Nice: Consider your maintenance folks when you select and position the flowmeter. For example, it’s a good idea to pay the extra money for the option of wall-mounted remote electronics when the equipment is, say, 20-feet in the air.


  • Mind Your Manuals: Make sure installer doesn’t throw away the installation and operating literature after the initial installation is complete. You can be sure you’ll need this information again, especially if you don’t have it.

  • Be Proactive & Benefit: Be sure to read the maintenance section of the manual, and list the requirements on Preventive Maintenance Schedules. In our experience, approximately 25 percent of catastrophic failures are maintenance-related.

  • Have Your Resources Ready: Most medium and small plants do not have an instrument technician on staff, even though the equipment continues to become more and more sophisticated. As such, it is important to maintain good relations with a qualified technician who can respond quickly and effectively when the inevitable crisis occurs.

  • Plan Ahead or Face the Consequences: Keep a long-term working life log with expected replacement dates, looking out as much as 10 years. This helps ensure accurate budgeting and reduces the number of those pesky surprises that always seem to occur at the worst possible time.

Mike Lynch is a mechanical engineer with 35 years of experience in flow measurement in a variety of application environments. Mr. Lynch currently handles flowmeter sales, metering systems design, custom controls, and flow project consulting for Controls & Meters Inc. He has also authored numerous technical articles and presented industry and academic courses. Mr. Lynch can be reached at or 952 944-3666.

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