Part l: The Swimming Pool Case

Feb. 28, 2012

Going poolside to investigate an allegedly faulty flow switch

David W. Spitzer

Work often puts people in unexpected places. Some years ago, a lawyer contacted me regarding a case where his client allegedly damaged her lungs after allegedly inhaling chlorine gas at a hotel swimming pool. I was not surprised to be contacted by a lawyer (lawyers have attended my Industrial Flow Measurement seminar), but I was surprised to be contacted by a lawyer representing a client who was injured in a seemingly non-industrial location.

Documents had led the lawyer to suspect that a flow switch in the swimming pool water treatment system had failed to operate properly and caused a cloud of chlorine gas to form at the pool. The lawyer set out to find a consultant with both swimming pool and flowmeter expertise. After an exhaustive search, we were the only consultants he could find who could understand the problem at hand.

Now hired, armed with my detailed flowmeter expertise and my partner’s swimming pool expertise, we visited the hotel to examine the flow switch in question, the chemical control system, and the pool area. (On a personal note, I later found myself to be somewhat “out of water” in the pool area wearing my khaki work clothes and steel-toed shoes while sketching and making notes among the young and old swimmers who were on vacation having a great time enjoying the pool and water park.)

We discovered that the flow switch was used for both process control and safety functions. In addition, the flow switch sample lines were piped in such a manner that the flow switch did not reliably sense a no-flow condition in the larger pipe. When it did not sense the no-flow condition, the chemical pumps would not be prevented from operating, so chemicals could accumulate in the pipe and react to form chlorine. The chlorine could then be pumped into the pool when the circulation pumps started, thus creating a chlorine cloud. In addition, there were other hydraulic issues that could periodically cause the loss of pump prime, resulting in no-flow conditions that were not detected by the flow switch installation.

…more next month.

David W. Spitzer is a regular contributor to Flow Control magazine and a principal in Spitzer and Boyes, LLC offering engineering, seminars, strategic, marketing consulting, distribution consulting and expert witness services for manufacturing and automation companies. He has more than 35 years of experience and has written over 10 books and 250 articles about flow measurement, instrumentation and process control.
David can be reached at 845 623-1830 or www.spitzerandboyes.com. Click on the “Products” tab ?to find his “Consumer Guides” to various flow and level ?measurement technologies.

David W. Spitzer and Flow Control will be presenting a three-day Industrial Flow Measurement Seminar, June 12-14, in New Orleans. To learn more, visit FlowControlNetwork.com/FlowSeminar.

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