By Rick Howard, Howard’s Pool Service, Inc./email@example.com
For those maintaining commercial pools, dealing with Health Department inspections is a way of life. In Pinellas County they have really started cracking down on both not enough flow and/or too much flow.
Commercial pools are engineered for a required flow to turn over the pool in six hours. Some pools are designed for high flow rates to accommodate a higher bathing load. A general guide is five gallons per minute per bather. So a bathing load of 20 means 100 gpm, usually anyway.
We regularly see flow meters incorrectly installed. To be accurate they must be installed as per manufacturer’s specifications. For the most common flow meters in use in our county that means 10 times the pipe size diameter before the flow meter and five times after of straight uninterrupted pipe. For example, a 2” flow meter requires 20” of straight pipe before the meter and 10” after. If the flow meter isn’t correctly installed the readings will be all over the place and not accurate.
We have seen pools approved with flow meters that were incorrectly installed. Good luck with those! All the inspectors will look at are the readings. The pool technician needs to be aware of whether it is properly installed or not. We also see flow meters installed on pool heaters to verify water flow through the units. The same rules apply. We see them installed up against an elbow. Save your money, they aren’t working and the readings are most likely totally wrong. If you see a flow meter incorrectly installed you really need to correct it.
The new permit forms that must be posted in the pool area now list the required flow. They usually accept 10% plus or minus without failing the inspection, but not always. It is best to look over the flow meters every visit to make sure they are working. Doing this can prevent possible pool closures and/or re-inspection fees!