A word of caution should also be given when attempting to use the max flow of a pump to size replacement drain covers on pools with 38 mm (1.5 in.) and 50 mm (2 in.) pipe. They have significantly lower flow ratings compared to the max flow of pumps, because they do not have the capacity to move as much water as the short pipe runs used for NSF-50 pump testing. In these instances, the flow rating restriction is not the drain cover, but the pipe it is connected to. When this situation arises, the actual flow of the operating VGBA suction system should be used to confirm VGBA-2017 compliance. While the flow ratings of drains compatible with 38 mm pipe appear very low, typical drain cover flow capacity far exceeds the flow the suction pipe can handle without cavitating the pump.
The author’s company has a certified NSF testing lab to conduct hair and body block testing to generate pipe-specific flow ratings. NSF is also their certification agency for all products in compliance with the revised federal drain cover standard ANSI/APSP/ICC-16 2017. These products are marked VGBA-2017. The company is able to provide many common (and even some uncommon) configurations, so customers have the information they need to ensure their pools are safe and VGBA-2017 compliant.
Conclusion
As with all products, it is always important to read the specifications before placing the order, then follow the instructions included with drain covers. Doing so will ensure proper safety and compliance with the updated VGBA-2017 standard.
Steve Barnes is the director of science and compliance for AquaStar Pool Products. He is the co-chair of the Pool & Hot Tub Alliance (PHTA) Technical Committee; chair of ANSI/APSP/ICC-16 2017, the Federal VGB Pool & Spa Safety Act drain cover standard writing committee; and past chair of the ANSI/APSP/ICC-15 Standard for Residential Swimming Pool Energy Efficiency. He is also a voting member on the International Code Council (ICC) Swimming Pool and Spa Code Committee, as well as all versions of ANSI/PHTA/ICC-7 Standard for Suction Entrapment Avoidance. Barnes has 38 years of experience in the pool industry, dating back to 1984, where he began as a hydraulics research and development lab technician. He then moved into lab management, new product development, and risk management. His career focus is on helping pool contractors make pool ownership more enjoyable, cost effective, and safe.
