By Rick Andrew
NSF/ANSI 50 Equipment for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilities includes requirements for a wide range of products and technologies. Equipment as diverse as pumps, sand filters and ultraviolet disinfection systems are all covered under various sections. In addition to a broad scope in terms of equipment covered, the end-use applications under this standard are also quite broad—everything from residential hot tubs all the way to commercial water parks is included under the standard. NSF/ANSI 50 includes general requirements for materials in contact with recreational water, including safety against leaching of harmful chemicals and corrosion resistance. Additional general requirements exist for design and construction of various types of equipment. For example, seals are required to be free of leaks and piping assemblies are required to be able to be disassembled for repair.
There are a number of types of equipment which have specific requirements established in NSF/ANSI 50 (see Figure 1). Sections 12 through 16 address process equipment. In addition to specific requirements for each type of process equipment, there are general requirements for all process equipment. These general requirements are indicated in Figure 2. Given the broad range of types of equipment covered, the standard includes a number of different testing protocols and equipment requirements designed specifically to address potential concerns with these types of equipment, as well as to evaluate the intended end use of each type of equipment. In addition to the 18 sections of the standard, there are also 14 annexes (A through N). These address details of test methods and other relevant information for specific types of products, and allow the main body of the standard to be focused more on the equipment requirements themselves.
|Equipment type||Section of|
|Recessed automatic surface skimmers||8|
|Mechanical chemical feeding equipment||9|
|Flow-through chemical feeding equipment||10|
|Ozone process equipment||12|
|Ultraviolet light process equipment||13|
|In-line electrolytic chlorinator or brominator process equipment||14|
|Brine (batch) type electrolytic chlorine or bromine generators||15|
|Copper/silver and copper ion generators||16|
|Water quality testing devices||18|
|Cleanability||Parts requiring cleaning must be accessible for cleaning|
|Design pressure||Parts subjected to pressure must meet a working pressure of 50 psi or be equipped with a pressure reducing valve pressure.set at the manufacturer’s working|
|Flowmeter||If the performance of the unit is dependent on a specific flow rate, then a means to monitor and control the flow must be provided|
|Performance indication||The equipment must be provided with an effective means to warn the user when a component of the equipment is not operating.|
|Operation and installation instructions||Specific informational requirements must be included.|
|Disinfection efficacy||A three-log reduction of influent bacteria is required when tested per the standard.|
|Valve and component identification||All valves and performance indication devices must have a permanent label identifying their operation.|
First adopted in 1977, the standard has a long history of development and evolution behind it as it has changed to keep up with developments in the sophistication of recreational water facilities and equipment. Section 18, Water Quality Testing Devices (WQTD) was added in 2009 to include requirements for test strips, chemical kits and probes used to monitor the quality of recreational water. Criteria exist for devices and kits used to evaluate pH, free and combined chlorine and bromine. These criteria include both accuracy and precision of the measurements obtained. Shelf life of reagents and components of testing devices is also addressed. Finally, there are informational requirements set forth for the operation and use instructions for these testing devices, as well as marking of the device or kit itself.
In 2010, a new requirement was added for UV systems used to treat Cryptosporidium. This change was to allow the use of test data from product evaluations for drinking water applications to be used in the evaluation of recreational water UV systems. This change simplified the evaluation process for UV system manufacturers serving both the drinking water treatment market and the recreational water treatment market, as well as reducing redundant testing.
In 2011, the standard was reorganized to create Section 11 specifically to house the requirements for filtration media, including precoat, sand and alternatives to sand. Previously, section 11 had housed the general requirements for process equipment. These requirements were moved into the relevant sections directly (Sections 12 through 16). These changes made the standard more user-friendly and easy to follow.
Appropriate standards and experts
Just as the NSF Joint Committee on Drinking Water Treatment Units has responsibility for the NSF/ANSI Drinking Water Treatment Unit Standards, NSF/ANSI 50 was developed by the NSF Joint Committee on Swimming Pool and Spa Equipment. Each committee includes experts with relevant backgrounds for the technical and regulatory issues pertinent to the products in question. As experts working diligently to assure that the standards keep up with technology and regulations, these joint committees will continue to evolve the standards as necessary to keep them relevant and effective for consumers’ safety and to provide a platform for manufacturers to demonstrate fitness-for-purpose of their products.
About the author
Rick Andrew is the General Manager of NSF’s Drinking Water Treatment Units (POU/POE), ERS (Protocols) and Biosafety Cabinetry Programs. He has previously served as the Operations Manager, and prior to that, Technical Manager for the pro- gram. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can bereached at (800) NSF-MARK or email: Andrew@nsf.org.