By Rick Andrew
There are many different forms, functions and configurations for products generally considered to be water coolers. Many of them heat the water in addition to cooling it or have a dispenser for room-temperature water. Some are free-standing while others sit on the counter top. Some of them offer ice makers and even sparkling water. Others are configured to include POU filters and/or RO elements to treat the water. Options and variations abound. There are two main standards covering requirements for sanitation as well as health and safety for these products: NSF/ANSI 18 and NSF/ANSI 61, under which water coolers can be classified in three broad categories:
- Non-plumbed with bottle
- Plumbed-in bottleless
- Plumbed-in bottleless with POU treatment
Non-plumbed coolers with bottles can be evaluated under NSF/ANSI 18 Manual food and beverage dispensing equipment. This standard includes requirements for materials in contact with beverages, as well as requirements for design and construction. The former are according to NSF/ANSI 51 Food equipment materials, which is largely based on US government requirements outlined in Title 21 of the US Code of Federal Regulations, with additional requirements for metals, coatings and some other material types.
Design and construction requirements under NSF/ANSI 18 are based on hygiene and the ability of users to effectively clean the system to prevent contamination. This is important because there is a possibility for contamination when the bottle is filled or replaced. One of the key requirements related to possible contamination is an in-place cleaning test. This test involves first contaminating the cooler with E. coli. The cooler is then cleaned according to the manufacturer’s instructions. After cleaning, the cooler is refilled with sterile, buffered dilution water, which is then dispensed and analyzed for E. coli. The standard requires that the E. coli must be reduced by 99.9999 percent (6-log) by the manufacturer’s recommended in-place cleaning procedure. NSF/ANSI 18 additionally requires that any water filters or RO treatment integral to the cooler must conform to the requirements of NSF/ANSI 42, 53 and /or 58, as applicable.
Vending machines of any kind, including the machines that vend drinking water and are frequently installed at supermarkets, are not covered under NSF/ANSI 18. They are covered under a standard specific to this type of equipment: NSF/ANSI 25 Vending machines for food and beverages.
Coolers that are plumbed-in bottleless can be evaluated under NSF/ANSI 61 Drinking water system components–Health effects. It addresses a broad scope of materials and components used in drinking water treatment and distribution (from source to tap), with different sections of the standard including specific requirements for various product types. For example, pipes and related products are addressed by Section 4, while joining and sealing materials used in a water distribution system are covered under Section 6.
Requirements for end-point devices typically installed in the last liter of the distribution system, including faucets and water coolers, are found in Section 9. Under this standard, safety of materials in contact with drinking water is established through extraction testing. The product is exposed to test water under specific conditions, after an initial conditioning period. Leaching of various contaminants is tested with exposure to water of specific pH and composition, with different types of contaminants evaluated with different exposure waters. Concentrations of any contaminants detected are normalized to the appropriate end use and then evaluated to determine if they are within acceptable levels.
Note that the scope of NSF/ANSI 61 is health effects only. It addresses the safety of materials in contact with drinking water. It does not address structural integrity of pressure vessels, mechanical durability of valves or other types of performance criteria. Also, POU water treatment products are excluded from the scope of this standard. Cooler systems that are sold with integral water filters or RO components are considered to be POU treatment systems. As such, evaluation of these products actually would fall under the scope of NSF/ANSI 42, 53 and /or 58, as applicable. Figure 1 describes each of these scopes.
Coolers designed to include POU treatment
Many coolers are not sold with integral water filters or RO treatment options, but they are designed so POU filters can be used. These coolers are manufactured with the intent that the end user can select the specific brand and/or type of filters they would prefer; then they can connect them to the cooler. Because these coolers are not sold with integral water filters or other POU treatment, they do not fall under the scope of NSF/ANSI 42, 53 and /or 58. Rather, these products are evaluated under NSF/ANSI 61, Section 9, as are other plumbed-in, bottleless coolers.
Just as there are a number of possible configurations and features of water cooler systems, there are also a number of possible standards under which these products can be evaluated. Figure 2 provides a summary overview of these possible configurations and associated standards. The key to understanding which standard is applicable to a given product is a clear understanding of the scope of each of the standards. Hopefully this discussion helps provide this clarity for water coolers of various configurations.
About the author
Rick Andrew is NSF’s Director of Global Business Development–Water Systems. Previously, he served as General Manager of NSF’s Drinking Water Treatment Units (POU/POE), ERS (Protocols) and Biosafety Cabinetry Programs. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at (800) NSF-MARK or email: Andrew@nsf.org