Center for Disease Control Facts on Recreational Water Illness
Recreational water illnesses (RWIs) are caused by germs spread by swallowing, breathing in mists or aerosols of, or having contact with contaminated water in swimming pools, hot tubs, water parks, water play areas, interactive fountains, lakes, rivers, or oceans. RWIs can also be caused by chemicals in the water or chemicals that evaporate from the water and cause indoor air quality problems.
RWIs include a wide variety of infections, such as gastrointestinal, skin, ear, respiratory, eye, neurologic, and wound infections. The most commonly reported RWI is diarrhea. Diarrheal illnesses are caused by germs such as Crypto (short for Cryptosporidium), Giardia, Shigella, norovirus and E. coli O157:H7.
Float Industry Regulations Effective Nationwide
NSF Standard 50 contains criteria for a wide range of equipment that is designed to disinfect pools and spas. These include chemical feeders, (mechanical and flow through), as well as and bromine, ozone, and UV systems.
Circulation System Components
NSF 50 has specific design, flow, durability and safety requirements for the integral components of the circulation system, including pumps, skimmers, pipe and fittings, suction fittings, and valves.
Centrifugal pumps are required to withstand a hydrostatic pressure of 150 percent of the maximum working pressure. There are design criteria for strainers, drain plugs and shaft seals. Each pump must be sold with operating instructions that must include a manufacturer's pump performance curve. NSF 50 includes a test method to verify these pump performance curves.
Multiport valves are required to meet a burst pressure of four times the maximum working pressure and shall not leak, rupture or burst when subjected to 1.5 times the maximum working pressure for five minutes. The ability of a multiport valve to seal off ports not in use during the filter and backwash cycles is judged by a differential pressure/leakage test. Valves are tested to verify the pressure loss claims of the manufacturer, and waste ports are tested for leakage.
Recessed automatic surface skimmers are required to meet dimensional requirements of NSF 50 for the housing, weirs and strainer basket. The structural integrity of a skimmer housing is evaluated by subjecting the housing to a vacuum of 85kPa for five minutes. Weirs are required to automatically adjust to changes in the water level when operating at the maximum design flow rate. Skimmers for commercial pools are required to have an equalizer line that prevents air from becoming entrained in the suction line. Leakage of water through the equalizer is not allowed to exceed 10 percent of the total flow through the skimmer under normal operating conditions.
NSF 50 establishes criteria for cartridge filters, diatomaceous earth filters and sand-type filters. In addition to the material requirements mentioned previously, NSF 50 addresses structural durability and filtration performance.
NSF 50 requires materials to be corrosion-resistant and to meet minimum criteria established to ensure that the materials do not contribute harmful contaminants to the water.
Materials that have more than 650 square centimeters of water contact area are required to meet leaching test requirements designed to identify harmful contaminants that may migrate out of the material and into the water. Material samples are exposed to a defined extraction water for three 24-hour periods.
The extractant water from the final 24-hour exposure period is analyzed for contaminants, which must be below acceptable levels based on -- USEPA drinking-water standards.
All electrical components of equipment are required to meet the requirements of the National Electric Code and referenced standards.
NSF/ANSI Standard 61
Materials are exempt from this requirement if the materials comply with the requirements of US Code of Federal Regulations 21 CFR 170-199. Alternately, materials also are acceptable if they comply with the American National Standard for drinking-water materials: NSF/ANSI Standard 61: Drinking Water System Components—Health Effects. NSF 61 has defined exposure protocols for various types of materials and components, which are more aggressive than the NSF 50 exposure protocol. Allowable levels of contaminants under NSF 61 are based on -- USEPA and Health Canada levels for drinking water. NSF 61 also contains toxicology evaluation criteria for unregulated contaminants.
NSF/ANSI Standard 14
Plastic pipe and fittings are required to conform to the American National Standard NSF/ANSI Standard 14 that establishes material, performance and durability requirements for plastic piping components. The safety and applicability of suction fittings is addressed via ASME A112.19.8M.
Chemicals that are used as an integral part of a system covered by NSF 50 also are considered acceptable if they meet the requirements of the American National Standard for drinking-water treatment chemicals:
NSF/ANSI Standard 60
Drinking Water Treatment Chemicals—Health Effects.
If you manufacture, sell or distribute water treatment chemicals in North America, your products are required to comply with NSF/ANSI Standard 60: Drinking Water Treatment Chemicals – Health Effects by most governmental agencies that regulate drinking water supplies. Developed by a team of scientists, industry experts and key industry stakeholders, NSF/ANSI 60 sets health effects criteria for many water treatment chemicals including all specialty chemicals used in drinking water treatment. (i.e. bromine)
Chemical feeders are required to sustain a hydrostatic pressure of 1.5 times the maximum working pressure for five minutes without distortion or leakage. Chemical feeders are subjected to a chemical resistance test to ensure the materials are resistant to degradation. Mechanical feeders also are subjected to an erosion test using dry chemicals or a DE suspension for slurry feeders. Mechanical feeders are subjected to a 3,000-hour-life test and must meet uniformity of output requirements +/- 10 percent of feeder setting from 25 percent to 100 percent of rated capacity.
Flow through feeders are not subjected to an extended life test, but they must meet uniformity of output requirements. The nature of the chemical type, size and configuration greatly effects the performance of flow through feeders. Using the wrong type of chemical in a flow through chemical feeder can result in over or under dosing of disinfectant or cause serious hazards such as fire or explosions.
Process equipment such as ultraviolet light (UV), ozone, brominators and ion generators are required to meet 3,000-hour-life tests. Ion generators and chlorinators/brominators are required to meet uniformity of output requirements, as well as chemical-resistance requirements.
NSF Standard 50 contains a disinfection efficacy test procedure for process equipment that is intended for supplementary disinfection of water such as UV, ozone and ion generators. The procedure requires a 3 log reduction in challenge organisms. NSF 50 also requires UV systems, ozone and ion generators to be used with residual levels of chemical disinfectants.