By Margaret Rayer

ANSI/NSF Standard 50—“Circulation System Components and Related Materials for Swimming Pools, Spas/Hot Tubs”—covers equipment and materials commonly included in the water circulation systems of both residential and public swimming pools, spas and hot tubs. The standard incorporates minimum requirements for materials, design, construction and performance of equipment, including:

  • Diatomaceous earth filters
  • Sand filters
  • Cartridge filters
  • Recessed automatic skimmers
  • Centrifugal pumps
  • Multiport valves
  • Adjustable output rate chemical feeding equipment
  • Flow-through chemical feeding equipment, and
  • Process equipment, including ozone, UV, ion generators, electrolytic chlorinators and brominators

Certification to the standard
Once a company applies for certification, specific technical information about the product is required, including materials of construction, diagrams and drawings, parts lists, intended uses for the product and capacities. After completion of the information gathering, testing and toxicological reviews necessary to certify the product need to be determined. The three main areas of consideration are: health effects, performance and chemical resistance.

Any material that has a significant water contact area requires a toxicological review of its formulation to verify harmful levels of contaminants won’t leach into the circulation system. On occasion, the material formulation itself may not provide enough information, in which case, a chemical extraction test will have to be performed. Materials not posing a health threat are accepted for water contact use.

An initial audit is required for any new manufacturer seeking certification. During the initial audit, the auditor explains the impact of the product’s certification on the manufacturing facility. The auditor reviews the plant’s procedures for items such as record keeping, product marking, raw materials handling, quality control, product manufacturing, product storage and shipping, and finished product distribution. The auditor also reviews additional certification policies, including requirements for unannounced compliance audits on an annual basis that involve complete physical evaluations of the product against applicable requirements of Standard 50. Such evaluations identify any data plate, manual, and design characteristics that don’t meet the requirements of the standard. Unannounced audits also verify the manufacturer is using only materials and designs accepted by the certifying agency.

Meeting qualifications
A representative sample of the equipment to be certified then undergoes testing to verify compliance with the performance requirements in the standard. The equipment is tested in a Hydraulic Testing Laboratory, similar to one NSF has in Ann Arbor, Mich. The laboratory personnel must also complete a physical evaluation of the product to ensure compliance with the requirements established in Standard 50 for data plates, manual components, and any applicable design constraints.

Materials within process and chemical feeding equipment that contact potentially corrosive chemicals such as chlorine and bromine undergo a chemical resistance test of 100 days exposure at the maximum end-use temperature for a pool or spa. This test determines whether exposing parts, normally in contact with the maximum in-use concentration of the manufacturer’s recommended chemical(s), will affect the equipment’s performance. The product is evaluated before and after exposure to determine chemical attack on the materials. This test provides assurance the certified process and chemical feeding equipment won’t corrode when operated in accordance with the manufacturer’s instructions.

Suction fittings, main drains
Historically, suction fittings and main drain covers were tested to ASME/ANSI A112.19.8M, “Suction Fittings for use in Swimming Pools, Wading Pools, Spas, Hot Tubs, and Whirlpool Bath Applications,” by various other agencies. However, state and local regulatory officials began to request development of a certification program for main drains and suction fittings. This new program would demonstrate a main drain or suction fitting’s conformance to performance requirements of the current ASME standard as well as sanitation requirements of Standard 50. NSF’s Joint Committee on Pool Equipment expanded the standard’s requirements in late 1999 to include reference to the ASME standard. The revised standard was designated as ANSI-accredited on Jan. 4, 2000. With this extra measure of testing, consumers can be confident that pool/spa main drain covers and other suction fittings bearing the certification agency’s mark for Standard 50 Certification have passed requirements for both performance and sanitation.

Product data plates
The product data plate on pool and spa equipment contains essential information for the end-user, as well as for the regulatory official inspecting the installation and operation. All data plates contain the manufacturer’s name, address and product model number. If the data plate doesn’t state the unit was evaluated specifically for pool use or spa use only, then it was evaluated for both pool and spa end uses.

Filter data plates contain other important information, including the product serial number, required clearances for maintenance, effective filtration area of the unit, maximum design flow rate, steps of operation and maximum working pressure.

Pump data plates have a serial number and an additional designation indicating a self-priming or non-self-priming pump. Data plates for multiport valves contain information regarding maximum head loss, flow rates and working pressure. Data plates of chemical pumps include the recommended chemicals and maximum output rate as verified by the certification body as part of the certification process.

Data plates play a key role for the regulatory authority and installer to ensure the equipment is installed properly and that it functions as designed and certified.

ANSI/NSF Standard 50 plays an important role in the pool and spa industry by providing requirements for equipment and materials commonly included in water circulation systems of both residential and public swimming pools, spas and hot tubs. The standard incorporates minimum requirements for materials, design, construction and performance of circulation system equipment.

Due to revisions in the standard in late 1999, consumers can be confident that pool/spa main drain covers and other suction fittings bearing the certification agency’s mark for Standard 50 have passed requirements for both performance and sanitation.

As the use of pools and spas continues to increase, it’s important the equipment used to treat the water is functioning properly. Use of equipment certified to Standard 50 provides an important baseline for both performance and health effects.

About the author
Margaret Rayer is the business unit specialist for the Pool & Spa Equipment Program at NSF International in Ann Arbor, Mich. She has a bachelor’s degree in ecosystems biology from Eastern Michigan University. Rayer can be contacted at (800) 673-6275, (734) 769-0109 (fax) or email: [email protected].


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