NSF/ANSI/CAN 50-2019, both an American National Standard and a National Standard of Canada, specifies information for not only swimming pools but also spas, hot tubs, and other recreational water facilities.
A Recent History on Swimming Pool Installations
2.1 million residential inground swimming pools were built between 1991 and 2006. This achievement is monumental when contrasted with preceding years. During this time, annual new pool installations shot up from 97,000 to 176,000. In fact, the 2.1 million inground pools built during this period equaled the entire number of pools installed since the emergence of the U.S. market in the 50s.
Reflecting on the latter half of the 20th Century, this information indicates substantial growth, but, when looking at the time since this inground installation boom, you can see a clear decline. In 2009, there were only 54,000 inground pools installed in the United States. The recession is largely to blame for this hit to the industry, but pool installations still have yet to return to their glory days.
Regardless, nearly 40 percent of all inground pools today were built between 1991 and 2006, placing a significance on the operation of existing pools.
Standard for Swimming Pool Equipment and Chemicals
NSF/ANSI 50-2019: Equipment and Chemicals for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilities covers materials, chemicals, components, products, equipment, and systems related to public and residential recreational water facility operation. This scope extends the standard’s applicability beyond just pools.
The NSF/ANSI 50-2019 standard document covers evaluation and testing guidelines for swimming pool treatment chemicals, filters, centrifugal pumps, non-integral strainers, valves, mechanical chemical feeding equipment, filtration media, UV light process equipment, automated controllers, heaters, flow metering devices, and numerous other components integral to the operation of recreational water facilities.
Changes to NSF/ANSI/CAN 50-2019
The 2019 edition of this standard is the most current, and it revises the 2017 version. This revision was substantial. The most noticeable change visible to past users is the addition of the “CAN” designation. In fact, this edition of the standard for swimming pool treatment chemicals and equipment is the first to be designated as a National Standard of Canada (NSC) in compliance with requirements and guidance set out by the Standards Council of Canada (SCC).
Other notable changes made to NSF/ANSI 50-2019 include:
- Language relating to chlorinator sizing from Annex I-1 (formerly Annex J) was removed.
- UV Treatment System requirements were clarified.
- Water quality testing devices accuracy levels were modified.
- Language regarding shelf life testing of water quality testing devices was adjusted.
- Units related to UV control panel requirements were corrected.
- The uniformity of output testing for chemical feeders was updated.
- Slip resistance testing.
- Head loss equations were revised.
- This revision brings consistency and clarity throughout the standard by way of a “clean-up” ballot.
- Language was revised regarding skimmer requirements.
- Normative references were moved out of Section 1 into their new Section 2. This marks an editorial adjustment that permeates throughout the entire document, as all other sections were moved up by a section number.
Furthermore, keeping in line with the change we have seen with other NSF International standards published in 2019, the annexes in NSF/ANSI 50-2019 were changed from alpha characters to numeric and preceded by “Normative” or “Informative.” For example, Annex A from NSF/ANSI 50-2017 is called “Normative Annex 1 (N-1)” in NSF/ANSI/CAN 50-2019.
Changes to NSF/ANSI 50-2017
NSF/ANSI 50-2017, which was published in 2018, replaced the 2016 version of the same standard.
Much like with the 2019 edition, one of the obvious changes made to the 2017 revision was with the title, as it explicitly included the chemicals related to recreational water facility operation. The scope was also updated to reflect the inclusion of chemicals. Other than this update, NSF/ANSI 50-2017 underwent the following changes:
- Language for UV disinfection was aligned with that in the 2014 Model Aquatic Health Code (MAHC).
- Language for shelf life testing for manufacturers of water quality testing devices was revised.
- The water quality testing devices (WQTD) sections were updated.
- Flow meter language was revised to reflect consideration of the devices being used in applications where specific gravity is greater than 1.0.
- Normative references were updated.
- Specific criteria for metal contaminant limits were added.
- Language adding clarity to effective size and uniformity coefficient calculations was incorporated.
- Language regarding chemical feeders was revised.
- Language regarding formulation testing in Annex A, “Materials review and qualification methods,” was revised.
- Exposure assumptions were updated in Annex R, “Toxicology review and evaluation procedures for swimming pool treatment chemicals.”
If you’d like to learn about the 2016 revision of NSF/ANSI 50 in depth, please read our post on NSF/ANSI 50-2016a: Equipment for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilities.
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