This Standard covers materials, components, products, equipment and systems, related to public and residential recreational water facility operation.

In this edition of NSF/ANSI 50 the following revisions were incorporated:

Issue 57 - CEC pump, energy and sound testing
This revision included an optional evaluation criteria and testing method for the evaluation of pumps for energy efficiency.

Issue 66 - Chemical feeders
This revision updated 5 - Filters to clarify the marking requirements for vacuum service filters to specify the collapse negative pressure in psi or inches of mercury. Sections 5 - Filters, 9 - Mechanical chemical feeding equipment and 10 - Flow-through chemical feeding equipment updated the product data plate to reference a web address and phone number by which users can obtain the installation, operation, and maintenance instructions.

Issue 66 - Equalizer line
This revision resolved the issue of public pool skimmer equalizer lines required as mandatory or optional. It provides the mechanism for continued production, testing, and certification, and the installation of skimmers equipped with equalizers where permitted or required by code and allows skimmers to be installed without equalizer lines to address jurisdictions and codes that prohibit equalizer lines and the additional submerged suction fittings.

Issue 70 - Normative Reference and mechanical chemical feeders
The revision added section within 4 to address special use suction fittings (i.e. the vacuum port fittings); updated the normative references; and 9 was revised to allow for mechanical chemical feeding equipment that operates at a fixed rate if it is controlled by a chemical controller that meets the requirements of 17 and the mechanical chemical feeder has a method of mechanically restricting the maximum output per day.

Issue 73 - Media labeling
This revision added requirements for filtration media labeling.

Issue 76 - Filtration media reorganization
NSF/ANSI 50 - 2011 was editorially reformatted to make the Standard more user friendly. A new section for filtration media was created (Section 11). The requirements in 11 - General requirements for process equipment were added to 12 - Ozone process equipment, 13 - Ultraviolet light process equipment, 14 - In-line electrolytic chlorinator or brominator process equipment, 15 - Brine (batch) type electrolytic chlorine or bromine generators, and 16 - Copper/silver and copper ion generators.