NSF ANSI 330:2019 pdf free download – Glossary of Drinking Water Treatment Unit Terminology
3.186.1 cation exchange: A process involving the reversible exchange of cations in solution with cations in a solid (cation exchange media).
3.186.2 demand initiated regeneration (DIR) water softener: (As used in NSF/ANSI 44) A water softener equipped with a flow meter or sensing control system that automatically initiates the regeneration process after determining the depletion, or impending depletion, of softening capacity.
3.186.3 efficiency rated (ER) water softener: (As used in NSF/ANSI 44) A water softener that complies with specific performance specifications intended to minimize the amount of regenerant brine and water used in its operation.
3.186.4 exhaustion point: (As used in NSF/ANSI Std 44) A point marking completion of useful ion exchange when 1 GPG (1 7.1 mg/L) of hardness is first measured due to the depletion of the initial supply of available exchangeable ions in the ion exchanger bed. A unit that is “exhausted” requires regeneration to restore its capacity to treat water.
3.186.5 grains per gallon (GPG): A unit of concentration equal to 1 7.1 mg/L as calcium carbonate equivalence, usually used to express the hardness of water.
3.186.6 hardness: A measurement of the concentration of divalent and trivalent cations, primarily calcium and magnesium, in drinking water. Hardness is typically expressed as GPG or mg/L as calcium carbonate.
3.186.7 hardness leakage: (As used in NSF/ANSI 44) Hardness present in the effluent from a water softener.
3.186.8 intermittent flow rate: (As used in NSF/ANSI 44) A flow rate higher than the maximum service flow rate that would be expected to occur rarely, and for a brief period of time. An intermittent flow rate may cause a pressure drop of greater than 1 03 kPa (1 5 psig) through a water softener.
3.186.10 ion exchange resins: Process media consisting of insoluble polymers having functional groups capable of exchanging ions.
3.186.11 maximum service flow rate: (As used in NSF/ANSI 44) The highest flow rate (regardless of its descriptive title) listed in manufacturer’s literature at which a softener will deliver water containing 1 GPG or less hardness repetitively with a pressure drop of 1 03 kPa (1 5 psig) or less through the softener.
3.186.12 rated salt efficiency: The allowable claimed salt efficiency that may be made for a specific water softener model determined in accordance with NSF/ANSI 44 (see water softener).
3.186.13 rated softening capacity: (As used in NSF/ANSI 44) The quantity of hardness removed by a water softener at a specified salt dosage during the production of softened water including any softened water used for regeneration, commencing at the completion of a regeneration cycle, and ending at breakthrough. The quantity is expressed in grains (mg) as CaCO 3 .
3.186.14 residential water softener: (As used in NSF/ANSI 44) A cation exchange water softener that is connected to the water system with conventional plumbing fittings not exceeding 1 .25 in NPS (nominal pipe size), that is designed for residential use, and that is regenerated in place. All operations of the regeneration process, which may include maintenance of the water supply to the residence