NSF ANSI 55:2019 pdf free download -Ultraviolet Microbiological Water Treatment Systems
1.2 Scope
This Standard covers UV microbiological water treatment systems and components for point-of-use (POU) and point-of-entry (POE) applications. This Standard covers systems which use UV radiation within the range of 240 nm to 300 nm inclusive. Systems are intended to be used under the following specific conditions.
1.2.1 Class A systems
Class A POE and POU systems covered by this Standard are designed to be used for treating microbiologically unsafe water, but do not reduce chemical or inert particulate contaminants. Systems covered in this Standard are designed to inactivate microorganisms, including bacteria, viruses, Cryptosporidium oocysts, and Giardia cysts, from water. Systems covered by this Standard are not intended for the treatment of water that has an obvious contamination or intentional source, such as raw sewage, nor are systems intended to convert wastewater to drinking water. The systems are intended to be installed on visually clear water (not colored, cloudy, or turbid). Systems with manufacturer claims that include components or functions covered under other NSF or NSF/ANSI Standards or Criteria shall conform to the applicable requirements therein. Class A systems not installed downstream of a device tested for cyst reduction / inactivation in conformance to the appropriate NSF/ANSI Standard may claim Cryptosporidium oocysts and Giardia cysts only. Class A systems installed downstream of a device tested for cyst reduction in conformance to NSF/ANSI 53 or NSF/ANSI 58 may make a general cyst claim when used on untreated surface waters, or ground water, or both, under the direct influence of surface water. NOTE — Current data support that Cryptosporidium oocysts and Giardia cysts are inactivated by UV treatment.
The Class B system is not intended for the disinfection of microbiologically unsafe water and may not make individual or general cyst claims. Class B systems shall not make microbiological health effects claims. Systems covered by this Standard (Class B) are not intended to be used with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system. Systems with manufacturer claims that include components or functions covered under other NSF or NSF/ANSI Standards or Criteria shall conform to the applicable requirements therein.
1.3 Variance from minimum requirements
Variations from the minimum requirements specified in Sections 4, 5, 6, and 7 may be permitted, provided that they give the system or component the same or greater resistance to corrosion, wear, and physical damage, or that they improve the general operation or performance of the system or component. Proposed variations shall be accepted by the testing agency prior to use. Systems with components or functions covered under existing NSF Standards or criteria shall conform to the applicable requirements therein.
2 Normative references
The following documents contain provisions that, through reference, constitute provisions of this NSF/ANSI Standard. At the time this Standard was balloted, the editions listed below were valid. All documents are subject to revision, and parties are encouraged to investigate the possibility of applying the recent editions of the documents indicated below. The most recent published edition of the document shall be used for undated references.