NSF Who is the NSF – NSF International, The Public Health and Safety Company™, a not-for-profit, non-governmental organization, is the world leader in standards development, product certification, education, and risk-management for public health and safety. Why the NSF - UV Pure Technologies chose the NSF to certify its systems because it is quickly becoming regarded as the global gold standard accepted by environmental regulatory authorities worldwide. See our FAQ for additional information on the different NSF standards. How do you search the NSF Site – Sorry we wish this site was a bit more user friendly. Go to the following link http://www.nsf.org/Certified/DWTU/ to find the systems that are NSF 55A certified. Check the box for Disinfection Performance, Class A.