Here are excerpts from NITC documents that say they have 4 recertification exams to the 2015 edition of NFPA 99.
This notice pertains to those who will be renewing/recertifying for the following:
Medical Gas Installer
Medical Gas Instructor
Medical Gas Inspector
Medical Gas Verifier
Each of the Recertification Examinations for Medical Gas Installer, Instructor, Inspector, and Verifier are proctored multiple-choice open book examinations. The Recertification Examinations are based on applicable sections of the following Official Examination References:
1. ASSE Standard Series 6000, 2012 Edition
2. NFPA 99 Standard for Health Care Facilities, 2015 Edition
When you login to the PSI website to register for your exam, there are choices available for both 2012 and 2015 editions for the recertification exams. Be careful to pick the right one!