Revision Standard - Active. Minimum performance specifications and testing methods for the evaluation of radiation portal monitors, also known as RPMs, are contained in this standard. These monitors are large-size permanently mounted-type instruments. These instruments are primarily designed for the detection of radioactive materials emitting gamma rays and neutrons. The specifications for general, radiological, environmental, electromagnetic and mechanical performance are given and the corresponding testing methods are described. The documentation to be provided by the manufacturer is listed as part of the requirements. A number of informative annexes that provide useful information and guidance in implementing this standard are also contained in this standard. (The PDF of this standard is available at no cost compliments of the Department of Homeland Security Domestic Nuclear Detection Office. https://ieeexplore.ieee.org/browse/standards/get-program/page)