API MPMS Chapter 7.5 (R2020) PDF
ISO 8310:2012 (Identical), Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels-General requirements for automatic tank thermometers on board marine carriers and floating storage.
This International Standard specifies the essential requirements and verification procedures for automatic tank thermometers (ATTs) consisting of platinum resistance thermometers (PRT) and an indicating device used for custody transfer measurement of liquefied natural gas, liquefied petroleum and chemical gases on board ships. Temperature detectors other than PRT are considered acceptable for use in the custody transfer service of liquefied gases if they meet the performance requirements of this International Standard and are approved by national regulations.