This document introduces several modifications to the standard modifying its field of application as follows: This standard applies to regulation and measurement sets, with an equivalent nominal flow of 6 m3 (n) / h and (6 + 6) m3 (n) / h of natural gas, intended to supply fuel gases of the 2nd or 3rd family according to UNE EN 437 and that the effective inlet pressure is between 50 mbar and 200 mbar, except in special cases, whose inlet MOP may be up to 400 mbar