This document applies to requirements and tests of excess flow valves (hereinafter referred to as "GS") up to a nominal diameter of DN 50 with a defined flow direction. They are operated with gases of the second and third gas family in accordance with DVGW Code of Practice G 260 (but not for LPG in the liquid phase) and apply to the operating pressure ranges from 15 hPa to 100 hPa. The document is based on the DVGW provisional test specification VP 305-1:2007-12 "Excessflow valves for gas installation". It regulates the requirements and tests on GS of types M (15 hPa to 100 hPa) and K (15 hPa to 100 hPa) in accordance with the requirements of DVGW Code of Practice G 600 "Technical Rules for Gas Installations - TRGI 2008". The maximum pressure loss of GS types M and K is limited to 0,5 hPa.