EN 13611:2019, Clause 1 applies with the following modification and addition: Modification: The 1st paragraph of EN 13611:2019, Clause 1 is replaced by: This document specifies the safety, design, construction, and performance requirements and testing for pressure regulators and pneumatic gas/air ratio pressure regulators (zero pressure regulators are included as a special type of pneumatic gas/air ratio pressure regulators) for burners and appliances burning one or more gaseous fuels, hereafter referred to as “pressure regulators”. This document is applicable to pressure regulators with declared maximum inlet pressures up to and including 50 kPa and of nominal connection sizes up to and including DN 250. Addition: This document is applicable to: - pressure regulators which use auxiliary energy; - pneumatic gas/air ratio pressure regulators, which function by controlling a gas outlet pressure in response to an air signal pressure, air signal differential pressure, and/or to a furnace pressure signal (zero pressure regulators are included as a special type of pneumatic gas/air ratio pressure regulators); - pneumatic gas/air ratio pressure regulators, which change an air outlet pressure in response to a gas signal pressure or a gas signal differential pressure. This document is not applicable to: - pressure regulators connected directly to a gas distribution network or to a container that maintains a standard distribution pressure; - pressure regulators intended for gas appliances to be installed in the open air and exposed to the environment; - mechanically linked gas/air ratio controls; - electronic gas/air ratio controls (EN 12067 2:2022). The 4th paragraph of EN 13611:2019, Clause 1 is removed.