ISO 9170-1:2017 is intended especially to ensure the gas-specific assembly, mechanical resistance, flow, leakage and pressure drop of terminal units and to prevent their interchange between different gases and services and applies to terminal units: a) intended for use in medical gas pipeline systems in accordance with ISO 7396-1; b) used as pressure outlets on pressure regulators in accordance with ISO 10524-1; c) used as pressure outlets on pressure regulators integrated with cylinder valves (VIPR) in accordance with ISO 10524-3.