ISO 3821:2019 specifies requirements for rubber hoses (including twin hoses) for welding, cutting and allied processes.This document specifies requirements for rubber hoses for normal duty of 2 MPa (20 bar) and light duty [limited to hoses for maximum working pressure of 1 MPa (10 bar) and with bore up to and including 6,3 mm].This document applies to hoses operated at temperatures −20 °C to +60 °C and used in:— gas welding and cutting;— arc welding under the protection of an inert or active gas;— processes allied to welding and cutting, in particular, heating, brazing, and metallization.This document does not specify requirements for hose assemblies; these are detailed in ISO 8207.This document applies neither to thermoplastics hoses nor to hoses used for high pressure [>0,15 MPa (>1,5 bar)] acetylene.