This International Standard specifies the minimum requirements concerning material selection, design, construction and workmanship, procedure and test at manufacture of refillable welded-steel gas cylinders of a test pressure not greater than 60 bar1), and of water capacities from 0,5 l up to and including 500 l exposed to extreme worldwide temperatures (−50 °C to +65 °C) used for compressed, liquefied or dissolved gases. Transportable large cylinders of water capacity above 150 l and up to 500 l may be manufactured and certified to this International Standard provided handling facilities are provided (see 8.6.4). This International Standard is primarily intended to be used for industrial gases other than Liquefied Petroleum Gas (LPG), but may also be applied for LPG. For specific LPG applications see ISO 22991.