This European Standard specifies the minimum requirements for the design, construction and testing during manufacture of transportable refillable welded steel Liquefied Petroleum Gas (LPG) cylinders, of water capacity from 0,5 l up to and including 150 l. This European Standard applies only to cylinders having a circular cross-section. Cylinders designed and constructed to the requirements of this European Standard may be over-moulded; additional requirements for these cylinders set out in Annex B.