This part of ISO 9809 specifies the minimum requirements for the material, design, construction and workmanship, manufacturing processes, examinations, and tests at manufacture of refillable seamless stainless steel gas cylinders of water capacities from 0,5 l up to and including 150 l for compressed, liquefied, and dissolved gases. This part of ISO 9809 is applicable to cylinders with a maximum actual tensile strength, Rma, of less than 1 100 MPa. NOTE If so desired, cylinders of water capacity less than 0,5 l and between 150 l and 500 l can be manufactured to be in full compliance with this part of ISO 9809.