ISO 11118:2015

ISO 11118:2015 specifies minimum requirements for the material, design, inspections, construction and workmanship, manufacturing processes, and tests at manufacture of non-refillable metallic gas cylinders of welded, brazed, or seamless construction for compressed and liquefied gases including the requirements for their non-refillable sealing devices and their methods of testing.
NOTE    The specific gases permitted in cylinders constructed to this International Standard can be limited by national or international requirements.
This International Standard is applicable to cylinders where
a)    the test pressure does not exceed 250 bar (i.e. ph ≤ 250 bar) for liquefied gases and 450 bar for compressed gases;
b)    the product of the test pressure and the water capacity does not exceed 1 000 bar·litres (i.e. ph V ≤ 1 000 bar·L);
c)    the test pressure exceeds 45 bar and the water capacity does not exceed 5 l (i.e. for ph > 45 bar, then V ≤ 5 l).