NOTE 1: ISO 7005-1 (steel flanges) PN 20, 50, 110, 150, 260, 420 are designed to be interchangeable with ASME B16.5 and MSS SP-44 flanges – ISO 7005-1 flanges are not identical to ASME B 16.5 and MSS SP 44 flanges but are deemed to comply with the dimensions specified in the ASME B 16.5 and MSS SP 44.
ISO 7005-2 (cast iron) flanges PN 20, 50 are designed to be interchangeable with ANSI/ASME B16.1 (gray cast iron) and B 16.42 (ductile cast iron) but they are not identical. They are deemed to comply with dimensions specified in ASME B16.1 (grey cast iron) and B 16.42 (ductile cast iron).
NOTE 2: ISO PN 2.5, 6 do not have a corresponding ASME class and ASME Class 75, 400 and 800 do not have corresponding ISO PN designation. The use of these PN and Class flange ratings are therefore not recommended.