MrPSK,
Here is the way I understand the ISO 15590-2:
1. It only provides the manufacturing standard/rules for the fittings for the matching Pipeline.
2. Unlike many American Standards, it doesn’t directly permits to use any alternative standard material or allows to qualify one.
3. However, it specifies ASME B16.9, MSS-SP-75, ASME B31.8 under ‘Normative References’. Normative Reference means these are widely used standards but doesn’t mean that it gives you permission to use these materials unless stated in the main document.
I suggest that you search for code cases/ interpretation where ISO may have given permission to use these materials.
You need to check:
If your state/local regulator permits direct use of ASTM/ASME standard materials.
Many Vendors will sell ASME B16.9, MSS-SP-75 standard materials but many not provide you with the delivery conditions of the fittings required by ISO 15590-2. Depending on the quantity, they might offer you with additional tests at added cost. Make sure that material chemical compositions stays within the iso 15590-2 limits.
Your project specification specifies you to use ISO 15590-2 fittings only. You might request a technical deviation for the ASME/ ASTM materials. The Owner must have used these materials elsewhere and might approve your request.
GDD
Canada