Which IEC or ASTM transformer oil standards are commonly applied?

Common IEC references include IEC 60296 for specifications of unused and recycled mineral insulating oils, and IEC 60156 for breakdown voltage testing. For DGA, IEC 60567 covers sampling and gas analysis procedures, while IEC 60599 covers interpretation. On the ASTM side, ASTM D3612 is widely used for dissolved gas analysis procedures. Exact combinations depend on the utility, region, and whether the asset is distribution or transmission class.