Dry type transformer K Factor

[Abusada]

Hi all

Using K-Factor dry type transformer is required when load generates harmonics in the network. However, who’s responsibility to define the K-Factor level of the transformer? Is it the EPC contractor or the transformer manufacturer? I understand it is the practice that EPC contractor should specify the K Factor based on the system (network) harmonic study that he did during detailed project design. However, is there any international reference such as IEEE, UL, etc. specify the responsibility?

Thanks in advance