UIH's contractor and the contractor that installed the line of STEC previous installation is not needed, supervise every step. He is aware of this standard as well.
UIH contractor and the contractor who installed the lines of STEC installed previously not require a person to oversee the process. He is well aware of this standard.
Contractors of the UIH and contractors installed lines of source STEC previously installed to มีคนมา control every step of the way. He was aware of this standard as well.