In use, the code generated by the ratios of dissolved gas data being collected in
the field at times did not match any given in the Standard’s diagnosis table. This led
various bodies such as utilities, transformer manufacturers, testing laboratories and
consultants to develop their own interpretation techniques based on the IEC Standard;
they were widely used to complement the IEC Code rather than replace it. A shortcoming
of these techniques was that although they were developed to give more
individual diagnosis for equipment, the diagnosis obtained was often not comparable
between techniques.