For the diagnosis of the “PCBs in oil and transformer” criticality, Sea Marconi applies its own diagnostic metrics, specifically:
Through the analysis of the oil the specific indicators (PCBs) are identified
The concentration of PCBs in new and in operation oils must be “non-detectable” that is PCB < 2 mg/Kg, determined with method IEC 61619
[IEC 60296 Ed. 4-2012, page 16; IEC 60422 Ed. 4-2013, tab. 3, page 24]
In relation to local norms, the PCBs thresholds in oil can be higher. For example:
50 mg/Kg for Stockholm Convention,
50 mg/Kg in Europe,
25 mg/Kg in Italy
2 mg/Kg in Sweden
2 mg/Kg in the Province of Buenos Aires, whereas at federal level it is 50 mg/kg
0,5 mg/Kg in Japan (see “Waste Disposal and Public Cleansing Law – Law No.137 of 1970)”, [source]).
To determine analytically infinitesimal thresholds, like the prescription in Japan, it is necessary to implement a special analytical protocol (always based on IEC 61619), activity unique to highest-level laboratories. Sea Marconi succeeded in this task modifying its internal procedures and improving the purification and pre-concentration phases of the PCBs reaching thresholds of total PCBs of 0.1 mg/kg (sum of congeners).
It is recalled that
– 2010 was the deadline for the decontamination and/or disposal of equipment with pure PCBs or PCBs > 500 mg/kg [CENELEC CLC/TR 50503:2010 (page 11)
– electric transformers with PCBs < 500 mg/Kg can stay in operation through the end of their operational life providing they are in “good operational state” do not show leakages nor risks for public health and the environment. [CENELEC CLC/TR 50503:2010 (Note at tab. 5 page 25)]
Thanks to the data bank the evolutions of the concentration of PCBs are observed to identify whether cross contamination phenomena occurred during the phases of the life cycle
The commercial mixtures of PCBs are evaluated on the basis of the peaks of the chromatographic profile
Based upon the evaluation of these key factors, the specific criticality is classified in terms of type and priority, defining at the same time, type and priorities of the corrective actions
