IEC 60480 GUIDELINES FOR THE CHECKING AND TREATMENT OF SULFUR HEXAFLUORIDE (SF6) TAKEN FROM ELECTRICAL EQUIPMENT AND SPECIFICATION FOR ITS RE-USE
8 Quality specification for re-use of SF6 in new or existing switchgear
8.1 Decision flowchart for SF6 removed from electrical equipment for treatment
As a guide for the operator, the following flowchart (Figure 1) defines the selection procedure to determine the best use of SF6 after removing it from equipment for potential treatment.
8.2 Maximum acceptable impurity levels for re-use of SF6
For the analysis, the sampling is a critical issue (see Clause B.1: Sampling).
• For impurities of water or decomposition products, the question of whether the SF6 is reclaimable on-site depends only on the performance of the filters available. If the SF6 is not reclaimable on-site, then it shall be returned to the SF6 manufacturer or sent to a reclaiming or disposal company.
• The case of contamination with air and/or CF4 shall be considered separately. If the concentration of air and/or CF4 exceeds the maximum acceptable impurity level as given in Table 2, and if the reservoir from which the sample has been taken contains liquid SF6, then transfer SF6 from the gas phase into a second reservoir. The transfer should be continued until a sample from the first reservoir satisfies the maximum acceptable level. The contents of the second reservoir cannot be reclaimed on-site. Any reservoir that contains no liquid SF6, i.e. only the gas phase, requires the analysis of only one sample for air and CF4 to determine if it is suitable for re-use or cannot be reclaimed on-site.
