Reconditioning SF6-Gas

SF6 gas is indispensable for safe operation of SF6-filled switchgear. However, it may occur that the SF6 quality is outside the required standards and the gas therefore has to be replaced, or a switchgear is decommissioned and you cannot continue to use the gas for the maintenance of other switchgear. But every kilo of new SF6 gas produced and used SF6 gas disposed of means further emissions and an additional environmental impact. DILO now offers an economical and sustainable alternative to filling your SF6-filled switchgear in a safe and emission-free way:


  • Low costs
    No costs for new SF6 gas, no costs for the disposal of used SF6 gas.
  • Avoiding taxes
    No C02 taxes for the import of new SF6 gar, no regional tayes when using new SF6 gas.
  • Effective environmental protection
    No resource consumption for the production of new SF6 gas, no environmentally harmful disposal of used SF6 gas..
  • Collection / dispatch in vessels rented or purchased from DILO or customer’s own pressure vessels.



The idea behind DILO Certified SF6 Gas is very simple: Instead of producing and circulating new SF6 gas or destroying used gas, SF6 gas that is no longer useable is reconditioned.

As a TÜV SÜD-certified waste management company, DILO uses a cryogenic separation process to recondition used SF6 gas, in which
by-products are separated by using pressure and cold via various stages. What remains is pure SF6 gas, which can then be used again.
We offer you the entire process from collection of the used SF6 gas to reconditioning and testing in our in-house laboratory to return transport. For a minimum quantity of 2 tonnes, the used SF6 gas can also be reconditioned on site.



  • DILO Certified SF6 Gas is proven to exceed the quality standards for new SF6 gas.
  • DILO is able to recondition SF6 with an SF6 gas content of at least 40 %.
  • DILO accepts SF6 gas with an SO2 content of up to 250 ppmv for reconditioning.
  • DILO also organises the collection or return transport of your SF6 gas on request.


Reconditioning SF6 Gas


Substance DILO Quality"Certified Gas" IEC 60376:2018* (New gas) ASTM D2472-15
SF6 > 99,9 Vol.%(> 99,99 wt%) > 98,5 Vol.% ≥ 99,8 wt%
H2O ≤ 8 µl/l < 200 µl/l ≤ 8 ul/l
Frost point (1 atm) ≤ -62 °C -36 °C -62 °C
Total acidity (HF equiv.) < 0,1 µl/l < 7 µl/l ≤ 0,3 ppmw
Air < 500 µl/l < 10.000 µl/l ≤ 500 ppmw (≙ 2500 µl/l)
CF4 < 500 µl/l < 4.000 µl/l ≤ 500 ppmw (≙ 830 µl/l)
Oil mist < 1 mg/kg < 10 mg/kg
SO2 < 0,1 µl/l


The following points must be observed before dispatch to DILO:

  • The quality of the gas must be known and the SO2 value must not exceed 250 ppmV (Download check lists). If the quality is unknown, an analysis in the DILO Lab is possible in advance.
  • The cylinder(s)/vessel(s) must be marked with the UN 3163 label for used SF6 gas
  • Only green vessels may be sent to DILO (yellow = toxic and corrosive)
  • As an additional service, we offer to change the labelling of the vessels from “yellow” to “green”.