Is all that is said about SF6 true?

Since the early 1970s, sulfur hexafluoride gas (SF6) has been used in very high voltage electrical applications. Its use has progressively spread to all voltage levels in electricity transmission and distribution and its installation has become widespread all over the world; it is estimated that, on average, around 80% of the MV and HV equipment currently manufactured contains SF6.

The reason for success is easily understandable, it is a solution (both for insulation and for the arc extinction when interrupting the electric current) that is technically excellent, economically competitive, industrially affordable and environmentally sustainable if treated with the appropriate ecological awareness after the products' shelf life.

Many have been the detractors who have been responsible for defaming this industrial gas. Many have been the detractors who have been responsible for defaming this industrial gas. Opinions such as "it destroys the ozone layer", "it contains carcinogenic substances", "it generates extremely toxic by-products", are some of the statements that SF6 has received over the years.

Sulfur hexafluoride is an inert, colorless, odorless and neutral gas, non-flammable and 5 times heavier than air, non-toxic and with no ecotoxic potential. It does not destroy the ozone; in fact, it is not considered in the Montreal Protocol.

Pure SF6 is physiologically harmless to humans and animals; it is even used for medical diagnostics. Because of its weight, it could displace oxygen in the air if large amounts were concentrated in deep, poorly ventilated places. No chemical legislation in the world has classified SF6 as a hazardous material.

Its outstanding electrical, physical and chemical properties allow it to offer significant benefits for the electricity supply network: it isolates 2.5 times more and has an arc extinction capacity 100 times greater than dry air and dissipates heat significantly better than air. Such a combination of extraordinary electrical, physical, chemical and thermal properties makes SF6 a unique and indispensable material in insulation and cutting equipment for MV and HV for which there is no substitute with equivalent performance.

The by-products generated by the high concentration of energy produced by the electric arc to be extinguished, are immediately recombined as soon as the energy source is extinguished, stabilizing the SF6 molecule again.

All life cycle assessment (LCA) studies have shown that the use of SF6 technology in electrical distribution switchgear equipment has a lower total impact on the environment than air-insulated installations.

Only one of the criticisms of SF6 is true, it is a powerful greenhouse gas, it has a high GWP (Global Warming Potential) of 22,000, which means that the discharge of one kilogram of SF6 into the atmosphere is equivalent to the emission of 22 tons of carbon dioxide. Their irresponsible use in open applications can contribute to the greenhouse effect caused by humans.

But in electrical switchgear, SF6 gas is always used in sealed compartments, greatly minimizing the risk of leakage throughout its shelf life. This makes the actual impact on the greenhouse effect very insignificant. It is internationally accepted that the total contribution to global warming made by SF6 used in electrical equipment is in the order of ten thousandths, i.e. absolutely despicable.

SF6, like any man-made industrial gas, should not be intended for use with open applications. In fact, in Europe and Japan it is no longer allowed to be used for sports shoes (Nike Air type), filling car tires in winter or casting magnesium in gaseous bed among others. All these open applications were used in the 80s and 90s and unfortunately they are still used in some places.