SF6 gas transport following ADR
Experts in transport of SF6 gas following ADR
The EU hazardous waste regulations by the ADR control the transport of hazardous goods on the streets. The main focus with this lies on being able to recover hazardous goods safely and limiting the potential dangers originationg from those goods in case of an accident. This is why there is a clear definition for each hazardous good in the ADR, stating how the packaging, load securing and labelling needs to look. Basically the ADR is built to raise the requirements for transport with the level of danger a good holds.
Since SF6 gas is gaseous at normal temperatures, it is mostly transported in gas bottles of various sizes. These need to be built in accordance with the respective safety standards, meet their specific construction requirements and have to be examined regularly. Sometimes the gas is built into the plants, leaving the plant acting as a pressure container. Gases are classified as category 2 in the ADR.
New SF6 gas has it’s own UN number in the ADR: UN 1080 with the label Sulphur hexafluoride. Since new SF6 gas is non toxic and not flammable, the biggest danger is suffocation through its characteristic of being an inert gas displacing oxygen. This makes it fall into classification code 2A and is transported in green bottles or bottles with a green rim for clear identification. Treated or recycled SF6 gas can also fall under this UN-code, as soon as it fits the Norm IEC 60376 specifications, so containing over 99,55% SF6 gas.
Used gas produces decomposition products due to it’s use in power plants under temperature influences. These can be toxic or corrosive. This is why used gas must always be handled by a caution principle, acting as if decomposition products are present. Through measuring SO2 it is possible to determine if the amount of decomposition products lie under the limit categorizing the gas as toxic/ corrosive by ADR. If the measurements show a SO2 value under 2000 ppm, used SF6 gas is categorized as UN 3163 with the label LIQUEFIED GAS N.A.G. The main danger still is suffocation, which means it has the classification code 2A and is transported in green bottles or bottles with a green rim, just as new gas would.
Used SF6 gas with more than 2000 ppm SO2 or used SF6 gas that has not been tested for decomposition products is classified as toxic and corrosive. This gives it the classification 2TC. They are also transported under UN 3308 with the label LIQUIFIED GAS, TOXIC, CORROSIVE, N.A.G. The bottles need to be yellow though due to their toxic and corrosive characteristics of the gas stored inside them. It is also required to use valves made from stainless steel, while UN 1080 and UN 3163 are allowed to use brass valves. Gas of UN 3308 falls under the category ‘Hazardous goods with high danger potential’ and needs to be transported with a safety plan, which means a big amount of expense. Therefore, it is always encouraged to perform a qualified analysis of used SF6 gas before transport.
