Although sulfur hexafluoride (SF6) is used mainly in medical and electrical equipment insulation applications, small quantities of sulfur hexafluoride gas for testing available for purchase are offered by some means. Taking an example from 2023 market figures, around 15% of SF6 vendors globally provide orders with a minimum order size of 1-10 kg but at a unit price 30-50% higher than in bulk orders. Airgas offers a 1 kg canister of SF6 (≥99.99% purity) for $450 / kg (approximate bulk price is about $280 / kg) with a $150 dangerous goods shipping charge (certified UN1079 package). European suppliers, such as Germany’s Merck, are billed a minimum order quantity of 5 kg, a unit price of 380 euros/kg, and a proof of laboratory use (e.g., an IEC 60480 standard compatibility statement), and the purchasing time is about 10-14 days.
Regulatory limitations are the largest obstacle for microprocurement. EU F-gas regulation dictates that SF6 buying must be registered for usage and declare annual usage, and 2024 non-power sector allocation is a mere 3% of the whole (about 186 tons), resulting in order approval time of small batch orders taking more than 20 days. For example, a French university research team submitted a purchase request for 2 kilograms of SF6 for dielectric strength test in 2023 (target parameter: breakdown voltage 75kV/cm), which was postponed for 3 months because it failed to offer the equipment leakage rate monitoring plan (≤0.1%/year required). Contrastingly, China’s pilot mini-scale implementation of procurement is relatively lax, Alibaba international website of approved suppliers (such as Jiangsu Huatai gas) ensure 500g minimum quantity order, price per unit 680 yuan/kg (inclusive of 13% VAT), but are required to promise to recycle 90% of the residual gas back to the assigned recycling center, or else the deposit (30% of the pay) will be lost.
Specialty gas distribution platform provides accommodative solutions for trace purchases. US web retailer Sigma-Aldrich sells SF6 in 40-liter cylinders (net weight 5 kg, pressure 1.5MPa) for $2,200 to enable worldwide supply, but shipping time is up to 4-6 weeks and a 15% temperature-controlled packaging charge applies in tropical regions. In 2023, Indian start-up Gasco India launched a “ready-use” 100g SF6 test kit (with purity certificate and micro-pressure reducing valve) with a unit price of $95, but only assures laboratory grade purity (99.9%), if you need power equipment grade (99.99%), it will cost $140, error rate ±0.05%. Another example is Showa Denko’s leasing model, which allows users to lease 10kg SF6 cylinders ($800/month) for short-term testing within six months without recycling fees if the gas loss is less than 10%, which has achieved 12% SF6 business expansion for the company in 2023.
Alternative options can reduce small procurement costs. Others acquire SF6 by breaking down retired equipment, for instance, in the 2022 North American power equipment auction, a retired GIS circuit breaker (with 8 kg of SF6) was auctioned off for just $12,000, which is equal to the cost of the gas at $1,500 / kg, but one has to incur the cost of purification (approximately $200 / kg) and toxic decomposition (e.g., SF4) detection risk. Additionally, the Swiss company ABB introduced “SF6-as-a-Service” SF6-as-a-service enables renters to rent inflators on an hourly basis (hourly rate of $45), minimum application of 0.5 kg, but one must pay $3,000 as a deposit. Research institutes can also share facilities by sharing labs, for instance, Green Grid Program members of the European Union can apply for a free SF6 test allowance of 2 kg annually, provided that the emission reduction technology verification data (e.g., alternative gas dielectric strength ≥ 80% SF6) is submitted.
Microeconomic effects of storage and transportation are significant. The transport price of SF6 microbatches typically takes up over 50% of the cost, e.g., 1kg from Germany to Brazil would be a maximum of $600 (insurance and charges for handling hazardous chemicals) by air, and should therefore comply with IATA packaging requirements (cylinder burst pressure ≥30MPa). In 2023, 5 kg of SF6 was transported by LCL from Shanghai to Vancouver by a Canadian laboratory, reducing the cost from $3,200 to $900 by air but extending the transit time to 60 days and the risk of humidity (dew point fluctuation ±5°C in the shipping container). For storage, trace SF6 requires a nickel-plated cylinder with a volume of less than 50 liters (US $800-1200 per unit), with a pressure gauge (accuracy ±0.1bar), with maintenance cost every year being about 8% of the cost of the cylinder, and if you are renting recyclable containers (e.g., Linde Group’s Eclipse cylinder), you can pay 60% less as the initial cost. But 15% of gas buying price is paid as rent.
Micro-testing is being reduced by technological development. SF6 Alternative gas simulation software, developed by the UK National Physical Laboratory (NPL), reduces physical gas tested by 80% based on quantum computing models (99.8% accuracy), and costs $15,000 per year for a single license, 40% lower than purchasing 5kg of SF6. In addition, 3M’s Novec 5110 gas has also been utilized in apparatus testing below 72.5kV, with GWP of 1, a price tag of $220 / kg, and accepting micro orders of 100 grams, but its dielectric strength is only 65% of SF6, limited to a smaller application. As of 2023, the global SF6 test gas market is worth $230 million, with micro-procurement accounting for 12%, and it is estimated that by 2025, with the increasing popularity of digital twin technology (such as Siemens’ GIS equipment virtual test platform), the demand for physical gas testing will decline by 25%. To promote the sulfur hexafluoride gas for sale into a high purity and high unit price professional market segment.