Our 11 kilovolt (kV) switchgear has never needed a gas top-up. Do we report zero sulphur hexafluoride (SF6) loss, or use an Intergovernmental Panel on Climate Change (IPCC) default?
No. The IPCC 2006 Guidelines define sealed-pressure equipment as needing no top-up for its whole life, so refill records show nothing though gas escapes slowly. Table 8.2 gives use factors of 0.002 (Europe) and 0.007 (Japan) of nameplate charge a year. The Japan figure covers all equipment types, so state which you used.
Two kinds of SF6 equipment
Volume 3 Chapter 8 splits SF6 equipment in two. Sealed-pressure systems are "equipment that does not require any refilling (topping up) with gas during its lifetime" and generally hold less than 5 kilograms of gas per functional unit; "Distribution equipment normally falls into this category." Closed-pressure systems need refilling during their life, generally hold between 5 and several hundred kilograms per unit, and transmission equipment normally falls here.
Our reading: gas-insulated 11 kV and 33 kV panels in a factory yard are distribution equipment, so most are sealed pressure. Check the nameplate or the maker's data sheet for the type.
Why refill records show nothing
The mass balance for use, Equation 8.6A, is the SF6 used to recharge closed-pressure equipment at servicing minus the SF6 recovered. A sealed panel is never recharged, so that sum is zero by design. The Guidelines say the emission-factor approach "is likely to be more accurate for sealed-pressure equipment everywhere", and that the pure mass-balance approach is likely to be appropriate for countries where emissions from sealed-pressure systems are likely to be negligible. Zero on the refill sheet is not evidence of zero loss.
The Tier 1 defaults in Table 8.2
- Europe: 0.002 of nameplate charge a year for use, which includes leakage, major failures and arc faults, and maintenance losses. Lifetime over 35 years. Fraction of charge left at retirement 0.93.
- Japan: 0.007 of nameplate charge a year for use. Lifetime not reported. Fraction left at retirement 0.95. Footnote c says the figures come from Japanese power company and manufacturer reporting that "did not distinguish among equipment types" and are "intended to be applied to all equipment types, including sealed pressure systems, closed pressure systems, and gas-insulated transformers". So the Japan value is not specific to sealed panels.
- The table is titled medium voltage switchgear. The chapter uses "up to 52 kV" as its medium voltage band elsewhere, so 11 kV and 33 kV fit. That link is our reading.
- The Guidelines say to choose factors from countries and regions with similar equipment designs and SF6 handling practice, and that because Japan and Europe supply most of the global demand for electrical equipment, designs are likely to be similar to one of the two. They also note the factors reflect 1995 practice, before industry reduction measures.
How this sits with our switchgear leak page
That page shows a 0.5 percent a year screening rate taken from a data sheet and puts refill records first. For sealed panels, use the data sheet rate only if the maker states it, and otherwise use one of the two IPCC values above. 0.005 (0.5 percent) sits between 0.002 (0.2 percent) and 0.007 (0.7 percent). If a service report does show refills for a panel, it is closed pressure by the Guidelines' definition, and the refill kilograms are the better measure, as that page explains.
Six sealed panels, 24 kilograms of SF6 on the nameplates
- Europe default: 24 x 0.002 = 0.048 kilograms of SF6 a year
- Japan default: 24 x 0.007 = 0.168 kilograms of SF6 a year
- An example data sheet rate of 0.5 percent: 24 x 0.005 = 0.12 kilograms of SF6 a year
- Multiply kilograms by the global warming potential of SF6 in your chosen assessment report to reach tonnes of carbon dioxide equivalent (CO2e)
The 24 kilograms is an example total, 4 kilograms a panel, under the Guidelines' 5 kilogram sealed-pressure guide; read your own nameplates. State the region you picked and the year of the table.
What Senseible does here
Senseible reads fuel invoices and electricity bills into dated records. It does not read switchgear nameplates or gas weights, so work out the SF6 line from your own asset list and add it to your inventory.
Sources: IPCC 2006 Guidelines, Volume 3 Chapter 8 (Section 8.2, Equation 8.6A, Table 8.2)
Last reviewed 2026-11-05. Defaults are the 2006 Guidelines' 1995-practice values for Europe and Japan. A maker's own leak-rate figure for your model is better evidence if you hold it.