Sulfur Hexafluoride (SF6) Emission Reductions from Gas Insulated Switchgear (GIS) - FAQs

This page last reviewed July 11, 2013

Frequently Asked Questions:

This page contains some of the most commonly asked questions regarding the Regulation for Reducing Sulfur Hexafluoride Emissions from Gas Insulated Switchgear. Additional FAQs will be added as needed. Please click the questions below to view the answers.

A. Purpose, Scope, and Applicability
  1. Are all gas insulated switchgear (GIS) owners subject to this regulation, even if the GIS owner is not an electric utility?

  2. Is there a de minimus level for the regulation?

  3. Will the first year of the sf6 regulation be a transitional year?

  4. My company hires a contractor to service our GIS. Does this alleviate my company from being responsible for the services the contractor is performing?

B. Definitions
  1. The definition of “Active GIS Equipment” specifies that the GIS equipment is “Connected through busbars or cables to the GIS owner’s electrical power system.” What if GIS equipment owned by one utility is connected to electrical transmission or distribution lines owned by a different utility?

  2. The definition of “Gas container” is “a vessel containing or designed to contain sf6. ‘Gas container’ includes pressurized cylinders, gas carts, or other containers.” Is “Gas-insulated switchgear” a gas container?

  3. “GIS Owner” excludes temporary ownership by the equipment manufacturer during equipment transport. When does this temporary ownership come to an end for the purposes of determining the “GIS Owner?”

  4. How can I tell if my device is “hermetically sealed”?

C. Sf6 Inventory Measurement Procedures
  1. Must scales used to weigh sf6 gas cylinders be certified by the manufacturer?

  2. If a scale has just been purchased, and has been calibrated by the manufacturer within the past year, does this satisfy the calibration requirement in section 95354(a)(3)?

  3. How often must the scales used to weigh sf6 gas cylinders be calibrated?

  4. If a facility does not currently own a scale, are they expected to purchase an approved scale?

D. Recordkeeping
  1. When must GIS owners “Establish and Maintain” a complete GIS equipment inventory by?

  2. How should GIS owners maintain an equipment inventory for equipment that they do not have access to the serial number or manufacturer date?

  3. The regulation requires that the physical address of each piece of GIS equipment be listed as part of the inventory. How should equipment in remote sites that do not have a physical address be listed?

  4. Is equipment in storage that has a slight charge considered “Active GIS Equipment?”

  5. Will ARB be developing an sf6 equipment inventory form?

  6. The sf6 regulation states that “GIS owners must” take certain actions and maintain certain records. Can operators of GIS equipment, or contractors, take these actions and keep the records on behalf of the owners?

  7. When equipment is out of service for maintenance is the GIS equipment still considered active?

  8. Some of the information that is required in the “Recordkeeping” section of the regulation is not necessary for calculating emissions. Will GIS owners be required to record all this information?

  9. What accuracy requirements apply when weighing sf6 transferred into or out of GIS equipment?

  10. For the sf6 container inventory, what is meant by “size” of the container?

  11. The container tare weight is needed to determine the weight of sf6 in each container. If the tare weight is unknown, can an approximate tare weight be used based on a similar sized container?

E. Annual Reporting Requirements
  1. Will ARB be developing sf6 annual report forms?

  2. Does an annual report need to be submitted if a GIS owner has no sf6 emissions for a given year?

  3. When is the first sf6 annual report due to the ARB?

  4. Are there any fees/costs that GIS owners must pay the ARB for submittal of the sf6 annual reports?

  5. If a GIS owner has a contractor performing maintenance, inventory, cylinder weighing, and preparation of reports, who is responsible for submitting the annual report?

  6. Who is required to submit annual reports via the electronic GHG reporting tool?

  7. If a GIS owner is exempt from the Mandatory Reporting Regulation, how should the annual reports be submitted?

  8. How often do sf6 gas cylinders have to be weighed?

  9. If a facility does not have a single sf6 gas cylinder that enters or leaves storage during the year, are the assumed emissions and emission rates zero?

  10. Will training be provided on the electronic GHG reporting tool?

  11. Will reporting be similar to the current method used for uploading mandatory reporting? We would like to be able to use what we are currently using (i.e., excel files).

  12. Does ARB’s Cal e-GGRT include a section for sf6 equipment that can be used now?

  13. Will there be a specific format for reporting data via the electronic tool?

  14. Does the regulation require third-party verification of sf6 emissions?

  15. Is the sf6 data that is required to be reported expected to cover all sf6 emissions associated with GIS?

  16. The annual report must contain a GIS equipment inventory report with the following information: a) a chronological record of the dates on which sf6 was transferred into or out of active GIS equipment (section 95355(a)(8)); and b) the amount, in pounds, of sf6 transferred into or out of the active GIS equipment (section 95355 (a)(9)). How should this information be presented in the annual report?

  17. In the formula for determining “Acquisitions of sf6,” how do utilities account for sf6 in new GIS equipment (not containers) that is purchased?

  18. Section 95356(d) requires the amount of sf6 purchased with or inside active GIS equipment as an input to the equation for determining annual sf6 emissions. For the amount of sf6 inside GIS equipment when shipped and received, the GIS owner depends on the accuracy of information from the manufacturer, distributor, or other entity. How does the GIS owner assure the accuracy of the information from the GIS equipment supplier?

  19. Where GIS equipment is jointly owned by two or more GIS owners, how should each owner calculate its annual sf6 emissions and average system nameplate capacity?

  20. The Regulation requires an attestation for annual reports by an “appropriate responsible official,” however the reporting tool requires verified by a “Designated Representative.” Who is responsible for verification of the annual reports submitted via Cal e-GGRT?

  21. We do not own any gas containers, what do we need to report for gas containers in the Reporting Tool?

  22. Is the OEM or GIS owner responsible for reporting SF6 emissions associated with the installation of new GIS equipment?

  23. If a GIS owner does not own SF6 containers, how are annual SF6 emissions determined?

  24. If my company is composed of a number of facilities that are each limited liability companies (LLC) under an umbrella company, at what level are we required to report?

F. Enforcement
  1. The emission rate is calculated in relation to active GIS equipment only, which is non-hermetically sealed equipment. Does the GIS owner have any liability in relation to hermetically sealed equipment?

  2. Are entities responsible for the loss of sf6 during transport of equipment that they purchased?

  3. What does ARB consider when determining an enforcement penalty?


A. Purpose, Scope, and Applicability

1. Are all gas insulated switchgear (GIS) owners subject to this regulation, even if the GIS owner is not an electric utility?
Yes. This regulation applies to all owners of GIS equipment that contains sulfur hexafluoride (sf6). The regulation makes no distinction as to whether or not a GIS device is owned by an electric utility.

2. Is there a de minimus level for the regulation?
No. Because sf6 is the most potent greenhouse gas (GHG)—about 24,000 times the global warming potential of carbon dioxide (CO2)—even small GIS devices could be responsible for significant emissions of GHGs. As such, ARB staff did not include an exemption threshold in the regulation.

3. Will the first year of the sf6 regulation be a transitional year?
No. As is standard protocol on emission reduction measures, the first year of the regulation is an enforceable period.

4. My company hires a contractor to service our GIS. Does this alleviate my company from being responsible for the services the contractor is performing?
No. The company is responsible for ensuring that the contractor is performing its duties in accordance with all the applicable requirements of the regulation; including, but not limited to, inventory, measurement, recordkeeping, and reporting requirements.

B. Definitions

5. The definition of “Active GIS Equipment” specifies that the GIS equipment is “Connected through busbars or cables to the GIS owner’s electrical power system.” What if GIS equipment owned by one utility is connected to electrical transmission or distribution lines owned by a different utility?
Those devices would be subject to the regulation as the definition of “Electrical Power System” is broad enough that the units described in the comment would be considered as “Active GIS Equipment.”

6. The definition of “Gas container” is “a vessel containing or designed to contain sf6. ‘Gas container’ includes pressurized cylinders, gas carts, or other containers.” Is “Gas-insulated switchgear” a gas container?
No. The definition of “Gas container” was not intended to include GIS, as the regulation treats GIS and gas containers in very separate fashions. For example, gas-insulated switchgear is not weighed, but gas containers are weighed annually to determine if there are sf6 losses from one year to the next.

7. “GIS Owner” excludes temporary ownership by the equipment manufacturer during equipment transport. When does this temporary ownership come to an end for the purposes of determining the “GIS Owner?”
The GIS owner’s responsibility begins when the owner has physical possession of the equipment.

8. How can I tell if my device is “hermetically sealed”?
If you or anyone other than the manufacturer could add gas to the device for any reason whatsoever, it is not hermetically sealed.

C. Sf6 Inventory Measurement Procedures

9. Must scales used to weigh sf6 gas cylinders be certified by the manufacturer?
Yes. Section 95354 of the regulation states that scales used to weigh sf6 gas cylinders must be certified by the manufacturer to be accurate to within one percent of the true weight.

10. If a scale has just been purchased, and has been calibrated by the manufacturer within the past year, does this satisfy the calibration requirement in section 95354(a)(3)?
If the manufacturer states in writing that the device meets the accuracy requirements upon delivery (after transport) then ARB staff would accept that as proof of having met the requirement of section 95354(a)(3).

11. How often must the scales used to weigh sf6 gas cylinders be calibrated?
Section 95354 of the regulation states that GIS owners must calibrate scales used to measure quantities reported under this subarticle prior to the first reporting year. Also, the scales must be recalibrated at least annually, or at the minimum frequency specified by the manufacturer, whichever is more frequent.

12. If a facility does not currently own a scale, are they expected to purchase an approved scale?
No. If a GIS owner does not currently own a scale, any scale can be used that meets all the requirements of the regulation. In these situations, the GIS owner would be expected to maintain records pertaining to any scale used, including such information as the make and model, calibration date, owner, location, etc. to demonstrate compliance with the regulation.

D. Recordkeeping

13. When must GIS owners “Establish and Maintain” a complete GIS equipment inventory by?
ARB staff expects that all GIS owners will have a complete equipment inventory by January 1, 2012. GIS owners will need the information contained in the inventory by this date in order to calculate their emission rates to demonstrate compliance.

14. How should GIS owners maintain an equipment inventory for equipment that they do not have access to the serial number or manufacturer date?

  • If a device does not have a serial number, then any permanently affixed unique identifier can be used in place of a serial number.
  • If the date that the device was manufactured cannot be determined, ARB staff would accept a best estimated date. ARB staff would expect that the GIS owner would record how the estimated date was determined.


15. The regulation requires that the physical address of each piece of GIS equipment be listed as part of the inventory. How should equipment in remote sites that do not have a physical address be listed?
For GIS equipment that does not have a physical address, it would be acceptable to provide some other type of location identifier (e.g., UTM coordinates, longitude and latitude, parcel numbers, distance and direction to and the name of the nearest cross streets.)

16. Is equipment in storage that has a slight charge considered “Active GIS Equipment?”
No. GIS equipment in storage is not “active GIS equipment.”

17. Will ARB be developing an sf6 equipment inventory form?
No. ARB staff will accept any format used to track sf6 equipment inventory.

18. The sf6 regulation states that “GIS owners must” take certain actions and maintain certain records. Can operators of GIS equipment, or contractors, take these actions and keep the records on behalf of the owners?
Yes. GIS owners are free to either use their own staff, contract labor, or a combination thereof to perform the duties required by the regulation. However, GIS owners will remain liable under this regulation for any errors or omissions and are responsible for complying with the regulation.

19. When equipment is out of service for maintenance is the GIS equipment still considered active?
Yes. GIS equipment will be considered active as long as the maintenance is performed with the equipment in-place; at its normal active position.

20. Some of the information that is required in the “Recordkeeping” section of the regulation is not necessary for calculating emissions. Will GIS owners be required to record all this information?
Yes. All information in the recordkeeping section is required to be recorded. This information will be used by ARB staff to evaluate the implementation of the regulation and possible revisions to the regulation.

21. What accuracy requirements apply when weighing sf6 transferred into or out of GIS equipment?
Since the transfer of sf6 into and out of GIS equipment is independent of the annual inventory and emissions calculation, ARB staff will accept best estimates of the weight for these transfers. ARB staff understands that the summed transfer weights may not equal the annual amount of gas transferred.

22. For the sf6 container inventory, what is meant by “size” of the container?
ARB staff expects that GIS owners will report the size or capacity of containers in terms of weight (pounds) as all measurements for the regulation are based on weight.

23. The container tare weight is needed to determine the weight of sf6 in each container. If the tare weight is unknown, can an approximate tare weight be used based on a similar sized container?
Title 4, California Code of Regulations, section 4051, Cylinder Labeling, requires that tare weights be legibly stamped on each cylinder used for the sale of gases. As such, if you have a container that does not have a tare weight, ARB staff recommends that you contact the distributor or the local weights and measures agency.

E. Annual Reporting Requirements

24. Will ARB be developing sf6 annual report forms?
Regulated parties submitting their annual reports via the ARB's electronic Greenhouse Gas (GHG) Reporting Tool will need to use the format specified by the tool for their annual reports. ARB staff will accept any format used for annual reports from GIS owners not using the mandatory reporting tool.

25. Does an annual report need to be submitted if a GIS owner has no sf6 emissions for a given year?
Yes. If you own GIS equipment, you are required to submit an annual report whether or not you have any perceived or detected sf6 emissions.

26. When is the first sf6 annual report due to the ARB?
The first annual report is due to the ARB by June 1, 2012, for calendar year 2011.

27. Are there any fees/costs that GIS owners must pay the ARB for submittal of the sf6 annual reports?
No. GIS owners do not have to pay ARB any fees to submit their annual reports.

28. If a GIS owner has a contractor performing maintenance, inventory, cylinder weighing, and preparation of reports, who is responsible for submitting the annual report?
It is the responsibility of the GIS owner to submit the annual report.

29. Who is required to submit annual reports via the electronic GHG reporting tool?
GIS owners subject to the requirements of title 17, California Code of Regulations (CCR), section 95100 et seq., must use the electronic GHG reporting tool. GIS owners not subject to the requirements of title 17, CCR, section 95100 et seq., may also use this reporting tool.

There are three categories of entities that must report via the electronic tool per the regulation:

  1. electricity retail providers and marketers;
  2. facilities that have the capacity to generate more than 1 MW of electricity and emit at least 2,500 metric tonnes of carbon dioxide equivalent (MTCO2e) emissions from generating activities; and
  3. facilities with 25,000 MTCO2e emissions.


30. If a GIS owner is exempt from the Mandatory Reporting Regulation, how should the annual reports be submitted?
In this case the GIS owner has the option to submit the annual report either via ARB’s electronic GHG Reporting Tool or via mail to Energy Section Manager, Stationary Source Division, Air Resources Board, P.O. Box 2815, Sacramento, CA 95812.

31. How often do sf6 gas cylinders have to be weighed?
sf6 gas cylinders must be weighed at least once per year. They must be weighed for annual inventory purposes and when they are added or removed from inventory.

32. If a facility does not have a single sf6 gas cylinder that enters or leaves storage during the year, are the assumed emissions and emission rates zero?
No. There is the possibility that gas cylinders may be defective or had valves left open, which can cause emissions.

33. Will training be provided on the electronic GHG reporting tool?
Yes. ARB plans to provide webinar training on the new electronic GHG reporting tool, Cal e-GGRT, in early 2012. To receive announcements on trainings and other reporting-related topics, please sign up for the “GHG Mandatory Emissions Reporting” e-mail list (ghg-rep) at http://www.arb.ca.gov/lispub/sublist.php. ARB staff will also send out a notice via the sf6 from GIS e-mail list. Additionally, you can contact staff working on the Regulation for Reducing Sulfur Hexafluoride Emissions from Gas Insulated Switchgear via the contact information listed on our webpage at: www.arb.ca.gov/cc/sf6elec/contacts.htm.

34. Will reporting be similar to the current method used for uploading mandatory reporting? We would like to be able to use what we are currently using (i.e., excel files).
ARB is developing a new reporting tool, Cal e-GGRT, for 2012 reporting of 2011 data. The new reporting tool will have the look and feel of U.S. EPA’s reporting tool, and the new tool’s user interface is more streamlined than the current mandatory reporting tool. Users will register with Cal e-GRRT through the registration module in the first year. After that, annual sf6 data will be submitted by completing a standardized reporting spreadsheet to be uploaded to the web tool. The spreadsheet template can be downloaded to the user’s local hard drive for working off-line.

35. Does ARB’s Cal e-GGRT include a section for sf6 equipment that can be used now?
ARB’s Cal e-GGRT tool will have a section dedicated to sf6 emissions from GIS reporting with on-screen instructions to guide users through the reporting process. Cal e-GGRT will be available for testing and training purposes in early 2012.

36. Will there be a specific format for reporting data via the electronic tool?
ARB will provide a standardized reporting template spreadsheet for submitting data via the ARB’s electronic GHG Reporting Tool. Data will be submitted by completing the reporting spreadsheet that is then uploaded to the web tool. Users will be able to work on the spreadsheet first from their local hard drives.

37. Does the regulation require third-party verification of sf6 emissions?
No. The regulation does not require third-party verification of sf6 emissions. However, the Mandatory Reporting Regulation requires third-party verification of sf6 emissions for calendar years 2010 and earlier.

38. Is the sf6 data that is required to be reported expected to cover all sf6 emissions associated with GIS?
Yes. The regulation requires the reporting of sf6 emissions to include all sf6 emissions associated with GIS, including, but not limited to, the operation, maintenance, transportation, and storage of GIS and gas containers.

39. The annual report must contain a GIS equipment inventory report with the following information: a) a chronological record of the dates on which sf6 was transferred into or out of active GIS equipment (section 95355(a)(8)); and b) the amount, in pounds, of sf6 transferred into or out of the active GIS equipment (section 95355 (a)(9)). How should this information be presented in the annual report?
There are many ways to accomplish this that are acceptable as long as all relevant information is available. An example of one way to accomplish this would be to list the date, identification, and amount in a tabular format such as:

Date Device Lbs.-In Lbs.-Out
2/15/11 1234 100
2/18/11 xyz 25


40. In the formula for determining “Acquisitions of sf6,” how do utilities account for sf6 in new GIS equipment (not containers) that is purchased?
sf6 inside new GIS equipment is to be counted as an acquisition from the time a GIS owner takes receipt of the equipment. When the device becomes “active” its capacity is used to determine the system capacity for the year.

41. Section 95356(d) requires the amount of sf6 purchased with or inside active GIS equipment as an input to the equation for determining annual sf6 emissions. For the amount of sf6 inside GIS equipment when shipped and received, the GIS owner depends on the accuracy of information from the manufacturer, distributor, or other entity. How does the GIS owner assure the accuracy of the information from the GIS equipment supplier?
ARB staff expects manufacturers to work with GIS owners to provide them with the information needed to comply with the regulation. Additionally, the U.S. EPA recordkeeping requirements in 40 CFR 98 Subpart SS require that electrical equipment manufacturers with an sf6 threshold of 23,000 pounds per year must retain “certifications of the quantity of gas, in pounds, charged into equipment at the electrical equipment manufacturer or refurbished facility as well as the actual quantity of gas, in pounds, charged into equipment at installation.”

42. Where GIS equipment is jointly owned by two or more GIS owners, how should each owner calculate its annual sf6 emissions and average system nameplate capacity?
Each joint owner is responsible for the proportion of the GIS equipment that they own. However, each joint owner may apply its equity share (ownership or entitlement share) of the relevant equipment when calculating annual sf6 emissions and average nameplate capacity based on the information provided by the operator to each joint owner.

43. The Regulation requires an attestation for annual reports by an “appropriate responsible official,” however the reporting tool requires verified by a “Designated Representative.” Who is responsible for verification of the annual reports submitted via Cal e-GGRT?
All annual reports submitted to comply with the SF6 from GIS regulation must be certified by a “responsible official” as defined in the SF6 from GIS regulation.

44. We do not own any gas containers, what do we need to report for gas containers in the Reporting Tool?
Regulated parties are required to report information for gas containers they own or store on their property.

45. Is the OEM or GIS owner responsible for reporting SF6 emissions associated with the installation of new GIS equipment?
Once GIS equipment has been delivered to a GIS owner the equipment becomes the responsibility of the GIS owner. All SF6 associated with the installation of a GIS device is the responsibility of the GIS owner and must be reported by the GIS owner.

46. If a GIS owner does not own SF6 containers, how are annual SF6 emissions determined?
In this type of situation, every SF6 container used to add or remove gas from the GIS devices would have to be weighed before and after every use at the GIS owner’s facilities on a scale that meets the standards of the regulation. Documentation that supports this was properly done would need to be retained by the GIS owner.

47. If my company is composed of a number of facilities that are each limited liability companies (LLC) under an umbrella company, at what level are we required to report?
As each LLC is an independent entity that legally owns the GIS at a facility, each LLC would be individually subject to the regulation. Each facility would have to meet all obligations independently, including the emission rate, recordkeeping, and reporting requirements.

F. Enforcement

48. The emission rate is calculated in relation to active GIS equipment only, which is non-hermetically sealed equipment. Does the GIS owner have any liability in relation to hermetically sealed equipment?
No. Hermetically sealed GIS equipment is exempt from this regulation.

49. Are entities responsible for the loss of sf6 during transport of equipment that they purchased?
ARB would not hold a GIS owner responsible for emissions that occur prior to taking possession of a GIS device. ARB staff would expect that any piece of equipment be checked for emissions within a reasonable timeframe after receipt. Any emissions that occurred prior to taking possession and the reason for the emissions should be documented by both the owner and manufacturer/distributor to substantiate a claim that the amount of sf6 delivered in the GIS is different than stated on the bill of lading or similar documentation.

50. What does ARB consider when determining an enforcement penalty?
The following factors are taken into consideration when determining an appropriate penalty:

  • The extent of harm caused by the violation.
  • The nature and persistence of the violation.
  • The length of time over which the violation occurs.
  • The frequency of past violations.
  • The record of maintenance.
  • The unproven or innovative nature of the control equipment.
  • Any action taken by the person including the nature, extent, and time of response of any cleanup and construction undertaken to mitigate the violation.
  • The financial burden on the defendant.
  • And any other relevant circumstances.


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