Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.1 

# CHAPTER 8

OTHER PRODUCT MANUFACTURE AND USEVolume 3: Industrial Processes and Product Use

8.2 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### Authors

Sections 8.1, 8.2, and 8.3 Deborah Ottinger Schaefer (USA)
Friedrich Plöger (Germany), Winfried Schwarz (Germany), Sven Thesen (USA), Ewald Preisegger (Germany), Ayite-Lo N. Ajavon (Togo), and Dadi Zhou (China)

Section 8.4 Nigel Harper (UK)Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.3 

# Contents

8 Other Product Manu facture and Use.............................................................................................. ...............8.6

8.1 Introduc tion................................................................................................................... ........................8.6
8.2 Emissions of SF 6 and PFCs from elect rical equipment.........................................................................8.6
8.2.1 Introduc tion ................................................................................................................... ................8.6
8.2.2 Methodologica l issu es .......................................................................................................... .........8.7

8.2.2.1 Choice of method............................................................................................................... ......8.7 8.2.2.2 Choice of em ission factors............................................................................................. ........8.14 8.2.2.3 Choice of activity data ................................................................................................ ...........8.17 8.2.2.4 Completeness........................................................................................................... ..............8.19 8.2.2.5 Developing a c onsistent tim e series.................................................................................... ...8.20
8.2.3 Uncertainty assessment ......................................................................................................... ......8.20
8.2.4 Quality Assurance/Quality Control (QA/QC ), Reporting and Documentation ...........................8.21

8.2.4.1 Quality Assura nce/Quality Control...................................................................................... ..8.21 8.2.4.2 Reporting an d Documentation ............................................................................................ ...8.22
8.3 Use of SF 6 and PFCs in other products ...............................................................................................8.23

8.3.1 Introduc tion ................................................................................................................... ..............8.23
8.3.2 Methodologica l issu es .......................................................................................................... .......8.23

8.3.2.1 Choice of method....................................................................................................... ............8.23 8.3.2.2 Choice of em ission factors............................................................................................. ........8.32 8.3.2.3 Choice of activity data ................................................................................................ ...........8.33 8.3.2.4 Completeness........................................................................................................... ..............8.33 8.3.2.5 Developing a c onsistent tim e series.................................................................................... ...8.33
8.3.3 Uncertainty assessment ......................................................................................................... ......8.33
8.3.4 Quality Assurance/Quality Control (QA/QC ), Reporting and Documentation ...........................8.33

8.3.4.1 Quality Assura nce/Quality Control...................................................................................... ..8.33 8.3.4.2 Reporting an d Documentation ............................................................................................ ...8.34
8.4 N 2 O from product uses............................................................................................................ ............8.35

8.4.1 Introduc tion ................................................................................................................... ..............8.35
8.4.2 Methodologica l issu es .......................................................................................................... .......8.36

8.4.2.1 Choice of method....................................................................................................... ............8.36 8.4.2.2 Choice of em ission factors............................................................................................. ........8.36 8.4.2.3 Choice of activity data ................................................................................................ ...........8.37 8.4.2.4 Completeness........................................................................................................... ..............8.37 8.4.2.5 Developing a c onsistent tim e series.................................................................................... ...8.37
8.4.3 Uncertainty assessment ......................................................................................................... ......8.37

8.4.3.1 Emission fact or uncertainties.......................................................................................... .......8.37Volume 3: Industrial Processes and Product Use

8.4 2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.4.3.2 Activity da ta uncerta inties ............................................................................................ .........8.38
8.4.4 Quality Assurance/Quality Control (QA/QC ), Reporting and Documentation ...........................8.38 References .................................................................................................................... .................................8.39 Annex 8A Examples of Tier 3 national SF 6 inventory systems....................................................................8.41



# Equations

Equation 8.1 Default emi ssion factor method.................................................................................... .........8.8 Equation 8.2 Equipment disposal emissions under country-specific emission factor method....................8.9 Equation 8.3 Tier 3 total em issions............................................................................................ ...............8.10 Equation 8.4A Equipment manufacturing emissions - pure mass-balance..................................................8.10 Equation 8.4B Equipment manuf acturing emissions - hybrid .....................................................................8. 11 Equation 8.5A Equipment installation emissions - pure mass-balance .......................................................8.11 Equation 8.5B Equipment inst allation emissions - hybrid........................................................................ ...8.11 Equation 8.6A Equipment use emi ssions - pure mass-balance....................................................................8. 11 Equation 8.6B Equipment use emissions - hybrid................................................................................. ......8.12 Equation 8.7A Equipment disposal and fina l use emissions - pure mass-balance.......................................8.12 Equation 8.7B Equipment disposal an d final use emissi ons - hybrid..........................................................8.12 Equation 8.8 Emissions from recycling of SF 6 .........................................................................................8.13 Equation 8.9 Emissions from destruction of SF 6 ......................................................................................8.13 Equation 8.10 Utility-level mass-balance approach.............................................................................. ......8.14 Equation 8.11 Retiring nameplate capacity ...................................................................................... ..........8.18 Equation 8.12 Emissions from AWAC S (default emission actor)..............................................................8.24 Equation 8.13 Emissions from AW ACS (user mass-balance)....................................................................8.25 Equation 8.14 University and research particle accelerator emissions (country-level) ..............................8.27 Equation 8.15 University and research particle accelerator emissions (accelerator-level em ission factor) ......................................................................................8.28 Equation 8.16 Total resear ch accelerator emissions ............................................................................. ......8.28 Equation 8.17 Research accelerator emissions (accelerator-level mass-balance).......................................8.28 Equation 8.18 Industrial/medical acceler ator emissions (c ountry-level) ....................................................8.30 Equation 8.19 Adiabatic property app lications.................................................................................. .........8.31 Equation 8.20 Double-glazed windows: assembly .................................................................................. ...8.31 Equation 8.21 Double-gl azed window s: use....................................................................................... ........8.31 Equation 8.22 Double-glazed windows: disposal .................................................................................. .....8.31 Equation 8.23 Prom pt emissions................................................................................................. ................8.32 Equation 8.24 N 2 O emissions from othe r product uses ..............................................................................8.36Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.5 

# Figures

Figure 8.1 Decision tree for SF 6 from electrical equipment....................................................................8.8 Figure 8.2 Decision tree for SF 6 from AWACS ...................................................................................8.24 Figure 8.3 Decision tree for SF 6 from research accelerators.................................................................8.27 Figure 8.4 Decision tree for industrial and me dical particle accelerators .............................................8.29 Figure 8A.1 Example of Tier 3 approach : Germany, High-Voltage equipment......................................8.42 Figure 8A.2 Example of Tier 3 approach: Germany, Medium-Voltage equipment ................................8.43



# Tables

Table 8.1 Avoiding double- counting or overlooking emi ssions: two examples..................................8.13 Table 8.2 Sealed pressure electrical equipment (MV Switchgear) containing SF 6 : default emissi on factors....................................................................................................... 8.15 Table 8.3 Closed pressure electrical equipment (HV Switchgear) containing SF 6 : default emissi on factors....................................................................................................... 8.16 Table 8.4 Gas insulated transformers containing SF 6 : default emissi on factors..................................8.16 Table 8.5 Uncertainties for default emission factors and lifetime .......................................................8.21 Table 8.6 Good practice reporting information for SF 6 emissions from electrical equi pment by tier.........................................................................................8.22 Table 8.7 SF 6 emissions per plane per year.........................................................................................8.24 Table 8.8 Nationa l AWACS fleets ................................................................................................ ......8.25 Table 8.9 Average SF 6 charge in a particle accelerator by process de scription...................................8.30 Table 8.10 Emission factor for each process description, (SF 6 emissions from industrial and medical particle accelerators) .......................................................................................8.30Volume 3: Industrial Processes and Product Use

8.6 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

# 8 OTHER PRODUCT MANUFACTURE AND USE

8.1 INTRODUCTION
This chapter outlines methods for estimating emissions of sulphur hexafluoride (SF 6 ) and perfluorocarbons (PFCs) from the manufacture and use of electrical equipment and a number of other products. It also provides methods for estimating emissions of nitrous oxide (N 2 O) from several products. In most of these applications, the SF 6 , PFC, or N 2 O is deliberately incorporated into the product to exploit one or more of the physical properties of the chemical, such as the high dielectric strength of SF 6 , the stability PFCs, and the anaesthetic effect of N 2 O. However, the applications discussed here have a wide range of emission profiles, ranging from immediate and unavoidable release of a ll of the chemical (e.g., use of PFCs as atmospheric tracers) to largelyavoidable, delayed release from leak-tight products after 40 years of use (e.g., manufacture and use of sealedpressure electrical equipment). The estimation methods presented in the chapter have been tailored to reflect these differences in emission profiles. Section 8.2 details methods for estimating SF 6 and PFC emissions from electrical equipment. Section 8.3 details methods for estimating emissions from the manufacture and use of a wide variety of other industrial, commercial, and consumer products that contain SF 6 and PFCs, excluding those discussed elsewhere in this volume (e.g., PFC emissions from electronics manufacturing, which are discussed in Chapter 6). (Please see the introduction to Section 8.3 for the list of excluded sources.) Fi nally, Section 8.4 discusses methods for estimating N 2 O emissions from anaesthetics, propellants, and other product uses.


# 8.2 EMISSIONS OF SF 6 

# AND PFCs FROM ELECTRICAL EQUIPMENT

8.2.1 Introduction
Sulphur hexafluoride (SF 6 ) is used for electrical insulation and current interruption in equipment used in the transmission and distribution of electri city. Emissions occur at each phase of the equipment life cycle, including manufacturing, installation, use, servicing, and disposal. Most of the SF 6 used in electrical equipment is used in gas insulated switchgear and subs tations (GIS) and in gas circu it breakers (GCB), though some SF 6 is used in high voltage gas-insulated lines (GIL), outdoor gas-insulated instrument transformers and other equipment. The aforementioned applications may be divided into two cat egories of containment. Th e first category is ‘Sealed Pressure Systems’ or ‘Sealed-for-life Equipment’, which is defined as equipment that does not require any refilling (topping up) with gas during its lifetime and which generally contains less than 5 kg of gas per functional unit. 1 Distribution equipment normally falls into this category. The second category is ‘Closed Pressure Systems’, which is defined to include equipment that requires refilling (topping up) with gas during its lifetime. This type of equipment generally contains between 5 and several hundred kg per functional unit. Transmission equipment normally falls into this category. Both categories of equipment have lifetimes of more than 30 to 40 years. In Asia, significant quantities of SF 6 are used in gas-insulated power transformers (GIT). Electrical equipment is the largest consumer and most important use of SF 6 , globally. It significantly contributes to worldwide SF 6 emissions. However, the importance of this source varies considerably from region to region and from country to country. The emissions from this category depend not only on the installed (banked) or consumed quantities of SF 6 , but also very much on the tightness of the products and the handling processes applied. Regional average emission rate s presently vary between far less than 1 percent to more than 10 percent. In general, emission rates have declined significantly since 1995. Targeted industry actions have reduced emissions by 50 to 90 percent in Europe and Asia (Ecofys, 2005; Aoyama, 2004). These actions include (1)

1 Formal definitions of ‘sealed-pressu re system’ and ‘closed-pressure system’ are contained in International Electrotechnical Commission (IEC) Standard 60694. (IEC, 1996)Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.7 designing equipment to require a smaller charge of SF 6 and to be more leak tight and (2) improving handling processes and handling equipmen t for all life cycle stages. 2 In some regions (e.g., North America and Japan), perflu orocarbons (PFCs) are used as dielectrics and heat transfer fluids in power transformers. PFCs are also us ed for retrofitting CFC-113 cooled transformers. One PFC used in this application is perfluorohexane (C 6 F 14 ). In terms of both absolute and carbon-weighted emissions, PFC emissions from electrical eq uipment are generally believed to be much smaller than SF 6 emissions from electrical equipment; however, there may be regional exceptions to this pattern.



# 8.2.2 Methodological issues

8.2.2.1 C HOICE OF METHOD

Emissions of SF 6 from electrical equipment can be estimated in a variety of ways with varying degrees of complexity and data intensity. This section describes good practice for using a Tier 1 method (the default emission

- factor approach), a Tier 2 method (the country-specific emission-factor appro ach), and a Tier 3 method (a hybrid that can use either mass-balance or em ission-factor approaches for different life cycle stages, depending on country-specific circumstances). Generally, emissions estimates developed using the Tier 3 method, which is implemented at the f acility level, will be the most accurate . Estimates developed using the Tier 1 method will be the least accurate. As is true for other emission sources, the tier selected will depend on data availability and whether or not the category is key . Figure 8.1, Decision Tree for SF 6 from Electrical Equipment, summarises the process for choosing among Tiers 3, 2, and 1. Good practice in choosing between the mass- balance and emission-factor variants of the Tier 3 approach is discussed in detail in Section 1.5 of Chapter 1. This choice will depend both on data availability and on country-specific circumstances . As a first step in assessing the importance of SF 6 emissions from electrical equipment a nd the other categories discussed in this chapter, inventory compilers are encouraged to contact chemical producers and supplie rs as well as electrical equipment manufacturers and utilities and/or their industry associations. These organisations can provide basic information on chemical consumption and on equipment stocks and applications that can help the inventory compiler estimate emissions and identify sources that merit further investigation. They can also provide important advice and support in establishing more extensive data collection systems to support Tier 2 and Tier 3 estimates.

2 International Council on Large Electric Systems (CIGRE) has published a guide on SF 6 handling, Guide for the Preparation

of customized “Practical SF 6 Handling Instructions,” Task Force B3. 02.01, CIGRE Publication No.276, August 2005. (CIGRE, 2005)Volume 3: Industrial Processes and Product Use

8.8 2006 IPCC Guidelines for National Greenhouse Gas Inventories Figure 8.1 Decision tree for SF 6 from electrical equipment 1

Estimate emissionsusing Tier 2 CountrySpecific Emission Factor Approach. Start

Can an annual survey of facilities that use SF 6 be completed, gathering data by lifecycle stage?

Are country-specific emission factors available?

Note: 1. In selecting an estimation method, it is good practice also to consider the criteri a presented in Table 1.7, Chapter 1, Section 1.5 of this volume for choosi ng between the mass-balance and emi ssion-factor variants of each tier. 2. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categorie s (noting Section 4.1.2 on limited resource s), for discussion of key categories and use of decision trees. 3. It is good practice to contact National/Regional associations of u tilities/users and manufacturer s to collect, check, and aggregate actual and historical data. Box 2: Tier 2 No

No Is the Other Product Manufacture and Use a

key category 2 , and is

this subcategory

significant? Estimate emissions using the Tier 1 Default Emission Factor Approach.

Box 1: Tier 1 Yes Estimate emissions using Tier 3 Hybrid Life-Cycle Approach.

Yes

Yes Collect data for

Tier 2 or 3 approaches ,3 Box 3: Tier 3

No



### TIER 1 METHOD – DEFAULT EMISSION FACTORS The Tier 1 approach is the simplest approach for estimating SF 6 and PFC emissions from electrical equipment. (Henceforth in this section, ‘SF 6 ’ will be used to denote ‘SF 6 and/or PFCs.’) In this method, emissions are estimated by multiplying default regional emission factors by, as appropriate, the SF 6 consumption of equipment manufacturers and/or by the nameplate SF 6 capacity of the equipment at each life cycle stage beyond manufacturing in the country. The term Installation Emissions may be omitted if (1) installation emissions are not expected to occur (i.e., for closed-pressure equipm ent) or (2) installation emissions are included in the emission factor for emissions from Manufacturing or Use. Default emission factors are given in Tables 8.2 to 8.4. It is good practice to use the following equation:

E QUATION 8.1 D EFAULT EMISSION FACTOR METHOD Total Emissions = Manufacturing Emissions + Equipment Installation Emissions + Equipment Use Emissions + Equipment Disposal Emissions
Where:Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.9 Manufacturing emissions = Manufacturing Emission Factor • Total SF 6 consumption by equipment manufacturers Equipment installation emissions = Installation Emission Factor • Total nameplate capacity of new equipment filled on site (not at the factory). Equipment use emissions = Use Emission Factor • Total nameplate capacity of installed equipment. The ‘use emission factor’ includes emissions due to leakage, servicing, and maintenance as well as failures Equipment disposal emissions = Total nameplate capacity of retiring equipment • Fraction of SF 6 remaining at retirement



### TIER 2 METHOD – COUNTRY-SPECIFIC EMISSION FACTOR METHOD The Tier 2 method uses the same basic equation as Tier 1, but requires reliable coun try-specific emission factors for each life cycle stage. Country-specifi c emission factors will be more accura te because they reflect the unique circumstances in which electrical equipment is used in a given country. In addition, if detailed data for equipment retirement are available, emissions due to retirement can be estimated more accurately. The expression for Equipment Disposal Emissions in the Tier 2 method includes terms accounting for SF 6 recovery at retirement and disposal, as follows:

E QUATION 8.2 E QUIPMENT DISPOSAL EMISSIONS UNDER COUNTRY
- SPECIFIC EMISSION FACTOR METHOD Equipment disposal emissions = Total nameplate capacity of retiring equipment • Fraction of SF 6

remaining at retirement • (1 – fraction of retiring equipment whose SF 6 is recovered • recovery efficiency • fraction of recovered SF 6 recycled, reused with no fu rther treatment, or destroyed*) *This final term is intended to account for emissions during chemical recycling and destruction. Note that to be considered Tier 2, estimates must be developed using only country-specific emission factors.



### TIER 3 HYBRID METHOD – EMISSIONS BY LIFE CYCLE STAGE OF EQUIPMENT
The Tier 3 method is the mo st accurate approach for estimating actual emissions of SF 6 from electrical equipment. This method is detailed but flexible, acco mmodating a wide range of national circumstances. The method is implemented at the facility level and incl udes separate equations for each phase of the life cycle of equipment, including equipment manufacture, installation, use, and disposal. Depending on the type of equipment, the life cycle stage, and country-specific circumstances, either a mass-balance approach or country- (or facility-) specific emission factors may be used. In general, it is good practice to use the mass-balance approach, except where (1) emission ra tes from a process are near or below the precision of the measurements required for the mass-balance approach (e.g., 3 percent of nameplate capacity per year or less), (2) equipment is never serviced during its lifetime (as is expected to be the case for sealed pressure equipment), or (3) equipment stocks are growing very rapidly, as may be the case in countries where electrical eq uipment has been introduced within the last 10-20 years. The hybrid approach enhances accuracy by permitting use of the mass-balan ce approach for some processes and life cycle stages and the emission-factor approach for other processes and life cycle stages. However, the combination of different approaches also introduces o pportunities for double-counting or overlooking emissions.Inventory compilers need to be aware of this problem and take steps to avoid it. Table 8.1, Avoiding DoubleCounting or Overlooking Emissions, provides examples of both the problem and some potential solutions. The annex to this chapter (Annex 8A) briefly describes an example of the Tier 3 appro ach as it has been applied in Germany. This example is intended to illustrate rather than prescribe; the precise approach taken by any given country will depend on country-specific circumstances. Ideally, data are obtained for every equipment manufactur er, electricity transmission and distribution facility (utility), equipment disposer (which may be a manuf acturer, electric utility, or other entity), and SF 6 recycling or destruction facility in the country, and the emissions of all manufacturers, utilities, di sposers, and recycling or destruction facilities are summed to develop the national estimate. The basic equation is:Volume 3: Industrial Processes and Product Use

8.10 2006 IPCC Guidelines for National Greenhouse Gas Inventories E QUATION 8.3 T IER 3 TOTAL EMISSIONS



### ∑ ∑ ∑ ∑ ∑

+ + + + =

n Destructio and Recycling SF from Emissions Emissions Use Final and Disposal Equipment Emissions Use Equipment Emissions on Installati Equipment Emissions ing Manufactur Equipment Emissions Total

6
Where: Equipment Manufacturing Emissions at the facility level can be estimated by Equations 8.4A and 8.4B. Equipment Installation Emissions at the facility level can be estimated by Equations 8.5A and 8.5B. Equipment Use Emissions at the facility level can be estimated by Equations 8.6A and 8.6B. Equipment Disposal and Final Use Emissions at the facility level can be estimated by Equations 8.7A and 8.7B. Emissions from SF 6 Recycling and Destruction at the facility level can be estimated by Equations 8.8 and 8.9. In the above equation, national emissions for each phase ar e equal to the sum of the emissions of all equipment manufacturers, equipment users, equipment disposers, or SF 6 recyclers/destroyers at th at phase. In practice, it is not always possible to obtain data for every facility; in these cases countries may us e one of the extrapolation methods discussed in Section 8.2.2.3, Choice of Activity Data. 

### Equipment manufacturing emissions Equipment manufacturing emissions can be estimated using either a pure mass-balance approach or a mixture ( hybrid ) of a mass-balance approach for some processes and an emission-factor based approach for others. The pure mass-balance approach is preferred except where a substantial fraction of a manufacturer’s emissions come from processes whose emission rates fall below the precisi on of the measurements required for the mass-balance approach (e.g., 3 percent of nameplate capacity per year or less). In these cases, it is good practice to use emission factors to estimate emissions from the processes with very low emission rates and to use the massbalance approach to estimate emissions from the other manufacturing processes. Pure mass-balance approach : Using the pure mass-balance approach, th e total emissions of each equipment manufacturer can be estimated using the following equation:

E QUATION 8.4A E QUIPMENT MANUFACTURING EMISSIONS
- PURE MASS
- BALANCE

6 6 6 SF of nts Disburseme SF of ns Acquisitio Inventory SF in Decrease Emissions ing Manufactur Equipment

− + =

Where:
Decrease in SF 6 Inventory = SF 6 stored in containers at the beginning of the year – SF 6 stored in containers at the end of the year Acquisitions of SF 6 = SF 6 purchased from chemical producer s or distributors in bulk + SF 6 returned by equipment users or distributors with or inside of equipment + SF 6 returned to site after off-site recycling Disbursements of SF 6 = SF 6 contained in new equipment delivered to customers + SF 6 delivered to equipment users in containers + SF 6 returned to suppliers + SF 6 sent off-site for recycling + SF 6 destroyed Hybrid approach : This method first requires that manufacturers separate the gas flows associated with processes for which the mass-balance approach will be used from the gas flows associated with processes for which the emission-factor approach will be used. Emissions from the former can then be estimated using the approach outlined in Equation 8.4A. Emissions from the latter can be estimated by multiplying the total nameplate capacity of equipment un dergoing each process (e.g., f illing) by the country- or f acility-specific emission factor for that process. Total emissions fo r each manufacturer are then estimat ed by summing the emissions from both sets of processes, using the following equation:Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.11 E QUATION 8.4B E QUIPMENT MANUFACTURING EMISSIONS
- HYBRID

process that for factor Emission process each undergoing equipment of capacity Nameplate A Equation Emissions ing Manufactur Equipment

• + =



### ∑ * 4

. 8

* Excluding that covered by Equation 8.4A 

### Equipment installa tion emissions Equipment installation emissions may be estimated using either a mass-balance or an emission-factor approach. Again, the mass-balance approach is preferre d except where emission rates are very low. Pure Mass-balance approach : Using the mass-balance approach, the tota l emissions of each equipment installer can be estimated using the following equation:

E QUATION 8.5A E QUIPMENT INSTALLATION EMISSIONS
- PURE MASS
- BALANCE

equipment new of capacity Nameplate equipment fill to used SF Emissions on Installati Equipment

− = 6

Hybrid approach : This method first requires that users separate the gas flows associated with equipment for which the mass-balance approach will be used from th e gas flows associated with equipment for which the emission-factor approach will be used. Emissions from the former can then be es timated using the approach outlined in Equation 8.5A. Emissions from the latter can be estimated by multiplying the newly installed nameplate capacity of each equipment type by the country- or facility-specific installation emission factor for that type. Total emissions for each in staller are then estimated by summing the emissions from both sets of equipments, using the following equation:

E QUATION 8.5B E QUIPMENT INSTALLATION EMISSIONS
- HYBRID

factor emission on Installati site on filled equipment new of capacity Nameplate Emissions on Installati Equipment

• + =



### ∑ * 8.5A Equation

* Excluding that covered by Equation 8.5A 

### Equipment use emissions Equipment use emissions may be estimated using either a pure mass-balance or a hybrid approach. The pure mass-balance approach is likely to be appropriate for countries where (1) electrical equipment that uses SF 6 has been in use for 10-20 years or more, and (2) emissions fr om sealed-pressure systems ar e likely to be negligible. The hybrid approach is likely to be appropriate for other countries. Pure mass-balance approach : Using the pure mass-balance approach, the total emissions of each equipment user can be estimated using the following equation:

E QUATION 8.6A E QUIPMENT USE EMISSIONS
- PURE MASS
- BALANCE

servicing at equipment pressure closed from ered cov re SF servicing at equipment pressure closed e arg rech to used SF Emissions Use Equipment

6 6

− =

Hybrid approach : This method first requires that users separate the gas flows associated with equipment for which the mass-balance approach will be used from th e gas flows associated with equipment for which the emission-factor approach will be used. Emissions from the former can then be estimated using the approach outlined in Equation 8.6A. Emissions from the latter can be estimated by multiplying the total nameplate capacity of each type of equipment by the country- or facility-specific emission factor for that type of equipment. The emission-factor approach is likely to be more accurate for sealed-press ure equipment everywhere and for allVolume 3: Industrial Processes and Product Use

8.12 2006 IPCC Guidelines for National Greenhouse Gas Inventories types of equipment in countries where electrical equi pment has been used for less than 10-20 years. Total emissions for each user are then estimated by summing th e emissions from both sets of equipment, using the following equation:

E QUATION 8.6B E QUIPMENT USE EMISSIONS
- HYBRID

factor emission Use installed equipment of capacity Nameplate Emissions Use Equipment

• + =



### ∑ * 8.6A Equation

* Excluding that covered by Equation 8.6A 

### Equipment disposal and final use emissions Equipment disposal and final use emissions may be estimated using either a pure mass-balance or a hybrid approach, based on country-specific circumstances. In both the pure mass-balance and hybrid approaches,emissions from closed-pressure equipment are estimated using a mass-balance equation. In the pure massbalance approach, emissions from seal ed-pressure systems are also estimated using a mass-balance equation. In the hybrid approach, emissions from s ealed-pressure systems are estimated us ing an emission-factor-based term. Pure mass-balance approach : In countries where the gas-collection infrastructure (including recovery equipment, technician training, and economic or legal incentives to recover) is not very well-developed or widely applied, it is good practice to use the pure mass-balance approach, as follows:

E QUATION 8.7A E QUIPMENT DISPOSAL AND FINAL USE EMISSIONS
- PURE MASS
- BALANCE

) ( MB equipment pressure sealed from Emissions equipment pressure closed from Emissions Emissions Use Final and Disposal

⋅ + ⋅ =

Where: Disposal and final use emissions from closed-pressure equipment= Nameplate capacity of retired closedpressure equipment – SF 6 recovered from retired closed-pressure equipment, and Disposal and final use emissions from sealed-pressure equipment ( MB ) = Nameplate capacity of retired sealed-pressure systems – SF 6 recovered from retired sealed-pressure systems Note that if the inventory compiler uses the emission-factor approach to estimate ‘use emissions’ from sealedpressure equipment, a term should be subtracted from the second equation to avoid double counting. See Table 8.1, Avoiding Double-Counting or Overlooking Emissions: Two Examples, for this term. Hybrid approach : In countries where the disposal of equipment is well controlled and understood (i.e., where an efficient gas collection infrastructure is in place) and wh ere emissions from use of s ealed-pressure equipment are accounted for under ‘use’ above, the hybrid approach may be used, as follows:

E QUATION 8.7B E QUIPMENT DISPOSAL AND FINAL USE EMISSIONS
- HYBRID

) ( EF equipment pressure sealed from Emissions equipment pressure closed from Emissions Emissions Use Final and Disposal

+ =

Where: Disposal and final use emissions from closed-pressure equipment= Nameplate capacity of retired closedpressure equipment – SF 6 recovered from retired closed-pressure equipment, and Disposal emissions from sealed-pressure equipment ( EF) = [(Nameplate capacity of retired sealedpressure systems) – (Nameplate capacity of retired sealed-pressure systems • Use emission factor • Lifetime of equipment)] • (1 – fraction of retiring equipment whose SF 6 is recovered • recovery efficiency) As noted above, emissions estimated using the above approach should be periodically checked, e.g., by using a pure mass-balance approach and/or assessing recovery frequency and practices. Inventory compilers should pay particular attention to the fraction of retiring equipment whose SF 6 is recovered and to the fraction of the charge that is recovered when recovery is performed (‘recovery efficiency’). Even in countr ies where it is the norm to recover SF 6 from retiring equipment, some venting may occur, and the venting of just a few percent of the SF 6 inChapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.13 retiring equipment will drive emission ra tes far above the minimum that is te chnically achievable and that would otherwise be a reasonable basis for an emission factor. 

### Emissions from SF 6 

### recycling and destruction Some SF 6 emissions occur after the chemical is recovered. These emissions include (1) emissions associated with recycling of SF 6 , and (2) emissions associated with the destruction of SF 6 . (Emissions associated with the shipment of SF 6 to off-site recyclers or destruction facilities ar e considered negligible.) Emissions from recycling of SF 6 are generally expected to be small — on the order of less than one percent of the total quantity fed into the recycling process. However, these emissions may be higher if state-of -the art handling equipment and practices are not used. In most cases, recycling is expected to oc cur on the site of the equipment manufacturer or user. In other cases, recycling may take place at a centralised recycling facility that is not associated with a chemical producer. Finally, recycling may take place on the premises of a chemical producer. Recycli ng emissions from chemical producers will be accounted for under chemical production (s ee Section 3.10 of this volume) and should not be included here. Emissions associated with the destruction of SF 6 depend on the destruction efficiency of the process and the quantity of SF 6 fed into the process. Given the high stability and dissociation temperature of SF 6 , the destruction efficiency may be as low as 90 percen t. Thus, up to 10 percent of the SF 6 fed into the destruction process could be emitted. The quantity of gas fed into the destruction process is generally expected to be small compared to that recycled. However, this may vary from country to country. It is good practice to develop country-specific emission factors for recycling and destruction that are based on full consideration of country-speci fic logistics and practices for SF 6 recycling and destruction. Emissions from recycling of SF 6 may be estimated using the following equation:

E QUATION 8.8 E MISSIONS FROM RECYCLING OF SF 6 * Emissions from Recycling = Recycling emission factor • Quantity SF 6 fed into recycling process *Emissions from recycling that occurs at chemical production facilities should be excluded. Emissions from destruction of SF 6 may be estimated using the following equation:

E QUATION 8.9 E MISSIONS FROM DESTRUCTION OF SF 6 Emissions from Destruction = Destruction emission factor • Quantity SF 6 fed into destruction process

T ABLE 8.1 A VOIDING DOUBLE - COUNTING OR OVERLOOKING EMISSIONS : TWO EXAMPLES Example 1 – Double Counting Example 2 – Omission
Situation: An emission-factor approach is used to estimate emissions from sealed-pressure equipment during use, and a mass-balance approach is used to estimate emissions during disposal of sealed-pressure equipment. Situation: A mass-balance approach is used to estimate emissions during use of closed-pressure equipment, but an emission-factor approach is used to estimate emissions during disposal of closed-pressure.

Potential problem: Emissions during use may be double-counted because some of the SF 6 that is found to be missing when the equipment is disposed has already been counted as emitted during use. Potential problem: Emissions that occur between the final servicing of the equipm ent and its disposal may be overlooked. These ‘final use’ emissions may account for a significant fraction of total use emissions, particularly if the equipment is refilled every 10 years or more.

Solution: Subtract lifetime use emissions (Nameplate capacity of retired sealed-pressure systems • Use emission factor • Lifetime of equipment) from emissions during disposal. Solution: Use the mass-balance approach for both the use and disposal phases of the closed-pressure equipment life cycle.Volume 3: Industrial Processes and Product Use

8.14 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### A special case of the Tier 3 method: the utility-level, pure mass-balance approach Countries that satisfy the good practice criteria for using the pure mass-balance approach beyond equipment manufacturing (i.e., countries where emissions during equipment installation, use, and disposal account for 3 percent or more of facility-level gas flows, where elect rical equipment has been used for 10-20 years or more, and where emissions from sealed-pressure equipment are ne gligible), may, with little or no loss of accuracy, use a simplified version of the Tier 3 method to estimate emissions during equipment use. When summed together and reformulated in terms of facility-level gas flows, equations 8.5A, 8.6A, and 8.7A result in the following equation:

E QUATION 8.10 U TILITY - LEVEL MASS
- BALANCE APPROACH User Emissions = Decrease in SF 6 Inventory + Acquisitions of SF 6 – Disbursements of SF 6 – Net Increase in the Nameplate Capacity of Equipment
Where:
Decrease in SF 6 Inventory = SF 6 stored in containers at the beginning of the year – SF 6 stored in containers at the end of the year Acquisitions of SF 6 = SF 6 purchased from chemical produ cers or distributors in bulk + SF 6 purchased from equipment manufacturers or distributors with or inside of equipment + SF 6 returned to site after off-site recycling Disbursements of SF 6 = SF 6 contained in equipment that is sold to other entities + SF 6 returned to suppliers + SF 6 sent off-site for recycling + SF 6 destroyed Net Increase in Nameplate Capacity of Equipment = Nameplate Capacity of New Equipment – Nameplate Capacity of Retiring Equipment Although the utility-level approach is less detailed than the full life cycle approach, it is simple, and for those countries whose national circumstances permit its use, it pr ovides estimates that are cl osely related to actual gas loss.



### SF 6 

### EMISSIONS FROM MANUFACTURING OF ELECTRICAL COMPONENTS Some electrical equipment components may contain 1 percent or less by weight of SF 6 in the insulating medium of the product. These components include but are not limited to medium voltage cast resin instrument transformers and high voltage bushings. In medium voltage (up to 52 kV) cast resin instrument transformers, SF 6 is used to fill up micro-cavities in the resin insulation to improve the dielectric quality and durability of the product. In High Voltage (above 52 kV) bushings, SF 6 is used as the blowing agent for the polyurethane resin in certain parts of the insulation system to improve the dielectric quality and durability of the product.
SF 6 emissions solely result from the casting/blowing process for the solid insulation of the product. All SF 6 usedis assumed to be emitted at the manufacturing stage. To estimate emissions from this source, the pure massbalance approach for equipment manufacturers (Equation 8.4A) may be used, setting the SF 6 contained in new equipment equal to zero. Emission reduction measures focus on limiting losses/improving rate of recycling by suction devices and/or improved casting processes. SF 6 in this type of high voltage bushings may be replaced by another blowing agent in the future.



## 8.2.2.2 C HOICE OF EMISSION FACTORS
Because emission rates can vary not only from country to country but from facility to facility, inventory compilers using emission-factor based methods are encouraged to develop and use their own emission factors. Surveying a representative sample of equipment manufactur ers and utilities within the country is an effective way to develop such factors. In general, it is good practice to document the eviden ce and reasoning supporting the selected emission factors, and to revi ew these factors at least every 5 years. Factors that influence emission rates include the design of the equipment (which varies depending on when and where the equipment was manufactured), SF 6 -handling practices, availability of state-of-the-art handling equipment, SF 6 prices, and regulations (e.g., recovery requirements). Variation of any one of these can change emission rates over time or among countries.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.15 

### TIER 1 METHOD Suggested default emission factors have been developed for some regions based on recent research. These factors are shown in Tables 8.2-8.4 below. It is good practice to select default emission factors from countries and regions with equipment designs and SF 6 - handling practices similar to those of the country whose emissions are being estimated

. Because Japan and Europe supply most of the global demand for electrical equipment, equipment designs are likely to be similar to those of either Japan or Europe. With the exception of the factors for the U. S., regional defau lt emission factors are those documented for 1995, i.e. , before any special industry actions for emission reduction were implemented. In Japan in 1995, approximately 70 percent of the SF 6 used to test equipment during manufacture was recovered, and a similar percentage was recovered during equipment maintenance for equipment rated 110 kv or higher. (The 70 percent recovery fraction reflected recovery from an initial pressure of about 5 bars absolute to a final pressure of 1 to 1.5 bars absolute .) No gas was recovered from equipment rated lower than 110 kV (Maruyama et al ., 2000). In Europe in 1995, gas supply systems for equipment manufacture were usually decentralised, and f illing tubes were not self-closing. Gas was reco vered to approximately 0.05 bars absolute during manufacturing and maintenance (Ecofys, 2005).

T ABLE 8.2 S EALED PRESSURE ELEC TRICAL EQUIPMENT (MV S WITCHGEAR ) CONTAINING SF 6 : DEFAULT EMISSION FACTORS Disposal (Fraction Nameplate Capacity of Disposed Equipment) Phase

Region Manufacturing (Fraction SF 6 Consumption by Manufacturers) Use (Includes leakage, major failures/arc faults and maintenance losses)

(Fraction per Year of Nameplate Capacity of All Equipment Installed) Lifetime (years) Fraction of charge remaining at retirement b
Europe a 0.07 0.002 >35 0.93 Japan c 0.29 0.007 Not reported 0.95

a Source: ‘Reductions of SF 6 Emissions from High and Medium Voltage Electri cal Equipment in Europe,’ Ecofys, June, 2005.

b This refers to the percentage of the original charge or nameplate capacity rema ining in the equipment at end of life; it repres ents the

fraction of the nameplate capacity potentially emitted before the equipment is recycled or disposed.

c Based on data reported by the Fe deration of Electric Power Companies (FEPC) and the Japan Electrical Manufacturers’ Association

(JEMA) (FEPC and JEMA, 2004). These organisations did not di stinguish among equipment types in reporting average emission factors. The factors are therefore intended to be applied to all equipment types, including sealed pressure systems, closed pre ssure systems, and gas-insulated transformers. Note: The emission factors above reflect the practices and tec hnologies in place in 1995, i.e., before mitigation measures were implemented. References per footnotes a and c show how these devel oped further upon successive impl ementation of various volunt ary measures later on. Another reference (Schwarz, 2006) relates stat e-of–the-art emission factors to mitigation measures in German y.Volume 3: Industrial Processes and Product Use

8.16 2006 IPCC Guidelines for National Greenhouse Gas Inventories T ABLE 8.3 C LOSED PRESSURE ELEC TRICAL EQUIPMENT (HV S WITCHGEAR ) CONTAINING SF 6 : DEFAULT EMISSION FACTORS Disposal (Fraction Nameplate Capacity of Disposed Equipment) Phase

Region Manufacturing (Fraction SF 6 Consumption by Manufacturers) Use (Includes leakage, major failures/arc faults and maintenance losses)

(Fraction per Year of Nameplate Capacity of All Equipment Installed) Lifetime (years) Fraction of charge remaining at retirement c
Europe a 0.085 b 0.026 >35 0.95 Japan d 0.29 b 0.007 Not reported 0.95
U.S. e f 0.14 g >35 h

a Source: ‘Reductions of SF 6 Emissions from High and Medium Voltage Electri cal Equipment in Europe,’ Ecofys, June, 2005.

b Includes emissions from installation

c This refers to the percentage of the original charge or nameplate capacity rema ining in the equipment at end of life; it repre sents the

fraction of the nameplate capacity emitted before the equipment is recycled or disposed.

d Based on data eported by the Federation of Electric Power Companies (FEPC) a nd the Japan Electrical Manufacturers’ Association

(JEMA) (FEPC and JEMA, 2004). These organisations reported averag e emission factors that include emissions from all equipment types, including sealed pressure systems, closed pressure systems, and ga s-insulated transformers.

e From the U.S. Inventory of Greenhouse Gases and Sinks, 1990-2002. (U.S. EPA, 2004). Value is from 1999, first year for which

representative country-specific data were available.

f No country-specific value available.

g Includes emissions from installation.

h Disposal emissions are included in use emission factor in the US. Note: The emission factors above reflect the practices and tec hnologies in place in 1995, i.e., before mitigation measures were implemented. References per footnotes a and d show how these devel oped further upon successive impl ementation of various volunt ary measures later on. Schwarz ( 2006) relates state-of–the-art emission fact ors to mitigation measures in Germany.

T ABLE 8.4 G AS INSULATED TRANSFORMERS CONTAINING SF 6 : DEFAULT EMISSION FACTORS Disposal (Fraction Nameplate Capacity of Disposed Equipment) Phase

Region Manufacturing (Fraction SF 6 Consumption by Manufacturers) Use (Includes leakage, major failures/arc faults and maintenance losses)

(Fraction per Year of Nameplate Capacity of All Equipment Installed) Lifetime (years) Fraction of charge remaining at retirement a
Japan b 0.29 0.007 Not reported 0.95

a This refers to the percentage of the original charge or nameplate capacity rema ining in the equipment at end of life; it repre sents the

fraction of the nameplate capacity emitted before the equipment is recycled or disposed

b Based on data reported by the Federation of Electric Power Companies (FEPC) and the Japan Electrical Manufacturers’ Associatio n

(JEMA) (FEPC and JEMA, 2004). These organisations did not di stinguish among equipment types in reporting average emission factors. The factors are therefore intended to be applied to all equipment types, including sealed pressure systems, closed pre ssure systems, and gas-insulated transformers. Note: The emission factors above reflect the practices and tec hnologies in place in 1995, i.e., before mitigation measures were implemented. References per footnote b show how these deve loped further upon successive impl ementation of various voluntary measures later on. Schwarz (2006) relates state-of–the-a rt emission factors to mitigation measures in Germany.



### TIER 2 METHOD Emission factors for the Tier 2 method are generally developed on the basis of data collected from representative manufacturers and utilities that track emissions by life cy cle stage, essentially using the Tier 3, pure massbalance method at their facilities for at least one year. (The disposal emission factor should also account for emissions that occur downstream of the utility site, as discussed below.) These emissions by life cycle stage are then divided by the corresponding SF 6 consumption or equipment capacity at that life cycle stage (i.e., SF 6 consumption for manufacturing emissions, total existing equipment capacity for use emissions, and retiringChapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.17 equipment capacity for final use and disposal emissions) to develop emission factors. For example, to develop an emission factor for manufacturing, total emissions from the survey of manufacturers are summed and then divided by the total SF 6 consumption of surveyed manufacturers. This emission factor can then be applied to the manufacturing sector as a whole, using national SF 6 consumption by manufacturers. A similar approach can be used to estimate and apply emi ssion factors for equipment use. The emission factor for dispos al should fully account for three factors: (1 ) the recovery frequency (the fraction of equipment whose charge is recovered), (2) the recovery efficiency (the fraction of charge recovered when recovery is performed), and (3) the emissions from recy cling and destruction of the recovered gas. The quantities in (1) and (2) will be automatically accounted for in emission factors base d on use of the Tier 3 mass-balance method at representative utilities. However, the quantity in (3) reflects emissions that occur both on site and downstream of the utility/user. Thus, it must be accounted for separately. See the Tier 3 Method discussion below for guidance on estimating recycling and destruction emission factors. The facility-level variant of the Tier 3 approach may also be used to develop emission factors, but these will be applied at a more aggregated level, i.e., to equi pment manufacturing and use (where the latter includes installation, use, and disposal) rath er than to each lifecycle stage.



### TIER 3 METHOD Because the Tier 3 method encourages the use of emissi on factors only when emissi on rates from processes are quite low (e.g., 3 percent of nameplat e capacity per year or less) or when electrical equipment has only recently been introduced into a country, emission factors for this method may be difficult to measure directly using a mass-balance approach. To estimate Tier 3 emission fa ctors, therefore, engineering studies may be used, identifying potential leak points and loss mechanisms and assigning probabilities and emission rates to these. Expected losses from service and maintenance should be f actored into overall emission rates, as should losses from rare but catastrophic events that result in the loss of most of the equipment’s charge. Past experience with similar processes and designs should be considered. To ascertain and verify emission factors for use, surveys of equipment in the field may be carried out after several years of use, with the number of years determined by the expected leak rate and the limit of detection of the measuring equipment. Manufacturer statistics on equipment failure rates should be monitored to help ensure that catastrophic or gradual loss rates are not higher than expected. Disposal emissions are extremely sensitive to recovery frequencies (the fraction of equipment whose charge is recovered) and to recovery efficiencies (the fraction of charge recovered when recovery is performed, which, due to time considerations, may be lower than what is technically achievable). Thus, these should be monitored and documented carefully before establishing disposal emission factors. Emission factors for recycling of recovered SF 6 may be based on professional judgement. Emission factors for destruction may be based on the rated destruction efficiency of the destruction technology, assuming that the technology is maintained and operated in a way that maintains its rated destruction efficiency.



## 8.2.2.3 C HOICE OF ACTIVITY DATA
The activity data necessary to carry out the various estimation methods may be gathered from chemical manufacturers, equipment manufacturers, equipment users, and equipment disposers and/or their industry associations in the country or the region. The best source(s) of data vary depending upon the method and national circumstances.



### TIER 1 METHOD
SF 6 consumption by equipment manufacturers: SF 6 consumption by equipment manufacturers can be estimated using information from the manuf acturers on their purchases of SF 6 , their returns of SF 6 to chemical producers, and changes in their inventory of SF 6 in containers. If information from equipment manufacturers is unavailable or incomplete, information from chemical producers and/or distributors on their sales to equipment manufacturers (less any returns) may be used. Nameplate capacity of new and retiring equipment : Nameplate capacity can be estimated using one or more of the following data sources: (1) information from equipment manufacturers/importers on the total nameplate capacity of the equipment they manufacture or import and export, (2) information from utilities on the total nameplate capacity of the equipmen t they install and retire each year, or (3) if information from (1) or (2) is not available, information from chemical manufacturers/importers on their sales of SF 6 to equipment manufacturers. The first two data sources are preferable to the third, because gas sales to equipment manufacturers will differ from the nameplate capacity of ne w equipment installed in the country, particularly if equipment imports or exports are significant. In estimating the nameplate capacities of new and retiring equipment, inventory compilers should include the na meplate capacity of imported equipment and exclude theVolume 3: Industrial Processes and Product Use

8.18 2006 IPCC Guidelines for National Greenhouse Gas Inventories nameplate capacity of exported equipment. (See Section 7.5, Refrigeration, Box 7.1, Accounting for Imports and Exports of Refrigerant and Equipment, for a full discussion of how to treat imports and exports in estimating these quantities. This guidance is directly applicable to this category.) In the case of retiring equipment, capacity or sales information should be historical, starting in the year when the current year’s retiring equipment was built. Typical values for the lifetime of electrical equipment range from 30 to 40 years. If information on the total nameplate capacity of retiring equipment is not available, it can be estimated from new nameplate capacity, using the estimated annual growth rate of equipment capacity. In estimating the growth rate, it is good practice to consider both the number of pieces of equipment sold each year and the average nameplate capacity of the equipment. 3 The following equation can be used to estimate retiring nameplate capacity, if this information is not available directly:

E QUATION 8.11 R ETIRING NAMEPLATE CAPACITY Retiring Nameplate Capacity = New Nameplate Capacity / ( 1 + g ) L

Where: L = equipment lifetime g = rate of growth According to a 2004 glob al survey, the average an nual growth rate of SF 6 sales to equipment manufacturers between 1970 and 2000 was approximately 9 percent. (Smythe, 2004). In the absence of country-specific information, a default factor of 9 percent may be used. Total nameplate capacity of installed equipment : The total nameplate capacity of equipment can be estimated using the same data sources as are used to estimate the nameplate capacity for new and retiring equipment. If data from equipment manufacturers is used, it should include data on sales over the full lifetime of the equipment (30 to 40 years).



### TIER 2 METHOD Quantities can be estimated as for Tier 1 above.



### TIER 3 METHOD To implement the Tier 3 method, information must be gathered at two levels. At the facility level, gas flows must be tracked correctly according to the Tier 3 meth od. At the national level, information from facilities (manufacturers, users, and disposers of equipment) must be collected, checked, summed, and if necessary, extrapolated to include estimates of emissions from facili ties in the country that do not collect data. Guidance regarding the information to be tracked by facilities is pr ovided in the descriptions of the Tier 3 method above. Gas consumption may be measured by weighing gas cylinders before and after filling or recovery operations or at the beginning and end of the year or by using flow meters (e.g., during equipment manufacturing). At the national level, trade associations for equipment manufactur ers and utilities can be very helpful in disseminating knowledge to their members regarding th e Tier 3 approach and in helping their members to track and report data consistently and transparently. Trade associations can also act as third parties to aggregate confidential or sensitive data so that it can be released (in aggregate) to the public. Where trade associations are not active, national inventory compilers can facilitate the collection of information at the facility level, as well as the reporting and verification of this information, by developing model emission tracking protocols or by adopting existing industry protocols that embody the Tier 3 approach. These protocols can then be distributed to the manufacturers, users, and disposers of electrical equipment. Electronic prot ocols such as spreadsheets further facilitate the tracking, documentation, and reporting of emissions and minimize opportunities for arithmetic error. Because emission rates can vary from region to region and facility to facility, it is good practice to survey as many facilities as practical. In addition to manufacturers and utilities, countries should survey industrial sites and other non-utility sites if these contribute substantially to emissions from electrical equipment. If the number of facilities in a country is large (e.g., over 50), it may be difficult to achieve complete reporting. In these cases, countries may estimate emissions from non-reporting facilities by applying the Tier 2 method to these facilities

3 While the number of pieces of equipment sold each year has generally grow n, the average nameplate capacity has generally declined.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.19 or by using alternative activity data as described in Chapter 2 of Volume 1, Approaches to Data Collection. Sector-specific considerations in selecting and us ing alternative activity data are discussed below. For sealed pressure equipment (which is widely di spersed among industrial users as well as utilities), manufacturers and distributors are likely to be the best source of complete information on national bank sizes and emission rates. To develop an accu rate estimate, inventory compilers should survey manufacturers regarding their sales of equipment between the present and the time when currently retiring equipment was installed, or, if equipment has not yet begun to be retired, between the present and the time when the equipment was introduced into the country. 

### Sector-specific considerations in selectin g and using alternative activity data for Tier 3 As discussed above, even when implementing a Tier 3 method it may not be possible to obtain data from all facilities. To obtain complete coverage of facilities, it is possible to use alternative activity data. For estimating emissions from non-reporting manufacturers, it may be possible to use the manufacturing capacity and/or collective market share (in terms of functional units) of the non-reporting manufacturers. For estimating emissions from non-reporting utilities, possible alternative data sets or drivers include (but are not limited to) the length of transmission lines, the combined length of transmission and distribution lines, or the number of substations of the non-reporting utilities. Transmission kilo metres are likely to be a good predictor of emissions where most SF 6 is used in high voltage transmission equipment, as in the U.S. (A discussion of how transmission kilometres are used to estimate emissions in the U.S. can be found in Volume 1, Chapter 2, Approaches to Data Collection.) Where a high percentage of SF 6 is used in medium voltage distribution equipment or in gasinsulated substations, one of the other types of data may be appropriate. Wherever alternative data sets are used, it is important to derive emission factors from a representative set of facilities to ensure that the resulting estimate of national SF 6 emissions is unbiased. Note that more than one factor may be appropriate, e.g., for different size utilitie s or for utilities in urban vs . rural locations. Because SF 6 use and emission patterns can change over time, it is good practice to update the analysis and emission factor(s) at least every five years. (For example, emission rates may change as compact and l eak-tight equipment replaces larger, leakier equipment and as sealed pressure equipm ent grows in importance.) In some cases, countries may be able to make use of emission factors developed in countries with similar electrical grids. In these cases, it is good practice to document the similarities between the grids befo re applying the emission factor from the other country.



## 8.2.2.4 C OMPLETENESS
Completeness for this source category requires accou nting for emissions during the manufacture, use, and disposal of equipment, and during the recycling or destruction of SF 6 recovered from equipment. Where Tier 3 methods are used, completeness requires that all significant SF 6 users (manufacturers and utilities) be identified. When facility-level emissions data are not available from all of these users, emission estimates should be developed for them using one of the extrapolation methods described in Section 8.2.2.3, Choice of Activity Data. In the manufacturing sector, this requires assessing emissions from:

• Manufacture of gas insulate d switchgear (GIS), gas circuit breakers (GCB), high voltage gas-insulated lines (GIL), outdoor gas-insulated instrument transformers, reclosers, switches, and ring main units of both types (sealed and closed pressure systems, respectively up to and above 52 kV), and other equipment including but not limited to cast resin instrument transformers and certain types of bushings using SF 6 either as gas for the casting process or as a blowing agent;

• Manufacturers of gas-insulated power transformers (GIT);

• Minor SF 6 users, including equipment remakers and servicing companies;

• The SF 6 distribution chain from producers and distributors to manufacturing facilities. In the utility and disposal sector , this requires accounting for all SF 6 losses associated with:

• New electrical equipment installations;

• Leakage, refill, maintenance, and equipment failures;

• Disposal of discarded electrical equipment;

• Recycling or destruction of SF 6 recovered from equipment (but recycling emissions from chemical producers should be counted under chemical production, which is covered in Section 3.10 of this volume).Volume 3: Industrial Processes and Product Use

8.20 2006 IPCC Guidelines for National Greenhouse Gas Inventories It is good practice to identify and include industrial, military and small-utility applications if these are believed to contribute substantially to total emissions from the electrical equi pment source category.



## 8.2.2.5 D EVELOPING A CONSISTENT TIME SERIES
When estimating emissions from equipment users over a time series, it is necessary to consider SF 6 emissions associated with the full set e quipment at users’ sites for the years of interest. Thus, when using approaches based on banks and emission-factors (e.g., the Tier 2 approach ), countries will require information on the capacity and emission rate of equipment purchased and installed for 30 to 40 years preceding the years of interest. In the user sector, if historical data are unavailable, good practice is to develop estimates using the top-down method, i.e., develop a model based on professional judgement by industry experts and inventory compilers and then calibrate as discussed below. Average leak rates for new equipment and the frequency of refill and routine maintenance all decreased from 1970 to 1995, and th is trend has continued to the present. It is not good practice to apply current (post-2000) overall loss rates to historical years. Aggregate loss rates estimated from historical sales can be used in this case as well. On the manufacturing side, if historical data for developing base year emissions for 1990/1995 are not available, the top-down method calibrated to more accurate es timates for current years may be applied. Since SF 6 handling practices of equipment manufacturers have changed substantially since 1995 (e.g., more gas is recovered), it is not good practice to apply current loss rates to historical estimates. Aggregate loss rates determined from global and regional sales and emission analyses may assist in pr oviding an unbiased estimate for earlier years. It is good practice to recalculate emissions according to the guidance provided in Volume 1, Chapter 5, with all assumptions clearly documented.



# 8.2.3 Uncertainty assessment When using the Tier 3 method, the resulting emissions estimates will have an accuracy of the order of ± 10 percent, and are likely to be more accurate than estimates developed using Tier 2 or Tier 1 methods.. If surveys are incomplete, the associated uncertainty will be great er. Particular sources of uncertainty may include:

• SF 6 exported by equipment manufacturers (either in equipment or separately in containers);

• SF 6 imported by foreign equipment manufacturers (either in equipment or in containers);

• SF 6 returned to foreign recycling facilities;

• Measurements of mass, density, and pressure (generally accurate to within one or two percent of the total quantity massed, but if emission rates are low, this may be a substantial percentage of those rates);

• Emission factors;

• Time lag between emissions and servicing; 4

• Lifetime of the equipment;

• Regression error associated with any extrapolative approaches. The estimated uncertainties in the default emission factors for the Tier 1 method are shown in Table 8.5, Uncertainties for Default Emission Factors for SF 6 Emissions from Electrical Equipment. These values are based on the variation observed in emission factors in Europe. If the factors in Tables 8.2-8.4 are applied outside the countries and/or regions in which they were developed, uncertainties will be greater.

4 See Chapter 1 of this volume for a discussion of this issue.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.21 T ABLE 8.5 U NCERTAINTIES FOR DEFAULT EMISSION FACTORS AND LIFETIME Disposal Phase Equip -ment Type Manufacturi ng Use (Includes leakage, major failures/arc faults and maintenance losses) Lifetime (years) Fraction of charge remaining at retirement

Sealed-Pressure a ±20% ±20% -20%/+40% d

Closed-Pressure b ±30% ±30% -10%/+40% d

Gas Insulated Transformers c ±30% ±30% -10%/+40% d

a Estimated from ‘Reductions of SF 6 Emissions from High and Medium Voltage Electrical Equipment in Europe,’ Ecofys, June, 2005;no

uncertainties available from Japa n; not relevant for USA..

b Estimated from ‘Reductions of SF 6 Emissions from High and Medium Voltage Electri cal Equipment in Europe,’ Ecofys, June, 2005;

U.S. emission factors have higher uncertainty for manufacturi ng (±70%) and slightly lower uncertainty for use (±15%) (U.S. Inventory of Greenhouse Gases and Sinks (U.S. EPA, 2004)). No uncertainties available from Japan.

c Estimated by analogy with closed pressure systems; actual un certainties may be somewhat higher. No uncertainties available from

Japan.

d No uncertainties available on fraction of charge remaining at retirement.



# 8.2.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation

8.2.4.1 Q UALITY 

## A SSURANCE 

## /Q UALITY 

## C ONTROL

It is good practice to conduct quality control checks as outlined in Volume 1, Chapter 6, and an expert review of the emissions estimates. Additional quality control checks as outlined in Volume 1, and quality assurance procedures may also be applicable, particularly if higher tier methods are used to determine emissions from this source category. Inventory compilers are encouraged to use higher tier QA/QC for key categories as identified in Volume 1, Chapter 4. Additional procedures specific to electrical equipment are outlined below: 

### Comparison of emissions estimates using different approaches Inventory compilers should sum the facility-level data us ed as part of a bottom-up, Tier 3 method and crosscheck the data against national level emissions calculated using country-level data (the Tier 2 method) and/or country-level data with the IPCC default emission factors (the Tier 1 method). The Tier 2 method may similarlybe checked against the Tier 1 method. Countries may also compare their results to those derived using a countrylevel mass-balance approach, as described in Equations 7.3 and 7.9 of Chapter 7. If countries do not have manufacturing facilities, they may also compare their estimates against potential emissions estimated using national apparent consumption data. 

### Review of facility-le vel emissions data In all instances where site-specific emissions data are obtained through surveys, inventory compilers should compare the emission rates between sites (adjusting for re lative size or capacity) to identify significant outliers. They should investigate any outliers to determine if the diffe rences can be explained or if there is an error in the reported emissions. As noted in Section 8.2.2.3, nationa l inventory compilers can f acilitate both the collection and verification of information at th e facility level by distributing emissi on tracking protocols that embody the Tier 3 approach. Electronic protocols such as spreadsheet s are particularly useful, as they minimize opportunities for arithmetic error. The calculations included in these pr otocols (whether electronic or not) can then be checked after they are submitted.Volume 3: Industrial Processes and Product Use

8.22 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### Comparison of emission rates with those of other countries Inventory compilers should compare effective emission factors (loss rates) with values reported by other countries in the region, or with defaults published in the scientific literature for equipment with a similar design and similar level of emissions control. Transparent re porting, as outlined above, is essential for making international comparisons.



## 8.2.4.2 R EPORTING AND 

## D OCUMENTATION

It is good practice to document and archive all information required to produce the national emissions inventory estimates as outlined in Volume 1, Section 6.11. It is not practical to include all documentation in the national inventory report. However, the inventory should include summaries of methods used and references to source data such that the reported emissions estimates are tr ansparent and steps in their calculation may be retraced. Some examples of specific documenta tion and reporting relevant to this source category ensuring transparency in reported emissions estimates are provided in Table 8.6, Good Practice Reporting Information for SF 6 Emissions from Electrical Equipment by tier. Confidentiality issues may arise wher e there are limited numbers of manuf acturers or utilities. In these cases, aggregated reporting for the total electrical equipment sector, or even total national SF 6 applications, may be necessary. National or regional associations of users and manufacturers may be willing to collect, check, and aggregate data, particularly when they have collected such data historically. They can then report the aggregated information to the inventory compiler, resolving the pr oblem of confidentiality. If survey responses cannot be released as public information, third party review of survey data may be necessary to support data verification efforts.

T ABLE 8.6 G OOD PRACTICE REPORTING INFORMATION FOR SF 6 EMISSIONS FROM ELECTRI CAL EQUIPMENT BY TIER
Data Tier 3 Tier 2 Tier 1 Annual, country-wide consumption of SF 6 by equipment manufacturers X X
Nameplate capacity of new equipment X X X Nameplate capacity of ex isting equipment X* X X Nameplate capacity of retiring equipment X X X
SF 6 destroyed X
SF 6 in inventory at beginning of year X
SF 6 in inventory at end of year X
SF 6 purchased by facility X
SF 6 sold or returned by facility X
SF 6 sent off-site for recycling X
SF 6 returned to site after recycling X
SF 6 used to fill new equipment X
SF 6 used to service equipment X
SF 6 recovered from retiring equipment X Emission/recovery factors X* X Documentation for factors, if country-specific X* X *Required for some variants of the methods.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.23 

# 8.3 USE OF SF 6 

# AND PFCs IN OTHER PRODUCTS

8.3.1 Introduction
This source category excludes the following source categories th at are addressed elsewhere in the 2006 Guidelines :

• Production of SF 6 and PFCs (Section 3.10);

• Production and use of electrical equipment (Section 8.2);

• Primary and secondary production of magnesium and aluminium (Chapter 4); and

• Semiconductor and flat panel display manufacturing (Chapter 6).

Identified remaining applications in this source category include:

• SF 6 and PFCs used in military applications, particularly SF 6 used in airborne radar systems, e.g., AWACS (Airborne Warning and Control System), and PFCs used as heat transfer fluids in high-powered electronic applications;

• SF 6 used in equipment in university an d research particle accelerators;

• SF 6 used in equipment in industrial and medical particle accelerators;

• ‘Adiabatic’ applications utilising the low permeability through rubber of SF 6 and some PFCs, e.g., car tires and sport shoe soles;

• SF 6 used in sound-proof windows;

• PFCs used as heat transfer fluids in commercial and consumer applications;

• PFCs used in cosmetics and in medical applications;

• Other uses e.g. gas-air tracer in research and leak detectors.



# 8.3.2 Methodological issues

8.3.2.1 C HOICE OF METHOD

The good practice method is to use either consumption data from users of SF 6 or PFCs or top-down import, export and consumption data from national SF 6 producers and distributors, disaggregated by major type of SF 6 or PFC application. Acquiring this data will entail a survey of all producers and distributors of SF 6 and PFCs to identify total net SF 6 and PFC consumption. Once the data are obtained, the amount of SF 6 and PFC consumed by application in this source category should be estimated.



### MILITARY APPLICATIONS

SF 6 

### EMISSIONS FROM OPERATION OF AWACS
SF 6 is used as an insulating medium in the radar systems of military reconnaissance planes of the Boeing E-3A type, commonly known as AWACS. The purpose of the SF 6 is to prevent electric flashovers in the hollow conductors of the antenna, in which high voltages of more than 135 kV prevail. When the plane ascends, SF 6 is automatically released from th e system and into the atmosphere to main tain the appropriate pressure difference between the system and the outside air. When the plane descends, SF 6 is automatically charged into the system from an SF 6 container on board. Most emissions occur during the pressure-balancing process on ascent, but emissions from system leakage can also occur during other phases of flight or during time on the ground. Annual emissions per plane have been estimated to be 740 kg, while the charge of each system is approximately 13 kg.Volume 3: Industrial Processes and Product Use

8.24 2006 IPCC Guidelines for National Greenhouse Gas Inventories Figure 8.2 Decision tree for SF 6 from AWACS

Use Emission-Factor Tier 1 approach. Start

Are detailed acquisition and disbursement data available for this category?

Is the Other Product Manufacture and Use a key category 1 , and is this subcategory

significant?

Note: 1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categories (noting Section 4.1.2 on limited resource s), for discussion of key categories and use of decision trees. Box 2: Tier 2

No

No

Box 1: Tier 1 Yes Use Mass-Balance Tier 2 approach.

Yes

Collect data for Tier 2 method.



### Tier 1 method – SF 6 

### emissions per plane If a country does not have data on SF 6 consumption by its AWACS, it may use a per-plane emission factor to estimate emissions. An emission factor of 740 kg per plane per year is presented in Table 8.7 below; this figure is based on estimates of SF 6 emissions from NATO Boeing E-3As. Note that actual emissions per plane are strongly influenced by the average number of sorties (t ake-offs) per plane per year. More frequent sorties will raise the emission rate above 740 kg/plane; less frequent sorties will lower it. Leakage rates during flight or during time on the ground will also affect the emission rate.

E QUATION 8.12 E MISSIONS FROM AWACS ( DEFAULT EMISSION ACTOR ) User Emissions = 740 kg • Number of planes in AWACS fleet

T ABLE 8.7 SF 6 EMISSIONS PER PLANE PER YEAR Emissions per plane per year (kg SF 6 ) Uncertainty 740 kg ±100 kg Source: Schwarz (2005)

Table 8.8 includes information on national AWACS fleets wo rld wide (Boeing, 2005); like other activity data, it may quickly go out of date. Countries are in the best position to know the numbers of planes in their AWACS fleets.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.25 T ABLE 8.8 N ATIONAL AWACS FLEETS Country/ Organisation USA Japan France UK Other NATO Saudi Arabia Total

No. AWACS 33 4 4 7 17 5 70 Source: Boeing (2005)



### Tier 2 method – user mass-balance method The most accurate method for estimating SF 6 emissions from AWACS is to track SF 6 consumption by the systems. To do so, the following equations, which are simila r to the utility-level variant of the Tier 3 method for electrical equipment, may be used. Note that for AWACS, acquisitions and disbursements of SF 6 containers are likely to be considerably more important to the result than acquisitions and retirements of operating systems.

E QUATION 8.13 E MISSIONS FROM AWACS ( USER MASS
- BALANCE ) User Emissions = Decrease in SF 6 Inventory + Acquisitions of SF 6 – Disbursements of SF 6 – Net Increase in AWACS Fleet Charge
Where:
Decrease in SF 6 Inventory = SF 6 stored in containers at the beginning of the year – SF 6 stored in containers at the end of the year Acquisitions of SF 6 = SF 6 purchased from chemical produ cers or distributors in bulk + SF 6 purchased from AWACS manufacturers or distributors with or inside of new planes + SF 6 returned to site after off-site recycling Disbursements of SF 6 = SF 6 contained in AWACS that are transferred to other entities + SF 6 returned to suppliers + SF 6 sent off-site for recycling + SF 6 destroyed Net Increase in AWACS Fleet Charge = 13 kg • (New AWACS – Retiring AWACS)



### SF 6 

### AND PFC EMISSIONS FROM OTHER MILITARY APPLICATIONS There is wide range of military applications using PFCs or SF 6 . 5 Military electronics are believed to be an important and growing application of PFC heat transfer fluids, which are valued for their stability and dielectric properties. The fluids are used in ground and airborne radar (klystrons), avionics, missile guidance systems, ECM (Electronic Counter Measures), sonar, amphibious a ssault vehicles, other surveillance aircraft, lasers, SDI (Strategic Defense Initiative), and stealth aircraft. PFCs may also be used to cool electric motors, particularly in applications where noise reduction is valued, e.g., in ships and submarines. The specific PFCs used in these applications are believed to be similar to those identified as heat transfer fluids in electronics manufacturing in Chapter 6. Spray cooling, jet impingement cooling, and pool boiling appear to be the favoured systems for heat removal. In all of these cooling app lications, the PFC is contained in a closed system, and neither replacement nor replenishment of the PFC liquid appears to be require d. Thus, the greatest opportunities for emissions are the manufacture, maintenance, and, especia lly, the disposal of the equipment.
SF 6 is used in high-performance ground and airborne radar systems in their hollow conductors for transmission of high-frequency energy pulses at high voltages from the klystron. Another application of SF 6 is as an oxidant of lithium in Stored Chemical Energy Propulsion Syst em (SCEPS), e.g., in naval torpedoes and in infrared decoys (Koch, 2004). Apparently, these applications of SF 6 , like those of the PFC heat transfer fluids enumerated above, are generally more or less enclosed, but servicing and testing procedures may lead to emission. The use of SF 6 for the quieting of torpedo propellers has also been reported (NIST, 1997). In addition, SF 6 may be emitted as a by-product of the processing of nuclear material for the production of fuel and nuclear warheads. SF 6 is known to be emitted from neutralising excess fluorine during the production of nuclear fuel for civilian applications (AREVA, 2005).

5 David Harris and James Hildeb randt, “Spray Cooling Electric al and Electronic Equipment,” COTS Journal , November

2003; C. Shepherd Burton, “Uses and Air Emissions of Liquid PFC Heat Transfer Fluids from the Electronics Sector,” Draft report prepared for Scott C. Bartos , U.S. Environmental Protection Agency.Volume 3: Industrial Processes and Product Use

8.26 2006 IPCC Guidelines for National Greenhouse Gas Inventories Although it is believed that the total amounts of SF 6 and PFCs consumed and emitted in this sector may be significant, no data on quantities are publicly available so far. Therefore, inventor y compilers should try to collect further information from the relevant authorities and, if possible, their suppliers. As noted above, the greatest opportunities for emissions from many of these app lications appear to be the manufacture, maintenance, and disposal of the equipment. Thus, if inventory compilers can acquire information on emission rates during the manufacture, maintenance, and disposal of the equipmen t, along with the quantities of equipment manufactured, in use, and disposed, they can use the Tier 2 or Tier 3 method for electrical equipm ent to estimate emissions. For applications with different emissions profiles (e.g., prompt emissions), the appropriate equation from Section 8.2 may be used.



### SF 6 

### EMISSIONS FROM UNIVERSITY AND RESEARCH PARTICLE ACCELERATORS
SF 6 is used in university and research operated particle accelerators as an insulating ga s. Typically, high voltage equipment is contained and operat ed within a vessel filled with SF 6 at a pressure exceeding atmospheric pressure. Charges range from five kilograms to over ten thousand kilograms, with typical charges falling between 500 and 3 000 kg. When the equipment requires maintenance, the SF 6 is transferred into storage tanks. SF 6 losses occur primarily during gas recovery and transfer, when pressure relief valves are actuated, and through slow leaks. Based on two recent studies annual SF 6 losses range between 5 and 7 percent of vessel capacity per year and generally depend on the vessel opening frequency plus the efficiency of the recovery and transfer equipment. World banked capacity is roughly estimated to be 500 tonnes with annual SF 6 emissions of 35 tonnes. Switzerland has developed a voluntary program to reduce SF 6 emissions from particle accelerators. Suggestions and techniques for reducing SF 6 emissions from these sources exist.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.27 Figure 8.3 Decision tree for SF 6 from research accelerators

Use Accelerator-Level Emission-Factor approach. Start

Are detailed acquisition and disbursement data

available for this category?

Are data on individual accelerator charges available?

Note: 1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categorie s (noting Section 4.1.2 on limited resource s), for discussion of key categories and use of decision trees. Box 3: Tier 3

No

Yes

Box 1: Tier 1 Yes Use Accelerator-Level Mass-Balance approach.

No

Collect data for Tier 3

or Tier 2 method. Is the Other Product Manufacture and Use

a key category 1 , and is this subcategory significant? Box 2: Tier 2

Use Country-Level approach. No

Yes



### Tier 1 method – country-level method In cases where individual user accelerator charge data is unavailable, one extr emely rough method involves determining the total number of univers ity and research particle accelerator s in the country and using several factors to determine the country-level annual emission rate as noted in Equation 8.14. For this Tier 1 method, the only data that requires collection is the total number of university and res earch particle accelerators in the given country.

E QUATION 8.14 U NIVERSITY AND RESEARCH PARTICLE ACCELERATOR EMISSIONS ( COUNTRY
- LEVEL ) Emissions = (Number of univer sity and research particle accelerators in the country) • (SF 6 Use Factor) • (SF 6 Charge Factor, kg) • (SF 6 university and research partic le accelerator Emission Factor)
Where: Number of university and research particle accelerators in the country = The total number of university and research particle accelerators in the country. This rough met hod does not require countries to determine the number of accelerators that use SF 6 . To determine if a country has a particle accelerator, go to http://www-e lsa.physik.uni-bonn. de/Informationen/accelerator_list.htmlVolume 3: Industrial Processes and Product Use

8.28 2006 IPCC Guidelines for National Greenhouse Gas Inventories SF 6 Use Factor = 0.33 Approximately one third of univers ity and research particle accelerators use SF 6 as an insulator.
SF 6 Charge Factor = 2400 kg, SF 6 , the average SF 6 charge in a university and research particle accelerator.
SF 6 university and research particle accelerator Emission Factor = 0.07, the average annual university and research particle accelerator emission rate as a fraction of the total charge.



### Tier 2 method – accelerator-le vel emission-factor approach If data on the quantity of SF 6 contained within each university and rese arch accelerator are available, a default emission factor of 7 percent may be multiplied by the total SF 6 charge contained in university and research accelerators in the countr y. The total country SF 6 emission rate from university and research accelerators is therefore calculated from Equation 8.15.

E QUATION 8.15 U NIVERSITY AND RESEARCH PARTICLE ACCELERATOR EMISSIONS ( ACCELERATOR
- LEVEL EMISSION FACTOR ) Total Emissions = SF 6 university and research particle accelerator Emission Factor

• ∑ Individual Accelerator Charges
Where:
SF 6 university and research particle accelerator Emission Factor = 0.07, the average annual university and research particle accelerator emission rate as a fraction of the total charge. Individual User A ccelerator Charges = SF 6 contained within each univer sity and research accelerator.



### Tier 3 method –accelerator- level mass-balance method SF 6 emissions from university and research facilities operating pa rticle accelerators may be most accurately determined at the user level on an accelerator-by-accelerator basis. Em ission calculations are estimated by tracking accelerator charge as well as SF 6 consumption and disposal. As detailed in Equation 8.16, the total emissions are equal to the sum of the individual users’ emissions. Note, under this method, as the overall SF 6 emission rate from particle accelerat ors is small compared to other SF 6 uses, the associated SF 6 lost in manufacturing is considered negligible and is not included in the calculation.

E QUATION 8.16 T OTAL RESEARCH ACCELERATOR EMISSIONS 

### ∑ = Emissions r Accelerato Individual Emissions Total
Each particle accelerator’s emissi ons can be calculated as follows:

E QUATION 8.17 R ESEARCH ACCELERATOR EMISSIONS ( ACCELERATOR
- LEVEL MASS
- BALANCE ) Accelerator Emissions = Decrease in SF 6 Inventory + Acquisitions of SF 6 – Disbursements of SF 6 – Net Increase in Accelerator Charge
Where:
Decrease in SF 6 Inventory = SF 6 stored in containers at the beginning of the year – SF 6 stored in containers at the end of the year Acquisitions of SF 6 = SF 6 purchased from chemical produ cers or distributors in bulk + SF 6 purchased from accelerator manufacturers or distributors with or inside of new accelerator components + SF 6 returned to site after off-site recycling Disbursements of SF 6 = SF 6 contained in components tran sferred to other entities + SF 6 returned to suppliers + SF 6 sent off-site for recycling + SF 6 destroyed Net Increase in Accelerator Charge = SF 6 Charge of New Components – SF 6 Charge of Retiring ComponentsChapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.29 

### SF 6 

### EMISSIONS FROM INDUSTRIAL AND MEDICAL PARTICLE ACCELERATORS
SF 6 is used as an insulating gas in two types of industrial particle accelerators (low and high voltage) and also in medical (cancer therapy) particle acceler ators, as is the case for university and research particle accelerators. However, the emission and charge factor s for industrial and medical particle accelerators are different from those of university and research accel erators, as discussed below. Global banked capacity for industrial pa rticle accelerators is roughly estimated to be 500 tonnes with annual SF 6 emissions of 35 tonnes. Global banked capacity for me dical (radiotherapy) partic le accelerators is roughly estimated to be less than 5 tonnes with annual SF 6 emissions of less than 5 tonnes. (Schwarz, 2005).

Figure 8.4 Decision tree for industria l and medical particle accelerators

Use User-Level EmissionFactor approach. Start

Are detailed acquisition and disbursement data available for this category?

Are data on individual accelerator charges available?

Note: 1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categorie s (noting Section 4.1.2 on limited resource s), for discussion of key categories and use of decision trees. Box 3: Tier 3

No

Yes

Box 1: Tier 1 Yes Use User-Level MassBalance approach.

No

Collect data for Tier 3

or Tier 2 method. Is the Other Product Manufacture and Use a key category 1 , and is this subcategory

significant? Box 2: Tier 2

Use Country-Level approach. No

Yes



### Tier 1 method – country-level method In cases where individual user accelerator charge data is unavailable, one extr emely rough method involves determining the total number of particle accelerators by process description in the country and using factors toVolume 3: Industrial Processes and Product Use

8.30 2006 IPCC Guidelines for National Greenhouse Gas Inventories determine the country level annual emission rate as noted in Equation 8.18. For this Tier 1 method, the only data that requires collection is the total numbe r of particle accelerators which contain SF 6 by process description in the given country.

E QUATION 8.18 I NDUSTRIAL / MEDICAL ACCELERATOR EMISSIONS ( COUNTRY
- LEVEL ) Emissions = (Number of par ticle accelerators that use SF 6 by process description in the country) • (SF 6 Charge Factor, kg) • (SF 6 applicable particle accelerator Emission Factor)
Where: Number of particle accelerat ors by type in the country = The total number of particle accelerators by type (industrial high voltage, industrial low voltage and radiotherapy) that use SF 6 in the country, 1, 2, etc. (Only count particle accelerators that use SF 6 . This differs for the Tier 1 calculation for university and research particle accelerators)
SF 6 Charge Factor = The average SF 6 charge in a particle accelerator by process description as noted below.
SF 6 particle accelerator Emission Factor = The average annual SF 6 particle accelerator emission rate as a fraction of the total charge by process description.

T ABLE 8.9 A VERAGE SF 6 CHARGE IN A PARTICLE ACCELERATOR BY PROCESS DESCRIPTION Process Description SF 6 Charge Factor, kg
Industrial Particle Ac celerators – high voltage (0.3-23 MV) 1300
Industrial Particle Accelerators –low voltage (<0.3 MV) 115 Medical (Radiotherapy) 0.5 a

a This is the average of values ranging from 0. 05 kg to over 0.8 kg, depending on model and manufacturer. Source: Schwarz (2005)



### Tier 2 method – user-level emission-factor approach If data on the quantity of SF 6 contained within each industry and medical accelerator are available, use the Tier 2 method for university and research facilities; however, mu ltiply the emission factor for each process description provided below by the total, country-specific SF 6 charge for that process description.

T ABLE 8.10 E MISSION FACTOR FOR EACH PROCESS DESCRIPTION , (SF 6 EMISSIONS FROM INDUSTRIAL AND MEDICAL PARTICLE ACCELERATORS ) Process Description Emission Factor, kg /kg SF 6 charge
Industrial Particle Ac celerators – high voltage (0.3-23 MV) 0.07
Industrial Particle Ac celerators – low voltage (<0.3 MV) 0.013 Medical (Radiotherapy) 2.0 a

a This emission factor is the average of values ranging from 1 kg to 10 kg per kg charge, dependi ng on model, manufacturer, and service

intervals. Source: Schwarz (2005)



### Tier 3 method – user-level mass-balance method To calculate SF 6 emissions from industrial and medical particle accelerators, use the same Tier 3 method as the university and research facilities. The customer service organisations for manufacturers and distributors of the equipment are likely to have information on equipment stocks, imports, and exports, and on the quantities of SF 6 used to fill and refill the equipment.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.31 

### EMISSIONS FROM OTHER APPLICATIONS OF SF 6 

### AND PFCs
It is good practice to contact all gas producers/distributors to identify SF 6 and PFC users and to investigate the gas consumption of source categories other than those mentioned above. The key difference among the applications discussed below is the typical delay between the purchase of the SF 6 or PFC and the release of the chemical. In some cases (e.g., SF 6 used in sound-proof glazing, PFCs used as heat transfer fluids), the chemical is fairly well contained during the life of the equipment or product, and most emissions are associated with the manufacture and disposal of the product . In these cases, the delay between the purchase of the chemical and its final emission depends on the lifetime of the product, ranging from three years for tyres and sport-shoes to 25 years for sound-proof glazing. In other cases (e.g., use of SF 6 and PFCs as tracers or in medical applications), the chemical is fully emitted within a year of its purchase. If, as a result of an initial survey, applications with distinctive delayed emissions appear significant, then good practice is to use a source category-specific emission calculation, taking into account the delay in emissions.



### Adiabatic uses Adiabatic uses of SF 6 and some PFCs exploit the low permeability of these gases through rubber. Historically, SF 6 has been the dominant gas in these applications; however, PFCs with similar molecular weights (such as C 3 F 8 ) have recently been used as well. Applications with a delay period of 3 years include or car tyres, sport shoe soles and tennis balls (Schwarz et al. , 1996). For applications with emissions that are delayed by three years, the following formula can be used.

E QUATION 8.19 A DIABATIC PROPERTY APPLICATIONS Emissions in year t = Sales in year (t – 3)



### Sound-proof glazing Double-glazed sound-proof windows : Approximately one-third of the total amount of SF 6 purchased is released during assembly (i.e., filling of the double glass wind ow) (Schwarz/Leisewitz, 1999). For the stock of gas remaining inside the window (capacity), an annual leakage rate of 1 percent is assumed (including glass breakage). Thus, about 75 percent of initial stock remains at the end of its 25-year lifetime. The application of SF 6 in windows began in 1975, so disposal is only beginning to occur. Emissions from this source sub-category should be calculated using Equations 8.20 to 8.22:

E QUATION 8.20 D OUBLE
- GLAZED WINDOWS : ASSEMBLY Assembly Emissions in year t = 0.33 • SF 6 purchased to fill windows assembled in year t

E QUATION 8.21 D OUBLE
- GLAZED WINDOWS : USE Leakage Emissions in year t = 0.01 • Capacity of Existing Windows in year t

E QUATION 8.22 D OUBLE
- GLAZED WINDOWS : DISPOSAL Disposal Emissions in year t = Amount Left in Window at End of Lifetime in year t • (1 – Recovery Factor)

Unless country-specific data are available, a default reco very factor value of zero should be assumed in Equation 8.22. If no specific information is av ailable for these sub-source categories, good practice is to treat them as prompt emissions.Volume 3: Industrial Processes and Product Use

8.32 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### PFCs used as heat transfer fluids in consumer and commercial applications PFCs are used as heat transfer fluids in a number of high-power-density commerc ial and consumer electronic applications. Commercial applications include cooling for supercomputer, telecommunication, and airport radar systems, as well as drive units (rectifiers) on high-speed trains (Burton, 2006). These applications consume much smaller volumes of liquid PFCs than electronics manufacturing, but are believed to be significant among ‘niche’ applications. Consumer applications include cooling kits for desktop computers that are operated at high voltages to increase their processing speed. The specific PFCs used in these applications are believed to be similar to those identified as heat transfer fluids in electronics manufacturing in Chapte r 6. In all of these applications, the liquid PFCs are used in closed modules, indicating that most emissions occur during the manufacture, maintenance, and disposal of the product or equipment. Thus, if inventory compilers can acquire information on emission rates during the manufacture, maintenance, and disposal of the equipment, along with the quantities of equipment manufactured, used, and disposed each year, they can use the Tier 2 or Tier 3 method for electrical equipment to estimate emissions. For applications with different emissions profiles (e.g., prompt emissions), the appropriate equation from Section 8.2 may be used.



### PFCs used in cosmetic a nd medical applications PFCs with relatively large molecular weights (e.g., C 10 F 18 ) are used in cosmetic and medical applications, exploiting their ability to carry oxygen to living tissue (May, 2006). Cosmetic applications include anti-wrinkle creams and are estimated to consume fairly small amounts. Current and potential medical applications include storage of pancreatic tissue for transp lants (using the ‘two-layer method’), eye surgery (to repair retinal tears), pneumonectomy (lung therapy and diagnosis), use as a contrast agent in ultrasonic and MRI examinations, blood extension, wound healing, and treatment of diseases of the middle ear. All but the first two medical applications involve only small quantities and/or are at the research st age. Storage of pancreatic tissue is a small but growing application. Emissions from medical uses are uncertain but are believed to be small. In all of these applications, the PFC is believed to be emi tted into the atmosphere within one year of its purchase. Thus, emissions from these sources can be estimated using Equation 8.23 for prompt emissions. 

### Any other uses of SF 6 

### and PFCs Other applications for SF 6 and PFCs that are not specifically addressed above include their use as tracers (in leak detection, indoor and outdoor tracking of air-masses, and oil recovery 6 ) and use of SF 6 in the production of optical cables (for fluorodoping of glass fibres 7 ). Often the gases or liquids are emitted within one year of purchase. In this case, good practice in calculating SF 6 and PFC emissions from these ‘prompt’ emissive applications is to use the following formula :

E QUATION 8.23 P ROMPT EMISSIONS Emissions in year t = (0.5 • Amount Sold in year t) + (0.5 • Amount Sold in year t – 1)

This equation is similar to the equation for prompt ODS Substitute applications (e.g., aerosols and solvents) addressed in Chapter 7 of this volume. The equation covers more than one year because both sales and emissions are assumed to be continuous over the year; that is, chem ical sold in the middle of year t-1 is not fully emitted until the middle of year t.



## 8.3.2.2 C HOICE OF EMISSION FACTORS
For ‘other’ source categories of SF 6 and PFCs that contribute substantially to a country’s SF 6 and PFCs emissions, countries are encouraged to develop country-specific emission factors based on occasional surveys of representative subsets of sources. It is good practice to clearly document such emission factors. Default emission factors are provided above for AWACS, accelerators, prompt emissive applications and adiabatic applications, including windows.

6 D. Vlachogiannis et al . (2005). This paper indicated that so me fraction of injected PFCs and SF 6 was destroyed during fuel

combustion, but the magnitude of this fraction (compared to the fraction of injected chemical that escaped before combustion) was unclear.

7 See further information on th is application in Schwarz (2005).Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.33 

## 8.3.2.3 C HOICE OF ACTIVITY DATA
The activity data for these sub-source categories should be consistent with the data used in the calculation of SF 6 emissions from other source categories (e.g., electrical equipment) to ensure that the estimate is complete and there is no double counting. For medical linear accelerators, the cu stomer service organisations for manufacturers and distributors of the equipment are likely to have information on equipment stocks, imports, and exports, and on the quantities of SF 6 used to fill and refill the equipment. Guidance regarding possible sources of activity data for other sources is provided under the method for each source category.



## 8.3.2.4 C OMPLETENESS
Data per application on import, export and consumption from national SF 6 and PFC producers and distributors will suffice, provided that (i) all SF 6 and PFC producers and distributors ar e identified, (ii) domestic consumers only purchase SF 6 and PFCs from national suppliers, and (iii) im ports and exports in products (e.g., sport attributes) are negligible. It is good practice to check regularly for additional distributors to ensure that no gas is imported directly (in bulk) by end-users and that identified products containing SF 6 or PFCs are not imported in sizeable amounts. Alternatively, if top-down data on chemical consumpti on is not available, countries may use information on the number of accelerators, AWACS, window s, etc. in use in the country, ap plying the emission factors that are supplied in the method for each source category.



## 8.3.2.5 D EVELOPING A CONSISTENT TIME SERIES
For base year estimates, data may be needed for a fe w years prior to the base year; one year for prompt emissions and more years for delayed emission applications. It is good practice to calculate emissions using the same method for every year in the time series. Where data are unavailable to support a more rigorous method for all years in the time series, it is good practice to recalculate according to the guidance provided in Volume 1, Chapter 5.



# 8.3.3 Uncertainty assessment
If the survey of domestic sales per application by national gas producers and distributors is complete, then the accuracy of annual apparent consump tion data will be high. The uncertai nty in emissions estimates will be similarly small when the uses are all prompt emissions. In case of delayed emission applications, the uncertainties are:

• Default delay times in adiabatic property applications: 3±1 year;

• Defaults for soundproof windows: 50±10% filling emissions and 1±0.5% leakage/breach emissions. If gas consumption data are not available, uncertain ties regarding the numbers an d usage of accelerators and AWACS, etc. become important.

• For accelerators, the total SF 6 charge and leak rate determine em issions and associated uncertainty

• For use of SF 6 in AWACS, the number of sorties per plan e has a significant impact on emissions and uncertainty.



# 8.3.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation

8.3.4.1 Q UALITY 

## A SSURANCE 

## /Q UALITY 

## C ONTROL

It is good practice to conduct quality control checks as outlined in Volume 1, Chapter 6, and an expert review of the emissions estimates. Additional quality control checks as outlined in Volume 1, and quality assurance procedures may also be applicable, particularly if higher tier methods are used to determine emissions from thisVolume 3: Industrial Processes and Product Use

8.34 2006 IPCC Guidelines for National Greenhouse Gas Inventories source category. Inventory compilers are encouraged to use higher tier QA/QC for key categories as identified in Volume 1, Chapter 4. Additional procedures specifi c to other sources of SF 6 are outlined below: 

### Comparison of emissions estimates using different approaches Inventory compilers should compare total national potential SF 6 and PFC emissions (minus the amount allocated to the source categories as per chapters 3.10, 4, 6 and 8.2) to the estimated SF 6 and PFC emissions from other uses. These adjusted potential national emissions can be used as an upper bound on emissions. 

### Activity data check Inventory compilers should compare the activity data submitted by different producers and distributors, and, adjusting for relative size or capacity of the companies, identify significant outliers. Any outliers should be investigated to determine if the differences can be explai ned or if there is an error in the reported activity. 

### Comparison of emission rates with those of other countries Inventory compilers should compare the emissions from other SF 6 and PFC end-uses included in the national inventory with information submitted by other similar co untries. For each source, emissions per capita or per unit of GDP should be compared with the corresponding emission rates of other countries. If national figures appear to be relatively very high or very small, a justification should be provided.



## 8.3.4.2 R EPORTING AND 

## D OCUMENTATION

It is good practice to document and archive all information required to produce the national emissions inventory estimates as outlined in Volume 1, Section 6.11. It is not practical to include all documentation in the national inventory report. However, the inventory should include summaries of methods used and references to source data such that the reported emissions estimates are tr ansparent and steps in their calculation may be retraced. For transparency, it is good practice to report both actual and potential emissions from the source category ‘other uses’ separately from other SF 6 and PFC emissions. In addition, providing information on the specific applications that are included in th is source category is useful for comp aring (estimates of) national practices with other countries, regionally, or globally. In addition, the methods applied and references should be documented. For delayed emission sub-source categories, annual emissions, delay times and emission factors per type of sub-source category should be reported.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.35 

# 8.4 N 2 

# O FROM PRODUCT USES

8.4.1 Introduction
Evaporative emissions of nitrous oxide (N 2 O) can arise from various types of product use, including:

• Medical applications (anaesthetic use, analgesic use and veterinary use);

• Use as a propellant in aerosol products, primarily in food industry (pressure-packaged whipped cream, etc);

• Oxidising agent and etchant used in semiconductor manufacturing;

• Oxidising agent used, with acetylene, in atomic absorption spectrometry;

• Production of sodium azide, which is used to inflate airbags;

• Fuel oxidant in auto racing; and

• Oxidising agent in blowtorches used by jewelers and others. In general, medical applications and use as a propellant in aerosol products are likely to be larger sources than others. It is good practice to estimate and report N 2 O emissions from these sources. Inventory compilers are encouraged to estimate and report N 2 O emissions from the other sources as well, if data are available.



### MEDICAL APPLICATIONS

Anaesthetic use of N 2 

### O N 2 O for anaesthetic use is supplied in steel cylinders containing a minimum of 98 percent N 2 O. N 2 O is used during anaesthesia for two reasons: a) as an anaesthe tic and analgesic and as b) a carrier gas for volatile fluorinated hydrocarbon anaesthetics such as isoflurane, sevoflurane and desflurane. The anaesthetic effect of N 2 O is additive to that of the fluorinated hydrocarbon agents. Not all anaesthetics require the use of N 2 O, and the use of N 2 O is contra-indicated in a small number of medical situations. The carrier gas during anaesthesia may be either N 2 O and oxygen or a mixture of air and oxygen, in which case N 2 O is avoided. Inhaled anaesthetic agents are increasingly administered via breathing systems which re-circulate the exhaled breath of the patient through a canister of carbon dioxide absorbent before directing the gases back to the patient. Using this method the flow of carrier gas can be reduce d considerably after the first few minutes of anaesthesia when uptake by the patient is high. This technique is known as Low Flow Anaesthesia. Low Flow Anaesthesia has the advantage of reducing emissions as well as reducing cost. Some anaesthetics may avoid both N 2 O and the fluorinated hydrocarbon agents completely by employing a technique in which an anaesthetic drug is continuously infused into a vein throughout the surgical procedure. This technique is known as Total Intravenous Anaesthesia. 

### Analgesic use of N 2 

### O Inhaled N 2 O is used to provide pain relief in certain situations. For example, it is supplied in steel cylinders containing pre-mixed N 2 O 50 percent and oxygen 50 percent as premixed nitrous oxide and oxygen mixtures in the UK. Premixed nitrous oxide and oxygen mixtures are used to provide pain relief in childbirth, and for painful procedures of short duration, e.g. for dressings to be changed in burns patients. Premixed nitrous oxide and oxygen mixtures are not used in countries with a very cold climate because the mixture can separate if the cylinders are stored below –6 degrees centigrade, with the consequent risk of administering pure nitrous oxide to patients with no oxygen. 

### Veterinary use of N 2 

### O N 2 O is also used during animal anaesthesia. Administ ration methods are similar to those used in human anaesthesia.Volume 3: Industrial Processes and Product Use

8.36 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### USE AS A PROPELLANT IN AEROSOL PRODUCTS, PRIMARILY IN FOOD INDUSTRY
N 2 O is also used as a propellant in aerosol products primarily in food industry. Typical usage is to make whipped cream, where cartridges filled with N 2 O are used to blow the cream into foam.



# 8.4.2 Methodological issues

8.4.2.1 C HOICE OF METHOD

It is good practice to estimate N 2 O emissions from data of quantity of N 2 O supplied that are obtained from manufacturers and distributors of N 2 O products according to Equation 8.24 below. There will be a time delay between manufacture, delivery and use but this is proba bly small in the case of medical applications because hospitals normally receive frequent deliveries to avoid ma intaining large stores. Ther efore, it is reasonable to assume that the N 2 O products supplied will be used in one year. In the case of use as a propellant in aerosol products, there is no reliable data that prove there is a significant time delay betwee n manufacture, delivery and use. Such being the case, it is consid ered practical to assume that the N 2 O products supplied will be used in one year. Equation 8.24 covers more than one year because both supply and use are assumed to be continuous over the year; that is, N 2 O supplied in the middle of year t–1 is not fully used and emitted until the middle of year t. Different tiers could not be defined for this source category, because there is no other reliable estimation method. For example, in the case of medical applications, estimations from numbers of anaesthetics given, number of surgical beds or hours of anaesthesia could be consid ered but these methods are likely to be inaccurate. (See Section 8.4.2.3, Choice of Activity Data.)

E QUATION 8.24 N 2 O EMISSIONS FROM OTHER PRODUCT USES 

## [ ] { } ∑ •

− • + • = i i i i O N EF t A t A t E ) 1 ( 5

. 0 ) ( 5

. 0 ) ( 2

Where:
E N2O (t) = emissions of N 2 O in year t , tonnes A i (t) = total quantity of N 2 O supplied in year t in application type i , tonnes A i (t-1) = total quantity of N 2 O supplied in year t -1 in application type i , tonnes
EF i = emission factor for application type i , fraction



## 8.4.2.2 C HOICE OF EMISSION FACTORS

MEDICAL APPLICATIONS
It is assumed that none of the administered N 2 O is chemically changed by the body, and all is returned to the atmosphere. It is reasonable to assume an emission factor of 1.0.


### USE AS A PROPELLANT IN AEROSOL PRODUCTS, PRIMARILY IN FOOD INDUSTRY
For N 2 O used as a propellant in pressurized and aerosol food products, none of the N 2 O is reacted during the process and all of the N 2 O is emitted to the atmosphere resulting in an emissions factor of 1.0 for this source.



### OTHERS For the other types of product use, it may not be appropriate to assume an emissions factor of 1.0. In case the inventory compilers estimate and report N 2 O emissions arising from product use other than medical applications and use as a propellant in aerosol pr oducts, they are encouraged to derive reasonable emission factors for that source from literature or measurements.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.37 

## 8.4.2.3 C HOICE OF ACTIVITY DATA

MEDICAL APPLICATIONS Total quantity of N 2 O supplied by application type should be obtained from manufacturers and distributors of N 2 O products. Alternatively, for medical applications, quantity of N 2 O usage may be obtained from the pharmacy department in individual hospitals that usually have records of the number and capacity of nitrous oxide cylinders purchased per annum. The duration of hospital stay following a surgical procedure varies considerably from less than one day to several days or weeks. Estimates of the number of an aesthetics administered which are calculated from the surgical bed occupancy are likely to be inaccurate.
Because N 2 O is used in only a proportion of anaesthetics its use cannot be estimated reliably from the number of anaesthetics given. The flow of N 2 O (L/min) delivered by the anaesthetic apparatus may be varied by the anaesthetist during the course of surgery, typically between zero and 6 L/min. Because of this considerable variability, estimates of consumption based on duration of anaes thesia are likely to be inaccurate. The proportion of anaesthetics in which N 2 O is used varies between countries and between individual anaesthetists in a given country. Over the recent years th ere appears to be a general reduction in the proportion of anaesthetics which incorporate N 2 O but data are sparse.


### USE AS A PROPELLANT IN AEROSOL PRODUCTS, PRIMARILY IN FOOD INDUSTRY Total quantity of N 2 O supplied by application type should be obtained from manufacturers and distributors of N 2 O products.



## 8.4.2.4 C OMPLETENESS
Data per application on import, export and consumption from national N 2 O manufacturers and distributors will suffice, provided that (i) all N 2 O manufacturers and distributors are identified, (ii) domestic consumers only purchase N 2 O from national suppliers, and (iii) imports and ex ports in products (e.g. sport attributes) are negligible. It is good practice to check regularly for additional distributors to ensure that no N 2 O is imported directly (in bulk) by end users and that identified products containing N 2 O are not imported in sizeable amounts.



## 8.4.2.5 D EVELOPING A CONSISTENT TIME SERIES

It is good practice to calculate emissions of N 2 O using the same method for every year in the time series. Where data are unavailable to support a more rigorous method for all years in the time series, it is good practice to recalculate according to the guidance provided in Volume 1, Chapter 5.



# 8.4.3 Uncertainty assessment

8.4.3.1 E MISSION FACTOR UNCERTAINTIES
In the published literature it is widely assumed that none of the N 2 O inhaled by a patient during anaesthesia is metabolised. N 2 O is taken up continuously from the lungs as dissolved N 2 O in blood. The portion which is nottaken up is exhaled in the next breath. Uptake by the patient is high initially and falls progressively in a nearexponential fashion over time. It is reasonabl e to assume that all the administered N 2 O is eventually returned to the atmosphere and the emission factor is 1.0. This is a pragmatic assumption because there are no reliable data. Any error in the emission factor is likely to be extr emely small in comparison with other uncertainties. Also in the case of use as a propellant in aerosol products, N 2 O is not likely to be reacted during the process. Therefore, it is a pragmatic assumption that emission factor is 1.0, and any error in the emission factor is likely to be extremely small in comparison with other uncertainties.Volume 3: Industrial Processes and Product Use

8.38 2006 IPCC Guidelines for National Greenhouse Gas Inventories In case the inventory compilers estimate and report N 2 O emissions arising from product use other than medical applications and use as a propellant in aerosol products , emission factor uncertainties may need to be carefully considered.



## 8.4.3.2 A CTIVITY DATA UNCERTAINTIES
The uncertainties in quantity of N 2 O supplied by application type obtained from manufacturers and distributors of N 2 O products may vary widely from country to country. If the uncertainty estimate s are obtainable from the manufacturers and distributors, those estimates should be used. Otherwise, activity data uncertainties should be estimated by expert judgement.



# 8.4.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation

It is good practice to document and archive all information required to produce the national emissions inventory estimates as outlined in Volume 1, Chapter 6. It is not practical to include all documentation in the national inventory report. However, the inventory should include summaries of methods used and references to source data such that the reported emissi ons estimates are transparent and step s in their calculation may be retraced. For transparency, providing information on the specific app lications that are included in this source category is useful for comparing (estimates of) national practices with other countries, regionally, or globally. In addition, the methods applied and references should be documented. It is good practice to conduct quality control checks and quality assurance procedures as outlined in Volume 1, Chapter 6. Inventory compilers are encouraged to use higher tier QA/QC for key categories as identified in Volume 1, Chapter 4. Additional procedures specific to this source category are outlined below: 

### Activity data check Inventory compilers should compare the activity data submitted by different manufacturers and distributors of N 2 O, and, adjusting for relative size or capacity of the companies, to identify sign ificant outliers. Any outliers should be investigated to determine if the differences can be explained or if there is an error in the reported activity. 

### Comparison of emissions with other countries Inventory compilers should compare the N 2 O emissions from types of product use included in the national inventory with information submitted by other similar co untries. For each source, em issions per capita or per unit of GDP with other countries should be compared. If national figures appear to be relatively very high or very small, a justification should be provided.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.39 

## References
SECTIONS 8.1 - 8.3 Aoyama, T. (2004). Japan Electrical Manufacturers’ Association (JEMA), “The Situation of Reduction in SF 6 Emissions from Gas-insulated Electrical Equipment In Japan” Paper and presentation delivered to the Conference on SF 6 and the Environment, Scottsda le, Arizona, December 1-3, 2004. AREVA (2005). AREVA, World energy experts, Activity and Sustainable Development Report 2004. (Registered office: rue Le Peletier – 75009 Paris – France, http://www.areva.com/ ), published in July 2005. Boeing (2005). “E-3 AWACS in Service Worldwide”, Ma rch 2005. Boeing Integrated Defense Systems, P.O. Box 516, St. Louis, MO 63166, (Available from http://www.boeing.com/defense-space/ic/awacs/docs/E3AWACS_overview.pdf) Burton, C. S. (2006). “Uses and Air Emissions of Liquid PFC Heat Transfer Fluids fr om the Electronics Sector,” Report prepared for Scott C. Bartos, U.S. Environmental Protection Agency. Ecofys (2005). Reductions of SF 6 Emissions from High and Medium Voltage El ectrical Equipment in Europe, Final Report to CAPIEL, S, Wartmann and J. Harnisch, June 28, 2005 FEPC and JEMA (2004). Federation of Electric Power Companies (FEPC) and the Japan Electrical Manufacturers’ Association (JEMA), “Japanese Emi ssion Factors.” (Personal communication from Mr. Kiyoshi Saitoh of Japan Electrical Manufacturers Association (JEMA) to Mr. Kiyoto Tanabe, IPCC Technical Support Unit, November, 2004.) Harris, D., and Hildebrandt, J. (2003). “Spray Cooling Electri cal and Electronic Equipment,” COTS Journal , November 2003. CIGRE (2005). International Council on Large Electric Systems (CIGRE) Publication No.276: Guide for the Preparation of customized “Practical SF 6 Handling Instructions”, Task Force B3.02.01, August 2005. IEC (1996). International Electro-t echnical Commission (IEC) Standard 60694: “Common specifications for high-voltage switchgear and controlgear standards,” Second edition, 1996-05. Geneva, Switzerland. Koch, E.C. (2004). “Special Materials in Pyrotechnics : III. Application of Lithium and its Compounds in Energetic Systems;” Propellants, Explosives, Pyrotechnics , Volume 29, Issue 2, Pages 67 - 80, 2004 May, G. (2006). F 2 Chemicals Limited. Personal communication with Deborah Ottinger Schaefer, January 23, 2006. Maruyama, S. and Meguro, M. (2000). “SF 6 Gas Emission Reduction From Gas-Insulated Electrical Equipment in Japan.”, Paper presented at the Conference on SF 6 and the Environment: Emission Reduction Strategies in San Diego, USA (November 2000). NIST (1997). Gases for Electrical Insulation and Arc Inte rruption: Possible Present and Future Alternatives to Pure SF 6 ; by L. G. Christophorou, J. K. Olthoff, D. S. Green; NIST Technical Note 1425, National Institute of Standards, November 1997. Schwarz, W. and Leisewitz, A. (1996). Current and future emissions of fluorinated compounds with global warming effect in Germany (in German). Report UBA-FB 1060 1074/01, Umweltbundesamt, Berlin. Schwarz, W. and Leisewitz, A. (1999). Emissions and reduction potentials of HFCs, PFCs, and SF 6 in Germany. Report UBA-FB 298 41 256, Umweltbundesamt, Berlin. Schwarz, W. (2005). Emissions, Activity Data, and Emissi on Factors of Fluorinated Greenhouse Gases (F-Gases) in Germany 1995-2002. Research Report 201 41 261/01, UBA-FB 000811/e, Umweltbundesamt, Berlin. Schwarz, W. (2006). “The German Monitoring System for SF 6 Emissions from Equipment for Electricity Transmission and Distribution.” Smythe, K. (2004). ‘Trends in SF 6 Sales and End-Use Applications: 196 1-2003.’ Interna tional Conference on SF 6 and the Environment: Emission Reduction Techno logies, December 1-3, 2004, Scottsdale, AZ. U.S. EPA (2004). U.S. Inventory of Greenhouse Gases and Sinks, 1990-2002. U.S. Environmental Protection Agency, April, 2004. Vlachogiannis, D., et al . (2005). Assessment of the impact of SF 6 and PFCs reservoir tracers on global warming, the AEOLOS study, Non-CO 2 Greenhouse Gases (NCGG-4), coordinated by A. van Amstel, Rotterdam, p. 389-396.Volume 3: Industrial Processes and Product Use

8.40 2006 IPCC Guidelines for National Greenhouse Gas Inventories 

### SECTION 8.4 Austria [Umweltbundesamt] (2004), AUSTRIA’S NATIONAL INVENTORY REPORT 2004, Submission under the United Nations Framework Convention on Climate Change Beatty PCW, Kay B and Healy TEJ (1984), Measurement of the rates of nitrous oxide uptake and nitrogen excretion in man . British Journal of Anaesthesia; 56: 223-232. Environment Canada (2004), Canada’s Greenhouse Gas Inventory 1990-2002 Jordan M. (1996), Pharmacology in the Practice of Anaesthesia p 43. Arold, London. Edited by Kaufman L and Tabener PV. U.S. EPA (2004). U.S. Inventory of Greenhouse Gases and Sinks, 1990-2002. U.S. Environmental Protection Agency, April, 2004.Chapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.41 

# Annex 8A Examples of Tier 3 national SF 6 

# inventory systems Figures 8A.1 and 8A.2 illustrate the Ti er 3 Hybrid approach as it is curr ently applied in Germany for closed pressure (high voltage) and sealed-pressure (medium voltage) equipment (Schwarz, 2006). In the diagram, ‘MB’ indicates processes or life cycle stages for which the mass-balance approach is us ed, while ‘EF’ indicates processes and life cycle stages for which emission factors are used. For example, in manufacturing, the massbalance approach is used to estimate emissions from the filling of gas-insulate d switchgear, while emission factors are used to estimate emissions from the filling of bushings, instrument transfor mers, and circuit breakers. In Germany, the latter processes have emission rates of 1 percent or less, making emissions difficult to measure using mass-balance methods. Note that this diagram is intended to be an example only; when implementing the Tier 3 approach, countries are encour aged to choose approaches and em ission factors appropriate to their national circumstances.Volume 3: Industrial Processes and Product Use

8.42 2006 IPCC Guidelines for National Greenhouse Gas Inventories Figure 8A.1 Example of Tier 3 approac h: Germany, High-Voltage equipment

Legend for Emissions Estimation in HV
Mass Balance Approach Symbol Equation
MB I Development Emissions = Consumption for Developi ng minus Return from Development Department
MB II GIS Charging Emissions = Consumption for Charging minus Char ge (nameplate capacities); also applicable to Gas insulated Lines (GIL’s)
MB III Operating Emissions I = Annually surveyed topping up by equipment operators
MB IV Operating Emissions II = Namepl ate capacity of decommissione d equipment minus gas recovered from this equipment Emission Factor (EF) Approach Symbol Kind of Emission Factor (EF) Multiplied by
EF 1 Factory Filling EF Bushings* NC** of bushings filled in factory
EF 2 Factory Filling EF Outdoor Instrument Transformers (ITs) NC of ITs filled in factory
EF 3 Factory Filling EF Gas Circuit Breakers (G CBs) NC of GCBs filled in factory
EF 4 Site Erection EF GIS and GIL NC of GIS and GIL filled on site
EF 5 Site Erection EF GCBs NC of GCBs filled on site
EF 6 Site Erection EF Outdoor ITs NC of Outdoor ITs filled on site
EF 7 Disposal EF NC of decommissioned equipment * Bushings are treated as integral parts of GIS as of Site erection. **NC = Total nameplate capacity of equipment undergoing a given processChapter 8: Other Product Manufacture and Use

2006 IPCC Guidelines for National Greenhouse Gas Inventories 8.43 Figure 8A.2 Example of Tier 3 approac h: Germany, Medium-Voltage equipment

Legend for Emissions Estimation in MV Mass Balance Approach Symbol Equation
MB I Development Emissions = Consumption for Developi ng minus Return from Development Department* Emission Factor (EF) Approach Symbol Kind of Emission Factor (EF) Multiplied by
EF 1 Factory Filling EF NC** filled in factory
EF 2 Site Erection EF NC*** filled on site
EF 3 Operating EF NC of operating equipment (t otal bank from this and previous years)
EF 4 Disposal EF NC decommissioned

* This mass balance approach also applies to manufactur ing of Cast Resin Instrument Transformers (ITs). **NC = Total nameplate capacity of e quipment undergoing a given process. *** In countries where MV equipment is already gas-filled in factories, site erection emissions are negligible.