Choice of emission factors

As in other applications, the first choice for emission factors is to develop and use peer-reviewed and well documented country-specific data based on field research on each foam type (open cell and closed cell) in support of a Tier 2a approach. As noted previously, if no information is available at the sub-application level, emission factors can be adopted from the Emission Factor Database (EFDB) or from the data contained in this section. However, it should be noted that the data contained in this section will not be replaced with updated values in the same way as may happen for the EFDB. Either country-specific or globally/regionally-derived approaches will lead to the necessary assessment of decommissioning losses.15

Figure 7.4 Decision tree for emissions from the foam application

Figure 7.4 Decision tree for emissions from the foam application

Box 1: Tier 1a

Note:

1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categories (noting Section 4.1.2 on limited resources), for discussion of key categories and use of decision trees.

Table 7.6, Default Emission Factors for HFC-134a/HFC-152a (Foam Sub-Application) and Table 7.7, Default Emission Factors for HFC-245a/HFC-365mfc/HFC-227ea (Foam Sub-Application) lists default emission factors

15 It has also been noted that decommissioning may not necessarily involve total loss of blowing agent at that point, either because of a level of secondary use or because the item has been discarded intact (e.g., many refrigerators). These could be considered as some of the end-of-life management options available to nations, but are clearly less effective than proper destruction or recovery technologies. Emission models should focus proper attention to end-of-life issues.

assumptions for the most important current closed-cell foam applications. Use of these factors will require data on chemical sales at the sub-application level for both current and historic consumption in order that the bank of chemical in equipment/products for these sub-applications is properly considered.

Table 7.6

Default emission factors for HFC-134a and HFC-152a uses (foam sub-applications )

(IPCC/TEAP, 2005)

Table 7.6

Default emission factors for HFC-134a and HFC-152a uses (foam sub-applications )

(IPCC/TEAP, 2005)

Sub-Application

Product Life in years

Loss %

Maximum Potential End-of-Life Loss %

Polyurethane - Integral Skin

12

95

2.5

0

Polyurethane - Continuous Panel

50

10

0.5

65

Polyurethane - Discontinuous Panel

50

12.5

0.5

62.5

Polyurethane - Appliance

15

7

0.5

85.5

Polyurethane - Injected

15

12.5

0.5

80

One Component Foam (OCF) a

50

95

2.5

0

Extruded Polystyrene (XPS)b - HFC-134a

50

25

0.75

37.5

Extruded Polystyrene (XPS) - HFC-152a

50

50

25

0

Extruded Polyethylene (PE) a

50

40

3

a Ashford and Jeffs (2004) assembled from UNEP FTOC Reports (UNEP-FTOC, 1999; UNEP-FTOC, 2003).

b Vo and Paquet (2004): An Evaluation of Thermal Conductivity over time for Extruded Polystyrene Foams blown with HFC-134a and HCFC-142b

Source:

a Ashford and Jeffs (2004) assembled from UNEP FTOC Reports (UNEP-FTOC, 1999; UNEP-FTOC, 2003).

b Vo and Paquet (2004): An Evaluation of Thermal Conductivity over time for Extruded Polystyrene Foams blown with HFC-134a and HCFC-142b

Some articles, such as reefers or insulated truck bodies, may spend almost all of their practical lives in transit between countries. Since these applications have very low in-use emissions it is reasonable if only the manufacturing and decommissioning losses are taken into account.

Table 7.7

Default emission factors for HFC-245fa/HFC-365mfc/HFC-227ea uses (foam sub-application)

HFC-245a/HFC-365mfc Applications

Product Life in years

First Year Loss %

Annual Loss %

Maximum Potential End-of-Life Loss %

Polyurethane - Continuous Panel

50

5

0.5

70

Polyurethane - Discontinuous Panel

50

12

0.5

63

Polyurethane - Appliance

15

4

0.25

92.25

Polyurethane - Injected

15

10

0.5

82.5

Polyurethane - Cont. Block

15

20

1

65

Polyurethane - Disc. Block for pipe sections

15

45

0.75

43.75

Polyurethane - Disc. Block for panels

50

15

0.5

60

Polyurethane - Cont. Laminate / Boardstock

25

6

1

69

Polyurethane - Spray

50

15

1.5

10

Polyurethane - Pipe-in-Pipe

50

6

0.25

81.5

Phenolic - Discontinuous Block

15

45

0.75

43.75

Phenolic - Discontinuous Laminate

50

10

1

40

Polyurethane - Integral Skin

12

95

2.5

0

Source: Ashford and Jeffs (2004) assembled from UNEP FTOC Reports (UNEP-FTOC, 1999; UNEP-FTOC, 2003)

If only aggregated chemical sales data for closed-cell foam are available and information on specific foam types cannot be obtained, the general default emission factors shown in Table 7.5 can be used in support of a Tier 1a method.16 This replicates the previous Tier 2 guidance contained in the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC, 1997) but is now classified as a Tier 1a method following the exclusion of potential emission methods for ODS substitutes.

Use of these default emission factors will result in 90 percent of the initial charges being emitted over twenty years of annual use, after the initial 10 percent during the first year.

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