Scope 1
Refrigerant leaks
Refrigerant that escapes from cooling equipment. There is no emission factor: the leaked mass is the measurement, and the gas's GWP turns it into CO₂e.
On this page you'll learn
- The mass-balance method
- The screening method, for when you have no leak log
- Why a missing GWP stops the calculation
- Scope
- 1
- Method
- Mass × GWP
- Screening
- EPA Refrigeration/AC tool v1.2, Worksheet 3
- Category code
fugitive_emission
Mass × GWP
- Mass
- 12 kg
- GWP of R-410A (AR5)
- 1,924
- Scope 1
- 23,088 kg CO₂e
A small leak of a high-GWP gas outweighs a lot of fuel: 12 kg of R-410A is about the same as 11,000 litres of petrol at DEFRA's 2.075 kg CO₂e per litre. Under AR6 the derived R-410A value is 2,255.5, giving 27,066 kg.
Each GWP value carries its provenance: published (in an IPCC or EPA table), derived (calculated from a blend's composition) or unverified. None are unverified today.
The screening method
If you know your equipment but don't keep recharge records ("40 chillers holding 300 kg of R-410A"), the screening method estimates leaks over three points in the equipment's life:
- assembly
- units installed × charge × assembly emission factor
- operation
- units operating × charge × annual leak rate × fraction of year
- disposal
- units retired × charge × (1 − recovery efficiency)
The three terms are applied to their own unit counts and returned separately, because assembly and disposal are one-off events while operation recurs every year.
Always preliminary
IPCC says inventories built on these default ranges are preliminary, and the result is marked so. Charge size can't be defaulted: industrial refrigeration spans 10 to 10,000 kg.
Only the estimated mass is saved as an ordinary leak record. The preview's CO₂e isn't stored, so the saved figure follows your organisation's GWP set rather than freezing whatever set answered the preview.
A missing GWP stops the calculation
The GWP is the answer here, so Slate never borrows one. A blend with no AR6 value (R-424A) under AR6 stops with the gas named.
Note
"Fugitive emissions" in IPCC Volume 2 Chapter 4 means coal mines and oil and gas systems, a different thing. See Coal, oil and gas.