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HFO/HFC blend (azeotropic) · ASHRAE 34 safety group A1

R-513A GWP and CO₂e

R-1234yf / R-134a blend — R-1234yf/134a (56.0/44.0). Current. An A1 (non-flammable) route away from R-134a, which is why it appears on chillers where an A2L would force a plant-room safety case.

Great Britain

631.4

Computed per retained Regulation (EU) No 517/2014, Annex IV, from Annex I/II component values

EU / Northern Ireland

629.5

Computed per Regulation (EU) 2024/573, Annex VI, from Annex I/II component values

These two figures genuinely differ. Use the one for the regime the equipment is in — Great Britain, or Northern Ireland under the Windsor Framework.

How this number is arrived at

R-513A is a blend, so neither regulation lists a GWP for it directly. Both set out the same method — a mass-weighted average of the components — and both list the component values in their own annexes. The arithmetic is below so you can check it rather than take it on trust.

Component% by massGWP (GB)GWP (EU/NI)
R-1234yf56%40.501
R-134a44%14301430

Great Britain: (0.56 × 4) + (0.44 × 1430) = 2.24 + 629.2 = 631.4

EU / Northern Ireland: (0.56 × 0.501) + (0.44 × 1430) = 0.28 + 629.2 = 629.5

Composition from ASHRAE Standard 34, as published in the ASHRAE Handbook—Fundamentals refrigerants chapter. Method from Regulation (EU) 2024/573 Annex VI and the retained GB Annex IV, which are worded identically.

Charge in kg → tonnes CO₂e

t CO₂e = charge (kg) × GWP ÷ 1,000. This figure, not the charge in kilograms, is what sets the statutory leak-check frequency.

Charget CO₂e (GB)t CO₂e (EU/NI)
1 kg0.630.63
2 kg1.261.26
5 kg3.163.15
10 kg6.316.29
20 kg12.6312.59
50 kg31.5731.48
100 kg63.1462.95

Leak-check thresholds in kg

The regulations set the bands in tonnes CO₂e. Converted to a charge of R-513A, the duty starts at these weights.

BandCharge (GB)Charge (EU/NI)Check at leastWith leak detection
≥5 t CO₂e7.92 kg7.94 kgAt least every 12 monthsEvery 24 months
≥50 t CO₂e79.2 kg79.4 kgAt least every 6 monthsEvery 12 months
≥500 t CO₂e792 kg794 kgAt least every 3 monthsEvery 6 months

Automatic leak detection is mandatory at 500 tonnes CO₂e and above. Hermetically sealed equipment labelled as such is exempt below 10 tonnes CO₂e. Records must be kept for at least five years. Sources: retained Regulation (EU) No 517/2014 Articles 4–6, Regulation (EU) 2024/573 Articles 5–7, and GOV.UK guidance on checking F-gas equipment for leaks.

As with R-454B, the regimes differ only on the R-1234yf component. The ASHRAE Handbook's 573 is an AR5 figure and is not the basis either regulation uses.

Where you meet R-513A

  • •R-134a replacement on centrifugal and screw chillers
  • •New water-cooled chillers where an A1 is required

Maintenance checklists for plant that runs on it

Chiller maintenance checklistWater-Cooled Chiller maintenance checklistProcess Chiller maintenance checklist
Work out a specific chargeCompare all 10 refrigerants

Frequently asked questions

What is the GWP of R-513A?
It depends which regime you are in. In Great Britain it is 631.4; in the EU and Northern Ireland it is 629.5. Both are correct — they come from different annexes valuing the same substance on different assessment-report bases, and the page above cites each one.
How do I convert an R-513A charge into tonnes CO₂e?
Multiply the charge in kilograms by the GWP and divide by 1,000. A 10 kg charge of R-513A is 6.31 tonnes CO₂e in Great Britain and 6.29 tonnes in Northern Ireland. That figure is what sets the statutory leak-check frequency, not the charge in kilograms.
At what charge does R-513A need leak checks?
The duty starts at 5 tonnes CO₂e, which for R-513A is about 7.92 kg in Great Britain. Six-monthly checks start at 50 tonnes (79.2 kg) and quarterly at 500 tonnes (792 kg), where an automatic leak detection system also becomes mandatory. Fitting leak detection doubles the interval at every band. Hermetically sealed equipment labelled as such is exempt below 10 tonnes CO₂e.
Does R-513A work differently in Northern Ireland?
As with R-454B, the regimes differ only on the R-1234yf component. The ASHRAE Handbook's 573 is an AR5 figure and is not the basis either regulation uses.
Where is R-513A used?
R-134a replacement on centrifugal and screw chillers; New water-cooled chillers where an A1 is required. Current. An A1 (non-flammable) route away from R-134a, which is why it appears on chillers where an A2L would force a plant-room safety case.