Refrigerant Selection for CRAC Systems: R410A, R134a, R513A, and R32 Under Australia's Phase-Down

Australia's obligations under the Kigali Amendment to the Montreal Protocol are translating into concrete import restrictions on high-GWP refrigerants. For data centre operators and mechanical contractors specifying or maintaining CRAC equipment, the phase-down schedule is no longer a distant policy concern. It is already affecting refrigerant pricing, equipment lead times, and long-term serviceability of installed plant.

This post compares the four refrigerants most commonly found in precision air conditioning: R410A, R134a, R513A, and R32. The comparison covers GWP, efficiency, safety classification, charge limits, and what each means for equipment decisions made today.

Australia's HFC Phase-Down: The Relevant Timeline

Australia ratified the Kigali Amendment in 2019. The Department of Climate Change, Energy, the Environment and Water administers HFC import quotas under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989. The baseline for Australia's HFC consumption was set using 2011 to 2013 averages, and the phase-down schedule calls for reductions to:

• 90% of baseline by 2024
• 70% of baseline by 2029
• 50% of baseline by 2034
• 15% of baseline by 2036

Those percentages are expressed in CO2-equivalent tonnes, which means high-GWP refrigerants consume quota far faster than low-GWP alternatives. A single kilogram of R410A (GWP 2088) consumes roughly 3.3 times the quota of a kilogram of R513A (GWP 631). As quota tightens, the landed cost of high-GWP refrigerants rises. R410A pricing in Australia has already increased materially since 2022, and that trend will continue.

For data centres with long asset lifecycles, the practical question is not whether the phase-down affects you. It is whether your equipment will still be cost-effectively serviceable in 2030 or 2035.

R410A: The Incumbent With a Shrinking Future

R410A is a 50/50 blend of R32 and R125. GWP is 2088. It has been the dominant refrigerant in precision air conditioning for two decades, and the majority of installed CRAC units across Australian data centres still run on it.

On efficiency, R410A performs well in conventional DX systems. Its high operating pressures allow compact heat exchanger design, which suited the equipment architecture of the 2000s and 2010s. Vertiv Liebert PDX and PCW units, Stulz CyberAir, and Schneider Electric Uniflair ranges were all predominantly designed around R410A.

The problem is not current performance. It is future availability. R410A is a blend, which means it cannot be topped up after a leak without risk of composition drift. Any significant leak event requires a full recovery and recharge. With import quotas tightening and bulk pricing rising, the cost of that recharge will increase each year. Contractors are already reporting longer lead times for bulk R410A in some markets.

New equipment specifying R410A is still available, but the major manufacturers have been transitioning their product lines. Specifying R410A equipment today means accepting a refrigerant that will become progressively more expensive to maintain over a 15-year asset life.

R134a: Lower GWP but Still in Phase-Down Scope

R134a (GWP 1430) is a single-component refrigerant used in chilled water plant compressors and some larger precision cooling systems. Unlike R410A, it can be topped up after minor leaks without composition concerns.

R134a has historically been used in centrifugal and screw compressor applications rather than the reciprocating and scroll compressors typical of room-based CRAC units. In the data centre context, you are most likely to encounter it in water-cooled chiller plant feeding CRAH units rather than in standalone precision air conditioners.

Its GWP of 1430 still places it firmly within the high-GWP category targeted by the phase-down. It consumes roughly twice the import quota of R513A per kilogram. The trajectory for R134a pricing mirrors R410A, though the timeline for impact in large chiller applications may differ slightly from small-charge CRAC systems.

R1234ze and R1234yf are the low-GWP alternatives being adopted in new centrifugal chiller designs, but that is a separate consideration from the direct-expansion CRAC equipment this post focuses on.

R513A: The Drop-In Transition Refrigerant

R513A is a blend of R1234yf (56%) and R134a (44%). GWP is 631, roughly 30% of R410A. It was developed specifically as a lower-GWP alternative to R134a in medium-temperature applications.

For precision cooling, R513A has gained traction as a retrofit option for systems originally designed for R134a, and as the factory fill in some newer equipment lines. Vertiv has introduced R513A variants in certain Liebert product configurations. The refrigerant operates at similar pressures and temperatures to R134a, which simplifies the transition for compatible equipment.

Efficiency in R513A systems is broadly comparable to R134a. Published coefficient of performance (COP) figures show R513A within 1 to 3% of R134a in most operating conditions, which is within the margin of real-world variation. The lower GWP does not come at a meaningful efficiency penalty.

Safety classification under AS/NZS 1677 and the ASHRAE 34 standard is A1 (non-flammable, low toxicity), the same as R134a and R410A. That matters for data centre applications where flammable refrigerants introduce additional compliance obligations under AS 1668 and require modified equipment room ventilation assessments.

The main limitation of R513A is that it is not a universal drop-in for R410A systems. Equipment designed for R410A operates at significantly different pressures and uses different compressor oil. A transition from R410A to R513A is not a simple recharge; it requires equipment designed or validated for R513A.

R32: Higher Efficiency, Flammability Classification Requires Attention

R32 is a single-component refrigerant with a GWP of 675. It is the refrigerant of choice in the current generation of variable refrigerant flow (VRF) systems and is increasingly appearing in precision cooling equipment, particularly in smaller in-row and close-coupled units.

The efficiency case for R32 is genuine. Its thermodynamic properties allow higher COP at typical data centre operating conditions compared to R410A. Independent testing by manufacturers and third parties consistently shows R32 systems delivering 5 to 10% better energy efficiency than equivalent R410A equipment in cooling-dominated applications. For a data centre running precision cooling continuously, that difference compounds meaningfully over a 10-year period.

The complication is flammability. R32 carries an A2L safety classification under ASHRAE 34: low toxicity, mildly flammable. It has a lower flammability limit than A1 refrigerants and requires an ignition source to combust, but the classification still triggers additional requirements.

In Australian data centre applications, the use of A2L refrigerants must be assessed against AS 1668.2 (mechanical ventilation) and the relevant sections of the National Construction Code. Equipment rooms housing A2L systems may require enhanced ventilation, refrigerant leak detection with automatic shutdown, and specific installation clearances. The IEC 60335-2-40 standard, which governs air conditioning equipment, sets charge limits for A2L refrigerants based on room volume and ventilation rates.

For large CRAC units with substantial refrigerant charges, the charge limits for A2L refrigerants in occupied or partially enclosed spaces can constrain system design. Manufacturers have responded by engineering systems that keep charge quantities within the permissible limits, but this is a factor that must be verified at the design stage, not assumed.

Stulz has introduced R32 variants in its MiniSpace and CyberAir ranges. Schneider Electric Uniflair units are available in R32 configurations in certain markets. The equipment is available; the compliance pathway needs to be confirmed for each installation.

Side-by-Side Comparison

| Refrigerant | GWP | Safety Class | Phase-Down Pressure | Efficiency vs R410A | Drop-In for R410A |

|---|---|---|---|---|---|

| R410A | 2088 | A1 | High | Baseline | N/A |

| R134a | 1430 | A1 | High | Similar | No |

| R513A | 631 | A1 | Moderate | Similar to R134a | No |

| R32 | 675 | A2L | Moderate | +5 to 10% | No |

Neither R513A nor R32 is a drop-in replacement for R410A. Any transition between refrigerant types requires equipment validated for the new refrigerant, correct compressor oil, and a full system assessment.

What This Means for Equipment Decisions

For data centre managers reviewing existing plant, the immediate priority is understanding the refrigerant type in each CRAC unit and its remaining service life. Units running R410A with five or more years of service life remaining will face increasing refrigerant costs. Budgeting for that reality is more useful than assuming prices will stabilise.

For mechanical contractors specifying new equipment, R410A should not be the default choice for any installation with a planned life extending past 2030. R513A and R32 are both available in precision cooling configurations from the major manufacturers. The selection between them depends on efficiency targets, room configuration, charge limits, and whether the installation can accommodate A2L compliance requirements.

For sustainability officers working toward Scope 1 emissions reduction, refrigerant leakage is a direct source of greenhouse gas emissions. A 10 kg charge of R410A released to atmosphere represents 20.88 tonnes of CO2-equivalent. The same charge of R32 represents 6.75 tonnes CO2-equivalent. Transitioning to lower-GWP refrigerants reduces both regulatory exposure and reported emissions.

The Kigali phase-down schedule does not require existing equipment to be retrofitted. It restricts the import of bulk refrigerant, which affects serviceability and cost. Planning equipment replacement cycles around that constraint is the practical response.

Getting Refrigerant Transition Planning Right

Refrigerant selection intersects with equipment compatibility, installation compliance, and long-term operating cost in ways that are not always obvious at the point of specification. The charge limits for A2L refrigerants, the oil compatibility requirements for different refrigerant types, and the equipment availability from specific manufacturers all need to be confirmed for each project.

CRAC Services Australia works with data centre operators across Brisbane, Sydney, and Melbourne on refrigerant management, including leak detection, recharging, and transition planning as the phase-down progresses. For guidance on how the phase-down affects your installed equipment or upcoming projects, visit [https://crac.services](https://crac.services).