Refrigerant Transition in Data Centers: Kigali Amendment & Low-GWP Cooling

Why Refrigerant Choice Is Now a Compliance Question

Refrigerant selection in a data center's cooling plant used to be a purely mechanical decision: whichever gas suited the chiller or CRAC or CRAH unit design, delivered the required capacity, and served the facility reliably. That is no longer the whole picture. The Montreal Protocol's Kigali Amendment, adopted by the international community to address hydrofluorocarbons (HFCs), introduces a phased reduction in HFC production and consumption that is reshaping refrigerant supply, pricing, and equipment specifications across the HVAC and refrigeration industry, data centers included.

Unlike the earlier phase-out of ozone-depleting CFCs and HCFCs under the original Montreal Protocol, the Kigali Amendment targets HFCs specifically because of their high global warming potential (GWP), not their effect on the ozone layer. HFCs became the standard replacement refrigerant after the earlier phase-out, and many of the refrigerants widely used in commercial chillers and precision cooling units today, including common HFC blends, fall within scope.

How the Phase-Down Actually Works

The Kigali Amendment does not ban HFC refrigerants outright or set a single global cutoff date. It establishes a schedule of stepped reductions in the total volume of HFCs a country may produce or import, measured in CO2-equivalent terms, with separate timelines for developed and developing economies. Countries that ratify the amendment commit to specific milestones along that schedule, and the practical effect on any given facility depends on which schedule its country follows and how its national regulator chooses to implement the reduction.

For a data center operator, the mechanism that matters is supply, not a legal prohibition on using existing equipment. As the allowed production volume for high-GWP HFCs shrinks over successive steps, the available supply of virgin refrigerant tightens and its price tends to rise, while reclaimed and recycled refrigerant becomes a larger share of what remains available for servicing older systems. New equipment manufacturers respond ahead of the regulatory deadlines by designing for lower-GWP alternatives, because selling into a shrinking-supply refrigerant category is a weak long-term position for an equipment line with a 15 to 20 year service life.

What Counts as Low-GWP

Global warming potential measures a refrigerant's climate impact per unit of mass released, relative to carbon dioxide, over a defined time horizon. Conventional HFC blends commonly used in commercial chillers and CRAC units carry GWP values in the thousands. The alternatives gaining ground fall into a few categories:

• Hydrofluoroolefins (HFOs) and HFO/HFC blends: engineered refrigerants with substantially lower GWP than the HFCs they are designed to replace, increasingly specified as drop-in or near-drop-in options for new chiller and CRAC equipment.
• Mildly flammable refrigerants (A2L classification): some low-GWP refrigerants carry a mild flammability rating under ASHRAE's safety classification system. This does not make them unsafe for data center use, but it does change equipment design requirements around charge limits, leak detection, and ventilation compared to the non-flammable (A1) refrigerants data centers have historically used.
• Natural refrigerants: carbon dioxide (R-744), ammonia, and propane-based refrigerants have very low or negligible GWP and see use in some large-scale and industrial refrigeration applications, though they carry their own handling, pressure, or toxicity and flammability considerations that affect where they make sense in a data center mechanical room.

None of these categories is a universal replacement. The right choice depends on the specific chiller or CRAC platform, the facility's climate conditions, and the safety design the mechanical room can accommodate, which is why this is a conversation with the mechanical contractor and equipment manufacturer rather than a specification an operator sets unilaterally.

What This Means for New Builds

For a new data center or a major chiller plant design, the refrigerant decision is now a first-order design input rather than an afterthought. Equipment manufacturers increasingly offer their chiller and CRAC lines in both legacy-HFC and lower-GWP configurations, and the lower-GWP option is often the one with a longer runway before it faces its own future phase-down pressure. Specifying refrigerant alongside capacity, efficiency, and redundancy early in the design process avoids a scenario where a facility commissions equipment on a refrigerant that is already on a shrinking-supply trajectory by the time the facility reaches mid-life servicing.

Where the chosen refrigerant carries an A2L mild-flammability classification, the mechanical room design needs to account for it: charge size limits per space, refrigerant leak detection tied to ventilation controls, and clearances that may differ from a legacy A1 refrigerant installation. These are standard, well-understood HVAC engineering practices, but they need to be built into the mechanical room layout rather than retrofitted after equipment selection.

What This Means for Existing Facilities

Operators running chillers and CRAC units on conventional HFC refrigerant are not required to swap refrigerant in working equipment ahead of its natural replacement cycle. The more immediate planning items are on the servicing side:

• Leak management discipline. As refrigerant supply tightens, the cost of topping off a leaking system rises, and regulatory leak-reporting thresholds in some jurisdictions apply regardless of the phase-down. Proactive leak detection and repair protects both uptime and the refrigerant budget.
• Reclaim and recovery practices. Reclaimed refrigerant, recovered from decommissioned equipment and reprocessed to meet purity standards, becomes a larger share of the available supply for servicing legacy systems as new production is constrained. Operators should confirm their maintenance contractor follows proper recovery procedures rather than venting refrigerant during service work, both as good practice and increasingly as a compliance requirement.
• Retrofit versus replace timing. When a chiller or CRAC unit reaches the point of a major overhaul, that is the natural decision point to evaluate whether a lower-GWP refrigerant retrofit or a full unit replacement makes more sense than restoring it to its original refrigerant configuration, factoring in the unit's remaining useful life against the facility's broader maintenance and service contract planning.

The UAE and Gulf Regulatory Picture

The UAE is a party to the Montreal Protocol and its Kigali Amendment, administering compliance through its national ozone-related regulatory functions, consistent with its broader participation in international environmental agreements. As with other Gulf states, the Kigali Amendment's developing-country schedule applies, which follows a different pace and set of milestones than the schedule developed economies follow. The practical implication for an operator building or servicing a facility in the region is to confirm current refrigerant availability and compliance requirements directly with mechanical contractors and refrigerant suppliers rather than assume the same timeline that applies in markets following the developed-economy schedule.

The Gulf's high ambient temperatures add a separate, climate-driven consideration on top of the regulatory one. Refrigerant and system performance in high-heat-rejection conditions, already a factor covered in our guides to absorption chilling and hot-climate cooling design, interacts with refrigerant choice: a lower-GWP refrigerant's thermodynamic properties and performance envelope need to hold up under Gulf summer conditions, not just meet a lab-rated efficiency figure.

Procurement and Planning Implications

For an operator planning capacity additions or equipment refresh cycles, the refrigerant transition adds a few practical questions to the procurement process: confirming which refrigerant a proposed chiller or CRAC line uses, understanding the manufacturer's roadmap for that refrigerant category, and factoring any A2L-related mechanical room design changes into the project timeline and budget alongside the equipment lead times already tracked for major mechanical and electrical gear. None of this changes the fundamentals of chiller plant design or PUE optimization; it adds one more variable to specify correctly at the start of a project rather than discover during commissioning.

Frequently Asked Questions

Does the Kigali Amendment ban HFC refrigerants outright?

No. The Kigali Amendment to the Montreal Protocol sets a schedule of phased reductions in HFC production and consumption rather than an immediate ban, with different starting points and reduction paces for developed and developing economies. Existing equipment charged with HFC refrigerant can generally keep operating; the phase-down mainly affects the future supply and cost of virgin refrigerant and pushes new equipment toward lower-GWP alternatives over time.

What does low-GWP mean for a data center chiller or CRAC unit?

GWP, or global warming potential, measures how much a refrigerant contributes to warming relative to carbon dioxide over a fixed time horizon. A low-GWP refrigerant, such as an HFO blend or a natural refrigerant, has a much smaller climate impact per unit of leaked gas than a conventional HFC. Some low-GWP options carry an A2L mild-flammability classification, which affects equipment design, charge limits, and ventilation requirements rather than performance.

Do existing data centers need to retrofit their cooling plant immediately?

Not immediately in most cases. Operators typically plan the transition around natural equipment replacement cycles, major retrofits, or new builds rather than swapping refrigerant in working chillers and CRAC units ahead of schedule. The more immediate planning items are servicing and leak-management practices for existing HFC equipment, since reclaimed and recycled refrigerant becomes a larger share of the supply as production is phased down.

Is the UAE subject to the Kigali Amendment phase-down schedule?

The UAE is a party to the Montreal Protocol and its Kigali Amendment, and administers compliance through its national ozone-related regulatory functions. As with other Gulf states, the applicable phase-down schedule and milestones follow the developing-country track under the amendment, which differs from the schedule developed economies follow. Operators should confirm current requirements with their mechanical contractor and refrigerant supplier rather than assume a single global timeline.