PFAS regulation and heat transfer fluids: what to confirm before you specify

Why a chemistry question became a specification question

Fluid selection for a data centre or an industrial process cooling loop has traditionally been argued on temperature range, viscosity, heat capacity and material compatibility. Since 2023 a fourth criterion has moved onto the shortlist: the regulatory position of the fluid's chemistry.

It matters most in electronics cooling, where fluorinated fluids have long been chosen for electrical insulation and non-flammability, and where the European Union's proposed restriction of per- and polyfluoroalkyl substances (PFAS) is now advanced enough to change procurement conversations. Buyers who signed five-year maintenance agreements on the assumption that a fluid's chemistry was a settled question are now being asked to justify it in an audit.

What follows summarises public documents on where the process stands and what they say specifically about heat transfer fluids. It is a reading of published sources, not legal advice, and not a determination of the regulatory status of any particular Glacier product.

Where heat transfer fluids appear in the restriction

The PFAS restriction proposal was submitted under REACH by the competent authorities of five EU member states in January 2023. It takes a grouping approach rather than listing substances individually, and by the updated dossier published in October 2025 the assessment had been extended to 23 sectors.

Heat transfer fluids are addressed as named uses rather than as one generic category. The updated dossier places "heat transfer fluids (immersion cooling, cold plate cooling), including battery cooling" within the scope of the electronics and semiconductors sector, and carries two specific provisions:

Two qualifications belong directly beneath that table. These are proposed derogations — time-limited permission to continue a use — and not agreed exemptions; the committees' opinions have already recommended narrowing the derogations in the original proposal. And both rows describe specific process uses. A single-phase water-glycol cold-plate loop is a different question, and its position should be read from the current legal text rather than inferred from two rows of a sector table.

The timeline, and what it does and does not decide

The procedural path matters more than any single date, because each stage can still change the outcome.

The practical reading: nothing is restricted today, the Commission is unlikely to adopt a restriction before the third quarter of 2027, and restrictions would not start applying before 2029. That is a long runway — but it is also shorter than the service life of a cooling loop specified this year.

The committee positions are the part worth watching. The Risk Assessment Committee's opinion supported the universal ban and supported only one of the proposal's derogations, for personal protective equipment, recommending that any others carry added risk-management measures. The Socio-Economic Analysis Committee's draft opinion was more open to time-limited derogations but still took a restrictive approach across sectors. A proposed 13.5-year transition is therefore a negotiating position, not a settled entitlement.

Two chemistry routes already sit side by side

Glacier's catalogue describes fluid families with materially different starting chemistries, and that is the useful fact for a buyer building a substitution plan.

The LM-14 series is described in the catalogue as modified perfluorinated compounds, offered for electrical insulation, chemical inertness and precision temperature control. The LM-17 series is described as modified hydrocarbons, developed for server immersion cooling with electrical insulation, thermal and oxidative stability and yellowing resistance. The LM-4 series is described as modified diols and is water-dilutable, and includes models the catalogue labels for data-centre use.

Read that paragraph for what it is: catalogue formulation descriptions. A description of a starting chemistry is not a regulatory classification, and it is not a statement that a product is inside or outside any restriction. The composition of a finished product, any threshold that applies, and the specific use all have to be assessed together against the legal text.

What the catalogue does support is a planning conversation. Where a project has both a fluorinated and a non-fluorinated route available, the substitution question becomes a documented comparison of thermal performance, material compatibility and electrical requirements rather than a scramble once a deadline is announced.

What to confirm before you specify

For a new project, or a renewal on an installed system, ask for the following in writing:

• The exact product designation and its current regulatory position, not the family's. A family can span several formulations.
• The use and the process, described as the restriction describes it — two-phase immersion, single-phase immersion, cold-plate circulation and vapour phase soldering are separate entries.
• The concentration and dilution in the installed system. Thresholds and compatibility apply to what is actually circulating.
• A documented substitution path, with the thermal and material checks that a change would require.
• The current technical data sheet and safety data sheet, plus any composition statement your compliance team needs.

What this article cannot tell you

It cannot tell you whether a specific product is in or out of scope, and it should not be read as legal advice. The restriction has not been adopted, the derogation list is still in play, and the definition of PFAS is broad enough that classification questions need the composition in front of you.

It also cannot tell you that a non-fluorinated fluid is automatically the safer commercial choice, or that a fluorinated one is finished. Thermal performance, electrical requirements, fire behaviour and equipment approval decide whether an alternative works in your system; the regulatory timetable only decides when you need to have the answer. If your project depends on this decision, confirm both the current legal text and the exact product status with your supplier and your compliance advisers — and get the answer in writing.

Related reading: indirect liquid cooling versus immersion covers how architecture decides which fluid questions apply, and the electronics cooling solution sets out how the fluid families map onto those architectures.