Data Center Knowledge ran a sponsored piece from Tate this week laying out the materials argument for liquid cooling loops. The piece quotes Dell'Oro's Alex Cordovil saying liquid cooling has consolidated its position as the dominant architecture for AI clusters and frames the market at roughly $3 billion in 2024 growing to about $7 billion by 2029. The interesting part is the specifications.
Building cooling loops historically run between 41 and 59 degrees Fahrenheit, roughly 5 to 15 degrees Celsius. Hyperscale data center loops now run at 122 to 140 degrees Fahrenheit, 50 to 60 Celsius, with some testing as high as 194 degrees Fahrenheit, 90 Celsius. That is a different temperature regime from anything the comfort cooling industry was built to handle.
Polypropylene piping is cheap, light, and easy to install. It is also rated for service temperatures that work for room-air HVAC and exhaust the bottom of their spec at the top of the direct-to-chip range. Long-term creep, oxidation, and joint integrity all degrade as the loop runs hot, and the deeper problem is that hyperscale facilities run at those temperatures every hour of every year. ASHRAE's Liquid Cooling Guidelines for Datacom Equipment Centers already excludes polypropylene from TCS loop piping for exactly this reason.
Stainless steel costs more up front and recovers the difference in operating life. The autopassivating chromium oxide layer resists corrosion across the chemistries used in modern coolants. The interior finish does not give microorganisms a foothold the way roughened plastic does, which matters when you are running glycol and biocides through the same loop for ten years. Thermal expansion stays predictable. That is the argument behind the supply chain race converging on metal infrastructure for the loops that actually matter.
The practical implication for operators is that the materials choice has to be specified at the procurement contract level, not left to the EPC's preferred fitter. A vendor quoting on a tight budget will reach for polypropylene if the spec sheet does not forbid it. Five years later the loop is the failure surface, and the operator is the one explaining a leak during an AI training run.
For cooling vendors, the takeaway is that material certifications are now a sales asset. Documented compliance with the ASHRAE TCS guidance, traceable mill certificates on stainless components, and chemistry data sheets for elastomers all reduce the operator's audit burden and shorten the procurement cycle. The mechanics of direct-to-chip cooling do not care about price points. They care about what survives at 60 Celsius for a decade.