AI racks pulling 100 kW+ have pushed data centers from air to liquid cooling, and that shift turns every white space into a fluid handling facility — with coolant distribution units (CDUs), secondary loops, manifolds, and thousands of connections that all have to stay dry. The hardware doing that work is industrial fluid hardware, selected for one unusual constraint: a single drip lands on live electronics.

The Two Loops

The facility water system (FWS) moves building chilled water to CDUs — conventional HVAC-style piping, valves, and gaskets. The technology cooling system (TCS) is the sensitive side: a treated coolant, typically 25% propylene glycol (PG25) with corrosion inhibitors, circulating from CDU to rack manifolds to cold plates. Material discipline on the TCS loop is strict because inhibitor chemistry and wetted-material compatibility drive both corrosion and biological growth.

Material Selection for PG25 Coolant

EPDM is the elastomer of choice for glycol service — hose tubes, O-rings, and gaskets — because glycols attack nitrile and swell many other compounds. Wetted metals stay in the stainless/copper-alloy family per coolant spec; avoid mixed-metal galvanic pairs. Hose for rack and manifold connections should be low-permeation, plasticizer-free EPDM or specialty constructions — ordinary shop hose leaches compounds that foul cold plate microchannels.

Dripless Quick Disconnects

Rack service depends on double-shutoff, dripless (flat-face) quick disconnect couplings: both halves valve closed on disconnect with essentially zero spillage and minimal air inclusion. Spec them by flow (Cv), pressure, EPDM seals for glycol, and blind-mate or hand-connect style per the rack design. Ordinary industrial QDs that weep a drop per cycle don't belong above servers.

Sealing the Loop

Flanged connections at CDUs and manifolds take EPDM or aramid-fiber gaskets rated for glycol at modest temperatures; tri-clamp hardware appears increasingly in manifold skids for cleanability. Threaded joints get anaerobic sealant or PTFE per coolant vendor guidance — some inhibitor packages are sensitive to sealant chemistry.

Practical Notes From Industrial Service

Pressure-test with the coolant, not city water, to avoid introducing untreated water; label and segregate FWS vs TCS hardware in storage; and keep certified spares (hoses, QDs, gaskets) on site — cooling loop downtime is measured in dollars per minute.

Coolant Loop Hardware, Quoted Fast

We supply EPDM hose assemblies, stainless fittings, quick disconnects, and custom gaskets for data center cooling projects — tested, tagged, and documented. Put sizes, coolant type, and quantities in the quote form at the top of this page, or call (979) 233-6223 — pricing back in 1–2 business hours.