Standards we follow
We follow public drafts and published specifications for liquid cooling and the standards for metering boundaries, so that the acceptance criteria we use stay aligned with industry standards.
What we follow
The documents below are the ones we have read and use. Where no stable public link exists we say so rather than link to a copy. Edition numbers for ISO and CENELEC standards should be checked against the publisher's catalogue before they are cited in a contract.
| Document | Number / version | Status | Original | What we look at in it |
|---|---|---|---|---|
| Modular Technology Cooling System for Cloud Scale Open Compute Project | Rev 1, August 2025 | Published specification | Publisher's page | Technology-cooling-loop boundaries between rack, CDU and facility; coolant quality; commissioning evidence |
| Open Rack V3 Blind Mate Manifold Specification Open Compute Project | Rev 1.0 (document dated April 2024) | Specification; the file is labelled a review version | Publisher's page | Rack manifold and blind-mate interface; connection testing |
| Thermal Boundaries in AI Infrastructure Open Compute Project | v0.98, 2026 | Public-review draft | No stable public link | Definitions of the thermal boundaries and who owns each |
| Project Deschutes CDU specification Google, contributed to OCP | v1.0, February 2026 | Released; presented at OCP APAC Summit 2026 | No stable public link | CDU approach at rated load (3 K at 2,000 kW, 500 gpm both loops); side-stream filtration |
| ISO/IEC 30134-6, Key performance indicators: Energy Reuse Factor (ERF) ISO/IEC | Current edition per the ISO catalogue | Published international standard | Publisher's page | How reused energy is counted and where it is measured |
| EN 50600-4-6, Energy Reuse Factor CENELEC | Current edition per the CENELEC catalogue | Published European standard | No stable public link | ERF definition, as used in EU reporting |
| Energy Reuse Effectiveness (ERE) The Green Grid | As published by The Green Grid | Published metric (white paper) | Publisher's page | Companion metric to PUE that credits reused energy |
| Commission Delegated Regulation (EU) 2024/1364 European Commission | 2024 | In force (EU) | Publisher's page | Reporting and metering boundary for EU data centres of 500 kW IT and above, including reused heat |
Last reviewed 2 October 2026.
What we have not found
The interfaces are being specified: in 2026 Google contributed its Project Deschutes CDU specification to OCP, and quick-disconnect suppliers have asked for the 2019 cold-plate requirements to be updated. Within the documents and versions listed on this page, as reviewed on 2 October 2026, we have not found a complete requirement for what a turnover package must contain; that is the gap our turnover package addresses. This is a statement about the listed documents, not about every standard in the field.
Energy-reuse metrics. The metrics that make heat reuse auditable already exist: ERF, ERE and the EU metering-boundary requirement listed above. We use them in our own reporting, and we recommend them wherever PUE is still the only number on the slide.
Public writing. The three-clock model, the ten leak points and the metering-boundary argument were all published first as open articles and posts, and revised in public with input from operators, water-chemistry specialists and insurers. The versions on this site are current and are revised as the industry discussion moves.
What we look for in a specification
- Every performance requirement names the load level, temperature and boundary it applies at.
- Every pressure boundary has a test, an acceptance criterion and a record owner.
- Cleanliness and passivation are treated as separate requirements with separate evidence.
- Heat reuse is measured at the hand-off boundary, not estimated from the IT load.
Questions this page answers
Which standards apply to liquid-cooling heat reuse and metering?
The Energy Reuse Factor (ERF) in ISO/IEC 30134-6 and EN 50600-4-6, the Energy Reuse Effectiveness (ERE) from The Green Grid, and the metering-boundary requirement in Commission Delegated Regulation (EU) 2024/1364 for EU data centres with at least 500 kW installed IT demand. For the thermal environment itself, ASHRAE's W-classes give the facility-water temperature envelopes. Return-water grade →
Is there an open specification for liquid-cooling commissioning evidence?
Not in the public documents we have read. The Open Compute Project's Cooling Environments workstream publishes drafts on rack, CDU and facility interfaces and white papers on liquid-cooling integration, and has received Google's Project Deschutes CDU specification (v1.0 released February 2026), but none of the public documents we have read fully specifies what a turnover package must contain. The record structure this site uses, three questions for each of ten leak points, supplements them; applicable standards, OEM documents and the project's acceptance criteria govern. The turnover package →