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Climate Data Licence Clearance — Investigation Report

Sub-chat deliverable — Session 17 prerequisite Scope: Licence clearance for every candidate climate / cooling-load data source the energy and lca.b6 modules could draw on, for the specific use case of committing values as static data in an AGPL-3.0-or-later open-source repository, distributed publicly via GitHub and served at runtime. Companion to EPD source licence clearance, which covers the same question for EPD programme operators. Date: 2026-08-29 Not legal advice. This is a technical and licensing assessment prepared for a decision session. The items in §5 need a qualified lawyer.

TL;DR

  • ASHRAE CLTD/CLF/SCL table values cannot go into the public AGPL repository. ASHRAE asserts full copyright over the Handbook and grants only non-transferable permissions. Even its paid Climatic Design Data License for Software Developers ($2 000 one-time) grants "the purchaser a non-exclusive license" — a grant that stops at the purchaser and cannot carry AGPL's requirement that every downstream recipient receive the same rights to redistribute and modify. No ASHRAE grant that clears that bar is on offer.
  • Change the method, not the licence. ASHRAE itself deprecated CLTD/CLF/SCL in favour of the Radiant Time Series (RTS) and Heat Balance methods, whose coefficients — conduction transfer functions, radiant time factors — are computable from first principles. Physics is not a copyrightable table. The licensing question disappears and the accuracy improves.
  • NASA POWER is the vendorable climate source; ERA5/Copernicus and PVGIS are the attribution- bearing alternatives. All three are continuous global gridded datasets, which dissolves the latitude-band interpolation problem rather than licensing it. Do not vendor climate.onebuilding.org ("All Rights Reserved") or Meteonorm (redistribution contractually prohibited, CHF 3 000-per-instance penalty clause).

§1 Question under investigation

Can values derived from ASHRAE Handbook CLTD/CLF/SCL cooling-load tables (indexed by latitude band) be committed as source-controlled data files in this repository (AGPL-3.0-or-later), distributed publicly via GitHub, and served at runtime to drive the energy module? For each candidate source, what is the operative licence, what does it permit, what does it prohibit?

The operative distinction is the same one the EPD clearance draws:

  • Vendoring — committing the values as static data in the repository, redistributable to anyone who clones it.
  • Runtime / cited-only — loading values at runtime from a licensed local copy or the source's own service, with a citation but no static copy committed.

AGPL adds a third and decisive test the EPD clearance did not have to apply, because ÖKOBAUDAT's DL-DE-BY-2.0 passes it trivially:

  • Downstream parity — every recipient of the conveyed program must receive the same freedom to run, study, redistribute, and modify. A licence that grants rights to this project only fails, however generous those rights are to this project.

§2 Scope and method

Each source's terms of use, data licence, and/or software-developer licence were reviewed as published at the time of this investigation (2026-08-29). Where terms were absent or ambiguous, the conservative interpretation (not cleared) is applied — the same rule the EPD clearance uses.

Copyright doctrine was reviewed to assess residual risk in reproducing table values versus re-expressing them algorithmically: US law via Feist; EU law via Directive 96/9/EC and the BHB / Football Dataco line; and the ASTM v. Public.Resource.Org precedent, in which ASHRAE was itself a plaintiff.

§3 Key findings

  1. ASHRAE's copyright assertion is explicit and broad. The Handbook–Fundamentals states that "no part of this book may be reproduced without permission in writing from ASHRAE… nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any form or by any means… without permission in writing from ASHRAE." Reuse runs through permissions@ashrae.org, which issues per-request reprint permissions and assumes the requester already owns the publication. A February 2025 AI policy additionally prohibits creating derivative works of ASHRAE IP using AI tools without express written permission.

  2. The relevant paid product exists but does not solve the AGPL problem. The ASHRAE Climatic Design Data License for Software Developers ($2 000 one-time) grants, at §1.1, "the purchaser a non-exclusive license to use the text, tables and data from ASHRAE Research Project RP-1923… in derivative software, with no end date for the use of this information", with attribution "Climatic Design Data © 2025 ASHRAE, www.ashrae.org. Used with permission." Two things defeat it here: (a) it covers Chapter 14 climatic design conditions — dry-bulb, dew-point, wet-bulb, wind — not the CLTD/CLF/SCL cooling-load tables; and (b) it is non-exclusive to the purchaser, so downstream users who clone an AGPL repo receive nothing.

  3. The legal background helps in the US and is uncertain in the EU. Under Feist Publications, Inc. v. Rural Telephone Service Co., 499 U.S. 340 (1991), facts are not copyrightable — "originality, not 'sweat of the brow,' is the touchstone of copyright protection" — and only original selection and arrangement of a compilation attracts thin copyright. Extracted numeric values re-expressed as regression or interpolation coefficients are therefore materially safer than reproducing literal tables. But the project's EU footprint brings the sui generis database right (Directive 96/9/EC) into play. British Horseracing Board v William Hill and Football Dataco limit that right to investment in obtaining or verifying data, not creating it — which helps, because CLTD/CLF/SCL values are computed outputs of ASHRAE's RP-472 methodology, whereas Chapter 14 design conditions are obtained and verified from weather-station records and are the stronger candidate for protection. Favourable, not free of doubt. Note too that contract can bind where copyright does not: ProCD, Inc. v. Zeidenberg, 86 F.3d 1447 (7th Cir. 1996).

  4. The ASTM v. Public.Resource.Org line does not help. In 82 F.4th 1262 (D.C. Cir. 2023) the court held that "the non-commercial dissemination of such standards, as incorporated by reference into law, constitutes fair use", finding the use transformative — providing "the public with a free and comprehensive repository of the law". The Handbook is not a standard incorporated into law, and AGPL distribution inside a tool is neither non-commercial nor a repository-of-the-law use. Do not rely on it.

  5. CLTD/CLF/SCL is a superseded method, so migrating is the strategic answer, not a workaround. Per Spitler, Fisher & Pedersen, "The Radiant Time Series Cooling Load Calculation Procedure" (ASHRAE Transactions): the RTS method "effectively replaces all other simplified (non-heat-balance) methods such as the cooling load temperature difference/solar cooling load/cooling load factor method (CLTD/SCL/CLF)". RTS and its underlying conduction-transfer- function and response-factor coefficients are derivable from first principles by state-space and Laplace-transform methods, documented in open solvers such as FastCTF and the EnergyPlus Engineering Reference. Nothing in that chain requires an ASHRAE table.

  6. Genuinely open replacement data exists, and it fits Sub-Saharan Africa better. NASA POWER is free, global, continuous, and carries no copyright restriction under NASA's open-data policy. ERA5 via the Copernicus Climate Data Store permits redistribution and commercial use with attribution to C3S/ECMWF. Both are meteorological and solar datasets rather than pre-computed cooling loads, so they entail the methodology change of Finding 5 — and both cover African locations where ASHRAE station density is thin.

§4 Verdict table

Statuses follow the EPD clearance convention: CLEARED — values may be committed to the public repository; RESTRICTED — usable at runtime with citation but not committed; BLOCKED — do not vendor, clearance not obtainable or not obtained.

Source Status for AGPL vendoring Operative licence Cost Drop-in vs methodology change AGPL downstream parity? Notes
ASHRAE CLTD/CLF/SCL tables (Handbook–Fundamentals) BLOCKED All-rights-reserved; per-request written permission only Permission fee varies; requires owning the publication Drop-in against the current data model No — permission is non-transferable Superseded method (Finding 5). Reproducing literal tables also risks US compilation copyright; re-expressed coefficients are safer, but the licence and contract barrier stands regardless.
ASHRAE Climatic Design Data License for Software Developers (RP-1923, 2025) RESTRICTED Non-exclusive perpetual embed licence; attribution "Climatic Design Data © 2025 ASHRAE… Used with permission." $2 000 one-time Not the cooling-load tables — Chapter 14 design conditions; methodology change still required No — non-exclusive to the purchaser Lets this project embed the data in its software; cannot license it onward under AGPL. Viable only as a closed optional component or a runtime layer the end user provisions. Covers 12 424 stations.
ASHRAE Weather Data Viewer 2025 BLOCKED Annual single-user subscription, terms-of-use gated Annual per-seat subscription Design conditions only No Subscription access, not a redistribution licence.
NASA POWER CLEARED US Government open-data policy — no copyright; commercial use and redistribution permitted; attribution requested as a courtesy Free Methodology change — raw meteorological and solar data, not cooling-load values Yes Solar irradiance components, dry-bulb, dew point, humidity, wind. ½° lat × ⅝° lon (MERRA-2) for meteorology, 1° × 1° (CERES) for solar. The best vendorable seed, and the recommended primary source. Continuous grid removes the latitude-band problem entirely.
ERA5 via Copernicus CDS CLEARED (attribution) Copernicus licence — reuse, redistribution and commercial use permitted with attribution to C3S/ECMWF Free Methodology change — reanalysis climate data Yes, with attribution retained Higher-resolution alternative or complement to POWER; larger data-handling burden (CDS queueing).
PVGIS (JRC, European Commission) CLEARED (attribution), verify EC reuse policy; built on SARAH / ERA5 (ERA5 = attribution) Free Methodology change — solar irradiance and climate Yes, with attribution Confirm the exact JRC reuse notice for the specific product used before relying on it.
climate.onebuilding.org (TMYx / EPW / DDY) BLOCKED (as-is) "Copyright © 2014-2026 Climate.OneBuilding. All Rights Reserved." — no redistribution grant Free download Would be near drop-in for design conditions (DDY) No — no licence granted Free to download is not licensed to redistribute; only a disclaimer and a citation request are published. The underlying NOAA ISD (US public domain) and ERA5 are redistributable at source — go to the primaries instead. Non-TMYx files carry separate national-service terms.
EnergyPlus EPW weather files (DOE / NREL) MIXED EnergyPlus Open Source License v1.0 covers software and docs; each weather file carries its own source terms Free Design conditions / hourly Per-file Many files are redistributable (US public-domain sources); others (e.g. ISHRAE © 2005, national met services) are "for use at no cost" only. Must be cleared file by file.
Meteonorm BLOCKED Proprietary EULA; redistribution of generated data to third parties, including via software or web apps, prohibited without a separate written agreement ~CHF 675 first licence (excl. VAT); ~CHF 350 each additional Design conditions / hourly No — explicitly forbidden EULA §II.c.8.2 bars "indirect provision of access… by making available to third parties results based on the data (e.g. through web applications, simulation software)", with a CHF 3 000-per-instance penalty at §VI. Only single-project client documentation is permitted (§II.c.8.3). Fundamentally incompatible with a public repository.
ISO 15927 (parts) / EN ISO 52016-1 (method) METHOD USABLE; text BLOCKED ISO standards are copyrighted and sold as DRM PDFs Standard purchase, per document EN ISO 52016-1 is a calculation method that replaces CLTD/CLF/SCL tables outright Yes for an independently implemented method; No for the standard's text and tables Methods are not copyrightable: the algorithm may be implemented, the text and tables may not be redistributed. Needs open weather data as input either way. ISO 15927-4 defines the TRY construction method used by TMYx.
RTS / CTF coefficients computed from first principles CLEARED No third-party licence — physics plus this project's own AGPL code Free (development effort) Methodology change to RTS / Heat Balance Yes Removes the table-licensing question entirely, and is the accuracy-superior path ASHRAE itself recommends. This is the recommended calculation method.

These gate Phase 3 (repository public, docs site published), not Phase 1 calculation. Tracked as AR-61 on the Action register.

  1. EU database-right determination on any ASHRAE-derived values. Confirm with EU IP counsel that re-expressed CLTD/CLF/SCL coefficients — created outputs — fall outside Directive 96/9/EC per BHB / Football Dataco, and that Chapter 14 design conditions (obtained and verified data) are treated separately. This only becomes live if the project ever revisits the ASHRAE path; until confirmed, treat all ASHRAE-derived values as not cleared for vendoring.

  2. Contract versus copyright. Even where Feist denies copyright in the numbers, the terms accepted when obtaining ASHRAE data may bind by contract (ProCD v. Zeidenberg). Counsel should confirm that no click-through or licence term is breached by residual ASHRAE-informed methodology knowledge.

  3. NASA POWER / ERA5 / PVGIS attribution wording must be embedded in the docs site, API responses, and exported reports, mirroring the ÖKOBAUDAT attribution discipline already adopted for EPDs (AR-28). One discipline, two data families.

  4. climate.onebuilding.org must not be vendored absent written permission from its maintainers; prefer the primary sources (NOAA ISD, ERA5).

  5. EnergyPlus EPW per-file clearance if any specific EPW or DDY file is ever vendored.

§6 Practical implications

6.1 The only path that keeps the public repo buildable and lawful

Derive design inputs from open data — NASA POWER as primary, ERA5 or PVGIS where higher resolution or an EU-specific product helps — and compute loads from a first-principles RTS / Heat-Balance or EN ISO 52016-1 implementation in project code. This is simultaneously the licensing answer and the accuracy answer, and it is the direction ASHRAE itself points.

6.2 This is a from-scratch build, not a migration

No cooling-load code exists to migrate. domains/energy, domains/thermal, lca.b4 and lca.b6 are five-line scaffolds with no logic, and services/interpolation.py is a NotImplementedError stub with zero call sites. Nothing is being thrown away; the decision changes what gets built, before anything is built. See AR-60.

6.3 Continuous gridded data dissolves the interpolation problem it was going to solve

The services/interpolation.py policy in METHODOLOGY.md §5a was written against table bands — "treating a 14.7°N project as if it were at 16°N". NASA POWER is a continuous global grid, so the question changes shape entirely: from which of five tabulated latitude bands, to bilinear interpolation between four surrounding grid points. The five rules of §5a survive unchanged in substance and now govern spatial grid-point interpolation; §5a has been revised to say so.

The hemisphere-transform concern raised in the interpolation-status audit — that ASHRAE's tables are tabulated for northern latitudes and would need a six-month month-shift for southern-hemisphere projects — is moot. NASA POWER has no hemisphere-specific data gap; it returns the same parameters for a site at 14.7°N and one at 14.7°S.

6.4 The $2 000 licence remains a fallback, outside the AGPL distribution

The ASHRAE Software Developer License is a legitimate option only if the ASHRAE-derived data stays out of the AGPL distribution — an optional separately-licensed closed data module, or a runtime layer the end user provisions themselves. It cannot be committed to the public repository.

6.5 Internal Handbook use is unaffected

Chiwara's internal use of the Handbook, under membership or purchase, remains lawful for internal engineering calculations. It simply does not extend to public AGPL redistribution.

6.6 Representativeness caveat carries over from the EPD clearance

As with ÖKOBAUDAT factors (EPD clearance §4.4), open global datasets have resolution and local-microclimate limits. NASA POWER's ½° × ⅝° meteorological grid is roughly 55 km × 60 km at Senegalese latitudes — a real limit for a site with local topographic or coastal effects. This is a pedigree/DQI matter, documented per input under the Weidema axes and propagated by the Monte Carlo engine, not a reason to reject the data.

  1. Immediate (Session 17). Adopt the determination: do not vendor ASHRAE CLTD/CLF/SCL tables or Chapter 14 climatic design data in the public AGPL repository. Record the §4 verdict table in THIRD_PARTY.md. Resolve AR-31 on this basis. Open AR-60 (the methodology pivot) and AR-61 (the §5 legal-review items). Revise METHODOLOGY.md §5a to the continuous-grid framing.

  2. Before the energy module is built (Phase 2). Build the climate-data service against NASA POWER, and the cooling-load kernel as a first-principles RTS / Heat-Balance implementation — or an independently implemented EN ISO 52016-1 — with CTF and radiant-time-factor coefficients computed in project code. Add ERA5 or PVGIS as secondary sources where resolution warrants, retaining their attributions. Note AR-62: the reference workbook's latitude selection is a CORRECTED formula under decision #23, not a parity target.

  3. Before public release (Phase 3). Obtain EU-counsel sign-off on §5 items 1–2. Finalise the attribution wording of §5 item 3 across all three surfaces. Confirm that no EPW, climate.onebuilding.org, or Meteonorm-derived value has entered the repository.

What would change these recommendations

  • If ASHRAE offers an explicitly sublicensable and redistributable grant — of the sort it made for Guideline 36-2018's control sequences — for the cooling-load or climatic data, vendoring under that grant becomes re-evaluable.
  • If the RTS / ISO 52016 build proves infeasible on schedule, keep the ASHRAE Software Developer License data as a closed, optional module outside the AGPL repository as an interim, and continue the migration.
  • If EU counsel confirms that re-expressed coefficients fall outside both copyright and the database right and that no contract term binds, a narrowly-scoped vendoring of re-derived coefficients could be reconsidered — but the methodology migration remains preferable on accuracy grounds alone, so this would not reverse the decision.

§8 Caveats

  • Not legal advice. The §5 items require a qualified lawyer: EU IP counsel given the project's EU footprint, plus US-law input given ASHRAE's US origin.
  • US and EU diverge, and the divergence is real. A "facts are not copyrightable" answer under Feist does not transfer to the EU, where the sui generis database right and contract terms can restrict reuse independently of copyright. The BHB / Football Dataco created-data limitation helps but does not guarantee.
  • Prices and terms change. The $2 000 Software Developer License fee, the Weather Data Viewer subscription price, and the Meteonorm list price were current at the time of investigation and should be re-checked at purchase time. The Meteonorm EULA notes that only the German-language version is legally binding.
  • Verdicts are as-published, not as-negotiated. Every BLOCKED and RESTRICTED verdict above reflects published terms. A written grant obtained directly from a programme owner supersedes the published position — as it would for any EPD source.