01
ASHRAE Handbook—Fundamentals, 2025
Chapter 1, Psychrometrics, is the primary authority retained for saturation-pressure equations, perfect-gas moist-air relations, thermodynamic wet-bulb equations, terminology and worked-example context. It defines the scientific model; it does not supply the site interface or chart artwork.
PsychroField is independent and is not affiliated with, sponsored by or endorsed by ASHRAE. Readers doing regulated or final design work should consult their legitimately obtained current standard directly.
02
NIST Building Science Series 21
Algorithms for Psychrometric Calculations is retained from the public NIST record for historical algorithmic and validation context. It provides an independent governmental reference point for how psychrometric relationships can be calculated and checked.
The engine code and editorial wording are original. The NIST publication is cited, not republished as site content.
03
Independent software comparisons
PsychroLib 2.5 and CoolProp 8 were used as independent numeric comparison implementations for selected fixtures. Their values help expose transcription, unit or inversion mistakes; they are not treated as the product specification.
No implementation source, UI, data table or chart geometry from either project was copied. Differences caused by formulation, reference state or rounding are retained in the validation evidence.
04
Pressure, elevation and unit contracts
The elevation estimator uses the documented standard-troposphere power relation in the engine contract. It is identified as an estimate because real station pressure varies with weather. All conversion constants are explicit at the interface boundary while canonical storage remains SI.
Every example names its total pressure and dry-air mass basis. This prevents a plausible-looking value from losing the assumptions needed to reproduce it.
05
Original chart and publication provenance
Saturation and RH curves are calculated at the selected pressure and rendered by original code. No ASHRAE or competitor chart artwork, coordinates, interface, dataset or wording is traced or reproduced.
The publisher retains source notes, fixture definitions, comparison outputs and reports in the production package. Public pages summarize that evidence in readable form without exposing proprietary copies of standards.