Methodology and Standards

ANSI/ASHRAE Standard 140 Compliance ASHRAE 140 Compliant

AIM Works has been tested against the applicable ANSI/ASHRAE Standard 140-2023 building-performance simulation test cases. All applicable test cases passed or produced results within the standard's prescribed acceptance ranges.

ANSI/ASHRAE Standard 140 provides standardized test procedures and acceptance criteria for evaluating building-performance simulation software. AIM Works uses these test cases as part of its validation process to verify the behavior of its building-performance calculation engine under defined conditions.

ASHRAE Standard 140 compliance applies to the building-performance simulation capabilities evaluated by the applicable test cases. It does not imply that every AIM Works workflow, AI recommendation, equipment selection, code check, or future module is covered by Standard 140. The results above are for the thermal-mass annual engine. Standard 140 testing on its own does not qualify a program for ASHRAE 90.1 Appendix G, 179D, or HERS submittals.

Maturity labels: Validated, Advisory, Reference

Every module carries one of three labels next to its method and code edition. The label stays with the number through the PDF report and the calculation package.

The calculation package includes the full maturity register for every computed module, so a reviewer sees the trust level of every number in the deliverable, not just in the app.

Validation results

Each row below is a reference check that a module passed to earn the Validated label. The checks re-run on every code change, and a result that drifts outside tolerance fails the build.

All other launch modules are labeled Advisory or Reference. Their methods are published below, and their numeric outputs are covered by a regression suite that fails on any unreviewed change. The annual energy engine is also tested against ANSI/ASHRAE Standard 140-2023; see Standard 140 compliance above.

Standards referenced

Standard	Used for	At launch
ASHRAE Handbook—Fundamentals 2021	Load calculations (RTS, Ch. 18), psychrometric properties, heat transfer	Live
ASHRAE 62.1-2019	Ventilation Rate Procedure (multi-zone, Ev correction) and compliance scoreboard	Live
ASHRAE 90.1-2022	Equipment efficiency floors and compliance scoreboard	Live
ASHRAE 170	Healthcare ventilation: per-zone air-change reference checklist	Live (Reference)
ASHRAE Guideline 36	Sequences of operation, parameterized per unit and plant	Live
NEC 430	Motor FLA, MCA, MOCP, reported with equipment for electrical coordination	Live
ANSI/ASHRAE Standard 140-2023	Method of test for the annual building-performance simulation engine	Meets the applicable acceptance criteria
SMACNA HVAC Duct Construction Standards 2006	Duct sizing, fitting equivalent lengths	V2 (targeted early 2027)
IMC 2021	Code-required ventilation and exhaust scoreboard	Planned
IFGC 2021	Fuel-gas piping and combustion air	Planned
NFPA 90A / 90B / 96 / 99	Air-handling installation, kitchen exhaust, healthcare facilities	Planned

Planned and V2 items have calculation engines in the codebase today, but they're parked as Coming Soon in the launch build. At launch, the compliance scoreboards are ASHRAE 90.1-2022 and 62.1-2019, plus the ASHRAE 170 reference checklist.

Calculation methods

Cooling and heating loads Advisory

Three methods, selectable per project:

• RTS (Radiant Time Series, ASHRAE HOF 2021 Ch. 18), the default for new projects. Clear-sky solar from Spencer declination and the published ASHRAE monthly clear-sky constants; sol-air conduction; mass-aware radiant time factors. Cooling loads are swept across the cooling season, and each zone is reported at its own peak month and hour, so south glass that peaks in September is sized for September, not July. Zone supply airflow comes from the room sensible load; ventilation outdoor air is reported separately as a coil-level load.
• CLTD/CLF (Cooling Load Temperature Difference / Cooling Load Factor)
• Simplified (peak design block load)

All three are altitude-corrected. Limits, stated plainly: these are design-day peak loads, and the month sweep varies solar by month while holding ambient at the summer design condition. That is conservative for shoulder months, and the method metadata says so.

Ventilation Validated

ASHRAE 62.1-2019 Ventilation Rate Procedure. Vbz = Rp × Pz + Ra × Az per zone; Voz = Vbz / Ez. System Vot uses the multi-zone Ev correction, with Ev taken from the load-calc primary airflows (Vpz). Per-unit demand-controlled ventilation (CO2-based) inputs and building pressurization / relief-air checks are included.

Psychrometrics Validated

Magnus formula for water-vapor saturation pressure; Sprung's wet-bulb approximation; altitude-corrected atmospheric pressure. State points, mixing, and coil analysis following ASHRAE Fundamentals, at sea level or altitude. IP units at launch; SI display is on the roadmap.

Equipment and plant sizing Advisory

Block-load capacity matching with engineering safety factors from the project's design criteria. Chiller, boiler, and DX efficiencies are checked against the ASHRAE 90.1-2022 minimum tables. Chilled- and hot-water flow is GPM = Btu/h ÷ (500 × ΔT). Stacked margins (safety × diversity × sizing factor × redundancy) are reported as a chain rather than folded into one number. A design-criteria override can tighten a code limit but never loosen it; an override that crosses a limit is rejected with the citation.

Motor circuit data

NEC 430: motor full-load amps, MCA (× 1.25), and MOCP rounded to standard breaker sizes per NEC 430.52, reported with the equipment for the electrical engineer. AIM Works does not do electrical design.

Design Review Advisory

Deterministic cross-checks over the computed project: supply airflow against zone sensible load, CFM per ton, plant capacity against connected load, and missing inputs. Each finding names the check that produced it. The AI can summarize and explain findings; it does not create them or change any number.

Duct and hydronic pipe sizing (V2, not available at launch)

Hydronics: Darcy-Weisbach with the Colebrook-White friction factor; velocity, head loss, and pump head per segment; Direct Return, Reverse Return, Primary/Secondary, and Ring Main (Hardy-Cross) topologies. Ducts: equal friction with SMACNA-tabulated fitting equivalent lengths. Both engines are built and tested, and both are parked for the V2 distribution release targeted for early 2027.

What AIM Works does not do

• No code-compliance energy modeling (ASHRAE 90.1 Appendix G, LEED, 179D, HERS). The optional annual energy estimate is an Advisory design-comparison tool, not a utility-bill prediction or a submittal model.
• No duct or pipe distribution sizing at launch (V2).
• No IMC, IFGC, or NFPA scoreboards at launch.
• No Division 23 specifications, equipment / terminal / valve schedules, P&IDs, or coordination sheets at launch.
• No electrical or plumbing design.
• No construction documents.
• No gbXML export.
• IP units only at launch; SI display comes in a later release.

Why this matters

Every calculation shows its method and standard inline, so a reviewer can check what's behind a number without opening a separate document.

Outputs are advisory. The user's engineering judgment is still required, and all calculations must be reviewed and stamped by a licensed Professional Engineer before construction.

For deeper questions about methodology, contact support@getaimworks.com.