{"standard":"Intry Verified","spec":"https://www.intrysys.com/verified","homepage":"https://www.intrysys.com","suite":{"assertionCount":21026,"buildDate":"2026-08-21","commitShort":"ae2fc52","note":"assertionCount is the number of automated checks that re-derive and source-check calculated figures against their locked source, and gate every deploy. It is a whole-suite count, not a per-tool count, and it is Intry's own deterministic gate, not a third-party audit."},"tools":[{"slug":"wire-size","name":"Wire Size Calculator","trade":"electrical","calculatedFrom":"NEC Table 310.16, NEC 210.19(A) and 210.20(A), NEC 110.14(C), NEC 310.15(B)(1) and 310.15(C)(1), NEC 240.6(A) and 240.4(B), NEC 240.4(D), NEC Table 250.122","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/electrical-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#wire-size"},{"slug":"voltage-drop","name":"Voltage Drop Calculator","trade":"electrical","calculatedFrom":"NEC Chapter 9, Table 9, NEC Chapter 9, Table 8, NEC 210.19 and 215.2 Informational Notes","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/electrical-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#voltage-drop"},{"slug":"conduit-fill","name":"Conduit Fill Calculator","trade":"electrical","calculatedFrom":"NEC Chapter 9, Table 1, NEC Chapter 9, Table 4, NEC Chapter 9, Table 5","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/electrical-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#conduit-fill"},{"slug":"box-fill","name":"Box Fill Calculator","trade":"electrical","calculatedFrom":"NEC Table 314.16(B)(1), NEC 314.16(B)(1) through (B)(6), NEC Table 314.16(A)","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/electrical-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#box-fill"},{"slug":"ev-charger","name":"EV Charger Circuit Calculator","trade":"electrical","calculatedFrom":"NEC 625.41 and 625.42, NEC 625.44, 625.54, and 210.21(B)(1), NEC Table 310.16, NEC 240.6(A), 240.4(B), 240.4(D), and Table 250.122, NEC Chapter 9 (voltage drop) and 210.19(A)","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/ev-charger-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#ev-charger"},{"slug":"load-calculator","name":"Existing-Load Panel Check (NEC 220.87)","trade":"electrical","calculatedFrom":"NEC 220.82, NEC 220.87, NEC 220.57, NEC 210.20(A), NEC 240.6(A)","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/load-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#load-calculator"},{"slug":"heat-pump-water-heater-circuit","name":"Water Heater Circuit Calculator","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"The unit nameplate has the final say on the breaker; your AHJ and local amendments govern the install.","engineModule":"src/lib/tools/water-heater-circuit-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#heat-pump-water-heater-circuit"},{"slug":"120v-induction-range-circuit","name":"120V Induction Range Circuit Calculator","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"The unit rating plate has the final say on the wall/charge draw; your AHJ and local amendments govern the install.","engineModule":"src/lib/tools/induction-range-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#120v-induction-range-circuit"},{"slug":"ev-load-management-calculator","name":"Biggest EV Charger Calculator (EVEMS)","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"Your AHJ and your actual metered demand have final say; any EVEMS must be listed and installed per its instructions, and the branch is always sized to the full charger output.","engineModule":"src/lib/tools/ev-load-management-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#ev-load-management-calculator"},{"slug":"conduit-bending","name":"Conduit Bending Calculator","trade":"electrical","calculatedFrom":"the bender geometry it was computed from","edition":null,"finalSay":"Field-verify against the actual bend. Bender take-up varies by tool and shoe.","engineModule":"src/lib/tools/bending-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#conduit-bending"},{"slug":"mca-mocp","name":"MCA & MOCP Breaker Calculator","trade":"hvac","calculatedFrom":"NEC 440.33, 440.34, 440.35 and 430.24, NEC 440.22, 440.22(A) and 440.22(B)(1), NEC 240.6(A), NEC 240.4(G) (Article 440), NEC 310.15(B)(1) and 310.15(C)(1), NEC 310.15(B)(2), NEC 110.14(C), NEC 440.14, 440.12 and 110.26(A), NEC 440.52, NEC Table 310.16, NEC Table 250.122, NEC 440.4(B) and 110.3(B), NEC Chapter 9 (voltage drop) and 210.19(A)","edition":"NEC 2023","finalSay":"The unit nameplate has final say. NEC Article 440 governs the sizing.","engineModule":"src/lib/tools/mca-mocp-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#mca-mocp"},{"slug":"changeout","name":"A2L Changeout Circuit Check","trade":"hvac","calculatedFrom":"the cited NEC Article 440 section","edition":"NEC 2023","finalSay":"The marked nameplate has final say. NEC Article 440 governs the sizing, and your AHJ has the last word.","engineModule":"src/lib/tools/mca-mocp-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#changeout"},{"slug":"superheat-subcooling","name":"Superheat & Subcooling Calculator","trade":"hvac","calculatedFrom":"the locked modules each figure is traced to: the manufacturer PT tables behind the saturation temperatures, superheat and subcooling, and the transcribed code and service-literature constants behind the charge, metering, airflow, approach and discharge line figures, each quoted with its own source in the panel it appears in","edition":null,"finalSay":"The unit nameplate and the manufacturer's charging chart have final say.","engineModule":"src/lib/tools/superheat-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#superheat-subcooling"},{"slug":"cold-climate-hp-capacity","name":"Cold-Climate Heat Pump Capacity Calculator","trade":"hvac","calculatedFrom":"the AHRI-certified NEEP ccASHP data it came from","edition":null,"finalSay":"The manufacturer's engineering data or a Manual-J load calculation by an HVAC pro has final say.","engineModule":"src/lib/tools/cold-climate-hp-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#cold-climate-hp-capacity"},{"slug":"line-set","name":"A2L Line Set Calculator","trade":"hvac","calculatedFrom":"Goodman/Amana IOG-4047, Carrier LLG-R454B-01, Goodman/Amana IOG-4047, p.1 (changeover cautions), Carrier R-454B FAQ, Bosch A2L Change Guide, Lennox/York R-454B IOMs","edition":null,"finalSay":"The manufacturer's installation guide for your exact unit has final say.","engineModule":"src/lib/tools/line-set-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#line-set"},{"slug":"a2l-charge-limit","name":"A2L Refrigerant Charge Limit Calculator","trade":"hvac","calculatedFrom":"UL 60335-2-40 (4th ed) Annex GG, ANSI/ASHRAE 15.2-2024, ASHRAE 34-2019 Addendum f (LFL values), IEC 60335-2-40 ed 6 / EN 378 (gravity-only)","edition":"UL 60335-2-40 4th ed / ANSI/ASHRAE 15.2-2024","finalSay":"The equipment listing and the manufacturer's installation manual for your exact unit, plus your AHJ, have final say.","engineModule":"src/lib/tools/a2l-charge-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#a2l-charge-limit"},{"slug":"outdoor-hvac-gfci","name":"Outdoor HVAC GFCI Requirement (NEC 210.8(F))","trade":"electrical","calculatedFrom":"the cited NEC section together with your state's own amendment to it","edition":"NEC 2023","finalSay":"This answer holds only for the jurisdictions whose amendments we have read from their own primary documents. Everywhere else the tool refuses, and your AHJ has the final say in every case.","engineModule":"src/lib/tools/gfci-210-8f-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#outdoor-hvac-gfci"},{"slug":"btu","name":"BTU / HVAC Load Calculator","trade":"hvac","calculatedFrom":"the ACCA Manual J basis it came from","edition":null,"finalSay":"A full Manual J on the actual house has final say.","engineModule":"src/lib/tools/btu-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#btu"},{"slug":"solar-backfeed","name":"Solar Backfeed Breaker Calculator (NEC 705.12)","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"Your AHJ and the utility interconnection agreement have final say; confirm the panel's busbar rating and that the backfeed sits at the opposite end of the bus from the main.","engineModule":"src/lib/tools/load-calc.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#solar-backfeed"},{"slug":"sub-panel","name":"Sub-Panel Wire Size Calculator","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"Your AHJ and local amendments have final say. Confirm before rough-in.","engineModule":"src/lib/tools/sub-panel-data.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#sub-panel"},{"slug":"tap-conductor","name":"Tap Conductor Calculator","trade":"electrical","calculatedFrom":"the cited NEC 240.21(B) tap rule and Table 310.16","edition":"NEC 2023","finalSay":"Your AHJ has final say. This sizes the conductor; the conditions each tap rule places on the installation still have to be met on the job.","engineModule":"src/lib/tools/tap-conductor-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#tap-conductor"},{"slug":"transformer-ocpd","name":"Transformer OCPD Calculator","trade":"electrical","calculatedFrom":"the cited cell of NEC Table 450.3(B) and the standard ratings in 240.6(A)","edition":"NEC 2023","finalSay":"Your AHJ has final say. Table 450.3(B) gives maximums, so a smaller device is usually permitted and often required by the load, the conductors or the transformer inrush.","engineModule":"src/lib/tools/transformer-ocpd-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#transformer-ocpd"},{"slug":"three-phase-motor","name":"Three-Phase Motor Calculator","trade":"electrical","calculatedFrom":"the cited NEC Table 430.250 and 430.248 full-load currents and the Article 430 branch-circuit rules","edition":"NEC 2023","finalSay":"Your AHJ has final say. The table current sizes the branch circuit; your motor's nameplate sizes the running overload device (430.32), which this tool does not size. Wound-rotor and DC motors take a different percentage from Table 430.52 and are out of scope.","engineModule":"src/lib/tools/motor-flc-data.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#three-phase-motor"},{"slug":"what-size-breaker-do-i-need","name":"What Size Breaker Do I Need","trade":"electrical","calculatedFrom":"the cited NEC section","edition":"NEC 2023","finalSay":"The equipment nameplate has the final say for nameplate-rated loads (HVAC, motors, welders, spas); your AHJ and local amendments govern the install.","engineModule":"src/lib/tools/breaker-by-load-data.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#what-size-breaker-do-i-need"},{"slug":"nitrogen-pressure-test","name":"Nitrogen Pressure Test Calculator","trade":"hvac","calculatedFrom":"the NIST standard-atmosphere and Rankine constants it was computed from","edition":null,"finalSay":"The equipment manufacturer and your AHJ have the final say on the required test pressure, the hold time, and pass or fail.","engineModule":"src/lib/tools/nitrogen-pressure-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#nitrogen-pressure-test"},{"slug":"dual-fuel-switchover","name":"Dual-Fuel Switchover Calculator","trade":"hvac","calculatedFrom":"the FTC 3,412 Btu/kWh and 100,000 Btu/therm constants and the RESNET defrost model it was computed from","edition":null,"finalSay":"The equipment manufacturer's dual-fuel guidance and the building's behavior in a cold snap have the final say. Set the lockout at or above the thermal balance point, not the economic crossover, so a cold snap never strands the load.","engineModule":"src/lib/tools/dual-fuel-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#dual-fuel-switchover"},{"slug":"combustion-air","name":"Combustion Air Calculator","trade":"hvac","calculatedFrom":"the IFGC 2021 Section 304 / NFPA 54 §9.3 combustion-air provisions it was computed from","edition":null,"finalSay":"The authority having jurisdiction and the appliance manufacturer's instructions have final say. This never certifies a space safe: a real combustion-air problem is confirmed by a draft, spillage, or CO test.","engineModule":"src/lib/tools/combustion-air-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#combustion-air"},{"slug":"gas-pipe-sizing","name":"Gas Pipe Sizing Calculator","trade":"hvac","calculatedFrom":"the fuel gas code Chapter 4 sizing equation and the Cr values it prints, which it was computed from","edition":null,"finalSay":"The authority having jurisdiction and the appliance manufacturer's instructions have final say. This computes the code-required size and never certifies an installation: a real problem is confirmed by a manometer reading at the appliance inlet under full load.","engineModule":"src/lib/tools/gas-pipe-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#gas-pipe-sizing"},{"slug":"manual-j-load","name":"Manual J Load Calculator","trade":"hvac","calculatedFrom":"the ACCA Manual J 8th Edition Form J1 worksheet procedure and the ASHRAE Chapter 14 design conditions it was computed from","edition":null,"finalSay":"A full permit-grade ACCA Manual J has final say. This is not ACCA-approved: its whole-house heating total rests on four site conditions you declare, and its cooling load rests on two more. It reports a whole-house COOLING load as the PAIR Manual J section 5-12 sizes equipment from: the total sensible load (Form J1ae line 20) and the total latent load (line 21). Either is withheld when a printed term of it is unanswered or has no printed route in the abridged edition, and the specific term is named on the result rather than folded in.","engineModule":"src/lib/tools/manual-j-load.ts","runnable":true,"resultMatchesEngine":true,"receipt":"https://www.intrysys.com/verified#manual-j-load"},{"slug":"cfm","name":"CFM Calculator","trade":"hvac","calculatedFrom":"the ASHRAE and ACCA airflow standards it was computed from","edition":null,"finalSay":"The OEM blower table for the actual coil, or a full ACCA Manual J/D design, has final say.","engineModule":"src/lib/tools/duct-airflow-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#cfm"},{"slug":"duct-size","name":"Duct Size Calculator","trade":"hvac","calculatedFrom":"the ASHRAE Fundamentals and ACCA Manual D duct-design standards it was computed from","edition":null,"finalSay":"A full ACCA Manual D duct design and the equipment's blower data have final say.","engineModule":"src/lib/tools/duct-airflow-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#duct-size"},{"slug":"duct-round-rect","name":"Round to Rectangular Duct Converter","trade":"hvac","calculatedFrom":"the ASHRAE Fundamentals equivalent-diameter standard it was computed from","edition":null,"finalSay":"A full ACCA Manual D duct design has final say; confirm the shape fits the space.","engineModule":"src/lib/tools/duct-airflow-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#duct-round-rect"},{"slug":"static-pressure","name":"Static Pressure & Friction Rate Calculator","trade":"hvac","calculatedFrom":"the ACCA Manual D friction-rate standard it was computed from","edition":null,"finalSay":"The blower's measured external static pressure and a full ACCA Manual D duct design have final say.","engineModule":"src/lib/tools/duct-airflow-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#static-pressure"},{"slug":"temp-rise","name":"Furnace Temperature Rise Calculator","trade":"hvac","calculatedFrom":"the temperature rise range printed on the unit's own rating plate, which you supply","edition":null,"finalSay":"The rating plate and the manufacturer's installation instructions for your model have final say, and a combustion analysis is what confirms the furnace is safe. A rise inside the plate band is not a clean bill of health.","engineModule":"src/lib/tools/temp-rise-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#temp-rise"},{"slug":"vacuum-decay","name":"Vacuum Decay Test Calculator","trade":"hvac","calculatedFrom":"the hold criterion in the installation instructions for your equipment, which you supply, judged alongside the vapor pressure of water derived from the NIST Antoine coefficients","edition":null,"finalSay":"The installation instructions for your equipment have final say on the hold criterion, and a nitrogen pressure test is what locates a leak. A system that holds a vacuum has not been pressure tested.","engineModule":"src/lib/tools/vacuum-decay-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#vacuum-decay"},{"slug":"leak-rate","name":"EPA Refrigerant Leak Rate Calculator","trade":"hvac","calculatedFrom":"the federal EPA rule (40 CFR part 84) it came from","edition":null,"finalSay":"The EPA rule text and a Section 608-certified technician have final say on coverage, thresholds, and reporting.","engineModule":"src/lib/tools/leak-rate-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#leak-rate"},{"slug":"tonnage-from-model","name":"Tonnage From Model Number","trade":"hvac","calculatedFrom":"the manufacturer model-number nomenclature it was decoded from","edition":null,"finalSay":"The unit's rating plate and its BTU/h rating have final say; brand nomenclature varies and changes across product generations.","engineModule":"src/lib/tools/model-tonnage.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#tonnage-from-model"},{"slug":"serial-number-lookup","name":"HVAC Serial Number Lookup","trade":"hvac","calculatedFrom":"the manufacturer serial-number date code it was decoded from","edition":null,"finalSay":"The date printed or stamped on the data plate (the MFG DATE field, where present) has final say, and the nameplate refrigerant governs over any year-based era mapping.","engineModule":"src/lib/tools/serial-decoder.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#serial-number-lookup"},{"slug":"water-heater-age","name":"Water Heater Age Decoder","trade":"hvac","calculatedFrom":"Bradford White: the consumer date-code page and the For the Pro bulletin, Rheem, Ruud and Richmond: Technical Service Bulletin 1207","edition":null,"finalSay":"The date printed on the rating plate has final say. Where a serial genuinely carries more than one possible date, this tool shows every one it can and publishes no age, and the manufacturer's own warranty verification is what settles a claim.","engineModule":"src/lib/tools/water-heater-decoder.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#water-heater-age"},{"slug":"nema-plug-chart","name":"NEMA Plug & Receptacle Identifier","trade":"electrical","calculatedFrom":"Hubbell Configuration Chart (Wiring Device-Kellems), Leviton Industrial Wiring Devices Catalog, Leviton product pages, straight blade 30A / 50A / 60A, Eaton Arrow Hart colour-coded locking devices selector guide","edition":null,"finalSay":"The rating stamped on the device face has final say. A configuration publishes here only where two independent manufacturers print it and agree. Blade dimensions live in NEMA WD 6 and are a separate layer we have not added yet.","engineModule":"src/lib/tools/nema-config.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#nema-plug-chart"},{"slug":"target-superheat","name":"Target Superheat Calculator","trade":"hvac","calculatedFrom":"the locked CEC Title 24 RA3.2-2 charging table it was computed from, which agrees cell for cell with one manufacturer piston grid and runs a mean 4.77F above another, on the sixth of the table where any manufacturer check exists","edition":null,"finalSay":"The manufacturer's charging chart for your exact fixed-orifice unit has final say, and where one exists it governs over this table.","engineModule":"src/lib/tools/target-superheat-calc.ts","runnable":false,"resultMatchesEngine":false,"receipt":"https://www.intrysys.com/verified#target-superheat"}]}