Intry Verified receipt
Is the Intry Combustion Air Calculator accurate?
The provenance receipt for the Intry Combustion Air Calculator: the exact authority its values derive from, the edition they are keyed to, who has final say, and what our automated checks hold them against, rebuilt from their cited source.
The receipt
- Calculated from
- IFGC 2021 Section 304.5, the 50 ft3 per 1,000 Btu/h confined-space threshold · IFGC 2021 Section 304.1, outdoor air where indoor air falls short · IFGC 2021 Section 304.6, outdoor opening divisors · IFGC 2021 Section 304.7, combining indoor and outdoor air · IFGC 2021 Sections 304.5.2, 304.5.3, 304.9 and 304.10. Reused verbatim from the locked engine, never re-written for this page. The documents it rests on are listed in the source receipt on the tool page.
- Edition
- IFGC 2021 Section 304 (NFPA 54 9.3 cited beside it)
- Checked
- Before any release, an automated check runs the locked engine that produces these figures and holds its answers against values written from the source it cites, so a checked number answers to its source and not merely to itself. The check covers the cases someone wrote a check for, not every input the tool accepts: it tells you where a number comes from, and it is not a proof of every value. As of the current build that suite holds 31163 checks, and this page has to clear them too. This is our own deterministic gate, not a third-party audit.
- Runnable
- A reference engine behind the published numbers on this site. Runnable access is offered on the calculators exposed at the Intry MCP endpoint.
- Final say
- 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.
Frequently Asked Questions
Is the Intry Combustion Air Calculator accurate?
It computes from the sources listed in the source receipt on its tool page, and our automated checks hold its answers against values written from those sources for the cases the checks cover, not for every input you can enter. 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. Every figure an Intry calculator computes comes from a locked source module, not hand-typed. 31163 automated checks, one suite for the whole site rather than a per-tool count, re-derive the numbers before each deploy from the tables this site transcribed from the IFGC 2021 Section 304 / NFPA 54 §9.3 combustion-air provisions it was computed from. This is our own deterministic gate, not a third-party audit. The per-tool receipt is public at https://www.intrysys.com/verified.