About our data

How we sourced, verified, and rated 1,112+ Authority Having Jurisdiction (AHJ) records across 23 states — and where the limits are.

Coverage

As of June 2026, Building Signal Check™ covers 1,112 jurisdictions across 23 states:

• Full coverage (named AHJ records, code amendments tracked): Texas (261), Florida (126), California (82), Arizona (50), Oklahoma (50), Utah (50, discretionary §510 statewide), Oregon (45, permit-gate model), South Carolina (45, statewide unmodified §510), Massachusetts (15, on 780 CMR §918 — a non-IFC state), North Carolina (17), Colorado (17), Washington (16), Tennessee (15), New York (14), Illinois (14), Georgia (14), Nevada (1).
• General framework analysis only: all other US states. The tool will still return a code-level verdict based on the model IFC §510, but without jurisdiction-specific amendments.

Primary sources

• ICC Digital Codes — authoritative text of the International Fire Code (IFC) editions 2018, 2021, 2024.
• NFPA — NFPA 1 (2024), NFPA 72 (2025), NFPA 1221 (2019), NFPA 1225 (2022 / 2025), UL 2524.
• AHJ-published ordinances — adoption ordinances, fire prevention codes, local amendments published on official municipal or county websites.
• FCC — 47 CFR §90.219 (signal booster authorization) and frequency coordination guidance.
• Direct AHJ correspondence — email or phone confirmation from fire marshals, plan reviewers, or designated code officials.
• State statutes — e.g., Florida Statute §633.202(18), Texas Government Code Chapter 233.

Confidence methodology

Every AHJ record is tagged with one of five confidence levels. The verdict page displays the confidence for your specific AHJ.

How we rate verdicts

Since September 2026 (rules engine v37) the result page states the adopted code rather than scoring the building. For each address the engine answers four questions in order:

1. Which fire code edition does the AHJ enforce? Taken from the adoption ordinance on file. If Zion has not yet confirmed the edition from a primary source, the tool says Not yet verified and states no threshold at all.
2. What does that code say? Every IFC edition since 2009 requires approved emergency responder radio coverage in all new buildings (§510.1), with exceptions at the fire code official's discretion; the 2024 edition adds Exception 4 for one-story buildings of 12,000 sq ft or less with no below-ground area. Existing buildings fall under §1103.2 on the schedule the adopting authority sets. The model code contains no other square-footage or story threshold, and Building Signal Check™ does not invent one.
3. What did the jurisdiction change? A local amendment or published fire-department policy that adds a threshold (for example a published square-footage or story figure), deletes an exception, or extends the requirement to existing buildings is applied only when the ordinance or policy itself is on file and is quoted on the result page with a link.
4. What does that mean for this building? The inputs you provide (new or existing, stories, area, below-grade space, occupancy) are compared against the code as adopted and amended.

State statutory overlays (for example Florida Statute §633.202(18)) are layered on top. The output is a statement of the adopted code, never a code determination; only the AHJ makes that call.

Update cadence

Records are re-verified on a rolling schedule, with Texas and other primary-market jurisdictions reviewed most often. Corrections received via codes@zion.us or through AHJ outreach are processed within 5 business days.

Known limitations

• Code adoption changes faster than our update cycle. A jurisdiction that adopted a new IFC edition within the past 90 days may not yet be reflected.
• Some AHJs do not publish their amendments. We rely on direct correspondence; gaps exist.
• Construction type and era are coarse signals. Site-specific RF behavior depends on many factors that no scoping tool can model — only a survey can measure them.
• The tool does not currently model fringe occupancies (R&D high-hazard, detention, military installations, federal buildings).
• Outside the 12 covered states, only model IFC §510 logic is applied.

Found an error?

Please email codes@zion.us with the jurisdiction, the specific code section, and your source. We respond within 5 business days and credit verified corrections.

Who built this

Building Signal Check™ is built and maintained by Zion Fire Protection, LLC. Lead architect: Joel Sadowsky — NICET Level III Fire Alarm, NICET Level III Special Hazards, NICET Level II Sprinkler, FCC GROL, 15+ years of fire-protection field experience.

Not an engineering report. Joel Sadowsky and Zion Fire Protection, LLC hold the licenses listed above. None of them substitute for a stamped engineering report. Where the IFC, NFPA, or local AHJ requires a PE-sealed design, only a licensed Professional Engineer can provide one.