About Codebook Carl
Code answers you can verify, built for the people who do the work.
Codebook Carl is a search tool for Canadian building and fire codes. Ask a question in plain language — the way you'd ask a senior colleague — and Carl finds the governing clause in the actual code text and answers from it, with exact citations you can check.
Why we built it
Anyone who works with fire alarm systems or building codes knows the routine: a question comes up on site, and the answer is buried somewhere across half a dozen documents — the Building Code, the Fire Code, and a stack of ULC standards, each with its own numbering system and its own jurisdiction. Finding the right clause means knowing which document governs, and that knowledge usually lives in someone's head after twenty years in the trade.
Carl is an attempt to put that judgment into a tool. It doesn't just keyword-match — it works out which document governs your question first, then reads the relevant sections of that document to find the answer, the same way an experienced practitioner would.
Why you can trust the answers
The most common concern we hear about AI tools is fair: "You can't trust AI — it makes things up." Carl is built specifically to avoid that failure:
- Answers come only from the code text. Carl reads complete sections from a fixed library of Canadian codes and standards. It is instructed to use nothing else — no outside knowledge, no guessing.
- Every answer cites the exact clause. Document, section number, page. You can verify every claim against the source.
- The references are shown below every answer. The cited code excerpts appear under the answer so you can read the original wording yourself.
- When the codes don't answer the question, Carl says so — instead of inventing something plausible.
What's in the library
- Ontario Building Code 2024 (Volumes 1 and 2)
- National Building Code of Canada 2025
- Ontario Fire Code
- CAN/ULC-S524 — Installation of Fire Alarm Systems
- CAN/ULC-S527 — Control Units for Fire Alarm Systems
- CAN/ULC-S536 — Inspection and Testing of Fire Alarm Systems
- CAN/ULC-S537 — Verification of Fire Alarm Systems
The library grows over time. If there's a code or standard you'd like to see added, we want to hear about it.
Who it's for
Fire alarm technicians, inspectors, designers and engineers, building officials, contractors, and property managers — anyone who needs a code answer they can verify, faster than flipping through PDFs.
A note on professional judgment
Carl is a reference tool, not a substitute for professional advice. Answers are for general reference; always verify against the full source documents and consult qualified professionals and the authority having jurisdiction (AHJ) before making compliance decisions.