Calculation model
Room planning uses a simplified lumen method: area × target lux ÷ utilization factor ÷ maintenance factor. Beam spread uses 2 × distance × tan(beam angle ÷ 2). Energy uses watts × quantity × operating hours ÷ 1,000. Pendant drop and ceiling grids use direct measured geometry.
Every factor remains visible. Defaults are starting examples, not hidden facts. Outputs use sensible rounding and often a range because input precision does not justify an exact-looking construction answer.
Source hierarchy
Public guidance from government bodies, standards organizations, and established technical institutions is preferred for definitions and consumer interpretation. Exact product decisions should use the current manufacturer label, cutsheet, installation instructions, warranty, and photometric file.
Paid standards are linked by title but not reproduced; only their public summaries are used here. A source supporting a concept does not endorse Glow & Gauge’s adaptation. Each field note links its starting references, names publishers in prose where a specific statement depends on them, and labels the tools as independent planning interpretations.
Verification and tests
Pure calculator functions have automated boundary and worked-example tests. Pages are statically rendered so explanatory content, formula, title, and limitations exist even before interactive JavaScript runs.
Before release, the site is checked for TypeScript errors, production build success, route generation, internal links, responsive rendering, keyboard access, visible focus, reduced motion, image dimensions, metadata, sitemap, and public HTTP behavior.
Known limitations
No tool here runs a fixture photometric model, daylight simulation, glare analysis, spectral calculation, electrical design, structural check, or code review. Screen color is not a calibrated color-temperature preview. An even grid is not a verified ceiling plan.
Do not cut, wire, purchase, or certify a project from a browser result alone. Verify the room and exact products, then involve appropriately qualified professionals.
Corrections and revisions
Material formula changes receive a test and a new review date. Editorial dates are not advanced for punctuation or styling alone. If a source becomes unavailable, it is replaced only after the claim is reviewed.
Send a reproducible issue—including page URL, inputs, expected result, and source—to the address on the contact page. Substantive corrections are acknowledged in the relevant page.