{"id":"mech-003","license":"CC-BY-4.0","data":{"title":"Why Type X gypsum works","file":"/diagrams/mech-003-type-x-calcination.svg","caption":"FA Exhibit MECH-003. Water of crystallization in gypsum delays heat. Not a permit and not a sixth numbered eave item by itself.","alt":"Sequence showing gypsum calcination, water of crystallization driven off as steam, and a Type X layer behind an exterior covering.","kind":"diagram","rights":"cc-by-4.0","depicts":"Type X gypsum calcination as the reason the covering-behind path works","identifiableAddress":false,"exifGpsStripped":true,"derivation":"After Gypsum Association Type X description and R327 Type X exception language. Not-to-scale chemistry schematic.","technicalReviewer":"Grayson Graham","lastVerified":"2026-08-23T00:00:00.000Z","sourceUrl":"https://www.oregon.gov/bcd/codes-stand/Documents/23orsc-r327-amend.pdf"}}