{"id":"iwuic-2021-class-1-2-quarter-inch-vent-mesh","license":"CC-BY-4.0","data":{"title":"2021 IWUIC Class 1 and 2 quarter-inch vent-mesh path","shortName":"2021 IWUIC Class 1–2 vent mesh","summary":"The unamended 2021 IWUIC specifies noncombustible corrosion-resistant mesh with openings no larger than one-quarter inch for Class 1 and Class 2 vents.","framing":"This record covers documented mesh size, material, and vent role only. The 144-square-inch opening limit, free area, installation, prohibited soffit and eave locations, alternative approval, official map, assigned class, project scope, and local amendments remain checks.","kind":"code","instrumentId":"iwuic-2021","jurisdiction":"Jurisdictions adopting unamended 2021 IWUIC Sections 504.10 and 505.10","appliesToCategories":["vents"],"quotedText":"noncombustible corrosion-resistant mesh with openings not to exceed 1/4 inch (6.4 mm)","source":{"title":"2021 International Wildland-Urban Interface Code, Sections 504.10 and 505.10","url":"https://codes.iccsafe.org/content/IWUIC2021P2/chapter-5-special-building-construction-regulations","publisher":"International Code Council","sourceType":"official","accessedOn":"2026-08-27T00:00:00.000Z"},"constraints":[{"attribute":"assemblyRole","op":"in","value":["foundation-vent","retrofit-mesh"]},{"attribute":"meshSizeInch","op":"lte","value":0.25,"unit":"inch"},{"attribute":"corrosionResistant","op":"eq","value":true},{"attribute":"noncombustible","op":"eq","value":true}],"relatedStandards":["iwuic"],"author":"grayson-graham","reviewStatus":"draft","lastVerified":"2026-08-27T00:00:00.000Z"},"applications":[{"id":"iwuic-2021-pennsylvania","title":"Pennsylvania Uniform Construction Code incorporates IWUIC 2021","instrumentId":"iwuic-2021","placeId":"us-pa","status":"active","geographicScope":"statewide","scopeSummary":"34 Pa. Code § 403.21(a)(11) adopts and incorporates by reference the International Wildland-Urban Interface Code of 2021 as part of the Uniform Construction Code. The November 7, 2025 amendment is effective January 1, 2026, and the State's final report says the 2021 IWUIC was adopted without modification. Whether a given lot is in a wildland-urban interface, which ignition-resistant class applies, and whether a given project type is in scope still depend on the official map and the building official.","effectiveOn":"2026-01-01T00:00:00.000Z","requirementIds":["iwuic-2021-class-1-2-20-minute-exterior-door","iwuic-2021-class-1-2-class-a-roof-assembly","iwuic-2021-class-1-2-multilayered-glazing","iwuic-2021-class-1-2-noncombustible-deck","iwuic-2021-class-1-2-noncombustible-exterior-door","iwuic-2021-class-1-2-noncombustible-exterior-wall","iwuic-2021-class-1-2-quarter-inch-vent-mesh","iwuic-2021-class-1-2-solid-core-exterior-door","iwuic-2021-class-1-noncombustible-eave","iwuic-2021-class-2-solid-eave-enclosure","iwuic-2021-class-3-class-b-roof-assembly","iwuic-2021-noncombustible-gutters","iwuic-2021-roof-profile-closure","iwuic-2021-roof-valley-flashing"],"requirementCoverage":"partial","requirementCoverageSummary":"Fourteen source-exact 2021 IWUIC product-semantic atoms are normalized from the reviewed Class 1, Class 2, and Class 3 Chapter 5 provisions. This is not full-code normalization; ignition-resistant, fire-retardant-treated-wood, heavy-timber, rated-construction, cap-sheet, debris-control, and approval paths without complete product-field semantics remain outside the set. No 2018 or 2024 requirement is carried in by resemblance.","requirementScopes":[{"requirementId":"iwuic-2021-class-1-2-20-minute-exterior-door","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This rated-door path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.9","505.9"]},{"requirementId":"iwuic-2021-class-1-2-class-a-roof-assembly","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This Class A roof path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.2","505.2"]},{"requirementId":"iwuic-2021-class-1-2-multilayered-glazing","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This glazing path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.8","505.8"]},{"requirementId":"iwuic-2021-class-1-2-noncombustible-deck","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This appendage path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.7","505.7"]},{"requirementId":"iwuic-2021-class-1-2-noncombustible-exterior-door","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This door-material path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.9","505.9"]},{"requirementId":"iwuic-2021-class-1-2-noncombustible-exterior-wall","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This wall-material path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.5","505.5"]},{"requirementId":"iwuic-2021-class-1-2-quarter-inch-vent-mesh","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This prescriptive vent path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.10","505.10"]},{"requirementId":"iwuic-2021-class-1-2-solid-core-exterior-door","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2"],"scopeSummary":"This door-leaf path applies only after official review assigns Class 1 or Class 2 construction.","sourceSections":["504.9","505.9"]},{"requirementId":"iwuic-2021-class-1-noncombustible-eave","scopeKeys":["ignition-resistant-class-1"],"scopeSummary":"This eave-material path applies only after official review assigns Class 1 construction.","sourceSections":["503.2","504.3"]},{"requirementId":"iwuic-2021-class-2-solid-eave-enclosure","scopeKeys":["ignition-resistant-class-2"],"scopeSummary":"This solid-enclosure path applies only after official review assigns Class 2 construction.","sourceSections":["505.3"]},{"requirementId":"iwuic-2021-class-3-class-b-roof-assembly","scopeKeys":["ignition-resistant-class-3"],"scopeSummary":"This Class B-or-better roof path applies only after official review assigns Class 3 construction.","sourceSections":["506.2"]},{"requirementId":"iwuic-2021-noncombustible-gutters","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2","ignition-resistant-class-3"],"scopeSummary":"This gutter-material path applies after official review assigns Class 1, Class 2, or Class 3 construction.","sourceSections":["504.4","505.4","506.4"]},{"requirementId":"iwuic-2021-roof-profile-closure","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2","ignition-resistant-class-3"],"scopeSummary":"This roof-profile path applies after official review assigns Class 1, Class 2, or Class 3 construction.","sourceSections":["504.2","505.2","506.2"]},{"requirementId":"iwuic-2021-roof-valley-flashing","scopeKeys":["ignition-resistant-class-1","ignition-resistant-class-2","ignition-resistant-class-3"],"scopeSummary":"This valley-flashing path applies after official review assigns Class 1, Class 2, or Class 3 construction.","sourceSections":["504.2.1","505.2.1","506.2.1"]}],"requirementCrosswalk":[{"modelRequirementId":"iwuic-2021-class-1-2-20-minute-exterior-door","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.9","505.9"]},{"modelRequirementId":"iwuic-2021-class-1-2-class-a-roof-assembly","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.2","505.2"]},{"modelRequirementId":"iwuic-2021-class-1-2-multilayered-glazing","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.8","505.8"]},{"modelRequirementId":"iwuic-2021-class-1-2-noncombustible-deck","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.7","505.7"]},{"modelRequirementId":"iwuic-2021-class-1-2-noncombustible-exterior-door","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.9","505.9"]},{"modelRequirementId":"iwuic-2021-class-1-2-noncombustible-exterior-wall","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.5","505.5"]},{"modelRequirementId":"iwuic-2021-class-1-2-quarter-inch-vent-mesh","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.10","505.10"]},{"modelRequirementId":"iwuic-2021-class-1-2-solid-core-exterior-door","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.9","505.9"]},{"modelRequirementId":"iwuic-2021-class-1-noncombustible-eave","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["503.2","504.3"]},{"modelRequirementId":"iwuic-2021-class-2-solid-eave-enclosure","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["505.3"]},{"modelRequirementId":"iwuic-2021-class-3-class-b-roof-assembly","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["506.2"]},{"modelRequirementId":"iwuic-2021-noncombustible-gutters","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.4","505.4","506.4"]},{"modelRequirementId":"iwuic-2021-roof-profile-closure","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.2","505.2","506.2"]},{"modelRequirementId":"iwuic-2021-roof-valley-flashing","disposition":"adopted-unchanged","replacementRequirementIds":[],"scopeSummary":"The State final report records the 2021 IWUIC as adopted without modification.","sourceSections":["504.2.1","505.2.1","506.2.1"]}],"supportingSources":[{"title":"2021 ICC Code Adoption Final Report","url":"https://www.pa.gov/content/dam/copapwp-pagov/en/dli/documents/ucc/documents/2021%20icc%20code%20adoption%20final%20report.pdf","publisher":"Pennsylvania Department of Labor & Industry","sourceType":"official","accessedOn":"2026-08-27T00:00:00.000Z"},{"title":"2021 International Wildland-Urban Interface Code, Chapter 5","url":"https://codes.iccsafe.org/content/IWUIC2021P2/chapter-5-special-building-construction-regulations","publisher":"International Code Council","sourceType":"official","accessedOn":"2026-08-27T00:00:00.000Z"}],"unresolvedPredicates":["official-hazard-map","official-hazard-class","project-type","official-confirmation"],"source":{"title":"34 Pa. Code § 403.21 Uniform Construction Code","url":"https://www.pacodeandbulletin.gov/secure/pacode/data/034/chapter403/s403.21.html","publisher":"Pennsylvania Code and Bulletin","sourceType":"official","accessedOn":"2026-08-27T00:00:00.000Z"},"author":"grayson-graham","reviewStatus":"draft","lastVerified":"2026-08-27T00:00:00.000Z"}],"products":[{"id":"firestorm-embermesh-roll","name":"FireStorm EmberMesh roll","url":"/materials/firestorm-embermesh-roll/","categories":["vents"],"complianceStatus":"attribute-match","documentedAttributes":[{"attribute":"meshSizeInch","value":0.0657,"source":{"title":"FireStorm EmberMesh sales sheet","url":"https://firestormbuildingproducts.com/wp-content/uploads/2025/01/Fire-Storm-Ember-Mesh-Sales-Sheet-opt.pdf","publisher":"New Cal Metals, Inc.","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"assemblyRole","value":"retrofit-mesh","source":{"title":"FireStorm EmberMesh sales sheet","url":"https://firestormbuildingproducts.com/wp-content/uploads/2025/01/Fire-Storm-Ember-Mesh-Sales-Sheet-opt.pdf","publisher":"New Cal Metals, Inc.","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"corrosionResistant","value":true,"source":{"title":"FireStorm EmberMesh sales sheet","url":"https://firestormbuildingproducts.com/wp-content/uploads/2025/01/Fire-Storm-Ember-Mesh-Sales-Sheet-opt.pdf","publisher":"New Cal Metals, Inc.","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"noncombustible","value":true,"source":{"title":"Fire-resistant mesh and EmberMesh installation","url":"https://firestormbuildingproducts.com/fire-resistant-mesh/","publisher":"New Cal Metals, Inc.","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null}]},{"id":"wildfire-defense-mesh-75-black-roll","name":"Wildfire Defense Mesh 75 black roll","url":"/materials/wildfire-defense-mesh-75-black-roll/","categories":["vents"],"complianceStatus":"attribute-match","documentedAttributes":[{"attribute":"meshSizeInch","value":0.1072,"source":{"title":"Wildfire Defense Mesh 75 black roll","url":"https://www.wildfiredefensemesh.com/wdm-product/wdm-75-mesh-roll-black","publisher":"Bushfire Mitigation Solutions","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"assemblyRole","value":"retrofit-mesh","source":{"title":"Wildfire Defense Mesh 75 black roll","url":"https://www.wildfiredefensemesh.com/wdm-product/wdm-75-mesh-roll-black","publisher":"Bushfire Mitigation Solutions","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"corrosionResistant","value":true,"source":{"title":"Wildfire Defense Mesh 75 black roll","url":"https://www.wildfiredefensemesh.com/wdm-product/wdm-75-mesh-roll-black","publisher":"Bushfire Mitigation Solutions","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null},{"attribute":"noncombustible","value":true,"source":{"title":"Wildfire Defense Mesh frequently asked questions","url":"https://www.wildfiredefensemesh.com/faq","publisher":"Bushfire Mitigation Solutions","accessedOn":"2026-08-24T00:00:00.000Z","sourceType":"manufacturer"},"documentLocation":null,"excerpt":null}]}],"matchContract":"Products appear only when their cited fields satisfy this requirement's normalized constraints. Application scope and unresolved predicates remain separate; an attribute match is not a permit decision."}