{
  "dataset": {
    "name": "Chimney Parts Reference Atlas",
    "version": "2026-07-27",
    "publisher": "Fort Wayne Chimney Repair Research",
    "description": "Sixty-six normalized chimney and fireplace component records across four residential system families, with definitions, system classification, commonly confused terms, source codes, specifications, verification tiers and verification dates.",
    "record_count": 66,
    "verification_tier_counts": {
      "★": 58,
      "●": 8
    },
    "verified_date": "2026-07-27",
    "methodology": "Direct review of cited model-code sections, current Indiana and Allen County code-status pages, Brick Industry Association Technical Notes 19 and 19B, the January 2025 DuraVent DuraTech 5–8 inch catalog, the May 2026 Majestic ASH36-B installation manual and Michigan LARA current-rule status; followed by terminology normalization and cross-system classification.",
    "sources": [
      {
        "code": "IRC2021",
        "title": "2021 International Residential Code, Chapter 10",
        "url": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
        "checked": "2026-07-27"
      },
      {
        "code": "INRC2020",
        "title": "2020 Indiana Residential Code, Chapter 10",
        "url": "https://codes.iccsafe.org/content/INRC2020P2/chapter-10-chimneys-and-fireplaces",
        "checked": "2026-07-27"
      },
      {
        "code": "IN-DHS",
        "title": "Indiana DHS Rules of the Fire Prevention and Building Safety Commission",
        "url": "https://www.in.gov/dhs/boards-and-commissions/fpbsc-rules/",
        "checked": "2026-07-27"
      },
      {
        "code": "ALLEN",
        "title": "Allen County Building Department",
        "url": "https://www.allencounty.in.gov/234/Building-Department",
        "checked": "2026-07-27"
      },
      {
        "code": "BIA19",
        "title": "BIA Technical Notes 19 — Residential Fireplace Design (January 1993)",
        "url": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
        "checked": "2026-07-27"
      },
      {
        "code": "BIA19B",
        "title": "BIA Technical Notes 19B — Residential Chimneys—Design and Construction (June 1980; reissued April 1998)",
        "url": "https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
        "checked": "2026-07-27"
      },
      {
        "code": "DV2025",
        "title": "DuraVent DuraTech 5–8 Inch All-Fuel Chimney Catalog (January 2025)",
        "url": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
        "checked": "2026-07-27"
      },
      {
        "code": "MAJ2026",
        "title": "Majestic ASH36-B Install Manual 4059-966, Rev G (May 2026)",
        "url": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
        "checked": "2026-07-27"
      },
      {
        "code": "MI-LARA",
        "title": "Michigan LARA Currently Open Rules — Construction Code Part 5",
        "url": "https://www.michigan.gov/lara/bureau-list/bcc/rules-acts/rules/currently-open",
        "checked": "2026-07-27"
      }
    ]
  },
  "records": [
    {
      "number": "1",
      "id": "part-chimney",
      "canonical_term": "Chimney",
      "system": "All covered systems",
      "plate": "A, B",
      "plain_definition": "The masonry structure or listed manufactured system that contains one or more flues and carries combustion products outdoors.",
      "aliases_or_common_mixups": "flue; flue liner; chimney pipe",
      "not_the_same_as": "The passage inside it or the lining material.",
      "governing_document": "2021 IRC Chapter 10; BIA TN 19B",
      "stated_specification": "No universal component count or geometry; the applicable system and governing document control.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Publish as the parent structure/system term."
    },
    {
      "number": "2",
      "id": "part-flue",
      "canonical_term": "Flue",
      "system": "All covered systems",
      "plate": "A, B",
      "plain_definition": "The passage through which smoke and combustion gases travel.",
      "aliases_or_common_mixups": "chimney; flue liner",
      "not_the_same_as": "The chimney structure or the material around the passage.",
      "governing_document": "2021 IRC Chapter 10; BIA TN 19B",
      "stated_specification": "A single chimney can contain more than one flue.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep distinct from chimney and liner in every diagram."
    },
    {
      "number": "3",
      "id": "part-flue-liner",
      "canonical_term": "Flue liner",
      "system": "Masonry chimney",
      "plate": "A, B",
      "plain_definition": "The approved material or lining system forming or protecting the inside surface of a masonry flue.",
      "aliases_or_common_mixups": "flue; chimney liner",
      "not_the_same_as": "The flue passage itself or the whole chimney.",
      "governing_document": "2021 IRC §R1003.11.1",
      "stated_specification": "Clay flue lining is referenced to ASTM C315; listed chimney lining systems are referenced to UL 1777 among the approved lining options.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "State standards only as referenced by the code; this project did not independently test materials."
    },
    {
      "number": "4",
      "id": "part-wythe",
      "canonical_term": "Wythe",
      "system": "Multi-flue masonry chimney",
      "plate": "B",
      "plain_definition": "A continuous vertical thickness of masonry; in a multi-flue chimney, masonry wythes separate adjacent flue linings.",
      "aliases_or_common_mixups": "divider wall; liner separation",
      "not_the_same_as": "A flue liner.",
      "governing_document": "2021 IRC §R1003.13",
      "stated_specification": "Masonry wythes separating adjacent flue linings are not less than 4 inches thick and are bonded into the chimney walls, subject to the section’s stated exception.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Publish with multi-flue context."
    },
    {
      "number": "5",
      "id": "part-chimney-shell",
      "canonical_term": "Chimney wall / shell",
      "system": "Masonry chimney",
      "plate": "A, B",
      "plain_definition": "The masonry surrounding the flue liner or liners.",
      "aliases_or_common_mixups": "chimney body; masonry wall",
      "not_the_same_as": "The flue liner.",
      "governing_document": "2021 IRC §R1003.10",
      "stated_specification": "Masonry chimney walls are constructed of solid masonry units or hollow masonry units grouted solid, with at least 4 inches nominal thickness.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Use “shell” as a plain-language alias, not a separate component."
    },
    {
      "number": "6",
      "id": "part-mortar-joint",
      "canonical_term": "Mortar joint",
      "system": "Masonry chimney",
      "plate": "A, B",
      "plain_definition": "The mortar-filled joint between masonry units.",
      "aliases_or_common_mixups": "mortar seam",
      "not_the_same_as": "The brick, block or stone unit.",
      "governing_document": "BIA TN 19B",
      "stated_specification": "BIA recommends Type N portland cement-lime mortar for chimneys, Type S where high lateral forces require it, and Type M where masonry contacts earth.",
      "verification_tier": "★",
      "source_codes": "BIA19B",
      "source_urls": "https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Label clearly as dated BIA technical guidance, not current law."
    },
    {
      "number": "7",
      "id": "part-chimney-crown",
      "canonical_term": "Chimney crown / masonry chimney cap",
      "system": "Masonry chimney",
      "plate": "A, B",
      "plain_definition": "The sloped cap covering the masonry around the flue liner or liners and shedding water from the chimney top.",
      "aliases_or_common_mixups": "wash; splay; chimney cap",
      "not_the_same_as": "A separate rain cap over a flue opening.",
      "governing_document": "2021 IRC §R1003.9.1; BIA TN 19B",
      "stated_specification": "The 2021 IRC calls for a concrete, metal or stone cap, a drip edge and a caulked bond break around flue liners in accordance with ASTM C1283, with the cap sloped to shed water.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Explain the code/trade terminology conflict rather than choosing one usage."
    },
    {
      "number": "8",
      "id": "part-drip-edge",
      "canonical_term": "Drip edge",
      "system": "Masonry chimney",
      "plate": "—",
      "plain_definition": "The projecting edge of the crown/cap that directs water clear of the chimney face.",
      "aliases_or_common_mixups": "overhang; drip",
      "not_the_same_as": "The entire crown.",
      "governing_document": "2021 IRC §R1003.9.1; BIA TN 19B",
      "stated_specification": "Required as an element of the masonry chimney cap assembly; BIA recommends corbeling the last two courses to form a drip where the cap does not overhang.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not imply that one construction detail fits every existing chimney."
    },
    {
      "number": "9",
      "id": "part-bond-break",
      "canonical_term": "Bond break",
      "system": "Masonry chimney",
      "plate": "—",
      "plain_definition": "The caulked separation around a flue liner that allows the cap and liner to move without being rigidly bonded together.",
      "aliases_or_common_mixups": "sealant joint",
      "not_the_same_as": "A mortar joint in the chimney wall.",
      "governing_document": "2021 IRC §R1003.9.1; ASTM C1283 as referenced",
      "stated_specification": "A caulked bond break is required around flue liners in accordance with ASTM C1283.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Standard is referenced through the code; no independent ASTM text is reproduced."
    },
    {
      "number": "10",
      "id": "part-rain-cap",
      "canonical_term": "Rain cap",
      "system": "Masonry chimney",
      "plate": "A, B",
      "plain_definition": "A separate cover above a flue opening that limits entry of precipitation and debris while allowing exhaust to leave.",
      "aliases_or_common_mixups": "chimney cap; flue cap",
      "not_the_same_as": "The masonry crown/cap around the flue liner.",
      "governing_document": "2021 IRC §R1003.9.3; BIA TN 19B",
      "stated_specification": "The net free area under a rain cap is not less than four times the net free area of the flue outlet it serves.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use “rain cap” when distinguishing it from the code-defined masonry cap."
    },
    {
      "number": "11",
      "id": "part-spark-arrestor",
      "canonical_term": "Spark arrestor",
      "system": "Masonry chimney where installed",
      "plate": "—",
      "plain_definition": "A screen or assembly intended to limit the escape of sparks and embers at the termination.",
      "aliases_or_common_mixups": "spark screen; screened cap",
      "not_the_same_as": "A rain cap, although the two may be combined in one listed or manufactured assembly.",
      "governing_document": "2021 IRC §R1003.9.2",
      "stated_specification": "Net free area is at least four times the flue outlet; screen material must meet the section’s heat/corrosion-resistance condition; openings may not permit passage of spheres larger than 1/2 inch or block spheres smaller than 3/8 inch; access for cleaning is required.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "State only where installed; do not imply every chimney has one."
    },
    {
      "number": "12",
      "id": "part-corbel",
      "canonical_term": "Corbel",
      "system": "Masonry chimney",
      "plate": "—",
      "plain_definition": "Stepped masonry projecting a chimney from a wall or foundation.",
      "aliases_or_common_mixups": "projection; racking",
      "not_the_same_as": "A flue offset.",
      "governing_document": "2021 IRC §R1003.5",
      "stated_specification": "The 2021 IRC limits corbeling by chimney-wall thickness and by each masonry unit’s dimensions.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Do not substitute the dated BIA dimensional rule for the current model-code text."
    },
    {
      "number": "13",
      "id": "part-offset",
      "canonical_term": "Offset",
      "system": "Masonry chimney",
      "plate": "—",
      "plain_definition": "A change in the horizontal position of a flue or chimney as it rises.",
      "aliases_or_common_mixups": "sloped flue; jog",
      "not_the_same_as": "A masonry corbel.",
      "governing_document": "2021 IRC §R1003.7; BIA TN 19B",
      "stated_specification": "The code controls the flue centerline at an offset; BIA TN 19B states a maximum flue slope of 30 degrees from vertical in its dated guidance.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep code rule and dated BIA recommendation visibly distinct."
    },
    {
      "number": "14",
      "id": "part-base-flashing",
      "canonical_term": "Base flashing",
      "system": "Masonry chimney at roof",
      "plate": "A, B",
      "plain_definition": "The lower sheet-metal flashing layer at the roof-to-chimney intersection.",
      "aliases_or_common_mixups": "step flashing; apron flashing",
      "not_the_same_as": "Counterflashing.",
      "governing_document": "BIA TN 19B",
      "stated_specification": "BIA recommends extending base flashing at least 4 inches up the chimney face and along the roof, with tabs at corners.",
      "verification_tier": "★",
      "source_codes": "BIA19B",
      "source_urls": "https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "BIA dimensions are recommendations, not presented as a universal statutory minimum."
    },
    {
      "number": "15",
      "id": "part-counterflashing",
      "canonical_term": "Counterflashing",
      "system": "Masonry chimney at roof",
      "plate": "A, B",
      "plain_definition": "The upper flashing layer inserted into or attached to masonry so it laps the base flashing.",
      "aliases_or_common_mixups": "cap flashing",
      "not_the_same_as": "Base flashing or a storm collar.",
      "governing_document": "BIA TN 19B",
      "stated_specification": "BIA recommends insertion 3/4 to 1 inch into a mortar joint, a lap of at least 3 inches over base flashing and at least 2 inches between higher and lower sections.",
      "verification_tier": "★",
      "source_codes": "BIA19B",
      "source_urls": "https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use “recommends” throughout."
    },
    {
      "number": "16",
      "id": "part-cricket",
      "canonical_term": "Cricket / saddle",
      "system": "Masonry chimney at roof",
      "plate": "A, B",
      "plain_definition": "A raised roof structure on the upslope side of a wide chimney that diverts water around it.",
      "aliases_or_common_mixups": "saddle",
      "not_the_same_as": "Flashing.",
      "governing_document": "2021 IRC §R1003.20; BIA TN 19B",
      "stated_specification": "Required where the chimney dimension parallel to the ridgeline is greater than 30 inches and the chimney does not intersect the ridge; height is set by Table R1003.20.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "The code threshold governs; BIA provides construction detail."
    },
    {
      "number": "17",
      "id": "part-fireblocking",
      "canonical_term": "Chimney fireblocking",
      "system": "Masonry chimney at floor/ceiling penetration",
      "plate": "—",
      "plain_definition": "Noncombustible material that closes the space around a masonry chimney at a floor or ceiling while preserving required separation.",
      "aliases_or_common_mixups": "firestop; draft stop",
      "not_the_same_as": "The full clearance air space.",
      "governing_document": "2021 IRC §R1003.19; BIA TN 19B",
      "stated_specification": "The code requires noncombustible fireblocking securely fastened in place at floor and ceiling penetrations.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not equate masonry fireblocking with a listed manufactured firestop component."
    },
    {
      "number": "18",
      "id": "part-clearance-air-space",
      "canonical_term": "Clearance air space",
      "system": "Masonry chimney",
      "plate": "—",
      "plain_definition": "The required separation between masonry chimney surfaces and combustible construction.",
      "aliases_or_common_mixups": "air gap; chimney clearance",
      "not_the_same_as": "Fireblocking.",
      "governing_document": "2021 IRC §R1003.18",
      "stated_specification": "The model code specifies 2 inches for interior masonry chimneys and 1 inch where the chimney is located entirely outside the exterior walls, subject to the section’s exceptions.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "State as 2021 model-code text; local amendments and existing-building rules may differ."
    },
    {
      "number": "19",
      "id": "part-footing-foundation",
      "canonical_term": "Footing / foundation",
      "system": "Masonry fireplace or chimney",
      "plate": "A, B",
      "plain_definition": "The support transferring fireplace and chimney loads to the ground or structure.",
      "aliases_or_common_mixups": "base; footing",
      "not_the_same_as": "Hearth support.",
      "governing_document": "2021 IRC §§R1001.2 and R1003.2; BIA TN 19",
      "stated_specification": "Not less than 12 inches thick, extending not less than 6 inches beyond the face on all sides and founded below frost depth, subject to the code’s stated conditions.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use combined term because the drawings show the supporting assembly, while the glossary distinguishes foundation wall separately."
    },
    {
      "number": "20",
      "id": "part-foundation-wall",
      "canonical_term": "Foundation wall",
      "system": "Masonry fireplace base",
      "plate": "—",
      "plain_definition": "The masonry or concrete wall above the footing that raises and supports the fireplace body.",
      "aliases_or_common_mixups": "base wall",
      "not_the_same_as": "The footing.",
      "governing_document": "BIA TN 19",
      "stated_specification": "BIA recommends a minimum 8-inch thickness and no voids except an ash pit and external combustion-air ducts.",
      "verification_tier": "★",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Dated technical recommendation, not a current code minimum."
    },
    {
      "number": "21",
      "id": "part-masonry-thimble",
      "canonical_term": "Masonry thimble",
      "system": "Masonry appliance chimney",
      "plate": "B",
      "plain_definition": "The lined opening through a masonry chimney wall that receives an appliance connector.",
      "aliases_or_common_mixups": "chimney inlet; pipe sleeve",
      "not_the_same_as": "A listed factory-built wall thimble.",
      "governing_document": "2021 IRC §R1003.16; BIA TN 19B",
      "stated_specification": "The code addresses inlet material and connector geometry; BIA recommends a thimble flush with the interior liner face, at least 18 inches below the ceiling, with at least 8 inches of liner below its lowest point.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not repeat BIA’s obsolete asbestos-cement material suggestion."
    },
    {
      "number": "22",
      "id": "part-connector-pipe",
      "canonical_term": "Connector pipe / stovepipe",
      "system": "Appliance connection",
      "plate": "B, D",
      "plain_definition": "Interior pipe connecting an appliance outlet to a chimney inlet, support or adapter.",
      "aliases_or_common_mixups": "stovepipe; smoke pipe",
      "not_the_same_as": "Insulated listed chimney pipe.",
      "governing_document": "BIA TN 19B; DuraVent DuraTech catalog",
      "stated_specification": "The connector’s listing and appliance instructions govern it; DuraVent’s catalog treats DVL/DuraBlack connector products and DuraTech chimney pipe as separate components.",
      "verification_tier": "★",
      "source_codes": "BIA19B; DV2025",
      "source_urls": "https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not claim a universal connector construction or clearance."
    },
    {
      "number": "23",
      "id": "part-appliance-cleanout",
      "canonical_term": "Appliance cleanout opening / door",
      "system": "Masonry appliance chimney",
      "plate": "B",
      "plain_definition": "Access near the chimney base for removing accumulated combustion by-products.",
      "aliases_or_common_mixups": "cleanout; soot door",
      "not_the_same_as": "A fireplace ash-pit cleanout or a manufactured tee cap.",
      "governing_document": "2021 IRC §R1003.17; BIA TN 19B",
      "stated_specification": "The opening is located within 6 inches of the base of each flue; its upper edge is at least 6 inches below the lowest chimney inlet; the opening height is at least 6 inches and the cover is noncombustible.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19B",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19b-residential-chimneys---design-and-construction.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "BIA notes that a cleanout may not be necessary for some clean-burning-fuel appliance arrangements; preserve that qualifier."
    },
    {
      "number": "24",
      "id": "part-fireplace-base",
      "canonical_term": "Base",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The supporting foundation and hearth-support portion beneath the firebox.",
      "aliases_or_common_mixups": "foundation assembly",
      "not_the_same_as": "The hearth surface.",
      "governing_document": "BIA TN 19",
      "stated_specification": "One of BIA TN 19’s four basic masonry-fireplace components; BIA says it does not affect burning performance.",
      "verification_tier": "★",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep distinct from the generic footing/foundation row."
    },
    {
      "number": "25",
      "id": "part-firebox",
      "canonical_term": "Firebox",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The assembly containing the fire, including the hearth, opening, combustion chamber, throat and often a smoke shelf.",
      "aliases_or_common_mixups": "fire chamber; fireplace box",
      "not_the_same_as": "The smoke chamber above it.",
      "governing_document": "2021 IRC §R1001.5; BIA TN 19",
      "stated_specification": "Back and side walls total 8 inches of solid masonry including at least 2 inches of firebrick lining, or 10 inches if unlined; firebrick joints do not exceed 1/4 inch.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use model-code dimensions only for masonry fireplaces."
    },
    {
      "number": "26",
      "id": "part-firebrick",
      "canonical_term": "Firebrick / refractory lining",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "Heat-resistant masonry units lining the firebox.",
      "aliases_or_common_mixups": "refractory brick",
      "not_the_same_as": "Molded refractory panels in a factory-built fireplace.",
      "governing_document": "2021 IRC §R1001.5",
      "stated_specification": "Firebrick is referenced to ASTM C27 or ASTM C1261 and laid in medium-duty refractory mortar referenced to ASTM C199.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Standards are cited as referenced by the code."
    },
    {
      "number": "27",
      "id": "part-combustion-chamber",
      "canonical_term": "Combustion chamber",
      "system": "Masonry fireplace",
      "plate": "—",
      "plain_definition": "The shaped cavity within the firebox where the fire burns.",
      "aliases_or_common_mixups": "fire chamber",
      "not_the_same_as": "The complete firebox assembly.",
      "governing_document": "BIA TN 19",
      "stated_specification": "BIA recommends nominal 4-inch brick and a 1-inch air space to the backup wall, while explicitly noting the air space was not required by the building codes it discussed.",
      "verification_tier": "★",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Label BIA recommendation and its dated context."
    },
    {
      "number": "28",
      "id": "part-fireplace-opening",
      "canonical_term": "Fireplace opening",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The room-facing opening at the front of the firebox.",
      "aliases_or_common_mixups": "firebox opening",
      "not_the_same_as": "The throat above it.",
      "governing_document": "2021 IRC §R1001.6; BIA TN 19",
      "stated_specification": "The 2021 IRC specifies a firebox depth of at least 20 inches; BIA uses opening size as a principal input for other fireplace dimensions.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not imply opening size alone determines performance."
    },
    {
      "number": "29",
      "id": "part-lintel",
      "canonical_term": "Lintel",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The noncombustible member or masonry element spanning the top of the fireplace opening.",
      "aliases_or_common_mixups": "header; angle iron",
      "not_the_same_as": "The mantel.",
      "governing_document": "2021 IRC §R1001.7; BIA TN 19",
      "stated_specification": "The code requires noncombustible support with at least 4 inches of bearing at each end; BIA provides steel-angle recommendations for conventional brick openings.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep code minimum and BIA detail separate."
    },
    {
      "number": "30",
      "id": "part-inner-hearth",
      "canonical_term": "Inner hearth",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The noncombustible floor inside the firebox.",
      "aliases_or_common_mixups": "fireplace floor",
      "not_the_same_as": "The hearth extension projecting into the room.",
      "governing_document": "2021 IRC §R1001.9.1; BIA TN 19",
      "stated_specification": "Not less than 4 inches thick under the 2021 model-code provision.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Applies to masonry fireplace construction, not listed factory-built hearth systems."
    },
    {
      "number": "31",
      "id": "part-hearth-extension",
      "canonical_term": "Hearth extension",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The noncombustible hearth area extending beyond the fireplace opening into the room.",
      "aliases_or_common_mixups": "outer hearth",
      "not_the_same_as": "The inner hearth inside the firebox.",
      "governing_document": "2021 IRC §§R1001.9.2 and R1001.10; BIA TN 19",
      "stated_specification": "At least 2 inches thick; projects at least 16 inches in front and 8 inches beyond each side, or 20 inches and 12 inches where the opening is 6 square feet or larger.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not apply masonry dimensions to a listed factory-built fireplace."
    },
    {
      "number": "32",
      "id": "part-throat",
      "canonical_term": "Throat",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The narrowed passage directly above the firebox through which combustion products enter the smoke chamber.",
      "aliases_or_common_mixups": "throat opening",
      "not_the_same_as": "The flue.",
      "governing_document": "2021 IRC §R1001.6; BIA TN 19",
      "stated_specification": "At least 8 inches above the fireplace opening and at least 4 inches deep; the minimum passage area through the throat, damper and smoke chamber is not less than the flue area.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use “passage area” rather than adding separate areas together."
    },
    {
      "number": "33",
      "id": "part-throat-damper",
      "canonical_term": "Throat damper",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "A movable ferrous-metal closure at or near the throat.",
      "aliases_or_common_mixups": "fireplace damper",
      "not_the_same_as": "A top-sealing damper at the chimney termination.",
      "governing_document": "2021 IRC §R1001.7.1; BIA TN 19",
      "stated_specification": "Located at least 8 inches above the top of the fireplace opening and operable from the room; BIA recommends an open area approximately twice the flue area.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Separate the code location/material rule from BIA sizing guidance."
    },
    {
      "number": "34",
      "id": "part-top-sealing-damper",
      "canonical_term": "Top-sealing damper",
      "system": "Some masonry fireplaces",
      "plate": "—",
      "plain_definition": "A damper mounted at the chimney top and operated from the firebox.",
      "aliases_or_common_mixups": "top damper; chimney-top damper",
      "not_the_same_as": "A throat damper.",
      "governing_document": "BIA TN 19",
      "stated_specification": "BIA says this alternative should be weighted or spring-loaded to remain open if its operating mechanism fails.",
      "verification_tier": "●",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "System-dependent component; no general IRC dimension is asserted."
    },
    {
      "number": "35",
      "id": "part-smoke-shelf",
      "canonical_term": "Smoke shelf",
      "system": "Many conventional masonry fireplaces",
      "plate": "A",
      "plain_definition": "A ledge at the base of the smoke chamber behind the throat or damper area.",
      "aliases_or_common_mixups": "shelf behind damper",
      "not_the_same_as": "The smoke chamber itself.",
      "governing_document": "BIA TN 19",
      "stated_specification": "BIA says the origin and need are not clear, provides recommendations where one is used and notes that Rumford fireplaces omit it.",
      "verification_tier": "★",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Present only where the design includes one."
    },
    {
      "number": "36",
      "id": "part-smoke-chamber",
      "canonical_term": "Smoke chamber",
      "system": "Masonry fireplace",
      "plate": "A",
      "plain_definition": "The chamber above the throat that transitions to and supports the flue liner.",
      "aliases_or_common_mixups": "smoke dome",
      "not_the_same_as": "The smoke shelf.",
      "governing_document": "2021 IRC §§R1001.8 and R1001.8.1; BIA TN 19",
      "stated_specification": "Walls total 6 inches with at least 2 inches of firebrick or at least 5/8 inch vitrified-clay lining, or 8 inches unlined; height and slope are limited by the section.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "State the lining options exactly and keep BIA support recommendation separate."
    },
    {
      "number": "37",
      "id": "part-mantel",
      "canonical_term": "Mantel",
      "system": "Masonry fireplace surround",
      "plate": "—",
      "plain_definition": "A shelf or projecting finish above the fireplace opening.",
      "aliases_or_common_mixups": "mantel shelf",
      "not_the_same_as": "The structural lintel.",
      "governing_document": "2021 IRC §R1001.11",
      "stated_specification": "Combustible material is restricted near the opening; within 12 inches, projection is limited by the section’s 1/8-inch-per-inch rule.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Avoid simplifying the full clearance rule into one universal mantel distance."
    },
    {
      "number": "38",
      "id": "part-fireplace-surround",
      "canonical_term": "Fireplace surround",
      "system": "Masonry fireplace",
      "plate": "—",
      "plain_definition": "The finished area immediately around the fireplace opening.",
      "aliases_or_common_mixups": "facing; trim",
      "not_the_same_as": "The mantel shelf or structural lintel.",
      "governing_document": "2021 IRC §R1001.11; BIA TN 19",
      "stated_specification": "The area immediately adjacent to the opening is subject to noncombustible-material and combustible-projection limits.",
      "verification_tier": "★",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use as a finish-zone term rather than a separate structural system."
    },
    {
      "number": "39",
      "id": "part-ash-dump-opening",
      "canonical_term": "Ash dump opening",
      "system": "Some masonry fireplaces",
      "plate": "A",
      "plain_definition": "An opening in or near the hearth through which cooled ash passes to a space below.",
      "aliases_or_common_mixups": "ash door in hearth",
      "not_the_same_as": "The cleanout door in the foundation wall.",
      "governing_document": "2021 IRC §R1001.2.1 context; BIA TN 19",
      "stated_specification": "No universal opening dimension is asserted; presence varies by fireplace design.",
      "verification_tier": "●",
      "source_codes": "IRC2021; BIA19",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Always publish with “where provided” or “some fireplaces.”"
    },
    {
      "number": "40",
      "id": "part-ash-pit",
      "canonical_term": "Ash pit",
      "system": "Some masonry fireplaces",
      "plate": "A",
      "plain_definition": "A masonry space below the firebox that receives ash through an ash-dump opening.",
      "aliases_or_common_mixups": "ash chamber",
      "not_the_same_as": "The cleanout opening used to empty it.",
      "governing_document": "BIA TN 19",
      "stated_specification": "BIA treats an ash pit as an optional void within the base assembly.",
      "verification_tier": "●",
      "source_codes": "BIA19",
      "source_urls": "https://www.gobrick.com/media/file/19-residential-fireplace-design.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Optional, system-dependent component."
    },
    {
      "number": "41",
      "id": "part-ash-cleanout-door",
      "canonical_term": "Ash-dump cleanout door",
      "system": "Some masonry fireplaces",
      "plate": "A",
      "plain_definition": "The access door in the foundation wall below a fireplace ash pit.",
      "aliases_or_common_mixups": "ash pit door; cleanout",
      "not_the_same_as": "The ash-dump opening in the hearth.",
      "governing_document": "2021 IRC §R1001.2.1",
      "stated_specification": "Ferrous-metal or masonry doors and frames are constructed to remain tightly closed except when in use and located so ash removal does not create a hazard to combustible material.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "State only where an ash-dump system is provided."
    },
    {
      "number": "42",
      "id": "part-exterior-air-intake",
      "canonical_term": "Exterior combustion-air intake",
      "system": "Masonry fireplace where exterior air is provided",
      "plate": "—",
      "plain_definition": "The exterior opening supplying combustion air to the fireplace air system.",
      "aliases_or_common_mixups": "outside-air hood; air intake",
      "not_the_same_as": "The interior air inlet at or near the firebox.",
      "governing_document": "2021 IRC §R1006.2",
      "stated_specification": "The intake is located to supply exterior air and is screened under the section’s material/opening provisions; prohibited locations and elevation limits are set by the code.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Avoid converting the section into installation instructions."
    },
    {
      "number": "43",
      "id": "part-combustion-air-passageway",
      "canonical_term": "Combustion-air passageway",
      "system": "Masonry fireplace where exterior air is provided",
      "plate": "—",
      "plain_definition": "The duct or passage carrying exterior combustion air toward the fireplace.",
      "aliases_or_common_mixups": "outside-air duct",
      "not_the_same_as": "The exterior intake or the interior inlet.",
      "governing_document": "2021 IRC §R1006.4",
      "stated_specification": "Not less than 6 square inches and not more than 55 square inches, subject to the section’s stated exception.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "Model-code dimension, not a design recommendation for every fireplace."
    },
    {
      "number": "44",
      "id": "part-combustion-air-inlet",
      "canonical_term": "Combustion-air inlet",
      "system": "Masonry fireplace where exterior air is provided",
      "plate": "—",
      "plain_definition": "The closable outlet delivering combustion air into or near the firebox.",
      "aliases_or_common_mixups": "inside air outlet",
      "not_the_same_as": "The exterior intake.",
      "governing_document": "2021 IRC §R1006.5",
      "stated_specification": "Located at the back or sides of the firebox or within 24 inches of the fireplace opening on or near the floor, and closable.",
      "verification_tier": "★",
      "source_codes": "IRC2021",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces",
      "verified_date": "2026-07-27",
      "publication_note": "State as 2021 model-code text."
    },
    {
      "number": "45",
      "id": "part-factory-built-fireplace",
      "canonical_term": "Factory-built fireplace unit",
      "system": "Factory-built wood fireplace",
      "plate": "C",
      "plain_definition": "The listed manufactured fireplace assembly installed as a system.",
      "aliases_or_common_mixups": "prefab fireplace; zero-clearance fireplace",
      "not_the_same_as": "A site-built masonry firebox.",
      "governing_document": "2021 IRC §R1004.1; Majestic ASH36-B manual",
      "stated_specification": "Listed, labeled, tested to UL 127 and installed in accordance with its listing and manufacturer instructions.",
      "verification_tier": "★",
      "source_codes": "IRC2021; MAJ2026",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not generalize one model’s dimensions to all factory-built fireplaces."
    },
    {
      "number": "46",
      "id": "part-refractory-panels",
      "canonical_term": "Refractory panels",
      "system": "Factory-built wood fireplace",
      "plate": "C",
      "plain_definition": "Manufactured heat-resistant panels lining the factory-built firebox.",
      "aliases_or_common_mixups": "molded brick panels; refractory brick panels",
      "not_the_same_as": "Site-laid firebrick masonry.",
      "governing_document": "Majestic ASH36-B manual",
      "stated_specification": "Panels are model-specific parts of the listed fireplace assembly and are installed according to the manual.",
      "verification_tier": "★",
      "source_codes": "MAJ2026",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Use current ASH36-B manual as the named example."
    },
    {
      "number": "47",
      "id": "part-factory-hearth-extension",
      "canonical_term": "Factory-built hearth extension",
      "system": "Factory-built wood fireplace",
      "plate": "—",
      "plain_definition": "The noncombustible floor protection in front of a listed factory-built fireplace.",
      "aliases_or_common_mixups": "hearth extension",
      "not_the_same_as": "A masonry hearth extension governed by prescriptive masonry dimensions.",
      "governing_document": "2021 IRC §R1004.2; Majestic ASH36-B manual",
      "stated_specification": "Installed in accordance with the fireplace listing; the code requires it to be readily distinguishable from surrounding floor. The Majestic manual supplies model-specific construction and dimensions.",
      "verification_tier": "★",
      "source_codes": "IRC2021; MAJ2026",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep model-code rule and product-specific details separate."
    },
    {
      "number": "48",
      "id": "part-chimney-chase",
      "canonical_term": "Chimney chase",
      "system": "Factory-built fireplace or enclosed manufactured chimney",
      "plate": "C",
      "plain_definition": "A framed enclosure around a manufactured fireplace chimney or chimney run.",
      "aliases_or_common_mixups": "chimney box; framed chimney",
      "not_the_same_as": "The listed chimney pipe inside it.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "Construction, clearances, insulation and ventilation details are system-specific; the Majestic manual shows a framed chase and requires the stated air space around its chimney.",
      "verification_tier": "●",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not call every chase a sealed or universally ventilated box."
    },
    {
      "number": "49",
      "id": "part-chase-top",
      "canonical_term": "Chase top",
      "system": "Factory-built fireplace in a chase",
      "plate": "C",
      "plain_definition": "The noncombustible cover closing the top of a framed chase around the chimney.",
      "aliases_or_common_mixups": "chase cover; chase top flashing",
      "not_the_same_as": "The termination cap on the chimney pipe.",
      "governing_document": "Majestic ASH36-B manual",
      "stated_specification": "The current manual identifies the chase top separately from chimney pipe, storm collar and termination cap and gives model-specific geometry.",
      "verification_tier": "★",
      "source_codes": "MAJ2026",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not use as a synonym for termination cap."
    },
    {
      "number": "50",
      "id": "part-protective-hearth-strips",
      "canonical_term": "Protective metal hearth strips",
      "system": "Majestic ASH36-B factory-built fireplace example",
      "plate": "C",
      "plain_definition": "Manufacturer-specified metal strips protecting concealed combustible flooring at the fireplace/hearth-extension interface.",
      "aliases_or_common_mixups": "metal hearth strips",
      "not_the_same_as": "The visible hearth extension.",
      "governing_document": "Majestic ASH36-B manual, §3F",
      "stated_specification": "For the ASH36-B, two strips are installed at the front edge with the overlap and extension specified in the manual; this is model-specific.",
      "verification_tier": "★",
      "source_codes": "MAJ2026",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Publish as a named manufacturer example, not a universal factory-built-fireplace part."
    },
    {
      "number": "51",
      "id": "part-factory-built-chimney-section",
      "canonical_term": "Factory-built fireplace chimney section",
      "system": "Factory-built wood fireplace",
      "plate": "C",
      "plain_definition": "A listed metal chimney section approved for the exact fireplace system.",
      "aliases_or_common_mixups": "fireplace chimney pipe",
      "not_the_same_as": "Generic stovepipe or an unrelated all-fuel chimney product.",
      "governing_document": "2021 IRC §R1005.4; Majestic ASH36-B manual",
      "stated_specification": "The current Majestic manual lists compatible SL1100-series chimney sections for the ASH36-B system.",
      "verification_tier": "★",
      "source_codes": "IRC2021; MAJ2026",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Compatibility is controlled by the exact listing and manual."
    },
    {
      "number": "52",
      "id": "part-decorative-shroud",
      "canonical_term": "Decorative shroud",
      "system": "Some factory-built fireplace terminations",
      "plate": "C",
      "plain_definition": "A decorative enclosure around a listed factory-built chimney termination.",
      "aliases_or_common_mixups": "shroud; field-constructed shroud; termination enclosure",
      "not_the_same_as": "The termination cap, chase top or any separate radiation shield required by the listed configuration.",
      "governing_document": "2021 IRC §§R1004.3 and R1005.2; Majestic ASH36-B manual, §6",
      "stated_specification": "Decorative shrouds are permitted only where listed and labeled for the specific system. The Majestic manual publishes tested shroud configurations and states that some require a separate radiation shield while others do not.",
      "verification_tier": "●",
      "source_codes": "IRC2021; MAJ2026",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Configuration-dependent; any associated radiation shield remains a separate component of the approved shroud/termination configuration."
    },
    {
      "number": "53",
      "id": "part-class-a-chimney-pipe",
      "canonical_term": "Class A chimney pipe",
      "system": "Listed all-fuel chimney",
      "plate": "D",
      "plain_definition": "Insulated, listed manufactured chimney pipe used within the applications covered by its listing.",
      "aliases_or_common_mixups": "all-fuel chimney; insulated chimney pipe",
      "not_the_same_as": "Interior connector/stovepipe.",
      "governing_document": "2021 IRC §R1005.3; DuraVent DuraTech catalog",
      "stated_specification": "DuraTech 5–8 inch is listed to UL 103 Type HT and CAN/ULC-604 and requires 2 inches of clearance to combustibles under its catalog.",
      "verification_tier": "★",
      "source_codes": "IRC2021; DV2025",
      "source_urls": "https://codes.iccsafe.org/content/IRC2021P2/chapter-10-chimneys-and-fireplaces; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "“Class A” is trade shorthand; the exact listing and manufacturer control."
    },
    {
      "number": "54",
      "id": "part-appliance-adapter",
      "canonical_term": "Appliance adapter",
      "system": "DuraTech listed all-fuel chimney example",
      "plate": "D",
      "plain_definition": "The listed transition connecting an appliance or connector product to the chimney support/pipe system.",
      "aliases_or_common_mixups": "DVL adapter; chimney adapter",
      "not_the_same_as": "The connector pipe itself.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "Named as position 18 in the DuraTech 18-position installation key.",
      "verification_tier": "★",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "DuraTech-specific component name and compatibility."
    },
    {
      "number": "55",
      "id": "part-anchor-plate",
      "canonical_term": "Anchor plate",
      "system": "DuraTech listed all-fuel chimney example",
      "plate": "—",
      "plain_definition": "A listed plate attaching chimney pipe to a compatible appliance or masonry-fireplace connection.",
      "aliases_or_common_mixups": "starter plate",
      "not_the_same_as": "A finishing collar.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "The catalog lists an anchor plate or anchor plate with damper as position 15 in its installation key.",
      "verification_tier": "★",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Configuration-specific DuraTech component."
    },
    {
      "number": "56",
      "id": "part-ceiling-support-box",
      "canonical_term": "Ceiling support box",
      "system": "DuraTech listed all-fuel chimney example",
      "plate": "D",
      "plain_definition": "A listed support carrying chimney weight at a ceiling penetration and providing the system transition.",
      "aliases_or_common_mixups": "ceiling support",
      "not_the_same_as": "A firestop radiation shield.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "For covered DuraTech configurations, catalog support boxes are rated to support up to 60 feet of chimney.",
      "verification_tier": "★",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Product-family figure, not a universal support capacity."
    },
    {
      "number": "57",
      "id": "part-firestop-spacer-shield",
      "canonical_term": "Firestop spacer / firestop radiation shield",
      "system": "Listed manufactured chimney systems",
      "plate": "C, D",
      "plain_definition": "A listed penetration component that closes or protects a framed floor/ceiling opening while maintaining the system’s required air space.",
      "aliases_or_common_mixups": "ceiling firestop; radiation shield",
      "not_the_same_as": "A ceiling support box that also carries chimney weight.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "The Majestic manual uses ceiling firestops; DuraVent requires a firestop radiation shield where DuraTech passes through a floor or ceiling without a support box.",
      "verification_tier": "★",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Name and function vary by listed system; preserve manufacturer terminology."
    },
    {
      "number": "58",
      "id": "part-attic-insulation-shield",
      "canonical_term": "Attic insulation shield",
      "system": "Listed manufactured chimney systems",
      "plate": "C, D",
      "plain_definition": "A shield that keeps insulation and other combustible material away from chimney pipe where the listed system requires it.",
      "aliases_or_common_mixups": "attic shield; insulation guard",
      "not_the_same_as": "A firestop or roof flashing.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "The Majestic manual requires it where insulation or combustible material could contact the chimney; DuraVent states it must be used in every DuraTech installation passing through an attic.",
      "verification_tier": "★",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "State each manufacturer’s rule separately."
    },
    {
      "number": "59",
      "id": "part-roof-support-bracket",
      "canonical_term": "Roof support / extended roof bracket",
      "system": "Some DuraTech configurations",
      "plate": "D",
      "plain_definition": "Listed support or bracing used at or above the roof where the DuraTech configuration calls for it.",
      "aliases_or_common_mixups": "roof bracket; extended roof bracket",
      "not_the_same_as": "Roof flashing.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "For DuraTech, an extended roof bracket is required when the chimney extends 5 feet or more above the roof penetration, with another bracket every additional 5 feet.",
      "verification_tier": "●",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Configuration-dependent and manufacturer-specific."
    },
    {
      "number": "60",
      "id": "part-roof-flashing",
      "canonical_term": "Roof flashing",
      "system": "Manufactured chimney at roof",
      "plate": "D",
      "plain_definition": "The listed or approved weather-shedding assembly around a manufactured chimney roof penetration.",
      "aliases_or_common_mixups": "roof boot; flashing",
      "not_the_same_as": "A storm collar.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "Pitch and component selection come from the exact system; the DuraTech catalog identifies flashing separately from the storm collar.",
      "verification_tier": "★",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not apply masonry base/counterflashing terminology to manufactured pipe."
    },
    {
      "number": "61",
      "id": "part-storm-collar",
      "canonical_term": "Storm collar",
      "system": "Manufactured chimney at roof",
      "plate": "C, D",
      "plain_definition": "A collar around chimney pipe above roof flashing or a chase top that directs water over the joint.",
      "aliases_or_common_mixups": "weather collar",
      "not_the_same_as": "The flashing or chase top.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "The DuraTech catalog requires a storm collar with roof flashing and specifies sealing its inner edge with non-hardening 500°F high-temperature sealant; the Majestic manual shows product-specific chase-top sealing.",
      "verification_tier": "★",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Keep manufacturer instructions tied to their systems."
    },
    {
      "number": "62",
      "id": "part-termination-cap",
      "canonical_term": "Termination cap / chimney cap",
      "system": "Manufactured chimney systems",
      "plate": "C, D",
      "plain_definition": "The listed top termination approved for the manufactured chimney system.",
      "aliases_or_common_mixups": "chimney cap",
      "not_the_same_as": "A masonry crown or a chase top.",
      "governing_document": "Majestic ASH36-B manual; DuraVent DuraTech catalog",
      "stated_specification": "The Majestic manual requires a cap approved and listed for its fireplace system; the DuraTech cap is removable for inspection and maintenance, with a spark arrestor offered separately.",
      "verification_tier": "★",
      "source_codes": "MAJ2026; DV2025",
      "source_urls": "https://downloads.hearthnhome.com/installManuals/4059_966_ASH36-B_INSTALL.pdf; https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not generalize one cap’s geometry to another system."
    },
    {
      "number": "63",
      "id": "part-wall-thimble",
      "canonical_term": "Wall thimble",
      "system": "DuraTech through-wall example",
      "plate": "D",
      "plain_definition": "A listed wall-penetration component used with the specified manufactured chimney pipe.",
      "aliases_or_common_mixups": "through-wall thimble",
      "not_the_same_as": "A lined opening built into a masonry chimney.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "For DuraTech, the wall thimble adjusts for the cataloged wall-thickness range and the chimney pipe extends 6 inches into the room beyond the interior wall.",
      "verification_tier": "★",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Product-family dimensions only."
    },
    {
      "number": "64",
      "id": "part-tee-with-cap",
      "canonical_term": "Tee with tee cap",
      "system": "DuraTech through-wall example",
      "plate": "D",
      "plain_definition": "A listed fitting turning a horizontal chimney connection upward, with a removable bottom cap for access.",
      "aliases_or_common_mixups": "chimney tee; cleanout tee",
      "not_the_same_as": "A masonry cleanout door.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "Named as position 11 in the DuraTech installation key; exact use and support follow the system instructions.",
      "verification_tier": "★",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Do not treat the tee cap as a universal cleanout design."
    },
    {
      "number": "65",
      "id": "part-support-brackets",
      "canonical_term": "Support brackets / wall straps",
      "system": "Some DuraTech configurations",
      "plate": "D",
      "plain_definition": "Listed supports that carry a tee or laterally stabilize an exterior vertical chimney run in the covered configuration.",
      "aliases_or_common_mixups": "tee support; wall strap; wall support",
      "not_the_same_as": "A roof support, roof flashing or ceiling support box.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "The DuraTech catalog gives configuration-specific tee-support capacities and wall-strap spacing; those figures do not transfer to other product families.",
      "verification_tier": "●",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Grouped configuration-dependent support category; exact capacity and spacing come from the listed system instructions."
    },
    {
      "number": "66",
      "id": "part-elbow-support-straps",
      "canonical_term": "Elbow and elbow strap",
      "system": "Some DuraTech offset/vertical configurations",
      "plate": "D",
      "plain_definition": "Listed angled chimney fittings and the strap used to support an approved offset.",
      "aliases_or_common_mixups": "elbow; elbow strap; offset",
      "not_the_same_as": "A connector-pipe elbow, wall strap or roof support.",
      "governing_document": "DuraVent DuraTech catalog",
      "stated_specification": "DuraTech elbows are fixed at 15 or 30 degrees; offsets over 30 degrees are not permitted by the catalog’s UL 103 configuration, no more than two offsets are permitted and at least one elbow strap is required for each offset.",
      "verification_tier": "●",
      "source_codes": "DV2025",
      "source_urls": "https://duravent.com/literature/Duravent_DuraTech_5-8_Catalog.pdf",
      "verified_date": "2026-07-27",
      "publication_note": "Configuration-dependent offset components; the cataloged angles and limits apply only to the named DuraTech product family."
    }
  ]
}