7. Design requirements for masonary chimneys./n 9.18 FIREPLACES Open Front Open Front and Side 60° min.- 8" (205) min. 4" (100) min. Open Front and Back Types of Fireplaces CSI MasterFormat 04 57 00: Masonry Fireplaces The flue creates a draft and carries off the smoke and gases of a fire to the outside. The smoke chamber connects the throat of a fireplace to the flue of a chimney. The smoke shelf at the bottom of a smoke chamber deflects downdrafts from the chimney. E The throat is the narrow opening between a firebox and the smoke chamber; it is fitted with a damper that regulates the draft in a fireplace. The firebox is the chamber where combustion takes place. The hearth extends the floor of a fireplace with a noncombustible material, such as brick, tile, or stone. Typical Fireplace Dimensions in Inches (mm) Width (A) Height (B) Depth (C) (D) Open Front 36 (915) 29 (735) 42 (1065) 32 (815) 48 (1220) 32 (815) 54 (1370) 37 (940) 60 (1525) 40 (1015) 72 (1830) 40 (1015) Open Front and Side 28 (710) 32 (815) 36 (915) 48 (1220) 24 (610) 28 (710) 30 (760) 32 (815) Open Front and Back 28 (710) 24 (610) 32 (815) 28 (710) 36 (915) 30 (760) 48 (1220) 32 (815) 20 (510) 20 (510) 20 (510) 20 (510) 22 (560) 22 (560) 16 (405) 18 (455) 20 (510) 22 (559) A fireplace is a framed opening in a chimney to hold an open fire. It must be designed and constructed to: • Sustain the combustion of fuel; • Draw properly to carry smoke and other combustive by-products to the outside; • Radiate the maximum amount of heat 16 (405) 16 (405) 17 (430) 19 (485) comfortably into the room; • Ensure proper distances from combustible materials. Thus the dimensions and proportions of a fireplace and its flue, and the arrangement of its components, are subject to the laws of nature and the requirements of the building and mechanical codes. The table below provides typical dimensions for three types of fireplaces. See facing page for key to letter heads (A) through (G). (E) 23 (560) 14 (355) 29 (735) 16 (405) 33 (840) 16 (405) 37 (940) 16 (405) 42 (1065) 18 (455) 54 (1370) 18 (455) (F) (G) 23 (560) 24 (610) 24 (610) 56(1420) 29 (735) 68 (1725) 30 (760) 72 (1830) 30 (760) 84 (2135) Multifaced fireplaces are especially sensitive to drafts in a room; avoid placing their openings opposite an exterior door. 44 (1120) 50 (1270) Flue Size 12×12 (305 x 305) 16×16 (405x405) 16x16 (405x405) 16×16 (405x405) 16×20 (405x510) 20×20 (510x510) 12×12 (305x305) 12×16 (305x405) 12x16 (305x405) 16x16 (405x405) 12×12 (305x305) 12x16 (305x405) 12 x 16 (305x405) 16x16 (405x405) Fireplace Plan . Flue should be centered over firebox to avoid uneven drafting.. Allow for expansion at damper ends. 8" (205) minimum to any combustible material Fireplace Elevation For typical fireplace dimensions, see table on previous page. . 8" (205) minimum A 8" (205) minimum 1'4" (405) minimum 1'6" (455) minimum Hearth of brick, concrete, or stone B Fireplace Section . . . . . . . 4" (100) minimum to wood framing . Noncombustible firestopping @wood floor joists 2" (51) minimum to wood framing 1" (25) space filled w/ noncombustible insulation 4" (100) firebrick Steel angle lintels • Back and sides splayed to radiate and reflect heat forward 4" (100) minimum thickness Fire-clay flue lining Sides of flue and smoke chamber should be smooth to minimize drag effect on the rising current of warm air. Provide structural support for flue lining.- Smoke chamber; parged Smoke shelf Damper regulates draw of fireplace. - Throat passes smoke into smoke chamber.- ……………………. FIREPLACE REQUIREMENTS 9.19 Firebox of firebrick Hearth of brick, concrete, or stone Reinforced concrete slab- Ashpit and outside air intake Foundations for masonry fireplaces and chimneys should be large enough that the resulting unit load on the supporting soil is equal under all parts of the structure. 9.20 MASONRY CHIMNEYS Rectangular flues Size = outside faces. • Modular flues • Size = actual + 1/2" (13)- • Round flues . 3' (915) minimum above flat roof To ensure proper draft, chimney should extend at least 2' (610) above any part of the building within 10' (3050) of it; consult building code for detailed requirements. Size inside ø. 8" (205) minimum when exposed to weather Cricket flashing Flue linings are smooth-surfaced units of heat-resistant fire clay or lightweight concrete. Maximum offset for masonry chimneys: 1 in 6 4" (100) minimum Fire-clay flue liner 2" (51) minimum clear from combustible construction; provide firestopping between chimney and wood framing. Each fireplace, woodburning stove, or furnace requires its own separate flue. Minimum Flue Sizes Square or rectangular: ¹/10th of fireplace opening Round: 1/12th of fireplace opening CSI MasterFormat 04 51 00: Flue Liner Masonry Diameter Area in. (mm) sq.in.* Chimney Hood 1 Typical Flue Dimensions and Areas Round VE //////////// Rectangular Size in. (mm) Area sq.in.* 8 (205) 47 81/2x8¹/2 (215x215) 51 10 (255) 74 81/2 x 13 (215x330) 79 12 (305) 108 13×13 (330x330) 125 15 (380) 171 13x18 (330×455) 168 18 (455) 240 18 x 18 (455x455) 232 20 (510) 298 20×20 (510x510) 279 * One square inch = 645.16 mm² Stone or precast concrete cap Reinforced cement wash to drain rainwater Wythe between adjacent flues to prevent downdraft Height of opening should be 1¹/4 x flue width. 4" (100) offset to prevent downdraft from one flue to the next Flue lining stands free of surrounding masonry; lining should have close- fitting joints and be left smooth on the inside. 4" (100) minimum; 8" (205) minimum when exposed to exterior Consult building or mechanical code for chimney requirements of high heat appliances such as incinerators. In certain seismic zones, masonry chimneys require reinforcement and anchorage to the structural frame of a building. Consult the building code for detail requirements. Four #4 bars minimum, tied @ 18" (455) o.c. w/ #2 bars Grout Oval flue liner 3/16" x 1" (5 x 25) steel straps cast at least 12" (305) into chimney and bent around reinforcement Modular Size in. (mm) Area sq.in.* 8×12 (205x305) 57 12×12 (305x305) 87 12 x 16 (305x405) 120 162 16x16 (405x405) 16x20 (405x510) 208 20×20 (510x510) 262 Prefabricated fireplaces and woodburning stoves should be certified by the Environmental Protection Agency (EPA) for burning efficiency and allowable particulate emissions. 20" (510) Rain cap Metal collar Fabricated metal chase top 2" (51) minimum flange 15° or 30° offsets Maintain 2" (51) minimum clearance from combustible construction. Insulated chimney sections Heated air return Noncombustible flush or projected facing Screened opening w/ glass doors Refractory brick lining Noncombustible hearth Cool room air intake; fan optional Outside combustion air intake Zero-clearance models have insulated shells and may be installed against combustible framing. Typical widths: 36", 38", 46", 48", 54" (915,965, 1170, 1220, 1370) Typical heights: 30", 32", 36" (760, 815, 915) Typical depth: 24" (610) Prefabricated Fireplaces PREFABRICATED FIREPLACES & STOVES 9.21 18" (455) minimum on loading side Noncombustible hearth of brick, slate, stone, or metal plate Verify installation details and requirements with stove manufacturer and building code. Woodburning Stoves . Rain cap Cable or rigid guy as required to stabilize tall chimneys Insulated metal chimney 3' (915) minimum above roof penetration and at least 2¹ (610) above any part of the building within 10' (3050); verify requirements with the building code. Flashing cone 2" (51) minimum clearance from any combustible construction Firestop spacer at each floor or ceiling 18" (455) minimum between uninsulated metal chimneys and combustible wall or ceiling surfaces 6" (150) minimum 36" (915) minimum 36" (915) minimum; may be 18" (455) if wall is protected by a noncombustible heat shield 1" (25) clear air space Insulating support Outside combustion air intake. Provide adequate ventilation for combustion if fans of mechanical equipment can generate negative pressure in the fireplace room. Provide access for cleaning flues CSI MasterFormat 10 31 00: Manufactured Fireplaces CSI MasterFormat 10 35 00: Stoves

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