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ANNEX B 415-15
<br /> Annex B Building Construction Types Exception No.3:Certain concealed spaces shall be permitted by the
<br /> exception to 3-4.4.
<br /> This annex is not a part of the requirements of this ATTA document 3-4.2 Wood columns supporting floor loads shall be not less
<br /> but is included for informational purposes only. than 8 in. (203 mm) in any dimension; wood columns sup-
<br /> B.1 Building construction types are defined in NFPA 220, porting roof loads only shall be not less than 6 in. (152 mm)in
<br /> Standard on Types of Building Construction.The following mate- the smallest dimension and not less than 8 in. (203 mm) in
<br /> rial is extracted from the 1999 edition of NFPA 220 and is depth.
<br /> included here as a convenience for users of this standard.Any 34.3 Wood beams and girders supporting floor loads shall
<br /> requests for Formal Interpretations (FIs) or Tentative Interim be not less than 6 in. (152 mm) in width and not less than
<br /> Amendments (TIAs) on the following material should be di- 10 in. (254 mm) in depth;wood beams and girders and other
<br /> rected to the Technical Committee on Building Construction. roof framing supporting roof loads only shall be not less than
<br /> 3-1 *Type I(443 or 332).Type I construction shall be that 4 in. (102 mm) in width and not less than 6 in. (152 mm) in
<br /> type in which the structural members, including walls, col- depth.
<br /> umns,beams,girders,trusses,arches,floors,and roofs,are of 3-4.4 Framed or glued laminated arches that spring from
<br /> approved noncombustible or limited-combustible materials grade or the floor line and timber trusses that support floor
<br /> and shall have fire resistance ratings not less than those speci- loads shall be not less than 8 in. (203 mm) in width or depth.
<br /> fied in Table 3-1 [shown here as Table B.1]. Framed or glued laminated arches for roof construction that
<br /> 3-21�pe II(222, 111,or 000).Type II construction shall be spring from grade or the floor line and do not support floor
<br /> that type not qualifying as Type I construction in which the loads shall have members not less than 6 in. (152 mm) in
<br /> structural members,including walls,columns,beams,girders, width and not less than 8 in. (203 mm) in depth for the lower
<br /> trusses,arches,floors,and roofs,are of approved noncombus- half of the member height and not less than 6 in. (152 mm)in
<br /> tible or limited-combustible materials and shall have fire resis- depth for the upper half of the member height. Framed or
<br /> tance ratings not less than those specified in Table 3-1 [shown glued laminated arches for roof construction that spring from
<br /> here as Table B.1]. the top of walls or wall abutments and timber trusses that do
<br /> 3-3 Type I11(211 or 200).Type III construction shall be that not support floor loads shall have members not less than 4 in.
<br /> type in which exterior walls and structural members that are (102 mm)in width and not less than 6 in. (152 mm)in depth.
<br /> portions of exterior walls are of approved noncombustible or Exception:Spaced members shall be permitted to be composed of two
<br /> limited-combustible materials, and interior structural mem- or more pieces not less than 3 in. (76 mm)in thickness where blocked
<br /> bers,including walls,columns,beams,girders,trusses,arches, solidly throughout their intervening spaces or where such spaces are
<br /> floors, and roofs, are entirely or partially of wood of smaller tightly closed by a continuous wood cover plate not less than 2 in.
<br /> dimensions than required for Type IV construction or of ap- (51 mm)in thickness,secured to the underside of the members.
<br /> proved noncombustible, limited-combustible, or other ap- Splice plates shall be not less than 3 in. (76 mm)in thickness.
<br /> proved combustible materials. In addition, structural mem- 34.5 Floors shall be constructed of spline or tongue-and-
<br /> bers shall have fire resistance ratings not less than those groove plank not less than 3 in. (76 mm) in thickness that is
<br /> Table 3 1 [shown here as Table B.1]. covered with 1-in. (25-mm) tongue-and-groove flooring, laid
<br /> specified in Ta
<br /> 3 4*Type bl(2HH) crosswise or diagonally to the plank,or with '/rin. (12.7-mm)
<br /> plywood;or they shall be constructed of laminated planks not
<br /> 34.1 Type IV construction shall be that type in which exte- less than 4 in. (102 mm) in width,set close together on edge,
<br /> rior and interior walls and structural members that are por- spiked at intervals of 18 in. (457 mm),and covered with 1-in.
<br /> tions of such walls are of approved noncombustible or limited- (25-mm) tongue-and-groove flooring,laid crosswise or diago-
<br /> combustible materials. Other interior structural members, nally to the plank,or with'/�-in. (12.7-mm) plywood.
<br /> including columns,beams,girders,trusses,arches,floors,and 34.6 Roof decks shall be constructed of spline or tongue-
<br /> roofs,shall be of solid or laminated wood without concealed and-groove plank not less than 2 in. (51 mm) in thickness;or of
<br /> spaces and shall comply with the provisions of 3-4.2 through laminated planks not less than 3 in. (76 mm) in width,set close
<br /> 34.6. In addition, structural members shall have fire resis- together on edge, and laid as required for floors; or of IVs-in.
<br /> tance ratings not less than those specified in Table 3-1 [shown (28.6-mm)thick interior plywood(exterior glue);or of approved
<br /> here as Table B.1]. noncombustible or limited-combustible materials of equivalent
<br /> Exception No. 1:Exterior walls greater than 30 ft(9.1 m)from the fire durability.
<br /> property line shall be permitted to be of heavy timber construction pro- 3-5 Type V(111 or 000).Type V construction shall be that
<br /> vided the 2-hour rating as required by Table 3-1 is maintained and type in which exterior walls, bearing walls, columns, beams,
<br /> such walls contain no combustible concealed spaces. girders, trusses, arches, floors, and roofs are entirely or par-
<br /> Exception No. 2: Interior columns, arches, beams, girders, and tially of wood or other approved combustible material smaller
<br /> trusses of approved materials other than wood shall be permitted,pro- than material required for Type IV construction.In addition,
<br /> vided they are protected to provide a fire resistance rating of not less structural members shall have fire resistance ratings not less
<br /> than l hour. than those specified in Table 3-1 [shown here as Table B.1].
<br /> 2008 Edition
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