9.4.2.1.Application (See Note A-9.4.2.1. and 9.4.2.2.)

(1) This Subsection applies to light-frame construction whose wall, floor and roof planes are generally comprised of frames of small repetitive structural members, and where (a) the roof and wall planes are clad, sheathed or braced on at least one side, (b) the small repetitive structural members are spaced not more than 600 mm o.c., (c) the clear span of any structural member does not exceed 12.2 m, (d) the maximum deflection of the structural roof members conforms to Article 9.4.3.1., (e) the maximum total roof area, notwithstanding any separation of adjoining buildings by firewalls, is 4 550 m2, and (f) for flat roofs, there are no significant obstructions on the roof, such as parapet walls, spaced closer than the distance calculated by Do = 10(Ho – 0.8 Ss / γ) where Do = minimum distance between obstructions, m, Ho = height of the obstruction above the roof, m, Ss = ground snow load, kPa, and γ = specific weight of snow taken as 4.0 kN/m3 or 0.43Ss + 2.2 kN/m3, whichever is lesser.