4.1.7.12.Attached Canopies on Low Buildings with a Height H ≤ 20 m

(See Note A-4.1.7.12.) (1) For the purposes of this Article, “attached canopy” shall mean a horizontal canopy with a maximum slope of 2% that is attached to a building wall at any height, hc, above ground level. (2) The specified external wind pressure, p, and the specified net external wind pressure, pnet, for attached canopies on exterior walls of low buildings with a height H ≤ 20 m shall be determined as follows: p = IW qCe Ct Cg Cp , and pnet = Iw qCe Ct (Cg Cp ) net where p = specified external wind pressure acting statically and in a direction normal to the upper or lower surface of the canopy, considered positive when acting towards the surface and negative when acting away from the surface, pnet = specified net external wind pressure acting statically on the canopy, considered positive when acting in a downward direction and negative when acting in an upward direction, IW, q, Ce, Ct = as defined in Sentence 4.1.7.3.(1), CgCp = gust pressure coefficient on the upper or lower surface of the canopy, as given in Figure 4.1.7.12.-A, and (CgCp)net = net gust pressure coefficient on the canopy, considering simultaneous contributions from the upper and lower surfaces of the canopy, as given in Figure 4.1.7.12.-B. Figure 4.1.7.12.-A Gust Pressure Coefficients on the Upper and Lower Surfaces of Attached Canopies With no Gap Between the Canopy and the Building Forming Part of Sentence 4.1.7.12.(2) Notes to Figure 4.1.7.12.-A: (1) The coefficients apply for any roof slope, a. (2) The reference height, h, is the mid-height of the roof or 6 m, whichever is greater. (3) Positive CgCp values denote forces acting towards the upper or lower surface of the canopy, whereas negative CgCp values denote forces acting away from the surface. Each structural element must be designed to resist both the positive and negative forces. Figure 4.1.7.12.-B Net Gust Pressure Coefficients on Attached Canopies, Considering Simultaneous Contributions from the Upper and Lower Surfaces of the Canopy Forming Part of Sentence 4.1.7.12.(2) Notes to Figure 4.1.7.12.-B: (1) The coefficients apply for any roof slope, . (2) The reference height, h, is the mid-height of the roof or 6 m, whichever is greater. (3) Positive (CgCp)net values denote net forces acting in a downward direction on the canopy, whereas negative (CgCp)net values denote net forces acting in an upward direction on the canopy. The canopy must be designed to resist both the positive and negative net forces.