Maximum clear span of purlins supporting rafters for roof pitch 15°–22.5° with imposed load 1.00 kN/m²

Table 4B.18 Maximum clear span of purlins supporting rafters (m); Roof pitch more than 15° but not more than 22.5°; Imposed load of 1.00 kN/m²; Timber strength class C24 Dead Load [kN/m²] excluding the self weight of the purlin Size of purlin (mm) | Not more than 0.50 | More than 0.50 but not more than 0.75 | More than 0.75 but not more than 1.00 Design spacing of purlins (mm) | 1500 1800 2100 2400 2700 3000 | 1500 1800 2100 2400 2700 3000 | 1500 1800 2100 2400 2700 3000 47 x 150 | 1.83 | | 47 x 175 | 2.13 2.00 1.88 | 2.02 1.89 | 1.93 47 x 200 | 2.44 2.28 2.15 2.05 1.96 1.88 | 2.31 2.16 2.04 1.93 1.82 | 2.20 2.05 1.94 47 x 225 | 2.74 2.56 2.42 2.30 2.20 2.11 | 2.59 2.43 2.29 2.17 2.04 1.83 | 2.47 2.31 2.18 2.02 63 x 150 | 2.03 1.90 1.80 | 1.93 1.81 | 1.84 63 x 175 | 2.37 2.22 2.10 2.00 1.91 1.84 | 2.25 2.10 1.99 1.89 1.81 | 2.14 2.01 1.90 1.80 63 x 200 | 2.70 2.53 2.40 2.28 2.19 2.10 | 2.57 2.40 2.27 2.16 2.07 1.99 | 2.45 2.29 2.16 2.06 1.97 1.89 63 x 225 | 3.04 2.85 2.70 2.57 2.46 2.36 | 2.88 2.70 2.55 2.43 2.32 2.23 | 2.75 2.58 2.43 2.31 2.21 2.12 75 x 125 | 1.80 | | 75 x 150 | 2.16 2.03 1.92 1.83 | 2.05 1.92 1.82 | 1.96 1.83 75 x 175 | 2.52 2.36 2.24 2.13 2.04 1.96 | 2.39 2.24 2.12 2.02 1.93 1.86 | 2.28 2.14 2.02 1.92 1.84 75 x 200 | 2.87 2.70 2.55 2.43 2.33 2.24 | 2.73 2.56 2.42 2.31 2.21 2.12 | 2.61 2.44 2.31 2.20 2.10 2.02 75 x 225 | 3.23 3.03 2.87 2.74 2.62 2.52 | 3.07 2.88 2.72 2.59 2.48 2.39 | 2.93 2.75 2.60 2.47 2.36 2.27 2 x 47 x 200 | 3.25 3.06 2.90 2.76 2.65 2.55 | 3.09 2.90 2.75 2.62 2.52 2.42 | 2.96 2.77 2.63 2.50 2.40 2.31 2 x 47 x 225 | 3.65 3.43 3.26 3.11 2.98 2.87 | 3.47 3.26 3.09 2.95 2.83 2.72 | 3.32 3.12 2.95 2.82 2.70 2.60 2 x 47 x 250 | 4.05 3.81 3.61 3.45 3.31 3.19 | 3.85 3.62 3.43 3.27 3.14 3.02 | 3.69 3.46 3.28 3.13 3.00 2.88 2 x 47 x 275 | 4.45 4.19 3.97 3.79 3.64 3.50 | 4.23 3.98 3.77 3.60 3.45 3.32 | 4.05 3.80 3.60 3.44 3.29 3.17 2 x 47 x 300 | 4.85 4.56 4.33 4.13 3.96 3.82 | 4.61 4.33 4.11 3.92 3.76 3.62 | 4.41 4.14 3.93 3.75 3.59 3.46