8 0.759 x 0.050 1.79 1.87 10 0.779 x 0.054 1.24 1.32 Class 2 Perforations Type SP D d WIA 12 0.3125 2.85 15 0.3125 2.11 18 0.3125 1.87 24 0.3750 2.68 30 0.3750 2.64 36 0.3750 2.61 42 0.3750 2.00 48 0.3750 2.00 Figure 1. Class 1 Perforations 12 to 18-inch Pipe 24 to 48-inch Pipe Figure 2. Class 2 Perforations 4 to 10-inch Pipe 12 to 18-inch Pipe