Specification BS3799 Nominal Size A (Min) W (Min) E (Min) b (1> C (Min) F (Min) Equal Reducing In DN In DN (2) 3M ï¼?2ï¼? 6M 1/8 (6) 11 26 10 5 2 6 1/4 (8) 15 36 15 8 6 6 1/4 x 1/8 (8x6) 15 31 15 5 2 6 10 3/8 (10) 18 40 16 11 8 8 3/8x174 (10x8) 18 39 16 8 6 8 15 1/2 (15) 22 48 20 14 11 8 1/2 x 3/8 (15x10) 22 44 20 11 8 8 16 172x1/4 (15x8) 22 43 20 8 6 8 15 3/4 (20) 27 52 21 19 13 10 3/4 x 1/2 (20x15) 27 50 21 14 11 9 20 3/4 x 3/8 (20x10) 27 46 21 11 8 9 16 1 (25) 35 60 25 24 17 10 1x3/4 (25x20) 35 56 25 19 13 10 21 1x1/2 (25x15) 35 55 25 14 11 10 20 1-1/2 (40) 50 68 26 38 30 16 1-1/2 x1 (40x25) 50 67 26 24 17 16 25 1-1/2x374 (40x20) 50 63 26 19 13 16 21 1-172x1/2 (40x15) 50 62 26 14 11 16 20 2 (50) 62 71 27 49 39 17 2x1-172 (50x40) 62 70 27 38 30 17 26 2x1 (50x25) 62 70 27 24 17 18 25 2x3/4 (50x20) 62 65 27 19 13 17 21 2x1/2 (50x15) 62 65 27 14 11 18 20