Common Steel Pipe Specifications Table

Pipe diameters should be measured in millimeters (mm), and the expression of pipe diameters should conform to the following regulations:

  1. Water and Gas Transmission Steel Pipes (galvanized or non-galvanized), Cast Iron Pipes, etc.:
    • The pipe diameter should be indicated by the nominal diameter DN.
  2. Seamless Steel Pipes, Welded Steel Pipes (straight seam or spiral seam), Copper Pipes, Stainless Steel Pipes, etc.:
    • The pipe diameter should be expressed as D×δ (outer diameter × wall thickness).
  3. Reinforced Concrete (or Concrete) Pipes, Clay Pipes, Acid-Resistant Ceramic Pipes, Tile Pipes, etc.:
    • The pipe diameter should be indicated by the inner diameter d.
  4. Plastic Pipes:
    • The pipe diameter should be indicated according to the methods specified in product standards. When the design uses the nominal diameter DN to represent the pipe diameter, a comparison table between the nominal diameter DN and the corresponding product specifications should be provided.
    • For rigid polyvinyl chloride (PVC-U) pipes used in building drainage, specifications are expressed as de × e (nominal outside diameter × nominal wall thickness) according to GB 5836.1-92.
    • For polypropylene (PP) pipes used for water supply, specifications are expressed as de × e (nominal outside diameter × wall thickness).

Conversion Between Metric and Imperial Units

  • 1 inch = 25.4 millimeters = 8 eighths 
Imperial Size Description Nominal Diameter (DN)
1/2″ Four-eighths DN15
3/4″ Six-eighths DN20
1″ DN25
1.2″ DN32
1.5″ DN40
2″ DN50
2.5″ DN65
3″ DN80
4″ DN100
5″ DN125
6″ DN150
8″ DN200
10″ DN250
12″ DN300

 

Outer Diameters and Theoretical Weights (kg/m):

Outer Diameter (mm) 2.5 mm 3.0 mm 3.5 mm 4.0 mm 4.5 mm 5.0 mm 6.0 mm 7.0 mm 8.0 mm 9.0 mm 10.0 mm 12.0 mm
12 0.586 0.666 0.734 0.789 – – – – – – – –
14 0.709 0.810 0.910 0.990 – – – – – – – –
18 0.956 1.110 1.250 1.380 1.500 1.600 2.070 3.110 4.470 – – –
20 1.080 1.260 1.420 1.580 1.720 1.850 2.810 4.320 5.950 7.320 – –
25 1.390 1.630 1.860 2.070 2.280 2.470 3.850 5.350 6.710 7.990 10.650 –
32 1.760 2.150 2.460 2.760 3.050 3.330 4.740 6.040 7.300 9.670 11.320 14.210
38 2.190 2.590 2.980 3.350 3.720 4.070 5.330 6.560 7.300 8.630 10.260 14.210
42 2.440 2.890 3.350 3.750 4.160 4.560 5.770 6.560 7.300 8.630 10.260 14.210
45 2.620 3.110 3.580 4.040 4.490 4.930 5.770 6.560 7.300 8.630 10.260 14.210
57 3.360 4.000 4.620 5.230 5.830 6.410 7.550 8.630 9.670 10.650 12.820 17.760
60 3.550 4.220 4.880 5.520 6.160 6.780 7.990 9.150 10.260 11.320 12.820 17.760
73 4.350 5.180 6.000 6.810 7.600 8.380 9.910 11.390 12.820 14.210 15.980 20.640
76 4.530 5.400 6.260 7.100 7.930 8.750 10.360 11.910 13.120 14.370 15.980 20.640
89 5.330 6.360 7.380 8.380 9.380 10.360 12.280 14.160 15.980 17.760 18.550 23.310
102 6.130 7.320 8.500 9.670 10.820 11.960 14.210 16.400 18.550 20.640 23.310 27.520
108 6.500 7.770 9.020 10.260 11.490 12.700 15.090 17.440 19.730 21.970 23.310 29.080
114 – – – 10.480 12.150 13.440 15.980 18.470 20.910 23.310 25.560 29.080
133 – – – 12.730 14.260 15.780 18.790 21.750 24.660 27.520 30.330 35.290
140 – – – 13.420 15.070 16.650 19.830 22.960 26.040 29.080 32.060 38.970
159 – – – – 17.150 18.990 22.640 26.240 29.790 33.290 36.750 43.500
168 – – – – – 20.100 23.970 27.790 31.570 35.290 38.970 46.170
219 – – – – – 31.520 36.600 41.630 46.610 52.380 57.950 70.140
245 – – – – – 41.090 45.920 52.280 58.600 64.860 77.680 90.510
273 – – – – – 45.920 52.280 58.600 64.860 70.140 90.510 102.590
325 – – – – – 62.540 70.140 77.680 92.550 102.590 115.900 139.490
377 – – – – – 81.680 90.510 102.590 115.620 128.230 154.290 175.960
426 – – – – – 92.550 102.590 115.620 128.230 139.490 175.960 197.630
480 – – – – – 104.540 115.620 128.230 139.490 154.290 175.960 197.630
530 – – – – – 115.620 128.230 139.490 154.290 175.960 197.630 220.300