AS 4041 Pipe Wall Thickness Reference

Carbon steel example values for pressure piping design, shown by DN and NPS. Use the assumptions below as a screening reference, not as a final design certification.

AS 4041 design formula

The calculation engine uses t = P D / (2(f E − P)) + c, where t is the required wall, P is design pressure, D is outside diameter, f is the AS 4041 design stress, E is joint efficiency, and c is corrosion allowance.

Example assumptions: P = 1.00 MPa, f = 138 MPa, E = 1.00, c = 0.75 mm, and design temperature 20°C. Confirm material grade, temperature derating, weld efficiency, corrosion allowance, loads, and code requirements for a project design.

Illustrative AS 4041 required wall thickness at 1 MPa
DN NPS Outside diameter (mm) Required wall t (mm)
6 1/8" 10.29 0.79
8 1/4" 13.72 0.80
10 3/8" 17.15 0.81
15 1/2" 21.34 0.83
20 3/4" 26.67 0.85
25 1" 33.40 0.87
32 1-1/4" 42.16 0.90
40 1-1/2" 48.26 0.93
50 2" 60.33 0.97
65 2-1/2" 73.03 1.02
80 3" 88.90 1.07
90 3-1/2" 101.60 1.12
100 4" 114.30 1.17
125 5" 141.30 1.27
150 6" 168.28 1.36
200 8" 219.08 1.55
250 10" 273.05 1.75
300 12" 323.85 1.93
350 14" 355.60 2.05
400 16" 406.40 2.23
450 18" 457.20 2.42
500 20" 508.00 2.60
550 22" 558.80 2.79
600 24" 609.60 2.97
650 26" 660.40 3.16
700 28" 711.20 3.35
750 30" 762.00 3.53
800 32" 812.80 3.72
850 34" 863.60 3.90
900 36" 914.40 4.09

For a complete calculation with material selection, design temperature, corrosion allowance, joint efficiency, and stocked pipe schedules, use the engineering calculations module. Compare nominal dimensions with the carbon steel pipe chart.