Note :

- Span are limited by maximum deflection of 12.5 mm
- Pipe stress not exceed 28 N/mm2.
- Pipe are assumed to be filled with water
- modulus of elasticity of carbon steel pipe (A106 Gr.B) = 203390 N/mm2
- modulus of elasticity of carbon steel pipe (A312 TP316L) = 195120 N/mm2
- span are based on formulae :

d = ( 98 x 10^6 w L^4 / EI ) - stress are based on formulae :

s = 981 wL^2 / z

W = 24.3 kg/m

Z = 52680 mm3

I = 3010500 mm4

E = 203390 N/mm2

Try L = 7 m.

You will get the result as this

deflection = 9.338 mm.

pipestress = 22.17 N/mm2