Clay Pipe Thickness Determination

I have work at clay pipe manufacturing for drains and sewer use. The product standard using is BS EN295 : 1995, Part 1. Requirement for crushing strength is in Class C120, C160, C200 and so on. The pipe strength is calculated in kN/m. For example for pipe ID DN 375 Class C160, the strength is (DN x Class)/1000 or (375 x 160)/1000 = 60kN/m.

My problem is how to calculate correct pipe thickness to meet with the strength requirement.

For information our clay Modulus of Rapture is about 17 kgfcm and the compressive strength is 75kN.

Pipe Crushing strength testing is calculated by the following formula :

• kN/m = (Pressure x Area x N)/(1000 x 2.2)
• Where = Pressure in psi
• Area of piston for crushing machines is 17.72in square
• N is newton = 9.81
• 1,000 is Newton to Kilo Newton
• 2.2 is poun to kg
• The result is in kN and must devided by 2 to get the answer in kN/m.

Your assistance is much appreciated

Thank you