Pipe Wall Thickness Calculation

This calculation is relative important , piping designer will utilise formular as shown below to determine the suitability of the materials correspond to the project specification and budget. The pipe wall thickness calculation for metallic pipe and fibreglass reinforced pipe will be slightly disimillar due to the inconsistent of materials properties.

The major different between steel pipe and FRP pipe , steel pipe has fixed outer diameter and the increasing of wall thickness will increase upon inward direction. Oppositely, FRP has a fixed internal diameter while the outer diameter is vary depending on thickness was built through winding process.Additional , FRP pipe also need to consider the liner on the outer layers. Due to this factor thus the formula between steel pipe and FRP pipe is different , pleasw refer following formula :



Formula per ASME B31.3 (Typical for Steel Piping )

t = PDi / ( 2FS+ P)

Where ,

t = Wall Thickness

S = Hoop stress ( Hydrostatic Design Stress, obtained from materials catalogue)

Di = Pipe Internal Diameter

P = Internal Pressure ( Design Pressure , obtained from project specification design data)


Modification of ASME B31.3 to determine pipe wall thickness for FRP (Typical for Fibreglass Reinforced Pipe)

t = [P(Di+tL)+2S*tL ]/ (2S - p)

Where,

t =Wall thickness ( Included structural wall thickness and liner )

S = Hoop Stress (Hydrostatic Design Stress, obtained from materials catalogue)

tL= thickness of outer layer ( Liner)

P = Internal Pressure ( Design Pressure , obtained from project specification design data)

Di = Internal Diameter