In this article I will discuss allowable displacement stress range equation given in the piping code B31.3 and the way that it is derived. Firstly, let’s see material behaviour under different types of loads. If pipe is loaded with external forces having stress larger than yield stress, pipe after unloading will be deformed due to forming plastic hinge.

# Engineering

## Pipe stress III

In this article I will discuss allowable thermal stress range equations given in piping code B 31.3. As per piping code B31.3, there are two equations for allowable stress range and we will explore different condition when one equation can be applied versus other equation.

## Buried pipe

In this blog I will discuss underground pipe stress calculation and different approaches for underground pipe modeling. During pipe thermal expansion, friction force from pipe to soil will occur resisting a pipe thermal expansion. Longitudinal forces from internal pressure must also be taken into consideration as well as forces as from Poisson shrinkage.

## Gaskets

In this blog I will briefly present gasket design criteria and bolt torque calculation. For this purpose spreadsheet has been made, where yellow fields are required data that will be entered. All equations, units and description are given in the figures. Calculation is conducted for 4″ flanges class 300 having Flexitallic spiral wound gasket.