# Barlow's Formula

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Barlow's formula, abbreviated as Ba, relates to burst pressure, the point just before or at when a pipe or tubing fails under pressure.

## Barlow's formulas

 $$\large{ p = \frac{2 \; S \; t}{D} }$$ $$\large{ p = \frac{4 \; S \; t}{ D \;+\; 2 \; t } }$$ $$\large{ p = \frac{2 \; S \; t}{ \left(D \;-\; 2 \; t \right) \; SF } }$$ $$\large{ p = \frac{2 \; S \; t}{D \; SF} }$$

### Where:

$$\large{ p }$$ = pressure

$$\large{ S }$$ = allowable stress

$$\large{ D }$$ = outside diameter of pipe

$$\large{ t }$$ = pipe thickness

$$\large{ SF }$$ = safety factor (generally 1.5 - 10, 1 for bursting pressure)

### Solve for:

 $$\large{ t = \frac{ p \; D }{2 \; S \; SF} }$$