Angle irons have quite a few different uses in construction. Made with a right angle, these irons fill many different structural needs, particularly when it comes to bracing joints or holding different components in place. The weakness that an angle iron has is exposed when force pushes against the right angle, either bending the ends together or apart. It is important to know the strength of your angle irons before installing them.
Use the tape measure to find the depth and width of the angle iron bar, and the bar's total length (both angled sections). Take the force pushing or pulling on the angle iron and multiply it by 3 and the total length.
Square the depth and multiply it by two times the width of the iron.
Divide the answer from Step 1 by the answer from Step 2. The result will give you the ability of your angle iron to resist breaking its angle, in units of Newtons per square meter.