API 620 roof compression ring design 1

[EngFax]

Hello,

I'm designing a roof compression ring based on API 620, the standard provides the equation for the required moment of inertia (5.12.5.8) when bracing is required.

What is the required moment of inertia if bracing is not required?

 

[JStephen]

There's not a requirement in that case. It would need to meet the width/thickness limitation in the first sentence.