"Charles Spitzer" wrote in message
...

well, it's supposed to have a center brace to prevent that. a braced tank
won't bow at all. an unbraced tank is one waiting for a blowout.

It had two centre braces. Was in operation for at least five years. No blow
out. Maybe you might consider me lucky, but the way I understood it, they're
going to bow out no matter what you do. As I was told, it's more important
to assist it from not bowing out too much instead of preventing any
expansion.