Anchor Chairs

[yosamitysamm]

Does anyone know why API 650 uses a 10' max spacing on the anchor chairs? I have a nozzle bank on a tank that is forcing me to space a pair of anchor chairs 12' apart. I am trying to find a way to determine if any reinforcement of the shell to bottom joint is required.

Thanks for any help you can provide.

Chris

 

[JStephen]

I would think the number is fairly arbitrary. For sizing, the bolts are treated as an equivalent ring of metal, so you don't want them too far apart, but I doubt it's a case where 10' is fine and 12' just won't work.

If I remember right, one of the tank standards had a 6' spacing when anchors were for seismic, or 10' for wind.