Holes/Sleeves in Steel Water Tanks

[ars001]

I have to make penetrations through the walls of a steel water tank. I can't remember from my past experience how far the holes have to be from the welded steel plate seems. Plus I can't find it in the AWWA standard. Can anybody help? Thanks

 

[Stl63]

Take a look at API 650, I'm looking at 10th Ed. 4th Addendum. Figure 3-22 on page 3-49 gives distances from vertical and horizontal shell seams to edge of hole reinforcing. It even allows holes to pass thru vertical weld seams, if certain distances are met.

 

[IFRs]

API has an 11th edition. I'm not sure if the spacing has changed. However, 650 is for new tanks. Look at API 653 for modifying tanks.

 

[JStephen]

Good practice is to locate connections away from weld seams, but AWWA D100 doesn't have any spacing requirements for the base design.

For Section 14 tanks (the former Appendix C), minimum spacing is the greater of 10" or 8 times the weld size, from edge of fillet to center of butt joint.