ASME finger-tight anchor bolts with staked nuts.

[Dave776]

I (think) I read in ASME VIII div 1 somewhere that to accomodate thermal expansion I can specify finger tight bolts with the nuts staked or tack-welded to the bolt to prevent accidental overtightening. What section is this in? 2007 VIII div 1 nonmandatory appendix S is obviously not the right place (flange connections).

 

[Duwe6]

Section VIII is to build a vessel, not operate it. Operational issues have to be communicated by the owner and addressed by the Design Engineer. Typically, the need for a 'floating vessel' is driven by pipe being anchored near the vessel, so vessel has to move. It is very common to have one 'fixed end' with tight anchor bolts, and one 'sliding end' with the finger-tight & staked nuts.

 

[Dave776]

I have anchored the centers of the two support channels, one on each side. I have slightly oversize holes in the center regions to absorb earthquake but allow some thermal growth. Other bolt holes are slotted for thermal growth. But if someone during erection whacks the bolts with a slug wrench, I will be slip-critical with overstress in the base channel. Is there anything in the ASME code that addresses "finger tight?"

 

[Duwe6]

Not that I know of. Make the tightening of the Hold-Down bolts a "Hold Point" and require an Inspection Dept or Eng Dept witness.

"In God we trust; everybody else gets checked & rechecked"

 

[Dave776]

Duwe6 - OK. I think I got the idea from Megyesy "Pressure Vessel Handbook" 12th ed p 100 Saddle for Support of Horizontal Vessels where he says "At the sliding saddle the nuts of the anchor bolts shall be hand-tight and secured by tack welding." The word "shall" led me to think it was code based rather than common practice based.