ASME Vessel Anchor Bolts

[dozer]

I'm reviewing drawings where the vendor has called out the anchor bolts as "SA-325". My understanding of ASME material specs are that they are usually the same as ASTM specs except that they have put an "S" in front of the designation. As a structural engineer I can tell you, you don't use ASTM A325 bolts for anchor bolts. The preferred spec is ASTM F1554 for anchor bolts. I suppose if you can find an A325 bolt long enough you could bury it in concrete and use it as an anchor bolt but I've never heard of it being done.

I've worked on quite a few plants and I don't think I've ever seen an ASME spec called out for anchor bolts. This is usually left to the civil realm where ASTM specs are used. My question is would there be some requirement in ASME pressure vessel code that would require a ASME spec'd anchor bolt?

My feeling is the anchor bolt should not be called out as "SA-325" but before I call the guy on it, I want to be sure there is not some requirement in the pressure vessel world that I'm ignorant of.

 

[doct9960]

dozer,

Anchor bolts are not in the scope of ASME.

As you mentioned, ASTM F1554 is the typical anchor rod for vessels on concrete, but for vessels sitting on a steel structure, I've seen ASTM A325 called out.

You need to check the calcs done by the vendor. If they called out SA-325 for the anchor bolts, they might have used a higher allowable bolt stress, instead of the lower allowable for ASTM F1554 Gr 36 or 55.

 

[TomBarsh]

If I remember correctly (and unless things have changed since...) the A-325 spec controls the thread length very closely as well. There's only sufficient threading for one heavy hex nut and a washer. So, with these used as anchor bolts they couldn't be double-nutted, which isn't uncommon for industrial structures, and the elevation/dimensional control of the foundation, grouting, etc, would have to be exemplary (read: unrealistic).

On the other hand, maybe you were given some calculations that were performed by someone who didn't know any better?

 

[marty007]

Did your specification spell out what material they were required to use? If not, they are forced to make their best guess based on past experience. I have certainly seen A325 used for anchor bolts, so their guess is not out of line.

To avoid this type of issue in the future, your equipment datasheets sent to vendors should specify the required anchor bolt material. (Speaking from the vendors perspective...)

 

[dozer]

Thanks for the replies. Tom, you make a good point about the thread length. Supplement S1 does allow you to thread the full length of the bolt but only for bolts equal to or shorter than four times the nominal diameter. I would think this would exclude most anchor bolts.

I've learned since I posted this that the anchor bolts are not in the vessel suppliers scope, which makes sense. He was just throwing something out there.