A325 Bolt Inspection
A325 Bolt Inspection
(OP)
Is there a definitive "right" amount of bolts to inspect, be it a number, percentage, or whatever when checking a building? I can't find anything in my paperwork, and I have been doing 10% of each connection. Is this overkill? Should it be 10% of the total number of bolts? We are using DTIs, but I am not a big fan of a squirt washer-sometimes it is a week before I get to inspect, and the silicone has disappeared.





RE: A325 Bolt Inspection
http://www.FerrellEngineering.com
RE: A325 Bolt Inspection
I am not familiar with your business of this bolt inspection but do know there are factors to be considered when using a sampling plan. Factors that come to mind may be; risk associated with failure, track records, installers qualification and experience, confidence in the bolt, difficulty of installation, lot and homogeneity, etc.
The company I work for adopts a sampling plan guideline published by Energy Power Research Institute's (EPRI)for procurement inspections.
Here is a copy h
It provides some rational on a sample plan that you may be able to draw from.
CYA. If you take it upon yourself and decide to inspect to a sampling plan without a basis or documented approval for its use and the building falls down and kills a bunch of people you will need a good lawyer.
RE: A325 Bolt Inspection
http://www.FerrellEngineering.com
RE: A325 Bolt Inspection
If failures occur, I increase the frequency, usually by 10 percent in each case.
RE: A325 Bolt Inspection
The sampling plan that I am familiar with is that when 1 is rejected this means confidence has been lost on the ones that were not inspected before the rejected one. The entire batch will require 100% inspection.
Sampling is kept at 100% thereafter until confidence is re established as per procedure. Rejections after that will force 100% inspection and sampling will not be permitted.
RE: A325 Bolt Inspection
Each erection 'Sequence' is a different 'Lot' to be sampled. Pick widely separated joints in this area and check several bolts in each joint. I 'Reject' when I find two joints/connection points with undertorqued bolts. Entire Sequence is rejected. Ironworkers now retorque all connections.
Sample size should similar to that in vanmorrison's linked document. Sample percent is high with a small lot size, and tapers off as the lot size [# of connections in Sequence] increases. Sampling works. I have several exhausted Ironworker boltup crews than can testify to that fact.
RE: A325 Bolt Inspection