Bolt size 2

[Jasmine55]

Hello Members,

This may be a stupid question.

Under sized bolts are used in some of the piping systems as follows,
16" - 300# flange
Used bolt size: 1 1/8"
As per ASME: 1 1/4"
The design pressure of the piping system is 25bar.

We found this discrepancy at the later stage of the project and changing now is huge task since the scaffolds and other resources are already demobilized.
Could any of the member ever came like this situation and what was the final decision made?
Is there any deviation/tolerance in ASME codes?

Thanks for your valuable feedback.

 

[LittleInch]

It's worth noting section 2.2 of B 16.5 -= A flanged joint is composed of separate and independent,
although interrelated components: the flanges,
gasket, and bolting, which are assembled by another
influence, the assembler. Proper controls must be exercised
in the selection and application for all these elements
to attain a joint that has acceptable leak tightness.

Your only get out is section 2.3.1 which basically says use of the flange ratings which do not comply with the standards is "the responsibility of the user". How good is your liability insurance??

Nearly always the only way to resolve to everyones satisfaction is to break out the cherry picker or get the scaffolders back ASAP.

Apart from the issue of bolt stress, you also have the issue of nut contact area being less. If you've used washers, they can become over stressed.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MJCronin]

In a situation here where there is a systematic failure, I think that there is a lesson here about third party spot inspection of a contractors work.

It is a lot easier to correct a situation like this if it is noticed as soon as sub-systems are installed and scaffolding/platforms are still in place.

The only questions that come to mind are:

1) Was the smaller bolting/stud substitution done because of fastener availability ?

2) If the bolting/stud fasteners are the wrong size, have you checked the materials ? Was A193/A194 materials specified but something else supplied

3) Has this contractor supplied other piping systems, for you or others in the past and were the flanges checked ?

4) Have these systems been pressure tested yet ? What were the results ?

25 bar is significant pressure.....

MJCronin
Sr. Process Engineer

 

[Jasmine55]

Thank you LittleInch!
Thank you MJCronin!
for your feedback.

The lines were hydro tested tested with 1.5 times the design pressure. Fortunately there was no safety incident during the high pressure test due to the inadequate bolt size.

 

[LittleInch]

So what are you planning to do??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

Passing hydro test doesn't override ASME code (if that code is the defining standard)- otherwise a qualified engineer needs to undertake a careful analysis of the situation after reviewing ALL the facts.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[SnTMan]

You could possibly confirm the bolt area using Sec VIII Div 1 Apx 2 or similar method, assuming all parties are agreeable.

My Sig line seems applicable here

Regards

Mike




The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[someguy79]

I'm looking at a reference for ASME/ANSI B16.5 that shows an NPS 16 Class 300 flange having quantity 20 bolt holes at 1-1/4" dia, to fit 1-1/8" bolts. Depending on temperature and material, the 25bar pressure may be well within allowable pressure for these components.

Maybe I missed something, but I don't see the problem here.

 

[SnTMan]

Well, I know I didn't check it, figured the OP knew his own problem

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[gerhardl]

Looking at the comments above, it seems clear that it is not possible to state that this is according to the given standard for the project. Although it anyway could be well within mechanical acceptable forces (at the present given application), it is no more within standard for this reason.

Things 'just a tiny bit out of standard' can go wrong, for instance by longterm pipe-stress or altered pressure conditions.

As said above: The cost of consequences if failure can be far higher than the cost of correcting now, and claims of changing can come later, even if 'someone' says OK now.

 

[LittleInch]

Not according to this. I think I looked it up in the latest spec as well. 20 bolts at 1 1/4 "

http://www.engineeringtoolbox.com/flanges-bolts-dimensions-d_464.html

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[gerhardl]

OK! (I stand corrected on facts, but not on necessary action if anything is wrong...)

 

[LittleInch]

We seem to have lost the OP, but this is the B 16.5 2013 class 300 listing for 16"
NOM OD ID BH No. Bolt size Bolt lenghts
16 650 571.5 1 3⁄8" 20 1 1⁄4" 190 205 165

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Jasmine55]

Thank you everyone for providing valuable feedback.
We have decided to replace the bolts as per ASME B16.5.

 

[SnTMan]

By far, best way for the long run.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[LittleInch]

good. Put it down to experience and you'll make damn sure next time someone checks before hand. I bet someone thought - these bolts feel a bit loose, but Hey, I haven't got any others....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.