Sample Quill Issue 1

[jayinwww]

During inspection I came across a Made Up Sample Quill that has a Swagelok fitting inside a tapped flange.

The one swagelok piece that's threaded in the tapped flange item number is: #1210-1-12-BT

https://www.swagelok.com/en/catalog/Product/Detail?part=SS-1210-1-12BT

Stainless Steel Swagelok Tube Fitting, Bored-Through Male Connector, 3/4 in. Tube OD x 3/4 in. Male NPT.

Here is a Picture

https://imgur.com/a/q7O5pQj

My issue I have here in relation to code is that the fitting knuckles(Part where the wrench goes.) looks to be buried into the flange and I'm unsure if there is proper thread engagement there.

Description above from the website says the male threaded end is NPT. But that fitting looks to be hitting part of the flange tips, so it does look like it bottoms out. But both are NPT.

As for ASME B1.20.1 chart above L1 is hand tight also considered the Minimum and L2 is desirable at tight which is underlined at 0.5457 in.

Now the picture

https://imgur.com/a/6PZcLxZ

the other side of the flange, I count 7 threads that have no thread engagement as you can see. From this Chart

https://imgur.com/a/DcAAElD

above shows 3/4" fitting has 14 threads per square inch. So that tells me that those 7 threads are .500 of an inch that have no thread engagement. Now as per B16.5 Table F16 for 3/4 class 600 flanges it reads the minimum threaded area length must be a minimum 0.62 inches. So it looks like we must measure the flange threads of those flanges. But the Vendor refused to take out that one fitting in order for me to see total thread length.

My question is, if part of a fitting "bottoms out" on something other that thread tightening, then is there something in code that I can use to reject this sample quill? Other than they can not prove to me thread engagement.

Code is B31.3 so B1.20.1 still applies correct?

 

[mk3223]

Who designed this sample quill with the threaded process connection, and acceptable for the process and Class 600 system? Can it pass the hydro test? Is it safe for operation without an isolation valve?

If you buying the quill, the vendor should reply your question or request, but not the other way around. Or, you can tell the Contractor that you may escalate it up to the Project Supervisor and/or Operation.

 

[jayinwww]

Thank you for the post mk3223, Yes it was approved for the process, at least threaded connections. It did in fact pass the hydro test. The isolation valve was added before the hydro. The vendor believes that it is fine the way it is. Other people I talk to say this just doesn't look right and normally sample quills are one piece all welded out...

 

[mk3223]

Other people I talk to say this just doesn't look right and normally sample quills are one piece all welded out...

Consider that who the "other people" are, and is the "one piece" type quill a requirement for this process (or chemical)?

IMO, it can be a potential issue if the sample quill connection is the only thread connection.

 

[SwinnyGG]

I count 7 threads that have no thread engagement as you can see. From this Chart

https://imgur.com/a/DcAAElD

above shows 3/4" fitting has 14 threads per square inch. So that tells me that those 7 threads are .500 of an inch that have no thread engagement.

That is only true if the threaded depth of the female hole is exactly 1"- which from your description, it appears you do not know with any certainty.

It also appears from your photo that when the fitting was installed, there is/was interference between the points of the hex and the bore of the flange- and the fitting was installed with enough torque that there are actually shavings standing from the flange face. It's hard to tell as the pic isn't super high-res but it certainly looks to me like the points of the hex have damaged the flange face:

The damage to the flange face itself isn't necessarily a problem, as this is an NPT fitting and it doesn't seal against that flange. However, this DOES indicate that the position of the fitting is controlled by the location of the hex relative to the flange. That is completely improper. Tapered fittings must be installed such that position is dictated by the appropriate amount of thread interference to create a reliable seal.

In short, whether this passed a leak test or not, you have no way to know or verify that this fitting has proper engagement and will seal properly in service and over the full design life.

If it were me, I would reject this assembly full stop.

If the service for this assembly is a health or life hazard, I would reject the assembly and be on the horn with whoever is responsible for safety, filling their ear with why this is a hazard.

 

[jayinwww]

Yes I rejected this assembly, but was trying my best to help my case by failing it for a code violation. But after I explained what I originally stated in the start of this thread to the engineers they then rejected this Quill as well. Thank you all for taking the time to look into this and your thread responses were great. It was an interesting somewhat unique situation.