Ring Joint Gasket Defect Types and their Consequences

A

Arjay

#1
Hello all!

I'd like to ask about the defects that may occur with ring joints and their consequences. So far, I've looked up the API and ASME requirements and there are at least a couple of defects I still haven't found out about.

So far I know about high hardness, unsatisfactory surface finish, and out-of-tolerance dimensions as these are clearly stated in the standards.

As for consequences, I've learned that high hardness can result in damaging the flange in that instead of the gasket conforming to the flange, it is the flange that changes and so its future sealability is compromised. I don't know what the consequences of the surface finish are though. For out-of-tolerance dimensions, I'm guessing that too small and a seal may not be formed while too large may result in the same case as high hardness or it may simply not even fit.

If anyone knows of any corrections or additional information to what I've said so far I'd appreciate it.

What I don't know about yet are cracks and blowholes. I haven't seen it mentioned in the API and ASME standards at least as far as ring joints are concerned. If these are covered in some other standards, like maybe for the raw material, I'd really like to find out.

Thus, I have no idea to what extent the presence of cracks and blowholes on a ring joint gasket is allowable, if at all. I can understand that leaking would naturally be a consequence. However, it has been reasoned to me that these are thus only critical if existing in a sufficient degree on a non-sealing surface or if it is on a sealing surface. Is this true? Is there, for example, no compromise with its structural capacity to withstand the high pressures that ring joints have to endure? Or can't leaking still be a potential if the cracks or blowholes happened to be connected to just beneath the sealing areas and possibly exposed after installation?

While I'm here, I might as well also ask if there are any justifications to pass ring joints with high hardness? I understand that so long as the flange material is definitely of a higher hardness than the gasket hardness then there is no problem. However, if there is no certainty of the flange material, is there some other reason to presume that a certain amount of extra hardness is negligible? Like maybe there is some standard that requires a safety margin between the flange and gasket hardness so exceeding hardness to some degree won't be a problem?

I hope I'm asking clearly and specifically enough as I think this will just be the first of many questions I'll be asking here. :D Even before I asked anything I've already learned a lot just from reading past posts. :agree1:
 
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Stijloor

Leader
Super Moderator
#2
Re: Ring joint gasket defects - types and their consequences

Hello all!

I'd like to ask about the defects that may occur with ring joints and their consequences. So far, I've looked up the API and ASME requirements and there are at least a couple of defects I still haven't found out about.

So far I know about high hardness, unsatisfactory surface finish, and out-of-tolerance dimensions as these are clearly stated in the standards.

As for consequences, I've learned that high hardness can result in damaging the flange in that instead of the gasket conforming to the flange, it is the flange that changes and so its future sealability is compromised. I don't know what the consequences of the surface finish are though. For out-of-tolerance dimensions, I'm guessing that too small and a seal may not be formed while too large may result in the same case as high hardness or it may simply not even fit.

If anyone knows of any corrections or additional information to what I've said so far I'd appreciate it.

What I don't know about yet are cracks and blowholes. I haven't seen it mentioned in the API and ASME standards at least as far as ring joints are concerned. If these are covered in some other standards, like maybe for the raw material, I'd really like to find out.

Thus, I have no idea to what extent the presence of cracks and blowholes on a ring joint gasket is allowable, if at all. I can understand that leaking would naturally be a consequence. However, it has been reasoned to me that these are thus only critical if existing in a sufficient degree on a non-sealing surface or if it is on a sealing surface. Is this true? Is there, for example, no compromise with its structural capacity to withstand the high pressures that ring joints have to endure? Or can't leaking still be a potential if the cracks or blowholes happened to be connected to just beneath the sealing areas and possibly exposed after installation?

While I'm here, I might as well also ask if there are any justifications to pass ring joints with high hardness? I understand that so long as the flange material is definitely of a higher hardness than the gasket hardness then there is no problem. However, if there is no certainty of the flange material, is there some other reason to presume that a certain amount of extra hardness is negligible? Like maybe there is some standard that requires a safety margin between the flange and gasket hardness so exceeding hardness to some degree won't be a problem?

I hope I'm asking clearly and specifically enough as I think this will just be the first of many questions I'll be asking here. :D Even before I asked anything I've already learned a lot just from reading past posts. :agree1:
Hello Arjay,

Welcome to The Cove Forums! :bigwave: :bigwave:

Great first post, and you're asking many questions. :)

To get quicker and more responses from my Fellow Covers, is it possible for you to condense your questions to one "burning" issue? You can always expand from there.

From your public profile, I learned that you are searching for: "Searching for info on ring joint gasket inspection (defects and their consequences)."

Is that a fair summary?

Let's see what happens.

Stijloor.
 
J

justncredible

#3
Re: Ring joint gasket defects - types and their consequences

We lost a space shuttle due to poor ring design.

Also I would guess that poor ring design cost huge dollars in combustion engines due to blow by and pressure lose.

You could imagine tons of places where lose could be found due a poor mating of joints, such as water lose in large citys, a dripping faucet is from a poor ring closure leading to waste.

All the way to a leaking oil pan gasket on a car leading to leaks that pose a envoimental concern. The results and applications are endless.
 
U

Umang Vidyarthi

#4
Re: Ring joint gasket defects - types and their consequences

Hello
all!
I'd like to ask about the defects that may occur with ring joints and their consequences. So far, I've looked up the API and ASME requirements and there are at least a couple of defects I still haven't found out about. So far I know about high hardness, unsatisfactory surface finish, and out-of-tolerance dimensions as these are clearly stated in the standards. As for consequences, I've learned that high hardness can result in damaging the flange in that instead of the gasket conforming to the flange, it is the flange that changes and so its future sealability is compromised. I don't knowwhat the consequences of the surface finish are though. For out-of-tolerance dimensions, I'm guessing that too small and a seal may not be formed while too large may result in the same case as high hardness or it may simply not even fit. If anyone knows of any corrections or additional information to what I've said so far I'd appreciate it.
Could you share here, where are you using the 'Ring Joints'? Mostly they are used on Gas, Chemical or on Oi lines. Secondly what type of gaskets are you using, oval or octagonal?

In case of poor surface finish, the sealing will be seriously affected, since the gaskets are heavy metallic.

Dimensions are easy to adhere, since the gaskets are available in standard sizes. You have to select the right one from the tables which give Ring joint dimensions, material specs and Hardness (Rockwell & Brinell). Tables also provide complete dimensions and weight of the gaskets w.r.t. ASA & API ring no. for R, RX, and BX gaskets. There are charts too, for Pressure rating vis-a-vis the Pipe size for oval & octagonal gaskets. IMO If you choose the right product, then there is no scope for over or under dimensioning.


What I don't know about yet are cracks and blowholes. I haven't seen it mentioned inthe API and ASME standards at least as far as ring joints are concerned. If these are covered in some other standards, like maybe for the raw material, I'd really like to find out. Thus, I have no idea to what extent the presence of cracks and blowholes on a ring joint gasket is allowable, if at all. I can understand that leaking would naturally be a consequence. However, it has been reasoned to me that these are thus only critical if existing in a sufficient degree on a non-sealing surface or if it is on a sealing surface. Is this true? Is there, for example, no compromise with its structural capacity to withstand the high pressures that ring joints have to endure? Or can't leaking still be a potential if the cracks or blowholes happened to be connected to just beneath the sealing areas and possibly exposed after installation?
I have not seen any 'standard' permitting cracks and blow holes. We are talking here about very high pressures (10-15 thousand psi at the least) and very high temperatures. Cracks or blow holes will adversely affect the sealing, and will give way in the long run.

While I'm here, I might as well also ask if there are any justifications to pass ring joints with high hardness? I understand that so long as the flange material isdefinitely of a higher hardness than the gasket hardness then there is no problem. However, if there is no certainty of the flange material, is there some other reason to presume that a certain amount of extra hardness is negligible? Like maybe there is some standard that requires a safety margin between the flange and gasket hardness so exceeding hardness to some degree won't be a problem?
I would advise you to go with the standards on this. Any deviation depends upon your own practical experience.

I hope I'm asking clearly and specifically enough as I think this will just be the first of many questions I'll be asking here. :D Even before I asked anythingI've already learned a lot just from reading past posts.:agree1:
You are most welcome to post as many questions as you wish. :caution: Try to be specific and precise. That will fetch you quicker responses.

Umang :D
 
G

Geoff Withnell

#5
Re: Ring joint gasket defects - types and their consequences

We lost a space shuttle due to poor ring design.

Also I would guess that poor ring design cost huge dollars in combustion engines due to blow by and pressure lose.

You could imagine tons of places where lose could be found due a poor mating of joints, such as water lose in large citys, a dripping faucet is from a poor ring closure leading to waste.

All the way to a leaking oil pan gasket on a car leading to leaks that pose a envoimental concern. The results and applications are endless.
Just for the record, we did not lose a shuttle due to poor ring design. We lost a shuttle for two reasons:

1. Failure of management to take action to mitigate the design problems when they became apparent. Data from previous flights had shown that the seal design was inadequate, not functioning as designed and was a flight safety issue.

2. Operation outside the design envelope. The lower temperature limit on the design was 0 degrees Celsius. The shaded side of the booster was covered with frost. The cold temp exacerbated the design flaw, and it is quite possible the failure would not have occurred had the flight been postponed until the temperature was within operating specs.

Design problems are going to happen. It is management's job to mitigate the problems they cause! The shuttle loss was not a design issue but a management issue. See the Feynman report.
:mad:

Geoff Withnell
 
J

justncredible

#7
Re: Ring joint gasket defects - types and their consequences

Just for the record, we did not lose a shuttle due to poor ring design. We lost a shuttle for two reasons:

1. Failure of management to take action to mitigate the design problems when they became apparent. Data from previous flights had shown that the seal design was inadequate, not functioning as designed and was a flight safety issue.

2. Operation outside the design envelope. The lower temperature limit on the design was 0 degrees Celsius. The shaded side of the booster was covered with frost. The cold temp exacerbated the design flaw, and it is quite possible the failure would not have occurred had the flight been postponed until the temperature was within operating specs.

Design problems are going to happen. It is management's job to mitigate the problems they cause! The shuttle loss was not a design issue but a management issue. See the Feynman report.
:mad:

Geoff Withnell
We agree Geoff, thanks for expanding the findings. As with most issues we run across it is managements duty to provide the support needed. 85% of all problems are a direct result of those that heard and did nothing to fix a problem. Arjay the OP maybe should do a FEMA and study what the effects of a failed ring design and complancy to standards can result in. If as he posted he knows the hardness is out of spec, what will happen as a direct result of his inaction to remedy the issue. If he knows of cracks what is the result of failure in the field?

o-rings and gaskets may appear to mundane but they have very real and serious duties to preform. Follow the standards would be the best approach, make sure the meet or exceed the extremes of the designed application. That way premature failure and waste can be avoided.

If your facet is dripping at a rate of one drop per second, you can expect to waste 2,700 gallons a year!
 
A

Arjay

#8
Sorry for the late response. Our server was down for a few days. Thanks for all the feedback!

Actually, the applications I was considering covers a lot so I was originally fishing for general concepts kind of like what I shared. If I were to choose the most significant applications I would go with those in the petrochemical industry. Both octagonal and oval are being used. I don't really know any more specific uses right now though I'll try and find out what our customer mainly uses them for.

Sorry for the lack of info as this is just my first job. :confused: I'd agree with management being capable of being a problem though. I'm actually investigating these issues behind my managers' backs to see if their claims that it is okay to be lax about following standards have any truth to them. :frust:

To shed some more light as to what I'm after, I should probably explain more of my scenario. We're not the ones using the gaskets. We're the ones supplying them to other companies, thus the wide range of applications. Our most valuable customers are the petrochemical companies though so that is why I would choose that as the area of focus. Plus I have some contacts I might be able to further verify with if such consequences are realistic.

I'm concerned about how my managers seem to compromise more than I'm comfortable with when it comes to the quality of the ring joint gaskets. So I'm trying to find out if I'm just being too stringent or they're the ones being too lax in following standards and assuring the good condition of the gaskets. Right now they have the upper hand of claiming I have less credibility than them in knowing what's right and wrong because of my being relatively new to work. This is still a real problem for me though since, as an inspector, my name is also put at risk by their practices.

So now you see what type of predicament I'm in. :(
 
J

justncredible

#9
I would quite as soon as possible, they keep records for the petrochem industry for as long as the life for the product. If you signed off on it you are responsible. I have heard horror stories. Do not ruin your name. Good Luck!
 
Z

zancky

#10
hi Arjay,
some years ago I was asked to solve a big problem about FKM (Viton) o-ring even if I was not an expert. I have asked help to all o-ring companies, compounder producers, some laboratories etc. We have worked two year in order to write the FKM o-ring specification (if You would like I can try to find a copy as I moved away from the company). It was a good job still used by some car company.
From that experience I suggest You to look at Parker manuals and software available on internet Parker web. there was also a free software called Simcat (it was perfect for o-ring calculation). Start with that and You will be on the right way.
Tell me if You need more help I can try to find something more but give me more information please.

bye
 
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