Question about failing bolts in chilled water pipe connectors (Victaulic) 13

[Lnewqban]

Dear all,
I am involved in an engineering problem related to pipe connectors that have been failing around every five years.
This has happened in Florida, in an office building, and for a chilled water piping system serving individual coils and fed by VFD pumps.
The bolts of the couplings have been failing, only weeks apart, and flooding the corridors of the building.
That happened about five years ago, time at which all the original bolts were replaced, and is currently happening again.
The manager of the building has contacted my company about a permanent solution to this problem.
Please, see attached picture of broken bolts.

There is a rooftop chiller, from which two main insulated pipes go down and branch out in two opposite directions for about 60 yards each way, making two closed loops.
The broken pipes (branches closer to the roof chiller and vertical pipes) should be 2-1/2 inches diameter, according to specified in the drawings.

A local AC contractor has estimated a cost for replacement of all the 375 couplings and rubber seals, installing stainless steel bolts rather than regular steel, as original.
The bolts that have failed show signs of normal corrosion and all have broke by the section where the nut meets the casing.
There are no expansion loops in the original system, and the broken sections show areas of corrosion and new metal, which make me believe that the failure may be caused by metal fatigue.
The system rests at night and moves chilled water during the day.

I don’t have any experience with this type of connectors.
I would love to learn your first impression about the probable causes or failure, and possible remediation.
Perhaps a type of coupling able to absorb the bending stress of thermal dilatation-contraction cycles?
Thank you for your time.

"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci

 

[FacEngrPE]

Use the criteria in ASME B31,9 (Same as requirements in the IBC). I would be really surprised if pipe flexibility was not enough, but do check.
If more flexibility is needed changing some rigid couplings to flexible type is OK, but then verify that the hangers are still appropriately supporting the pipe.

 

[Don Industrial Eng.]

We know of an immediate solution for this issue. Someone keeps deleting our post 3-4 times now? There is a patented device that will allow the bolts to be replaced to keep the system from going down. This would be the immediate remedy, allowing further analysis of the metallurgical degrading of the bolts. The aggressiveness of the corrosion points to a metallurgical issue many are pointing out due to the chlorides in the air. It appears you definitely have a vapor barrier issue with your installed insulation, which allows the chlorides to come in contact with the bolts and the coupling. Vibration is always a concern, so the exact location of the reoccurring failure positions in proximity to the pumps needs to be reviewed to identify this. But, it appears the vapor barrier needs to be upgraded, or the original design is missing a proper vapor barrier. Either way, we can help determine a better-suited bolt material to replace the bolts with after the vapor barrier is corrected, which we believe is your core problem. We know of a patented device that will allow all the bolts in your system to be replaced without downing the system to keep you out of failures until the proper metallurgical analysis can be performed on the failed bolts. We have many technical links to send to you, but someone deletes our post whenever we put a link in. There is a real injustice going on on this site, segregating responses that are keeping you from receiving a solution.



Donald Gibeaut

 

[LittleInch]

It's probably seen as advertising or spamming.

Why don't you just name the company or product and then if anyone is interested they can search for it.

I think it's all the links which cause an issue.

That and the original question was nearly 6 months ago, so likely it has been sorted by now. The OP hasn't been seen for 3 months...

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

 

[Don Industrial Eng.]

Thank you very much for your input. We have put 3 or 4 posts, and all have been deleted from the thread. Our original post did have links to technical pages outlining the conditions and solutions for this issue. We have removed all links from the last 2 posts, and they were removed. Accordingly, we believe there is a political agenda for deleting our post. We have the most experience in this issue and have spent a year investigating; we can not get our solution to the OP for the deletions for no good reasons outside of segregation. We have contacted this site's administration with our concerns, and they said they delete posts without viewing them when flagged. In this case, it is allowing someone to segregate our solutions to this OP. Thus, the need for the administration to review the post better when flagged for someone is using the flagging to eliminate others with solutions it is appearing. I am chairman of the BOD for the International Tube Association, and we are not selling but trying to offer solutions that are directly related to the core issues.

 

[LittleInch]

There is no political agenda.

It's just the site gets a lot of spam and adverts masquerading as posts and unfortunately yours might have got caught in the crossfire.

the red flags were answering a post long after it had come to a natural end and including a lot of links without any real explanation.

But if you can say what to search for that would be useful for anyone else with a similar issue who does a search, without posting a link.

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

 

[RVAmeche]

There's no grand conspiracy to suppress yours or other products. But even these two posts come off in more of a salesman way (we know a patented device, we can help, etc) instead of simply just saying it appears the vapor barrier could be an issue, we've used/recommended people use *this bolt device that prevents the system from needing to go down*.

People talk brands and makes/models on this site all day. People have experience and thats good information. But manufacturer's coming and pitching their stuff/self advertising is not good.

 

[Don Industrial Eng.]

We never projected a grand conspiracy, just an injustice that has to be hurting the effectiveness of this site. It is someone who does not want our solution posted for competitive reasons, or the site is negligent in controlling the content getting flagged by individuals who should not be a final judgment of the content. We were forwarded this thread so that we could offer a solution as we have given to others for the same conditions. After 3-4 attempts to do this, we believe we have completely wasted our time in trying to help someone from a referral to do so. We understand the crazy spammers. I deal with all of this at a cost to control constantly.

But even these two posts come off in more of a salesman way (we know a patented device, we can help, etc) instead of simply just saying it appears the vapor barrier could be an issue, we've used/recommended people use *this bolt device that prevents the system from needing to go down*

This policing is way over the top. In this case, and I suspect that many others are being judged unfairly when trying to offer help, reducing this site's effectiveness by unqualified individuals without oversite. It appears this site is a good thing being limited by unqualified individuals judging content too aggressively. I do not want to look a gift horse in the mouth, so to speak, for I was told individuals flag content, not paid overseers. But, I hate to see a good thing go bad over an individual's ego and over aggressiveness without any oversite. In this case, it has hurt everyone.

 

[SwinnyGG]

You're way, way overreacting.

Stop sounding like you're selling something, and your posts will stop getting flagged. It's not hard.

You could quite easily point OP, or anyone else who comes across this thread, in the right direction instead of making esoteric posts about the things you know but don't want to share. If you don't want to do that, that's on you.

 

[Don Industrial Eng.]

That is not the case at all; I wrote out a complete thread with links, went back, read through the rules of the post, and resubmitted it 3 more times, reducing the content and changing the wording, trying to make it worthy. I tried to share our knowledge but could not. That is the whole issue you missed. We "dumbed" it down to just a mention without details, trying to get one thread posted, and even just a casual, no technical content post was removed. This is the issue!

Stop sounding like you're selling something, and your posts will stop getting flagged. It's not hard.

Correction, IT IS VERY HARD! TOO HARD that is the point here.

I write technical articles for 3 magazines and am on a technical BOD for article acceptance and review for a major international magazine for Tube and Pipe manufacturers. I reply to blogs all the time without any of this trouble and censorship that is way over the top to the end; you can not even present a solution with any content or substance.

 

[LittleInch]

We know of an immediate solution for this issue.

Great - what is it exactly that you propose?

we are not selling but trying to offer solutions that are directly related to the core issues.

Again - if you actually explain what this solution is then we'll all be happy.

We know of a patented device that will allow all the bolts in your system to be replaced without downing the system

All this alluding to some magic device is the issue here - all talk and no details as far as I can see. Prove me wrong.

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

 

[Don Industrial Eng.]

There is a Victaulic article link on pre and post-pump vibration dampening with some proven design methodologies deploying multiple grooved coupling in systems before and after vibration-generating components like the pumps.

http://www.integrityinds.com/risk-mitigation/

Our 2 cents on the issue of this blog and on this condition:
• Your corrosion problems and solutions are directly related to the multi-layer insulation and jacketing of your external piping. Accordingly, your system's vapor retarding layer should be targeted for investigation. I would be very concerned if my bolts corroded to the point of failure, that excessive C.U.I. (Corrosion Under Insulation) is evident in my piping.

• The comment regarding the grooves cut into the piping has a lot of merits. The installation contractor machines the grooves into the pipe, NOT the O.E.M. of the couplings like Victaulic. Thus, the groove cut into the piping may have quality variations. In addition, the groove dimensions directly impact the vibration-dampening capabilities of the grooved coupling design. We have had this discussion with multiple application engineers at Victaulic. In addition, Victaulic has investigated vibration dampening in groove piping systems at NASA's seismic testing facility. Extensive research by industry leaders backs their methodology and the harmful conditions.

• Upgrading your bolts is a proactive solution to increase their life expectancy. This blog has several good suggestions for alloy changes to a more anti-corrosive bolt and nut. In addition, a patented clamp system now allows the replace the bolts without disrupting your system operations. Thus, this proactive solution can be deployed at any time; the root cause we believe should be addressed first, as outlined in our previous bullet points. Proactive upgrading of the bolts can then be deployed when applying the root cause solution.

In conclusion: There is a much more affordable and less disruptive solution to your problem that does not involve shutting down and draining your entire system. US Patents: US9739410 & US10711938


This was one of our posts removed. we had links to each condition but have removed all the links except 1. I have attached a case study of one project where bolts were breaking, and the NEW patented clamping mechanism was utilized for the solution. This is a NEW advancement in HVAC systems using grooved sealed connections. There is a ton of material from over 2 years of development in links we can not share.

 

[SwinnyGG]

In conclusion: There is a much more affordable and less disruptive solution to your problem that does not involve shutting down and draining your entire system. If you want to learn more, please give us your direct contact information so we can discuss this matter and plot a short and long-term custom solution with you.

This is why your post was removed.

You sound like you're selling something. Stop it and this problem will go away.

 

[Don Industrial Eng.]

Thank you for your help and feedback. Sorry, this has frustrated me to no end. I have been over a month just trying to reply to the thread. we have revised our post without a call to contact us to work together toward a solution; please review for acceptance. We have a host of technical data to share, but we can not get it done. We are trying to play by the rules and appreciate why you have them. We have invested a lot in the issue and have developed a proven solution; thus, we are trying to get this information out to the industry. This problem is exactly why we have spent so much time and money on patents and implemented this new technology in the field, which is performing as designed. The O.E.M's Victaulic and Grinell deny the existence of these issues, which is why they do not reply. When they do, they say the bolts and coupling last the lifetime of the system, a boilerplate response. Thus, there is no help to be had from them at the moment. We will be approaching them for alternative education upcoming to this condition, as described in this blog as being a real issue people are addressing at great cost.