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February 24, 2021

Pipe Support Design Philosophies with Jan Kålhus - Part 2



Luuk Hennen 0:01 

All right, and we are live.

Welcome to all of you to this live stream of EngineeringTrainer TV. My name is Luuk Hennen. I'm one of the founders of And today, we will be having part two of our conversation with Jan Kalhus.

Now the recording of Part one is available on our YouTube channel. And since we enjoyed speaking to each other, and we had some sound issues during the Q&A of part one, we will continue our conversation today. If you haven't found the time to watch the recording of part one, you know, I invite you to do that after the session. Today we'll be discussing some additional examples and also have an extended Q&A and they got time to answer some of the questions that have not yet been answered. The estimate is to take around 20 to 30 minutes for this live stream. But that will depend a little bit on the types of questions that you will be asking as well. And for those of you that haven't seen part one, or didn't join us at the time, Jan, the founder of Pipe Support And he has several decades of experience as a pipe support engineer organising, supporting for all kinds of industrial piping systems. If you want to know more about that, I would recommend you to check out the recording of part one. Having said that, let me say that I'm really happy that you guys joined us of course. I want to invite everyone to participate in the chat and ask your question, say hello, hello, say it. Nice to have you on board, of course welcome. And if you like this type of content, please consider subscribing to the YouTube channel of EngineeringTrainer. And also consider following the company profiles of five support verification, or engineering trainer on LinkedIn. Having said all of that, let's start with the actual conversation Jan. How are you doing today? I'm fine. Thanks, Luke. Nice to be here. And awesome. Happy to have you. Thanks again, for taking the time to continue our conversation. I wanted to start with just giving a brief summary of part one in which we basically spoke about what defines a good support, piping support, and also the different factors and requirements which are relevant for support design. And then we'd started discussing the interface between the pipe support department on the one hand and the pipe stress department on the other hand, and one of the key key takeaways that you made Jan is that that it's very much recommended to have five support, do a first draft of the support arrangement of the system, which should then function as the starting point for for five stress department. And we discussed several examples of why this approach is relevant. In the second session, we're first going to have some discussions about examples and new slides that Jan prepared, including some examples, and then we're gonna have a q&a in which we discuss the questions that were not answered last time and also any new questions. Alright, so let's get started. Yon I'm gonna give you the screen of course. Thank you. Yes, there you are. And Jan, the floor is yours.

Jan Kalhus 3:44 

Thank you very much.

What I prepared just a few slides this time. Hopefully, some of these can answer some of the questions we had from last time when we missed some sound. So we just quickly go through and in addition to that, I also have some slides showing some typical examples to be aware of when it comes to pipe support and all also today a little bit related to the cooperation between stress and pipe supports.

So if we can start with some examples, we see that the supporting of the louche system can be a challenge. And our experience is important too. You have to have a close eye on the supporting of others; these are normally not necessarily stress critical lines. There are projects where only the headers and the main or the main headers are stress critical. So it's very important to have a couple of points in mind when it comes to supporting the loose subheaders and nozzles. And first of all, it's having a welded attachment line stop where you were where you need the line stop. And also is our recommendation to all the other line, or all the other pipe supports on that side whether to be the restaurant guide, hold on, usually, we have every second line guide, every sec can hold on, but for this system is very recommended to have rest line guide Hold on, on every support as long as it doesn't in the introduce any unwanted effects on the battery systems

Luuk Hennen 5:45 

on the temperature must be really low. I think this is like you said a delusion. Yes, like water just like a fire hose. Right?

Jan Kalhus 5:54 

Yeah. So it's the relay, the fact that these subheaders and this system are usually empty before startup. So when you start up the loop system, it's a lot of water coming in all the elbows and then it's shaking and rattling a lot. That's why we recommend to actually keep it a little bit more supportive than usual, that is what some other systems require. That is the second point to have focused on. And of course to have proper supporting of the delusional source, which tends to be longer throughout the project, when other things come in the way of the spray, spray call. As it tends to be long, and there are different things you can do to have optimal pipe support, the first thing is really to try to get this woman she branches and also the branches. Ask them to be increased to an inch, then you can avoid the pipe support at all. And the reason why we do this is that these muscles are usually quite far from the deck, because they need to reach the equipment they are going to protect, and so forth. So when you need, let's say you need the pipe support, at the far end of a long, long branch. That's a huge part of the frame, maybe three-four meters. So if you can try to avoid that by increasing the size with two inches, for instance, that will be very beneficial, provided this needs to be done in close cooperation with safety, of course, because they have the pressure drop calculations and everything. So they need to approve that you can increase the size to some point, so regarding the dilution,

Luuk Hennen 8:02 

What is the bottom left? There's this green, I think it has to do with thermal expansion maybe.

Jan Kalhus 8:09 

Yeah, it's just to show that if stress or that way that we see that we need more flexibility, that you need to just have a little off loop setup. But as you say, the temperature here usually is quite ambient. So, you don't have that much expansion. Some examples I must say, unfortunately, are bad design. Here are two examples where you have a long narrow framework lap welded to a strainer. And you see here that both of them have line stop functions which don't have this support, even though we have lines that will not function as a line these are without the brace in the longitudinal direction of the pipe. So, this is and the one on the right is even worse because there we have used sh s profiles sh s profiles are very, very good the torsion wise strength portion-wise, but in this case that welded to string there is no difference whether you can use angle or etc. So, this

Luuk Hennen 9:39 

this would be a typical example in which the pipe stress calculation if they assume like regular support stiffness in their models is completely deviating from the actual system since the support stiffness is really flexible in the direction it needs to take right to solve this

Jan Kalhus 10:02 

exactly as you say that stress is always put in line stop and expect that to be stiff in the light. So direction may even probably be without some kiloNewtons in loads, but then the sign with no bracing long meeting or in the line stop direction, it will not function as a line stop. So, the responsibility here is really on the pipe support designer that needs to be aware of and have an understanding of how this framework will behave in such a situation. So, as you're saying, in this dress I saw, and the intention is to have livestock in real life if this was going to be fabricated and installed, you really don't have a license,

Luuk Hennen 10:52 

I actually once saw a think it was it was an actual stop on a relatively small line. But the actual stop was supported by an iframe steel bar, which was you know, or oriented search that only the center of the eye in the frame had to take the actual load. So it basically connects in no time of course. So that really showed me the borders of what you're saying here. Yeah.

Jan Kalhus 11:26 

Yeah, so it's, it's important to have an eye on is not only to the standard details line stop on the pipe support frame and think that you have a line stop. Another example is not about the design of this but it's a substantial one. And this is a typical, or how typically this but pipe supports near to relief devices, in this case, ruptured disk and creates a huge load. And then, of course, a huge substantial pipe support. So this is just to show that there are quite heavy pipe supports on these lines. So this is an anchor point, like all directions, right? Yeah, it's not welded to the structure but it's what we call out this is not held on. This is the rest line guide the line stop

Luuk Hennen 12:33 

Yeah, and just they just started going Oh, just thinking out loud, like as soon as the ruptured disc bursts. Good, maybe the pipe shoot through the pipe shoe or is it welded on it.

Jan Kalhus 12:51 

Now, this weapon in red hair is welded on. In this case, probably because it's acoustic pipe spec. So you actually have a requirement of us who fully circumferential wavelength, then it's two trunnions on each side, welded to the riverbed, and then welded shoe at the bottom and then we have used a lot of line stops to take, because here we are talking about 30 2030 pounds of force. So in those cases, so in these cases, no need to put extra contingencies on the stressor. Alright. And now, this slide was there was one question regarding vibration and the use of vibration onto vibration units from the last conversation. So what do we see here? This is actually the question was really how to accommodate the vibration dampening. And there are two ways of doing it. Basically, first of all, you can have a good cooperation to certain companies that are specializing on vibration dampening, they are manufacturing the units and they can also help with the design and the pipe support. If you have a special vibrating system that is 111 ways of doing it. In this case, it's just an example from one company called Viva tech. There are many of them. That you can actually have your design if you have an exhaust pipe or something that causes a lot of operations that you want to do. To get the with high or large temperature expansion, you could actually send isometrics to these companies and have them evaluating and support them for you if you want everything to be vibration damped so that is one way of doing it. Another way is that you actually procure the vibration units yourself bring that into your detail, standard detail standard or pipe support standard details, and then you do the design yourself in this example areas he This is an exhaust pipe from a generator into a silencer. Yeah, you have a high-temperature issue, because I think it was it's usually five or 600 degrees off. And then you have ordinary lines, open line guides, and yeah, we have these vibration units that was purchased. So you can design with them yourself, what are they? These typical, there are different types you have rubber ones are made of rubber, you have also some units that are based on springs. In this case, it was a special kind of steel foam ish with a plate on top and bottom that actually was taking up the vibration.

Luuk Hennen 16:40 

Okay, but it's still it's so it still provides the static support load that it should but but

Jan Kalhus 16:48 

a yes, but you need to make sure that it can take the load because if you see the head this vibration, and the vibration unit here can take less loads sideways than this long guide. Yeah, so if you need it's, you can take less load, so you need to make sure that these vibration units are within the loads that you experienced from the stress is

Luuk Hennen 17:21 

great. I mean, I'm just curious like how it functions. So it has some kind of the way I interpreted at this moment is that it is like a static support but then with like flexible material maybe to make sure that any movement that is within the margins of the static support is dampened out by these rubber kinda materials.

Jan Kalhus 17:47 

Yeah, is basically to avoid any vibration and mainly sound to go through and into the structural steel

Luuk Hennen 17:58 

Yeah, okay. Can I ask one question about the previous slide? Yeah. Yeah, these green items displayed here, what kind of supports would those be

Jan Kalhus 18:15 

there these are rods basically you have logged on the pipe and under structural and then you have logs like a rod with this out and the vibration units in the middle. If you go into let's say for instance liberal Thank you, you will see a lot of examples of different types really, they are base mounted like we saw on that slide. But you also have this rod the pipes, okay. The other Greenwald's is really bellows

Luuk Hennen 18:51 

Yeah, yeah. Yeah, sure. Yeah. And these, these also do both the static force as that they remove or are done to remove the vibrations. Is that correct?

Jan Kalhus 19:03 

these rods, yes. Okay. And here is also different types, because sometimes you actually just want to isolate and then noise coming from the pipe through the pipes of water into the structure steel, that is one pipe, but then you also have items that can actually physically contribute to dampening the vibrations in the system. Okay. Another question from last time was, I think I misunderstood the question. When I read it, I hope I understood it better. So my interpretation of that question now was really, what if you have a welded shoe, almost the pipe where you have where you actually need to have a good installation of the pipe to avoid heat loss and there are really not that many options. You need to have it on some kind of shoe unless you will rest insulation directly to this tail. So, on this top example, there is a possibility to make this welded shoe as small as possible meaning as small area as possible prior to protruding the insulation to minimize the heat loss, depending on the strength of course, that it needs to take from the loads from the or the load takeoff the loads from the pipe

if that

ends up to be too steel to have too high heat loss from the pipe, the alternative is really the bottom right to clamp it on on the outside of the insulation. And there are systems, therefore, having special insulation that can take a little load. It's sort of a cryogenic method of supporting Yeah, I haven't seen that. That's Sorry,

Luuk Hennen 21:13 

I haven't seen those before. I mean, I can imagine that that is a little bit of a maybe a challenge to have the support load passing through the insulating material

Jan Kalhus 21:25 

you mean the top one no the bottom right like the bottom right Yeah, that's true that is for special cases I've only seen it's usually if you have very low temperatures and operating temperatures below zero to avoid ice buildup and that kind of thing. And also if you have LNG a type of system so is very very cold then you see these systems that is called cryogenic issues or cryogenic pipes and then you put all the supports on top and the challenge is of course that you then you are have usually used clown shoes with the limitation of loads that means so many but the the usual design of a popsicle shoe is to have it produced or going through the insulation Yeah, but back back to the question if I think it's two ways of seeing this is to maybe design a welded pipe welded to that so that have the less area going through the insulation to and you can of course also think that you can you can actually have a combination but then you need to design it properly that you have let's see you have ordinary welded shoe down to the middle hair somewhere and then you put the isolation you can have a bolt the plate to both the plates with insulation material in between Yeah, and then put the pipe insulation beneath that break sort of so then of course then you will get strength and isolation you

Luuk Hennen 23:21 

need Yeah, because that is one of the This was my main question is like couldn't you just isolate insulate? Sorry the support maybe

Jan Kalhus 23:31 

Yeah, but you need to do it. Do it here because down here you need is resting on structural steel, you need the guide. It moves probably a lot at least in one direction. So you actually need to do the whole thing before you come to the intersection to the pipe support framework. So but yes, you can have it maybe a little higher and then I have these double plates bolted because then you can use more than four bolts if necessary. And then having insulate insulation material in between. Okay, yeah. Next slide is a common thing for both pipe support and stress. It's a typical PSV arrangement. And our experience here is that in on the stress ISO, you probably only need this black pipe supports downstream the PSV, you have lines top line guide, and then you have rest and line guide depending on the rest of the system, of course. But usually you don't need a guide upstream. If this leg is quite short. We see often that we Need as a private support group, we need to put the line guy there. Because this PSV is taken out once a year. Yeah. for maintenance. And then just to keep this upstream pipe in place during that time, we really need to guide here. And usually, I haven't. I haven't drawn the vows here. But you see in the picture that there are valves both downstream and upstream that PSV Yeah, so usually it's quite a challenge to get room for this type of support.

Luuk Hennen 25:40 

Can we see it in the picture? Or is it not there?

Jan Kalhus 25:43 

Now this here is either it's or shorter, that's, not the pipe support here. I think the head there is just directly below the route. So but it was just to illustrate a typical system or arrangement. That is, yeah. But that is something that is very nice for both pipe support and stress to be aware of that, even though you don't need these pipes report, due to pipe stress in need due to valve maintenance and keeping the pipe upstream the PSP in place when the PSP is a very short one. I noticed in the conversation that you had with stress, man, yeah. Yeah. So in that chat, there was some question about U bolts. And I would just want this give our opinion on the use of U boats is that u boats have very little connection surface to the pipe. So we would recommend that you use some kind of use strap for pipe size, about two-inch or two inches and above. And the reason behind that is again, that some systems are now at least offshore and the project we have contributed lately is fairly small, or thin-walled pipe. And then we do this in them calculation is local calculation using our formula. Yeah. And there we see that you really need even the area guiding the pipe hair is small, because it's really just a strip. It's far better than this single point. Also, if you have a line guide, or nonrenewable, and the line starts to move, you get this very small area, they can start with a road the pipe. Yeah, that's what we are afraid of. So it was just just just our statement, or our opinion to use strap when needed, instead of the bolts

Luuk Hennen 28:15 

to understand correctly, that these U bolts can actually compress the circumference of the pipe. Is that is that the failure mode? No, not

Jan Kalhus 28:28 

probably not this one because you see there is no gap on top pair. So that's probably great view bolt. In that case you will have touched a pipe all the way around. But so some of these are non-grip, then you have a small gap on top and then is only the sideways force going into this single point. Everything depends on the load of course and the how much it moves. I can't say that this is a bad design because if this is a very thick pipe or thick-walled pipe, no temperature and its grip is steady. It might function. Okay, but as a general opinion, if you have a use strap rather than U bolt on bigger pipes, we think that is a better solution.

Luuk Hennen 29:16 

All right, and in what cases would you say that that it's even better or that you should use like a shoe clamp and shoe below the pipe instead of even use a strap.

Jan Kalhus 29:35 

Usually, we say that pipes that are insulated Of course needs to be put on shoes because of the insulation, except for the personal protection insulation marking kit cut off locally on each side of the support, but basically insulated pipes and pipes above 10 inch. We recommend to put on shoes. Yeah. Okay, thanks. Last slide is really just an example, a story about a 12 inch to face 1500 psi pipe, wall thickness, 21 millimeters. So it was quite a high pressure pipe which was designed with the, with the supports. What happened when they started up the system was that they come some real large slug loads running through the pipe. And when they hit this bam, this elbow, it actually lifted up the whole pipe from its support, moved it a little bit sideways, and then crushed the line guide down into the side. As you see in the pictures. The stress is also that it shouldn't have any level down areas just a restaurant guide. And the callback from these liaison screamed a lot for was a wrong design and we are stressed or support or had done something wrong. Yeah. But then it was asked what really happened? How did you start up this system? And it turns out that they actually open this big role without pressuring the system through the bypass on the other side. So it was really a wrong operation that was caused. So with all that said, just a picture over there. If you don't operate correctly, you can unleash quite high, high loads. Yeah, it wasn't.

Luuk Hennen 32:03 

Was it clear to you when you saw these pictures, or you did the inspection? What happened, and

Jan Kalhus 32:09 

not immediately because the message we got was quite clear that we had done something wrong. So we had to go through a whole, all our design and stress had to go through their calculations. But they couldn't find anything wrong. And I couldn't understand it. And then we put some questions back. And then after some information back and forth, it came through that they had opened this love without pressurizing the system through the bulk bypass then, so communication is important.

Luuk Hennen 32:48 

Yeah. And would there be something that you would recommend to design the system for such instances? Like No,

Jan Kalhus 32:58 

no, no, I wouldn't recommend the design 444 wrong operation of the system. So it's like I said, the design and the supporting and everything was fine here.

Luuk Hennen 33:14 

Alright. And I believe that that was also the final slide. The Jan Is that correct? Yes. All right. So I think you answered several of the questions that were left open during the board one session. I have one more question that we got regarding gaps and clearances. Of course, that's always an interesting topic. And the question that we got was, I thought that was an interesting one is can we correlate the support gap, the clearance with the pipe diameter? And or even the displacements? So is there like one number that is typical? I think you mentioned three to six millimeters last time? And is that related to the diameter of the pipe?

Jan Kalhus 34:08 

Oh, it's not related to the diameter of the pipe, as far as I know, in our experience is that if you have a line guide, the line standard line guide gap is three millimeters on each side. If you have a hold on is three millimeters on the whole down direction before the whole down starts functioning sort of Yeah. And that there you have this little mismatch between the real-life and the suicide. So because usually stress also has a zero millimeter gap. But that is something with just this little mismatch. We say that okay, it's probably seen as a conservative approach, a little less conservative approach to keep it zero in the stress ISO, and then if you have the standard, the three-millimeter gap, that wouldn't hurt the system and will only make it a little bit flexible and really sometimes get to lower load or less load on the lines. And then if you didn't have to get

Luuk Hennen 35:13 

Yeah. All right. Okay, so, y'all I want to thank you for these additional examples. And I think we went through all the questions that were asked last time, and I think you answered most of them actually, during the slides. We did receive that much questions today. So we'll leave it at this. I mean, the time is, we've been talking for well over half an hour or so. So that's completely as scheduled. We just got one question, though. Let's just pick up on that. One is? What is the price difference between EU gold versus US traps? And is that a consideration? In your opinion?

Jan Kalhus 36:03 

I'm afraid that I don't have it on top of my head. Depending on what coating and how that u bolt is being manufactured, on the top of my head, I think it might be easier to just bend the road, Rob, and so that the U bolt is may be cheaper, but I really don't know off the top of my head or from the top of my head.

Luuk Hennen 36:28 

All right. All right. Well, no worries. Thanks. Thanks again. Those are all the questions. Jan, thank you. Thank you very much for your time for the second session. And if people have questions, you know, connect with us on LinkedIn, shoot us a message. And I invite everyone of course to follow both Pipe Support Verification, or linked sorry, EngineeringTrainer on LinkedIn. Have a great day to all of you and Jan. Thanks again and have a great day also. Thank you. Bye Bye. 

Have a great day. Bye.

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