Recently we have come across a strange piping layout near a large multi stage centrifugal compressor where the connected piping are not provided any flexibility because of fixing stiff guides very near to compressor nozzles, yet fulfilling 3X NEMA SM-23 nozzle allowable checks for various stages of the high speed rotating machine using Caesar-II through a strange theoretical simulation.

Is not this layout prone to having nozzle misalignment possibility as rigid restraints may not be as ideally stiff & properly located without friction as modelled in Caesar-II ?

With progress of time, are we proceeding backwards due to low cost work share models of engineering firms and providing the owner a maintenance-prone machine ?

Please voice your opinions on such funny engineering of theoretical restraints near steam turbines and centrifugal compressors, if you have found somewhere while auditing/reviewing and suggest what should we do in such a situation when engineering is almost over.

regards,
sam

We expected a few denials at least from the ten MNC E/C firms we are currently working with that they do not follow such a customer-cheating practice. But, we got disappointed so far!

Last 33 years I am working in this power/process plant design arena, I have noticed steady decline in professionalism in the behaviour of engineers in the developing country we serve world wide. It is not lack of knowledge that is generating this wrong attitude.

In the projects we work, we have had right systemic requirements set to be followed by E/C firms from the conceptual stage. Before 30% model review we insisted on freezing such piping analyses so that maximum freedom can be provided in piping layout within the overall plot plan. But, even at 90% engineering completion, the compressor nozzle qualification is not successful with realistic supporting arrangements!

In our part of World, competition has been fully throttled by majoritarian exclusivism of democracy in technical education and people with wrong attitude are studying this field nowadays.
Our engineers do not bother to learn the basics; only superficial skills like 3D modelling, SPR handling & Caesar-II usage makes them earn a very good reputation of piping stress engineering serving developed world needs through work share due to this ENRON like creative model of "low cost high value" theme. They never bother to think that they are not competitive enough to serve the customer adequately and never feel the need to learn through any continuous learning programs. Even we the end users in the domestic market suffer from this erosion of quality and morality in this feudal paternalistic and seemingly religious environment of E/C community.

If we need to make World-Class products here, we need to respect the interest of our customers and let fair competition play in the field of engineering. It is not playing a video game with some one else's belief that he is in safe hand!

regards,
sam

I saw this kind of solution some years ago. It was a pump suction system with the classic flat layout that designers give to you to validate and with rigid struts placed half meter one from another on each suction. Pumps were ok on paper despite the huge loads on struts. It was a past work that I was reviewing trying to understand the capabilities of the team. My comment was that I do not believe that is working. A picture from site was shown to me. The lines were not straight, some thick reinforcing plates were applied on thin stainless steel pipe.

You are right, but I guess that now this apply everywhere in the world. I think that people follows the model that seems to be the path to success. But I am stubborn and I insist on the path that I consider is right. I continue to share to the others my experience. I'm not doing stress work anymore but I often go to talk with the stress engineers and let them know my opinion on their problems.

One of my good friend, older that me and much wiser than me told me a story.

Abot 20 years ago, when PDS was in their days of glory, people was so enthusiasted that they said: We do not need anymore engineers, we only need two push buttons, one green for go ahead and one red for stop.
Some years later they reconsider the value of studies on 2D as priceless and reapplied as mandatory on every project.

Eventually people will find a way back to the values. Maybe not exactly as the old ones, but a balance is always achieved.

Regards,

Thank You, Sir, for this frank response.

Now, people have immense faith in technology. I have seen people telling us that they have copied similar plants running elsewhere built with similar wrong principle, why do we object. similarity ends with layout only, sizes of pipes are totally different - diameter and thickness wise; rotaing machines connected are of different makes from the reference one. If required, they will do FEA without informing the equipment vendor and proceed! How strange!

Our problem is that we need to derisk our owner from continuous operating problems throughout the lifetime.

People from operatng & erecting community who validate PDS modelin 30%, 60% & 90% completion never know that they are witnessing a faulty piping around their precise rotating machines.

Only putting the faith in youth is not enough! They need to be armed with proper insight.

This forum helps us in finding the right balance between technology and sound reasoning and questioning.

regards,
sam

I can not believe no one is willing to say more on this subject. People come here to find answers, but you also have to give something to the forum. Don't be shy. I bet most of you dream to be a leader. Start acting as one. I must confess I am provocative but hey! everibody have something to say something on this. Lookat this forum in the past, was full of debates. But this was the thing that keep this forum alive. Or not?

Hi Sam & Dan ,

First, I have to admit that I was the guy who concentrated the superficial skills like CII as you described ever.
Truly,I can't agree with you anymore and I also want to share my thought in this forum today.
"Time is money" can be for all the clients,the owners want to get the more benefit from all kinds of plants which will be completed by their investment ; then , the engineering companys are required to lowest their proposal man-hours to obtain the opportunity of these valuable contracts.
However , for example , there are so many unreasonble man-hours in lumped-sum projects for engineering design stage and some of the project management members are always like to urge the engineers to make only a general(poor) design for dealing with the clients.Becasue the project team members want to acheive the dead line and want to see the good perfomance in their progress reports only. "Cost" is rooted in some guy's mind , and will push more pressure for each designer and engineer.
To complete the task force , some engineers just focus on their "paper work" without any engineering judgement gradually.For example , a few stress engineers even did the tricks in their stress models to make the report looks like good.Once the plants were built and the operation was fine , they still felt it's a sucessful project. NO! How lucky for this world!
I'm appreciated to get a lot of useful ways and thoughts from this forum and I have saw the "attitude" and "responsibility" from some wisers.We should be proud of our work , not a "typing" machine for input and output only. Any analysis step has its meaning ; in some moments , seeing is not believing and we should find the truth just because we are "engineers".

Thanks & Regards,

Hello Dan & Sam,

I'm a tiny grain of sand against your vast years of experience & knowledge.

However, in my small career of ten years where I've led some projects in Stress, I've come across the multifacets of this whole issue.

True, that the guys in our era are more money centric & want to learn bits & pieces of everything but master of none!!

While imparting training to joiners, I've found guys less inclined to learn the basics of pipe stress but more eager to know about the Caesar. How to "operate" Caesar?

The problem is the mindet. They forget that Caesar is just a software or rather a complex calculator which does many engineering calculations in quick time.

There was popular adage in computer filed.."GIGO- Garbage In Garbage Out".

The other face is the client. They crunch the schedule as well as cost to an extent that in this competitive environment sometimes unwantedly designs are made which only is a design which "works" but not a good design.

I've seen some client adamant on passing big turbine with one NEMA even if the vendor agrees to provide 3xNEMA.The reasoning the client gives is when others can do it why can't you. This enatils to designs which work only on "paper". Though I don't advocate such designs!!

Clients should also think of the long term goals rather than short term.I've seen in some EPCs designs of big flare lines running in long runs without a loop!!!Reasoning: Design temperature is fictious & doesn't come in the whole of the line.

That's how the things are unfortunately at the moment.

Dear Youngsters,

May be you might have misunderstood my comment.

I didn't blame on the use of technology like Caesar-II, NozzlePro etc. Neither on your youth & material-minded attitude.

As ccckkkk has rightly noted, A/E firm is the engineer. Client can ask for anything; engineer need to give a wise advice.

Clearly wrong layout if you sell by showing its simulation in software, in few monts of operation the lapse will be caught and client will not return just for your 3D modelling & 3D printed physical model you advertise.


So, only cheap soultion is not enough; it has to be a solution, at least!

Keep learning!

regards,
sam

Sam

I rather think your comments are something in between of two ideas: today's ethics of E/EP/EPC contractors and the fact one can realize is well prepared to deal with a world that no longer exists.

My best regards.

Yes Sir!

You have found it right.

We are in a funny World now where we have given the cockpit control to a gaming console to child just fired with aspiration. And sorry part of the problem is that we are ill prepared for it.

For example, last week we were in a walk-through audit of a just erected process plant piping from the owner's side.

Here, people of the audit team had been acquired from the A/E DEC engineering community. Their whole thrust was fully to complete the piping given to us with the manpower within the timespan available. Quantity, not the quality of audit was the motto. The PARETO principle with which we make criticality of C1/C 2/C3 lists is lost.

So, we may need to be prepared to the World we witness today!
regards,
sam

This thread appears to be dated, but still relevant. I concur with the first thread that restraints should be applied as far away from equipment nozzle as possible. And also consider if using clamps lined with Fabreeka (a search on net will locate the manufacturer). I have seen some cheap replacement like neoprene - but neoprene becomes hard if the line is hot therefore not a suitable substitute for Fabreeka.