About Piping Welding, Calculations and Codes 5

[Gabrielsfe]

Dear colleagues:

I m working in a project where I have to design a water piping system DN 900 using "curved" metal Sheets ( I'm not sure if "curved" is the correct word in English).

I have an issue:

I don't know which is the a code or standard that indicates me the way to calculate and design the longitudinal seam and the seam between two consecutive tubes. Where is the formula/e?. I must do a Calculation Report indicating the formula, allowable stresses, safety coeficients, etc., and the source of the data, etc.



Thanks

I would appreciate your help.

PD 1: The specifications say I have to use AWWA Codes ( they doesn't help too much...)

PD 2: I have access to ASME Code VIII Div 1 Rules for Construction of Pressure Vessels but one paragraph says that this code doesn't apply for piping...

 

[XL83NL]

The answer is in your own post. You're best off hiring an experienced consultant or engineer who is skilled to do this job. Second you should tell your boss he should hire people to do what they are trained for, or first train people before letting them do what they're aimed for doing.

 

[Gabrielsfe]

Thank you for the answer,
I have no boss. My work is to do the detailed engineering for different types of subjects, eg metallic structures, In this oportunity I have to face the engineering of the water piping and this topic is very interesting for me as a Engineer.

If you could assist me I would apreciate.

 

[pennpiper]

Gabrielsfe,
Where are you?
What is your education?
What is your experience?
PN900? That's 36" pipe, what the heck are you building?
What is this project (be very descriptive)?

Sometimes its possible to do all the right things and still get bad results

 

[Gabrielsfe]

pennpiper

I'm in Argentina, Mechanical Engineer and more than 10 years as Project Engineer managing Capital Investments Projects.
Now and since 1 year ago I am working in the "other side of the table" doing the detailed engineering and specifications to build metallic structures, air compressed piping up to 6", etc.

As I said, appeared in my desk this new project in which I don't have experience because of that I resorted to the forum for assistance.
The easy way is to hire to an specialist but, I am an Engineer, I want to know how to do...

You can find an attached file that explain the work.
Then, I have the geometry, I have the Pipe, I have the internal Pressure,but I don't quite sure how to stablish the thickness and how to design or verify the longitudinal seam and the seam between two consecutive tubes, and put them in a calculation report.

Was I clear?

Thanks and I look forward to your comments or information

 

[weldstan]

Take a look at B31.3.

 

[curtis2004]

Why B31.3, when specification say use AWWA codes?

Curtis

 

[weldstan]

It appears that the OP is in over his head. At least B31.3 provides pressure calculation formulae.

 

[Gator]

XL83NL's answer is the best answer and I'm not sure what "I have no boss" means.

 

[Gabrielsfe]

Yes gator, maybe it is the solution, but it remains the same easy way.
To sum it up, I want to solve it because I want to know how to do it regardless of whether the project will be executed or not.

weldstan and curtis2004 gave some tools and now I'm reading AWWA 200,206,207,208 and others related to coating and lining (I can't download Manual M11 de AWWA, If anybody has it ......)

Comment to weldstan: I was reading ASME 31.3-2008 , Chapters 1 to 6 and only find typical details of attachments welds, butt welds, etc. but I can't find, if exist, the way to verify Longitudinal and Circumferential weldings. May be I'm looking for something that there isn't in the code. But must exist a method/code/standard that indicates,with no doubts,the way to calculated/verify the two types the weldings: the allowable strength to be adopt, the theory of rupture used, the Safety coefficients ( yes , B31.3 mentions something in thickness calculation, but nothing for weldings).

I hope I was clear and you can see what I need. If I'm in the wrong way, or there is another way to face the situation, please let me know.

 

[dhengr]

Gabrielsfe:
You shouldn’t be asking the questions you have asked, the way you have asked them, while pretending to be a qualified engineer for this project. Wherever you are, you are still dealing with the public health, safety and welfare, and if you aren’t qualified, by past experience, you shouldn’t be doing this kind of engineering without supervision by someone who is qualified. We all have to do any given engineering problem for the first time, intending to learn from that effort, so your willingness to learn is good (“this topic is very interesting for me as a Engineer”),
but we should be doing this under the supervision of an experienced engineer who can give us guidance. We should not be messing around with other’s safety and health while we learn a new subject. You have to know what you are doing to be a responsible engineer, not just have a bunch of formulas from a code, or some computer program. It seems to me that you should be buying some appropriate pipe for your project, and then making girth welds between lengths of pipe, both controlled by your design and building code for this piping system, not actually manufacturing the pipe from rolled (“curved”) steel plate (“Sheets”) as you seem to indicate.

 

[Gabrielsfe]

dhengr,
It seems to me that what you wrote talks more of you that of me. You don't know me.
If you can't add something positive, please don't give me lessons about SHE.

Meanwhile the subject remains what I asked to the forum.

 

[Gator]

But Gabrielsfe, it seems pretty clear that you are involved in something where you're not even sure where to start.

This probably doesn't instil confidence in forum readers who are wondering where is your guidance for this project.

Have all the other engineers been laid-off and now management is doing the technical work? Are engineers required to stamp drawings where you are?

 

[XL83NL]

Gabriel, all replies here are provided by volunteers who share their experience for the best of those who ask for your help. Weve provided help, and though it may not be the reply you hoped for, it's the best there is. Take it without thanking us, but don't be stubborn. It's in the beat of your interest..

 

[Gabrielsfe]

Ok Gator, I understand you and appreciate your interest.
I don't have formal guidance for this subject and because of that I resorted to the forum.
I'm not sure if I am doing the correct questions. As you can see in previous posts I have data input, and the data output is a calculation report. In the middle, the way, I have to respect codes/standards and explain why I propose what I propose.

After several posts is probable that the core of the subject I want to solve has been lost. Basically is the "Comment to weldstan" in a previous post.

If you have a question that clarify what I try to say, please let me know.

 

[LittleInch]

Gabrielsfe,

You're new on this site so a few tips,

The site is called Eng tips, not Eng-free consultancy.
Reacting to advice given in a negative way generally does not elicit further responses
To get the best you need to provide some background and data. Note I tried to download your file and it wouldn't. Much better to use .pdf or .jpg rather than .dwg

I'm still confused as to what you're trying to do here.

You appear to be trying to make seamed pipe from rolled plate. Why?? All the piping and pipeline codes I deal with assume you buy ready made pipe to acceptable materials and pipe specifications which they list in their design codes.

I'm not familiar with the AWWA codes, but B 31.3 and B 31.4 especially provides you with allowable hoop stress calculations for given diameters, pressures and yield strength of different materials.

The codes indicate certain key welding information, codes and parameters to use.

I've been doing this type of work for over 30 years and never had to "design and calculate" the seam or girth weld. I just buy pipe to a certain specification and specify a welding code to use and that's it.

I think there seems to be a lack of experience all round if you're being asked for this data.

You say you're being asked to design the system, but the questions imply you're designing the base pipe itself??


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

 

[DSB123]

Gabrielsfe,
A Project Engineer will never be a good technical engineer - that's why they opt for the project engineering route!!!

 

[MJCronin]

Amen DSB, ....Amen !!!!

MJCronin
Sr. Process Engineer

 

[Gabrielsfe]

DSB:
I agree with you but when you have to change to the rhythm of the needs and the new scenarios in the professional career, you must adapt (excuse me my written English).

 

[Gabrielsfe]

LittleInch:

Following the piece of advice "More details = better answers":
I have attached the file in PDF version (dimensions in mm). I hope it explain your question about "designing the base pipe itself" in your last paragraph.
Hypothesis: Currently I'm reading the B31.3-2008. The scope mentions that apply por water piping.
It seems to me that B31.4 applies for hidrocarbures, liquid anhydrous ammonia and related but not for water ( please see the Scope).
With regards to the pipe, due to the diameter aprox. 900 mm (NPS 36") and according with purchaser's specifications we have the option to made the pipes from curved steel plates. B31.1 considers this situation using a Basic Quality Factors for Longitudinal Weld Joints in Pipes,
Tubes, and Fittings,(Ej). The Basic allowable stress "S" and "Ej" are used to calculate the thickness "t", accoprding to B31.3. In this case I have to perform a Calculation Report.

But, here is where I not sure what is the code or method to apply, if the pipe is made from welded curved steel plates as mentioned above, to verify the Longitudinal Seam.
Or just, with "t'" I adopt a Commercial pipe thickness "T" and I verify the Longitudinal Seam using the known formula for full-penetration welded butt joints, as usual?


If you need additional details, please let me know.