GRP lines

Hello Dears,

My company has decided to work on a project that has some critical GRP lines. I should analyzed one of them but in Caesar reports the allowable stress is zero. I don't have enough knowledge about GRP lines and don't have enough time to search for many document. Is there anyone to get me some document and an example about these lines.

Thanks,

If you don't have the knowledge, simply don't do it. Especially not when it is critical. Copying a file from someone else is easy, making a trusthworthy piping system isn't.
Keep in mind that most GRP manufacturers don't give you the properties you need for a c2 analysis, which makes it a little more difficult.

Thanks corne,

But what should i do? I should do it as soon as possible.

Hi Mohammad,
Please tell me piping code you are following to analyse GRP lines.Piping allowables and dimensions you have to get from the vendor.This is the starting point to begin our analysis.

See Caesar II techical reference manual, Chapter 6 "Pipe Stress Analysis of FRP Piping " pages (6-77 to 6-84)
that will give u an idea.


Regards,
Siva

First, get all the data you can get from the vendor. Then check which data you've received so you can determine which piping code you can use.
Build your C2 model, be careful with wall thicknesses (bends and tees often have larger wall tichknesses) and enter it all correctly.

Hi learner2001,

It's BS7159.

Thanks,

If you're using BS7159, make sure you have the correct mechanical properties from the vendor. Some vendors automatically supply the needed input for UKOOA/ISO14692.

Hi,
Here are sume thumb rules.
1.Support every large size valve on both sides.
2.Dont not support on elbows.
Also attached a file for your reference

Hi learner,

I have two big problems:

1- I couldn't know how much is allowable stress for GRP lines
2- If i get it ,I couldn't understand that how should we insert in *.frp file in Caesar lib.

Best wishes,

Get it from vendor.Who is the pipe supplier? Why you trying for that.
Select the Mat 20# represents FRP pipes.

I can guide you if u follow ISO14692 for your failure envelope values.
what are the input parameters u have?

satheeshpiping@gmail.com

Hello Dears,

They aren't my answer. I want to sure my allowable stress result by code calculating formula is correct and will be compared with Caesar's report. I want to have an clear example. I was wondering if any one make an example with my attached file.

Thanks,

Hi Dears,

I want to have my answer as soon as. Please answer my question.

Please see attached instruction,

It explained about UKOOA code. My problem is BS7159. Although I couldn't my answer, I have another question:

Does any deference between steel supporting and GRP supporting. Of course I want to know about method of GRP supporting no about support types.

Thanks,

BS7159, Sec 9,9-5
Also see Learner 2011 pdf file sec 2.D
Search about proper suppoting to overcome waterhammer as well,

Go to Smithfibercast(National Oilwell Varco) website:

http://www.nov.com/folderDocs.aspx?id=13279&taxID=5340&?linkid=Library

at "Engineering & design" section: E5000

also they have a software "Success by design" that can help you.

Regards,

Thanks for your helping but I think no anyone can understand my more important mean:
I want to know that how can calculate allowable stress(SH)with my attached file from AMERON. If no, what should I do?

Dear M.Mohammad,
If you are going to use BS 7159 then,
Design stress=Design strain x youngs modulus. Find your suitable design strain value from Table 4.3

Dear friends,

I've decided to analyze by UKOOA standard, but I have some question:
1- Our vendor is AMERON and there isn’t any value for shear modulus in its data for inserting in *.FRP file. What should I do?
2- In some of the *.FRP files, there is a part under * UKOOA envelope for straight, ell, tee, what is it and how should I define it?
3- When I choose MATERIAL NO. #20 and specified my system’s temperatures, CAESAR II doesn’t show any value for Sh for allowable stress in spread sheet. Should we determine it ourself? If not, what should we do? If yes, Sh = f1*LTHS and LTHS is value for HDB in AMERON but there are two values for this term Static and Cyclic, which of them should be selected?
4- I want to get some information about supporting method for GRP lines, is there anyone to help me?

Thanks,

1. first of all you don't have to make a *.frp file. You can also insert all values directly in C2. It's just what you find most useful.
Ask Ameron for the missing values. They will give them.
2. for UKOOA and ISO14692 you can define different stress curves for straigt pipe and for elbows and tees. As Ameron doesn't have the values for bends and tees use the values for pipe in all cases.
3. You should define SH yourself. In case of UKOOA you need to enter LTHS.
Your correct. Use the static value.
4. Supporting for GRP lines is not much different from steel lines. Use standard pipe shoes and guides and axial stops where desired.

Dear mohammad
actually we are working in vendor side. we are GRP pipe manufacturer . u can tell me ur all question .

actually allowable stress of the GRP pipe will come from HDB . HDB value will come from 10,000 h test result. our HDB value value is 132 MPa .
allowable stress in axial direction when u r using code UKoOA code is f1*f2*f3*HDB/2
where f1= 0.77 (vendor data)
f2= 0.67 (sustain codition)
=.83 (operating condition)
=.89 (occ. condition)
f3=.85 for above ground
=1 for underground

span length for supporting are mentioned in the UKooa code and ISO 14692
the thermal expansion of GRP is more higher than the steel so span length is less.
all rigid element has to be supported properly .

if still u have some clarification u can come back to us

Dear prakash

Thanks for you answer. but can you tell me more about f3?
In UKOOA standard there are some note about this term but it's complicate.

Dear Mr. Mohammad

As per ISO 14692 the f3 factor will be 0.85 for above ground piping system and 1 for under ground system.

however you can also calculate the f3 factor by using the ISO 14692 part 3

F3=1-((2* axial stress due to bending)/(r* f2*sigma fs)) .....equation 13

where r = test data = short term axial stress(0:1)condition / short term axial stress(2:1)condition

and sigma fs= (Qualified pressure *mean Diameter)/ (2* reinforced thicknes)

hope this will give you some idea about f3 factor.

Dear Friends,

As per our client requirement we need to use ISO 14692 for GRP.
This is the first time I am doing GRP lines that too in ISO 14692.
Can anyone pl. help me how to input in CAESAR II v.5.2 and pl.
give me some basic idea reg. this.

Thanks in advance
regards,
Alagappan.

Hello Dears,

I've done a system in UKOOA standard and attached in this reply.
I was wondering, If someone check it and specify my probable mistake.
And I have another question. I work for a company that someone believe modifying GRP system is so difficult. Is it really? If yes, why?

Stress analysis of GRP pipes is little difficult in a way, if you don't get all the required data from the vendor.
The data varies mostly from vendor to vendor because of manufacturing processes and thermosetting properties of the material used.
There are other factors which may affect the analysis like the no. of laminate used in the pipe. GRP pipes are generally consists of 2-3-4 laminates. The thickness of the laminates depends on type of service and environmental conditions.

Note if the pipes are glass lined and if so then the installation is more difficult than the analysis as these are more suscestible to brittle fracture. In this case allowables would be less than the normal GRP material. Also, GRP pipes fail mainly because of warping/warpage over a period of time, so it will be ideal to respect the data provided by the vendor.

As a GEP(good engineering pratice), all the runs of the GRP pipes used for water service should have a nominal anchor(Rest+Guide+Axial stop). It is preferable to guide the pipe throuout the run except near the equipment connection which will depend on allowables. The specing between the weight carrying supports is lesser than that used for same sized metallic pipe.
All this applies for the above ground piping.

Please correct me if I have given any false information.

Thanks MORE-P for your guides.

But I want to know is correct my job? If no, why?

Prakash,

Can you please tell me how to obtain the qualified stress in ISO 14692? as far as i know, the vendor should determine the Qs by Qs=PD/2t...so are they going to supply us the value? because the previous material properties of GRP from the vendor there is HDB value,how to treat the HDB when using ISO 14692?