I have a 4" well head line of 43C operating temperature and 77C design temperature with a imposed displacement of +/- 50mm at well head due to well head movement.
As per design philosophy, i have considered only operating temperature and developed load cases as follows,
L1 = WW+HP (WW-water weight, HP-hydro pressure)
L2 = W+D1+T1+P1 (D1-disp due to operating temp)
L3 = W+D1+D3+T1+P1 (D3-imposed disp due to well head movement +50mm)
L4 = W+D1+D4+T1+P1 (D4-imposed disp due to well head movement -50mm)
L5 = W+P1
L6 = L2-L5
L7 = L3-L2
L8 = L4-l2
L9 = L6+L7+L8

Is this load case combinations right?

And My another problem is, i have left the ambient temperature as default of 21.1C, But the site condition have varying temperatures from 15C to 32C from month to month. should i give the minimum temperature experienced in site as installation temperature? the pipe would experience the minimum of 15C, if installed during that month of cold condition. Please suggest me to get a optimal design.
please clarify me if i have to keep 21.1 as ambient and develope another load case with T2-15C. I dnt think it makes sense.
What we eactly specify by this ambient/installed temperature?

Dear Shan,

In my opinion, you shall use 15C as ambient temp for worst condition of line. There are two alternative for this case.

First, you can generate two file of piping input for 15C and 32C ambient temperature case.

Second, you can only generate one piping input file with adjusting temperature differences between ambient to max operating temp (MOT) and between ambient to design temp (DT.
For example, say ambient is 21.1C. So, you can generate 4 (four) temp. case. such as:

T1 = value of 21.1 + (DT - 15)
T2 = value of 21.1 + (MOT - 15)
T3 = value of 21.1 + (DT - 32)
T4 = value of 21.1 + (MOT - 32)
note :
T1,T2 will generate delta temp. between ambient temp. (15C) to DT or MOT
T3,T4 will generate delta temp. between ambient temp. (32) to DT or MOT

For all, please CMIIW.

Regards,
Fernanda A

Hi Fernanda,

Thanks for your reply. I am taking 15C as ambient temperature since the operating is positive value (43C). In case, if the operating temperature is negative value (-), then i will have to take 32C as installation temperature. (this is suggested by our seniour engineer).

But, I think i should not consider many thermal cases here like T1, T2, T3 & T4 as you have suggested. incase, if i have two operating cases with one temperature above ambient and another case below ambient, then i have to go for taking different thermal cases as you suggested. But, since there is only one operating condition in my system, i think changing the ambient to 15C and take one thermal case for maximum operating temperature and analyse the system is adequate.

If you have different openion in this regard, please suggest me fernanda.

or anyone else have other openion that contradicts with mine, please cite out here. I would like to explore this further. Thanks in advance to all of you.

There are several ways to incorporate the effects of ambient temperature in CAESAR II.

I want to point out that, as I see it, ambient temperature in CAESAR II is the temperature at which the pipe is cut to length and installed. Other than that, it is not related to environmental variations.

What if the cut temperature doesn't match the install temperature? Let's say some fab shop on the Texas Gulf coast build your piping spool on a hot summer day. You then ship it up to Alberta for a winter installation. It's going to be short. You'll have to pull the pipe to button it up. If you care to model this, these "gaps" would be modeled as material 18 - Cut Short.