Control/Origin point + coordiantes in ISOMETRIC drawing 2

[Alaa1992]

Hy all

I'm working on a new project (construction of new process lines in oil&gas facility) and i'm in charge with new ISOMETRIC drawings delivery correspondings to those spools during and after design/construction.

I have been provided by old ISOMETRIC drawings for other line brenchs (Constructed by another company) and i couldn't figure out where control/origin point (used in those ISO drawings) was been taken.

So to specify ISO-coordiantes of the new installation, can i create/consider arbitrary, a new origin point or keep the same point used, previously, as reference in all old drawings (if the latter case, how and from where can i get informations about it ?)

I have read many books talking about elevation value, Used in all petrochemical facilities; which consider that ground elevation is always starting from 100'-0", as a fixed elevation and as a matter of convenience. Is that can be valid to any place ?

Thanks for your prompt reply



Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer

 

[pennpiper]

Alaa1992,
By your writing it appears you are not a native speaking American. That is not a problem but it means we need to dig deeper into what you are saying and what you mean.
Please be aware that by posting here you will get many, many different answers by many different respondents. Not all of them will be good answers.

1) That said, please tell us where you are from/where you live and some general information about yourself and your Company.

2) Your question: "I couldn't figure out where control/origin point (used in those ISO drawings) was been taken.". I am reasonable sure there is a clue to what the original "Plant Elevation" is, but we will need to find it. To do this we (you) will need to collect all the old/existing Isometrics. We will talk more on this later.

3) Your question: can I create/consider arbitrary, a new origin point or keep the same point used. I would not advise that you start a "New" origin point. It would be better to find and use the same elevation base as the original work.n You need to find the original base on the existing drawings or have the Client supply the information.

4) Your question: which consider that ground elevation is always starting from 100'-0". Elevation 100'-0" is most often the normal practice, however the Client should be ready, willing and able to provide this type of information.
This is just a start.
Regards,
James O. Pennock (Jop or PennPiper

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

 

[Alaa1992]

Hy Pennpiper

As a beginner in piping engineering, I'm just asking to strength, as fast as possible,my knowldege about ISOMETRIC secrets.
I don't care about bad answers, and i will consider only good ones

As u know, Drawing an ISOMETRIC isn't easy. it require a certain amount of informations related to call-outs and how to present where line is located, oriented and elevated.

1) I'm from tunisia, working in a petroleum service contractor scince 03 years, I asked my boss to let me in charge with As built ISOMETRIC drawings pertaining to this project, because my coleague, CAD engineer, is enjoying now his holidays

2) I have all drawings provided by the other contractor + orthogonal drawings of the CPF. if you know any general rule/guidelines to figure out the reference point used , without asking them, please let me know.
3) I'm sure about that, and it have logicaly a sens
4) I have asked already our client to provide those DATA, just i m trying to get some clarifications Through this thread

Hope we get a deep conversation about all the prvious
Best regard
Alaa edine SMAALI

Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer

 

[pennpiper]

Alaa,
This is a collection of Isometric Piping drawings for study.

https://www.google.com/search?q=pip...kAhWFzVkKHWrZAeQQsAR6BAgFEAE&biw=1024&bih=657

I will get back to you soon.

Regards,
Jop

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

 

[LittleInch]

The reference point should be on the overall site plan or model if you're using 3D software.

100,100,100 somewhere in the SW corner of the plant is very common.

If you're doing new drawings for new piping tying into existing pipework then you need to use their coordinate system.

surely the drawing of the existing isometric has a reference point in x, y and Z. Just work it out from there to your tie-in point.



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

 

[Alaa1992]

Thank you littleinch

It was kind to consider my question

I checked all the existed drawings of the facility(including Arragement drawings) but i can't findd it, I contacted the First founder contractor / client also no result/answere.. it is seem to me strange and funny in the same time

One last question, I'm thinking surely that there are a specific symbol existing somewhere on dwgs about this ref point
If you have any knowldege about this share it please with me.


Thnak you in advance


Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer

 

[LittleInch]

It's normally a cross with a circle inside it.

Sometimes it has two quadrants filled in, listed in the notes column and found on the overall plot plan or GA drawing.

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

 

[Alaa1992]

Thank you for your help


Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer