Piping Specification and Piping Class

Sabir,
Can you give us more information about where and how these terms were used?
I suspect that you may have heard someone ask:
"What is the piping specification?"

or

"What is the piping spec?

or

"What pipe class are we using?"

or

"what is the line class?"

For each of these I would suggest that they were talking about the "Piping Material Specification Line Class" for a specific line. They were each using a more common abbreviated form of the longer and more formal term.

"we are ought to create the Line list….what are the parameters to be included in the Line List. Hope u understand my question."

The information below covers Line Numbering and Line List.
The other part of your question is not clear to me yet, I will need to give it more thought.



Line Numbering
The question:
“Is there a common system for line numbering and if so what is it?”

I could be wrong but I think it is safe to say there is no “common pipe line numbering system” in use in the process plant engineering and design world. There are just too many companies and people and clients and project types to be able to achieve such commonality. I don’t remember seeing anything in ASME B31.3 (or any other Code), but then again it is not the purpose of the B31 Code to dictate a line numbering system.
To properly discuss this subject we need to understand the purpose of the “Line Number.” We also need to acknowledge that some companies use the term “Line Designation.” Whether your company uses the term “Line number” or the term “Line designation” the purpose is the same. It is for line identification. This identification is necessary through out the project and is used for many purposes by different people or groups. The line numbering should be controlled by the piping group for the project and done by the piping material engineer for that project.
As with any of the other “gray hair” pipers, I too have seen many different line numbering systems in my working past. Of all of them I have determined that there are some similarities but no totally common system.
Here are some details that I have been able to determine for myself. There are two basic areas that tend to govern line numbering. These are the line number method and the line number elements.
• Methods - There are two basic line numbering “methods.” The first method is based on the Purpose or Function of the line. The second method is based on the line “Size.”
• Elements - There are many potential line identification elements that may be included in a line numbering system. The elements that are most commonly included in a line numbering scheme are: Plant Location, Line Identity, Line Class (or Line Specification), Size, Insulation Type (when required) and Heat Tracing Type (when required).
The “purpose or functional” method of line numbering is where the line is best defined as a single line having an origin and a terminus consistent with a purpose or function. An example of this might be a pump suction line. It might come from a Storage Tank, a Tower Bottom or an Accumulator. It travels some distance and then splits and connects to the two pumps designated for that one service or function. This is one line, it serves one purpose or function therefore it has only one line number. Another example would be the pump discharge that leaves both of these pumps and join to form the single pipe line that runs to the next piece of equipment. This line also has one purpose or function therefore it has only one number.
The “line size” method is where the line number changes whenever and wherever the line size changes. When compared to the first (purpose or function) method, the pump suction line might have five line numbers instead of one. The pump discharge might also have five or more depending on what happens at the destination end of the line.
One or the other of these two methods becomes the “Rule” for a company, client or project. As we all know, for every rule you will always be able to find an exception. One exception that is common to both of these “Rules” is the rule of the change of line class (or line specification). The change in line class is most often caused by a change in pressure or material. A line might be the same size from one point to another but includes a pressure control valve that lets the pressure down to a level that allows a lower flange rating and or another material therefore a different line class. There are other line class change initiators but I think you get the idea. Any change in a lines conditions or material causes a mandatory change in the line number no mater which line numbering method is being used.

The elements of a line number might be arranged and look something like this:

10-1021-CA1A-12”- IH -ST
Where:
10 = the plant Unit or Area (mandatory)
1021 = the numeric line number (mandatory)
CA1A = the line class (mandatory)
12” = the line size (mandatory)
IH = Hot Insulation (only when required) (1)
ST = Steam Tracing (only when required) (2)

(1) Other types of insulation include IC = Cold Insulation, IS = Safety Insulation, IA = Acoustic (or Sound) Insulation, etc.
(2) Other types of tracing include: ET = Electric Tracing, CWT = Chill Water Tracing, TT = Thermon (Hot Oil) Tracing, etc.

I have no doubt that there are other items of information that could be or are added in some form or another based on the preference of a specific company of client. My credo is “Keep It Simple.” The manner of arranging the Elements to form a line number is something that is also dictated by the Company and or in some cases the Client. The sequence that is shown above is in the order of information priority that I am used to.

The line numbering activity should only be done when the P&ID’s are well along in the development process. The more complete the P&ID’s are the less hours will be wasted and the better the results of the line numbering effort. The degree of P&ID completeness prevents recycle when new equipment or systems are added or when equipment or systems are deleted.

Line List
As the Piping Material Engineer (or designate) performs the line numbering of the P&ID he or she also initiates the first draft of the Line List (or Line Designation Table) data base. The resultant document from this data base will be extensive for a whole project but will be broken down by plant area.

In addition to the line identification elements (indicated above), the Line List (data base and document) will or should also include important information for the design process and construction process such as the following:
• The line commodity
• The phase (liquid or gas)
• The origin of the line
• The destination of the line
• The line pressure, both the normal operating pressure and the maximum operation (or Design) pressure
• The line temperature, both the normal operating temperature and the maximum operation (or Design) temperature
• An indicator code for Stress Analysis requirements
• PWHT (post weld heat treatment) requirements
• The insulation thickness (optional)
• The line schedule (optional)

The line list once initiated will have many additions, deletions and be used by lots of people throughout the project both in the design office and in the field.

One of the first and most important activities where the line list is used is when the definitive labor hour estimate in generated. The number of lines on a project has a direct bearing on the labor hours required. This is true for the piping design activities in the home office, the pipe fabrication shop and for the installation contractor in the field. So it is very important to get it right.

From Sabir

Our client has different classes of lines and had given some documents which describes about the CLASS. The Engineering and Design Team has made a Piping Specification out of these documents. So I’m confused whether the Piping Specification is made out of this or is it an independent entity to be designed before the CLASS specification. And now our client wants us to verify the Piping Specification as well.

I am not at all sure what you are saying here. I could make some guesses and get something right or be totally wrong. I do not know what your client gave you and I do not know what your company did with them and I also do not understand what you are being asked to do.

Are the client documents in English?
Are the client documents in electronic format?
Are your documents in English?
Are your documents in electronic format?

If the answer to all of these questions is yes then perhaps you could E-mail me a small sample from each. With these I might be able to offer more help.

Sadir,
Thank you for sending me the samples of the documents in question. I am now able to understand your question better.
First:
Both of these documents are the same in function and purpose. They just have different formats. You could have chosen to use the client's piping specification as it is or you could change it to your company format. You elected to change it. In doing so you must insure that you do not miss any of the client's information.

Second:
With a few exceptions your Design Team has done a good job of converting the Client's (many page) "Pipe Class" document into a single page document. The clients document is more complicated to use and is not normal for you pipers to use therefore could lead to errors.

Third:
There appears to be a few (see below) specific items did not get transferred from their document to your document along with the "Notes". Maybe this is what the Client was meaning when they asked your company to "verify" the piping specifications.

Items that appear to be missing:
-From "Basic Features"

Rating
Corrosion Allowance
Maximum Hydro test
Seal Welding
Butt Welding

Then there are the "Notes"

If you have already covered these items then you should have no problems.
Good Luck