What Is Tie-In Point?

If you have an existing installation (or pipe) and you want to connect some other piece of equipment or pipe, point where you are making such conection usually calls Tie-in point.

[Tie-in points occur in many other industries, as well as oil & gas.]

A tie-in point is a location on an existing plant where a new installation is to connect to. Until such time as new installation is built and ready for testing the tie-in points will be unused.

It is common to specify the fluid properties avaliable at the tie-in points for the use of the future installation equipment's designers.

It is thoughtful and helpful to install a valve-with-blank at tie-in points for prospective future installations when constructing the original installation, or at maintenance shutdowns on the system. Utilities delivery networks (steam, cooling water, compressed air, gas....) are obvious examples of long-life systems whose use can change with the arrival and departure of shorter-life equipment, and not having a suitable valve-with-blank can cause serious timing issues with other users when commissioning becomes due on new equipment.

Flow diagrams for the shorter-life equipment will most likely show tie-in points at the package boundary, for project design, and contract definition and administration purposes.

A tie-in is the location & specification for any piping connection made to a vessel, piece of equipment or other pipeline.

Being in the piping industry in paper mills and other places that run year round, 24 hours a day tie-in points can be a pain in the keester. We somtimes must plan ahead as much as 2 years for the right moment of "down-time" to install tie-in points for future projects. Most of the time they consist of a valve arrangement that is installed in the existing piping so that we can continue to run the system till the new equipment is installed and to switch over afterwards. Somtimes when we just have to make the tie-ins on the run we utlize a "hot tap" machine as well as other methods to tie into energized lines.

in cross country pipeline construction 'tie-in' points are left every kilometer or so and at road crossings and the like. A tie in crew comes behind the main line lower and lay to weld the tie-ins and thus make a continuous line.

A Tie-in Point is the point where the new piping connects to the existing pipe.

Ya I Agree with this, i think this is the correct answer......

Questions on this subject have come up on other Piping related forums before. The following is my answer to them. Others out there are invited to add other items that may have been found to be of importance their individual projects.

Piping Tie-Ins (Revision #14)

Cold Tie-In Procedure

The question

I have a Piping Fabrication and Installation Procedure. Is this procedure the same as tie-in procedure? If they are different, does anybody have a cold tie-in procedure?

My answer:

There are a number of questions that come up as a result of your question.

Example:

• What is covered in the Piping Fabrication and Installation Procedure?
• Are you sure you will be doing a "cold" tie-in?
• Who are you in the overall picture of this Tie-in? Are you the Client? The primary engineering company planning the Tie-in? Or are you the Mechanical Contractor who will be overseeing the actual Tie-in? Or are you someone else in the grand scheme of things?
• What is the line size and wall schedule of the tie-In?
• What is the commodity normally in the line?
• How far to the closest valves up stream and downstream of the Tie-in Point?
• Can the upstream and downstream piping be drained and steamed out?

Tie-In Planning

1. Identify each Tie-In(s) schematic location on P&ID - Process Engineer
2. Review with Piping - Process & Piping Design
3. Create a Tie-In Index (or List) with key information about each Tie-In - Piping Design & Process Engineer
4. Review with Client - Process Engineer
5. Go to the Field to locate physical point of Tie-In - Piping Design/Process
6. Meet with plant personnel and review Tie-In requirements - Piping Design, Process, Plant Operations, Safety
7. Discuss different types and configurations of Tie-Ins - Piping Design, Process and Plant personnel
8. Establish physical Tie-In location point and type - Piping Design & Plant Personnel
9. Define if the line can be shut –down, when, how long, draining, depressuring, steam-out and other safety issues - All personnel
10. Visually inspect the existing pipe. Are more extensive tests needed to determine condition and suitability for the Tie-In - Piping Design and Plant personnel
11. Mark or tag the selected Tie-In point - Piping Design & Plant Personnel
12. Photograph the Tie-In point - Piping Design
13. Draw sketch and take all required measurements - Piping Design
14. Determine locations of all existing block valves, vents and drains - Piping Design
15. Determine the location of all existing anchors and guides - Piping Design
16. Based on selected Tie-In location and type determine if additional vents or drains will now be required - Piping Design, Plant Operations
17. Include new vents or drains (if any) on sketch - Piping Design
18. Insure that this process is followed for all Tie-Ins - All participants
19. Get plant personnel to sign off on all data collected in the field - Piping Design & Process Engineering
20. In the office modify the P&ID as required - Process Engineer
21. Convert all field sketches into appropriate production drawings (Isometrics) - Piping Design
22. Prepare a Plot Plan style "Tie-In Location Key Plan"
23. Update the Tie-In List as required - Piping Design
24. Review all Tie-Ins with Pipe Stress for effect on existing system piping and new system piping - Piping Design
25. Finalize (check, correct and approve) all Tie-In isometric drawings - Piping Design

A "Tie-In" List will normally have a Title Block area and a Tie-In List "Data" area.
Note: [piping] indicates responsibility

The Title Block area should have the following:
- Title (Example- "Piping Tie-In List")
- Document Number
- Sheet No.
- Project Name
- Project Number
- Unit Number
- Issue Date
- Issue Description
- Prepared By (name)
- Checked By (name)
- Approved By (Name)

A Tie-In List Data area should (or may) have the following:
For the new line: [indicates responsibility]
- Tie-In No. [piping]
- P&ID No. [piping]
- Piping Plan No. (new) [piping]
- Tie-In Iso. No. (if different than Line Number)[piping]
- Line No. [piping]
- Conn. Type [piping]
- Commodity [piping or process]
- Oper. Press. (this should be the same as the existing line so you do not need it twice)[piping or process]
- Oper. Temp. (this should be the same as the existing line so you do not need it twice) [piping or process]
- Test Media [piping]
- Test Press. [piping]
- NDE Req'd. [piping]

For existing line being tied into:
- Exist. Piping Plan [piping]
- Exist. Line No. [piping]
- Exist P&ID [piping]
- North Coord. [piping]
- East (or West) Coord. [piping]
- Center line Elev. [piping]

Construction:
- Pre-weld Inspection [welding engineer]
- Welding Comp/tested [construction]

Schedule Data:
- Req'd Complete Date [Client]
- Schedule Shut-down [Client]
- Completion Client Sign-Off [Client]

Other:
- Remarks [all groups]

How to do a Tie-In

The question:

What methods and techniques are used to break into pipelines? I know that the easiest way would be to a blind flanged tie-in point or if a line is to be modified post a flange/valve then it is easiest to make a new spool between two flanges. My question relates to when you have to put a new tie-in into a pipeline and the above isn't viable, i.e. there is no option but to break into the line. I told one option on a gravity drain line for example would be to cut the line then put a bung into the pipe to stop drains backing up, make up the new spool then weld them back together. With piping I am aware it isn't always as simple as this as sometimes welding isn't an option either. I know you could also use an o'let for branching.

My answer:

To start, let's correct the terminology. The term you used "to break into (a) pipeline" is called a "Tie-In" by more than 95% of the piping profession. The balance of the people use "Tie-Point" or some other term. Regardless of which of these terms you use they mean the same.

There are two basic conditions that exist when doing a "Tie-In." The first condition is when a Tie-In must be made and the line can be shutdown and made safe for welding or other work. This is called a "Cold" tie-in. The second condition is when a Tie-In must be made and the line cannot be shutdown. This is called a "Hot-Tap" tie-in.

Some Hot-Tap tie-ins also require a procedure called "Stopple". This is where a second Hot-Tap is made downstream of the first one. The flow is routed through the first tie-in while an articulated plug is inserted into the second Hot-Tap to blank off the flow. Various kinds of work can then be done to the remaining pipe.

The "Cold" tie-in is simple to design and install. With only a few exceptions you can handle them the same as you would for any new piping. The exceptions include:

· Make a proper survey of the condition of the existing pipe material. Is it too corroded to join the new pipe to?

· The existing line can be shut down but can the environment around the existing pipe be made safe for any required welding?

The "Hot-Tap" tie-in is more complicated. There are many, many questions and issues that need to be resolved. These include:

· Will the tie-in be a plain tie-in or a more complex "Stopple" tie-in?

· Will this be a single tie-in point or a multiple tie-in point?

· Will the tie-in be made with a "split-Tee" branch or an "O-Let" branch?

· Is there proper space available for the piping fittings and the valve?

· Is there proper space for the Hot-Tap machine and the Hot-Tap operators?

· What is the commodity? Is this commodity safe for doing a Hot-Tap?

· What is the operating pressure? Can the Hot-Tap machinery handle this pressure safely?

· What is the operating temperature? Can the Hot-Tap machinery handle this temperature safely?

· Can flow be maintained (required for cooling) during the cutting part of the Hot-Tap process?

· What is downstream (direction of flow) of the Hot-Tap that might be damaged by the cuttings from the Hot-Tap process?

· Has there been proper consultation with one or more "Hot-Tap" Specialty Contractors?

Issues for all tie-ins:

· Has Process Engineering reviewed and approved the location and type of tie-in?

· Has Plant Operations reviewed and approved the location and type of tie-in?

· Has the Installation Constructor reviewed and approved the location and type of tie-in?

· Has the tie-in location been tagged for easy and proper identification?

· Have the proper drawings been prepared and checked?

· Has the proper material been ordered?

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