Tie- In Procedure

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?

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Are you sure you will be doing a "cold" tie-in?

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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?

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What is the line size and wall schedule of the tie-In?

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What is the commodity normally in the line?

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How far to the closest valves up stream and downstream of the Tie-in Point?

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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, steamout 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 HotTap 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?