HOT TAPPING ON SUPERHEATED STEAM LINE 2

[geliberman]

We are looking for a procedure for hot tapping a 4" branch on a 12" run pipe superheated steam 430C and 50Bar.
The line is 25 years old.
Cn anybody help me?

 

[pennpiper]

Geliberman,
The best advice I can give you (and I am sure anyone else can give you) is:
1) Do not try to do this yourself.

2) Contact one or more "Hot-Tap" Specialty Contractors and have them come in and look at your specific situation, ask them for their recommendation.

3) Ask each of them for a quote to do the work.

 

[Duwe6]

Concur -- hire your 'experience'. Watching professionals make a Hot Tap makes you think it is easy. And it is.

But if anyone on the tapping crew makes a significant mistake, somebody dies.

It is like watching Ironworkers prancing around on 8-inch wide beams. Anybody can do it -- close to the ground. Only the pro's do it 150-ft in the air.

 

[zuccus]

X3, hire the experts on this one.

 

[geliberman]

Dear Friends,
We are looking for the procedure only, it means that the step by step actions, safety precautions,..
then we will hire an expert company to perform the hot tapping.
Thank you

 

[pennpiper]

Here are some guidelines for developing Tie-In procedures (both Cold-Tie-Ins and Hot-Tap Tie-Ins)

How to do a Tie-In
To start, let’s define the terminology. Making a “New” piping connection to older existing Piping or Equipment is called a “Tie-In”. This term is used by (I’m sure) more than 95% of the piping profession. The balance of the piping related world may use “Tie-Point” or some other term. Regardless of which of these terms you use they mean the same. For the purpose of this article and any subsequent training we will use the term “Tie-In”.

There are three basic conditions that exist when doing a “Tie-In.”
1. The first condition is when a Tie-In is to be made and the line can be shutdown and made safe for welding or other work. This is called a “Cold” tie-in.
2. The second condition is when a Tie-In must be made but the line cannot be shutdown. This is called a “Hot-Tap” tie-in.
3. 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.
Cold Tie-In
What is a “Cold” Tie-In? A “Cold Tie-In” is just the shutting off of a piping system, draining and making it safe so it can be opened up and the new line attached. This attachment is normally by a flanged connection.
Will the presents of Piping Tie-Ins require any special procedures or special “Fabrication and Installation Specifications”? There are a number of questions that come up regarding this and can only be answered by a detailed review of the specific situation.
The following are issues that need to be resolved. Example:
• 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?
• What is covered in the normal Piping Fabrication and Installation Procedure?
• Are you sure you will be doing “cold” tie-ins?
• What is the line size, Flange rating 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 shut-off, drained and steamed out?

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 simple 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 and is this commodity safe for doing a Hot-Tap?
• What is the operating pressure and can the Hot-Tap machinery handle this pressure safely?
• What is the operating temperature and 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 Construction and the Installation Contractor 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?


Tie-In Planning
1. Identify each Tie-In 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, depressurize, 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 upstream and downstream block valves, vents and drains - Piping Design
15. Determine the location of all existing upstream and downstream 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 (these become new Tie-Ins) - Piping Design
18. Get plant personnel to sign off on all data collected in the field - Piping Design & Process Engineering
19. In the office modify the P&ID as required - Process Engineer
20. Convert all field sketches into appropriate production drawings (Isometrics) - Piping Design
21. Prepare a Plot Plan style “Tie-In Location Key Plan”
22. Update the Tie-In List as required - Piping Design
23. Review all Tie-Ins with Pipe Stress for effect on existing system piping and new system piping - Piping Design
24. Finalize (check, correct and approve) all Tie-In isometric drawings - Piping Design
25. Insure that this process is followed for all Tie-Ins - All participants



Tie-In List
A "Tie-In" List will normally have a Title Block area, a “Technical Data" area and an area to identify Revisions.


The Title Block Data area should have the following:
- Document Title (Example- "Piping Tie-In List")
- Document Number
- Sheet No. (At the top of each page)
- Project Name
- Project Number
- Unit Number
- Unit Name
- Unit Lead Name
- Piping Lead Name

A Technical Data area should have the following [indicates responsibility]:
- Tie-In No. [Piping]

Existing line (or equipment) being tied into:
- Existing Line No. [Piping]
- Existing Piping Plan [Piping]
- Existing P&ID [Piping]
- North Coordinates [Piping]
- East (or West) Coordinate [Piping]
- Center line Elevation [Piping]
- Existing Line Size [Piping]
- Pipe Wall Schedule [Piping]
- Material [Piping]

New line:
- P&ID No. [Piping]
- Line No. [Piping]
- Line Size [Piping]
- Tie-In Connection Type [Piping]
- Commodity [ [Piping or Process]
- Operating Pressure (1) [Piping or Process]
- Operating Temperature (1) [Piping or Process]
- Hydrotest Pressure [Piping]

Construction:
- Pre-weld Inspection [Construction]
- Post-Weld Inspection complete & tested [Construction]

Schedule Data:
- Required Completion Date [Project/Client]
- Schedule Shut-down [Project/Client]
- Actual Completion [Construction]

Other:
- Remarks [any group]


Revision Box
- Revision Number
- Revision Description
- Prepared By (Name) [Piping]
- Checked By (Name) [Piping]
- Company Approval (Name) [Project]
- Client Approval (Name) [Client]

Notes:
(1) This should be the same as the existing line so you do not need it twice

 

[DRWeig]

Try Furmanite, Easy-tapper, Koppl

Stick 'em in Google for contact info, and call 'em up. They have lots of tech support available.

Good on ya,

Goober Dave

 

[Duwe6]

And DO NOT DICTATE PROCEDURES TO EXPERTS, like you seem IMHO to be wanting to do. If you are not fairly expert in Hot Taps, you are by definition not competent to write the rules. Sorry.

The only reasonable approach I see for you to develop a procedure for your company would to adopt a spec/procedure from one of the major companies, after awarding them the work for your first Hot Tap. Furmanite or TEAM.

As my favorite philospher Mr. Harry Calahan sait "A man's gotta know his limitations".

 

[geliberman]

Thank you, all.

 

[rmw]

Duwe6.

Did you leave off the last word of that quote? - "BANG". I think it is germane to the discussion here.

rmw

 

[Longinthetooth]

One extra point, not mentioned in Pennpiper's list is ultrasonic (or similar) thickness measurement on the existing line. If you cant confirm this, hot tappers may refuse to do the job.

 

[saplanti]

To me this terminology is misleading. It should be called "Live Pipe Tapping, or Tapping pipe in operation.

I guess you will never find a procedure for hot tapping for hot temperature piping as you have. If there is it must be for laboratory conditions only.

Approaching the hot steam line at that temperature is very difficult without shielding or/and insulation on the piping. Probably the insulation thickness is about 200-250 mm range for heat conservation.
Under the thermal loading and high pressure you can not do any welding; even if you do try the welding operation with automatic machines without human contact, the fusion and metallurgy during/after welding can not be guarantied.

Other might be the piping specification you have to follow in accordance with power piping code. At those temperatures the procedures can only ask for but weld fitting, not the ones we normally used for hot tapping.

As far as I know the power plants organise themselves to do this kind of jobs during the shut-down.

I trust this is sufficient.

Ibrahim Demir

 

[ripaldee]

If the piping material requires PWHT hot tapping is not recommended.

 

[Berndt]

Welding can be done on hot, live lines granted that due diligence is followed. In this regard PRCI have a FEM based program, which can predict the chance of burn through and under bead cracking given a set of welding parameters.

 

[saplanti]

Kriegfix,

We are talking about creep range temperature, right? Do you think your claim is valid for these temperatures as well?

Regards,

Ibrahim Demir

 

[Berndt]

Hi Ibrahim,

Yes, I have seen on-line welding done successfully at such temperature and it seems that my case was not isolated as Furmanite claims to be able to perform hot taps on lines operating at temperatures of 1200F.

 

[saplanti]

Kriegfix,

Interesting, it is really. Most of the piping wall thicknesses are selected narrowly for economy to work at high temperature and pressure in superheater piping, and it is under thermal expansion. The fructure resistance is very important due to very high operating temperature and pressure.

The hot tapping we are talking about is attaching two pieces around the pipe, and welding them together to each others around the pipe, and to the pipe, than connecting the special valve with cutter, and cutting the steam pipe for the new piping attachment.

Other than welding, metallurgy of the HAZ, the operation is too difficult due to heat radiation. The connected hot top pieces need to be at the same temperature with the main pipe and kept at the same temperature not to cause cracks during the welding. Managing this with one or two tools is required. Second, the hot top flange at that pressure and temperature probably minimum Class 900 and above. Is this flange going to be welded after two pieces welded to seal the area? And probably they use an extension in between not to cause thermal stresses between thse two pieces and the flange. So the cutting tool must be a lot longer than usual.

Another one is the connection of the new flanged pipe after the removal of the cuttung tool. Thay will be cold before the start up. If the same main is to be goingt to be the content of this pipe even the start-up may be a big problem. If the new piping attached to the main is going to have high pressure lower temperature water, the problem will be a lot less, but the introduction of the water into steam will require special equipment or valve. That part is more complicated.

I would like to hear about if someone has a procedure that explain stages.

Is this used as a permanent solution, or temporary solution until the next outage?

Kind regards,

Ibrahim Demir

 

[saplanti]

Kriegfix,

I have just found time to go through Furmanite web site, and could not find any evidence about your claim. I have provided a link for their case studies which they are proud of. I have provided the link below:

http://www.furmanite.com/CaseStudies/tabid/59/Default.aspx

I was wondering if there is a link to support your claim somewhere in their web site or a copy of the brochure or letter.

Kind regards,

Ibrahim Demir

 

[Berndt]

As requested:

http://www.furmanite.com/Services/ServiceDisplayPage/tabid/54/obj/13/lang/1/Default.aspx

Quote:
"Hot Taps performed on systems operating to 1200 Degrees F."