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Oil and Gas - Piping Tie In Schedule

7 replies [Last post]
Jithin Kambhikanam
User offline. Last seen 9 weeks 5 days ago. Offline

Hello Everyone,

What are the Ativities to be considered in a Piping Tie In Schedule. I do know Hight LEvel Activities but would like to know more like breaking it into Level 5.

The case is " The Oil and Gas Plant is live and we would be shutting down the Plant to do the Tie In. So within 3 or 4 hours we need to do the Tie In. And the Tie In is a Welded Joints. so we need to cut the Pipe and Weld a new Pipe to that Line when the Plant is Shut Down.


So can someone who is experienced in such kind of Tie In give me there input.





Jithin Kambhikanam
User offline. Last seen 9 weeks 5 days ago. Offline

Hi Kiran and Steven,


Thanks for a really good explanation.



Ya I was looking for the Execution part and I did cover all those activitiers in the schedule. All the prework would be before the Execution.

Right now the Tie in has been changed to just boltup connection which would be in the Executuion stage. All the on field welding till the Tie in Point would be done part of Prework.




Kiran Nath
User offline. Last seen 16 weeks 3 days ago. Offline
Joined: 4 Mar 2017
Posts: 2
Groups: None

Tie-in Preliminary works

  • Notification from Company
  • Pre-fabrication of Tie-in spool
  • NDE
  • Hydrotest for Tie-in spool
  • UT for existing Tie-in line
  • Excavation for foundation (if required)
  • Foundation installation (if required)
  • Scaffolding installation
  • Structure, Platform, Support installation

Tie-in Execution Works

  • Positive Isolation from Company
  • Blinding (Gas free line)
  • Cold cutting
  • Installation of tie-in spool
  • Welding
  • NDT
  • Hydrotest
  • Line Blowing and Drying
  • De-Blinding and client handover


  • Touch-up and painting
  • Scaffoldning removal and house keeping
  • Handover to operation team/company
Steven Auld
User offline. Last seen 4 hours 49 min ago. Offline
Joined: 13 Sep 2017
Posts: 106


If you are shutting down the platform, is the platform going to be fully nitrogen purged?

If not, you may have to look at having pressurised habitat's to complete the welding scope if the full area is not hydrocarbon free. If a pressuised habitat is not required, has a spark retention habitat been built?

What diameter of pipe are you welding - there may be requirements for Pre-Heat of the weld area, along with a potential for post weld heat treatment which will extend the hot work period.

What material is the pipe? - the pipe size & material will both affect timings for the weld.

Make sure that the welding equipment is on site & fully tested prior to the shutdown - wouldn't be the first time we have gone to complete a welding scope & found an issue with the welding kit. Also make sure that the correct welding materials have been sent out as per the weld procedure. Make sure that the welder correctly coded for the material to be welded.

Measure & mark cut points prior to the shutdown - this should be done more than once before the shutdown to confirm the correct cut point.

NDT Inspection of the cut point(s) - save cutting into the spool to find an issue that means you cannot then weld in the new spool & have to move the cut point. Complete this well before the shutdown start.

Isolation requirements - do you need to use a Mechanical Plug to get confirmed isolation from the remaining process pipework? - these can also cause their own issues.

Confirmation of Hydrotest requirements - again isolations may affect this as you will be testing to higher pressures than a normal leak test.

Check your timings between completing the welding scope & the Hydrotest - if you do this when the weld site is still hot then you could crack the pipework due to thermal shock - also the NDT may require some time for the pipework to cool sufficiently before this can be completed.

You have not mentioned the cold cut of the existing pipework & removal of the old pipe - depending on the size this may take a bit of time to complete.

Don't forget to add a final dimension check immediately prior to completing the cut on the existing pipework - measurements should be compared to the new spool that should already be on site by this time.

You mention the PTW, however you may want to include gas testing as an activity, as depending on the work site, this may take a bit of time to complete properly.

Confirm that there are no simultaneous operations in the area that may affect the site (breaking containment for other scopes for example) - these can have a knock on affect to the overall shutdown duration if not managed. 

Probably a heap of other things that I can't think of right now.



Jithin Kambhikanam
User offline. Last seen 9 weeks 5 days ago. Offline

Ya its a Live Plant and the High Level Activity which is hapeening on the day after Shutdown is like,

  • PTW
  • Shut Down
  • Flushing and Purging
  • Handover and Sign PTW
  • Fit Up 
  • Welding
  • NDT
  • NDT Result
  • Hydrotesting
  • Mechanical Walkdown with Company
  • Handover

All the above would be plotted in hours and I do know the Productivity of the crew and I do know the Quantity also , So I can put the duration.

But apart from the above activity is there any further breakdown. 




Anoon Iimos
User offline. Last seen 22 weeks 3 days ago. Offline
Joined: 22 Sep 2006
Posts: 1416
Sorry but I don't understand what you meant by "Hight level activity". It is an existing facility so you just check the actual installations and confirm the actual productivity of your crew. I suggested the steps I mentioned earlier. If you mean "Hot Tapping", then that would be another story.
Jithin Kambhikanam
User offline. Last seen 9 weeks 5 days ago. Offline


That would be normal for all the Tie In. But I want to know how detailed would you go in a schedule like duration based in Hrs.

I do know how much would be done and I know the Time to do it on a Hight level activity. So I want to know if the high level which I have is enough to plot a schedule or can be broken down even more.

So I want to know how the experienced personels break Tie In Construction Schedule into.




Anoon Iimos
User offline. Last seen 22 weeks 3 days ago. Offline
Joined: 22 Sep 2006
Posts: 1416
First, review your Safety Procedures (especially for hot works). Second, talk to your team and conduct visual inspection, while in conversation with your team, list down all the activities that they mentioned. Third, go back to your office and review the activities that you listed (when in doubt, repeat the Second).