Loca hydrotest of closing seam. 1

[khati]

Hello everyone,

We have a column of alloy steel. Inside the column we have to install a reboiler, but the reboielr shall be install after the Hydrotest and during the Hydrotest of the column reboiler shall not be present inside the vessel. What we have thought is install the reboiler after the Hydrotest of the column by cutting the closing seam of the vessel and again reweld it and do the local PWHT. My qts is how can we do the local Hydrotest of the closing seam, or what is the correct method and procedure..?

regards

 

[metengr]

I agree with your approach after the hydrotest of the column. At this point the vessel is completed. Hydrotest the reboiler as a separate component, install the reboiler and perform volumetric examination (RT or UT) of the closing seam weld and any connecting welds on the column. There is no need to hydrotest the closing seam or connecting welds if 100% volumetric examination can be performed. What you are doing is repairing a completed vessel using the above approach.

 

[khati]

Thanks metenger for your early respond. can u elaborate more on what is volumetric examination.

 

[metengr]

khati;
Volumetric nondestructive examination (NDE) is a method to evaluate the entire volume of weld metal deposited and surrounding base metal. The two basic volumetric test methods are either radiographic testing (RT) similar to an x-ray, and ultrasonic testing (UT) using shear wave or phased array techniques. This type of work requires a company that is qualified and specializes in RT and/or UT nondestructive test (NDT) methods.

For more background information, search the internet for either NDT method.

 

[khati]

Thanks metengr for the info.. I was jus confused between volumetric and surface examination.
now it got cleared.

thanks.