Process to Add Nozzles to a Vessel 2

NewMechanicalEngr;
The installation of new nozzles to an existing ASME Section VIII, Div 1 vessel should be performed to one of two in-service codes - either the National Board Inspection Code, or
API 510.

To provide a high level summary, both in-service codes deal with two aspects; the first is making sure the new nozzle is adequately designed in accordance with the original code of construction (ASME Section VIII, Div 1) rules and the second piece of this is the actual installation of the nozzle. For this, the work needs to be performed under an approved quality control program as stated by the NBIC or API 510. An approved quality program means either you or a contracted organization has a current National Board Certificate of Authorization to perform the nozzle installation.

Your part of this project should be to review the design rules for a new nozzle installation (weld joint connection detail, need for reinforcement, preheat requirements and post weld heat treatment requirements) and nondestructive testing requirements. Once this design review is completed you can turn this information over to an organization that holds a National Board R Certificate to install the nozzle.

Hopefully, you've checked into this, but if you can add a tee onto one of the existing pipe connections, it would be vastly simpler.

Welding details may vary on the new nozzles- check with the installer to see what is simplest, which may be different from that used on the original construction.

We deal with revamp/modification all the time. Here is what you need to do: Formally run the calcualtion per the existing code for nozzle thickess, flange rating and nozzle reinforcement. NBIC also allow you to use the latest code under certain conditions. You shall have cover sheet for your calcaution. PE stamp is not mandatory but preferred. Issue it to client.
Then, formally make the detail design dwgs with proper title block. Couple dwgs may be required. First dwg will be exsitng vessel GA dwg with design data, such as code/year used, design condition, material(watch out in specific service, normalization may be mandatory), corrosion allowance, flange rating, hydrotest test pressure, PWHT requirement, etc. You shall add the new nozzles elevation and orientaions to this dwg so contractor knows where to put it. The second dwg will be all details that you can definitely copy from the existing design, you will need to specify NDE(normally MT or PT root and final is good enough). Watch out if it is sour, caustic hydrogen or amine service, then NDE can be different. Dwg must be formally issued to your client.
Then, you need to find a R stamp holding vessel shop, and hire AI to represent you for inspection and sign off.
Pay attention to the following:
1. Highly recommend to check the existing wall thickness where you want to install nozzles, and adjust your calcaulation for wall thickness accordingly.
2. Re-hydrotest is normally required per NBIC. However, there are certain conditions you don't need to do it per NBIC. In many of our cases, we do not re-hydrotest for towers that have packing, trays or complicate internals. Only AI and owner have the right to waive hydrotest. So you need to talk to them. If proper welding and NDE are done, most of the time it will be waived for 2" nozzles.
3. You shall have welding engineer to review/approve WPS/PQR/NDE/ procedures and MTR submitted by the vessel shop. AI needs to see calculation, dwgs, and all approved procedures, MTR before work can be started.
4. There will be certain code paper work that shop will do so you do not need to worry. AI will sign it off.
5. You can use existing dwg to add the new nozzles, no need to create new one. Just rev it up is good enough. But for new nozzle details, the simple way is to add new nozzle numbers to the existing details with additioanl NDE requirement. Make sure you cloud all the changes with new revision.
6. Use LWN if possible. If you use weld neck, the weld between flange and neck shall be hydrotested per code.
7. We normally add a bracing to 2" nozzle. If it is C.S.,2" wide 3/8" thick.
Hope it will help.

Add things to my previous post:
in addition to MT/PT, we do request UT shear wave examine for nozzle welding. Also if vessel is stamped PWHT, you willl need to do local PWHT, and you will need to run stress calcualtion to make sure your tower will not buckle if it is vertical, otherwise, you will need to add additioanl temporary support.
Point# 5, it is not as simple as I stated just adding nozzle # to existing detail. The considerations are many folds:
Existing weld design may not be suitable for field. You need to talk to contractor. The factors are:
Wall thickness, safety, accessibility from inside and outside, fire hazard due to back gouging, back gouge from inside or outside, can GTAW be use w/o back gouge ?(we do this only there is access problem). These factors will determine whether you can use existing weld design or create a new one.

Details above are very clear and I would like to advise that you should not install any nozzle on the knuckles of the tank heads.

As a new engineer, you need to review UG-36, UG-37 and UW-16 of ASME VIII, Div. 1. Also review Part 3, 3.3.2, 3.3.3 and 3.4.3 of the National Board Inspection Code regarding Repairs and Alterations.