Rerate HX

[picasa]

An old Shell and tube HX built and designed per TEMA back in 1968 needs to be rerated for new temperature and pressure. Any guidelines on how to proceed will be really appreciated. Does TEMA have any guidelines on how to rerate an existing TEMA HX? I presume ASME Section VIII Div 1 UHX will have nothing to do with this problem since this is about rerating an HX and not a new HX.

 

[lostsailor]

picasa,
The National Board Inspection Code will, more than likely, be your governing document. You would be well advised to check with your local jurisdiction.
Regards,
RLS

 

[metengr]

lostsailor is correct if your Jurisdiction or your insurer is involved. The applicable section in the National Board Inspection Code (NBIC) is Part RC-3000, and involves re-rating of pressure retaining items, which is considered an alteration.

 

[rzrbk]

Save yourself some headaches and just do some preliminary calcs to make sure your desired conditions are reasonable for the exchanger. Then get a quote from an exchanger vendor that you currently work with to provide: eng. calcs, new nameplate/bracket, misc. paper work, etc. This can usually be provided at a very reasonable cost. You will need to provide them with drawings and recent inspection records.

In most cases your own personnel can weld the new bracket in place with the AI (Authorized Inspector) witnessing it. Hydro and other tests required may depend on the AI.(Inspector can possibly be provided by the Vendor depending on local rules)