heat exchanger re-rate

[picasa]

A 1968 HX was built in year 1968 but before 1968 ASME Section VIII code came into effect. That HX needs to be rerated for a higher temperature. Both old and new temperature is well below the temperature where allowable material stress reduces due to higher temperature. The HX is a shell tube HX with TEMA type 'AET'. I guess the rerate is mainly going to involve repeating tubesheet calculations per TEMA 1965 code. I looked at API 510 to see what it says about rerate. Figure 7-1 in API 510 says that if vessel was not built to 1968 or later edition of ASME code, then vessel or component cannot be rerated using the latest edition/addendum of the ASME code allowable stress. Thus in this case, calculations have to be done per TEMA 1965. Is there any software out there which can do TEMA 1965 calcs for this HX? If not, is the only option hand calculations? What else will this rerate procedure involve?

 

[metengr]

The requirements for re-rating are typically based on the rules of your local Jurisdiction where the vessel is installed. Is this vessel located in the US? If so, you will most likely fall under the National Board Inspection Code requirements for re-rating (see Part RC-3022). I know of only a handful of States that do not regulate pressure vessels. In this situation, you can certainly use API 510 and you would need to work with your boiler/machinery insurer, if you are not self insured.