We operate large HRSG's and have maintained them to 'ASME intent' for a number of years. Although you would expect this type of information to be readily available, it's not. The question is; does anyone else use an interpretation of the ASME codes to maintain their HRSG's.

Any information or guidance would be most appreciated.

We have several HRSG's and we follow OEM guidelines for operation and maintenance activities. In-service inspections and repair fall under the National Board Inspection Code requirements. I am not sure what "ASME intent" is that you are referring to because ASME B&PV code is a construction code, NOT an in-service code.  

If it is in reference to ASME B&PV Code Sections VI or VII these are good sources for additional information on operation/maintenance of heating and Power boilers. We have used information from these sources to develop our own specific procedures for operating and maintenance of HRSG's to supplement OEM guidelines. However, we are not bound by nor required to follow ASME B&PV Code Section VI or Section VII.

Most Jurisdictions in the US reference and require the National Board Inspection Code (NBIC) publication NB-23 for Inspection, Repair and Alteration activities of boilers and pressure vessels. The NBIC references the orignal code of construction in "so far as practical" to be used in performing repairs/alterations. As far as inspections, the NBIC has all of the necessary information related to this activity - ASME B&PV should not be used.

To answer your question regarding repair, yes, you can use other options for weld repair that are listed in the NBIC. For example, NBIC Part RD contains various alternative weld repair methods that are not mentioned in the ASME B&PV codes because you are dealing with an in-service pressure retaining item. In some cases, the orignal code may have required PWHT. However, this can become impractical or even result in damage to the component in certain field installations, that is why we developed alternative welding methods in the NBIC.

I would suggest you purchase a copy of the 2001 NBIC with the 2003 Addendum. Even though I sit on the NBIC main committee this is not a commerical plug valve, nor do my comments reflect those of the main committee.

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