Field Instruments on PV and Piping?

[bmoorthy]

Dear All

Field Instruments such as Thermowell, Level Gauges, Transmitters etc that are mounted on Pressure vessel and Piping are found to contain Welding and on some instruments we find reservoirs.

Which Code governs from the point of view of Welding and NDE and Pressure testing requirements for the field instruments? Are there ANSI guidelines for the same, Does ASME Specify any specific requirement for field instruments.

 

[metengr]

If the attachments, which I call appurtances, are directly welded to the vessel AFTER the pressure vessel has been in service, either API or the National Board Inspection Code (NBIC) would govern in terms of welding requirements. The actual Code depends on your Jurisdiction regulations where the vessel is installed. If this is a new vessel, the Code of Construction rules must be followed.

For either in-service or a new vessel, the Code of Construction rules must be followed for any material and weld detail for direct attachment of the appurtances to the vessel pressure boundary.

 

[bmoorthy]

The attachments are flanged and Bolted construction.

When i have to procure these field instruments, i need to specify the NDE requirements and Welding requirements.

 

[jsummerfield]

Different installation requirements may apply. Different codes apply to different industries. Is this for a section I or section VIII vessel, onshore, offshore, etc.? Are the instruments mounted on the vessel or on a bridle?

I would require hydrostatic testing. With hydrocarbon products and other high pressure applications I prefer magnetic level indication and assorted technologies in lieu of level gauge glasses. If using gauge glasses offshore they require a protective shield.


John

 

[GenB]

If the connection of the instrument to the vessel is flgd or thrd there is not Code of construction for the instrument if it is under the size specifically in the Code (ASME Sect VIII-1 or piping constructuion)
in ASME VIII-1 non.Code vessel can be 6 in or less welded or not.
The instrument has to be meet/certified to ANSI stds.

genb

 

[1969grad]

If the instruments have bolted (flanged) or screwed connections to the vessel then the applicable piping code applies such as B31.3.

Instruments like level gauges usually are not required to be hydrostatically tested as they fall under the category that a protype has been tested to failure so the specific item is not required nor desirable to be field tested.