Is a telltale hole required for Wrapper plate or Wear plate for Saddle supprted vessel?

This may be required for remove the produced gases during the welding.

Please clarify.

_________________
hi

You won´t find a clear requirement in VIII-1, saddles are not part of the mandatory part. This means, when there is no rule noone can force you to drill one. However, a good advice is to follow UG-37(g).
Michael

When there is no way to ensure whether the shell below that wear plate got corroded thru, there's possibility that the wear plate becomes a pressurised component and its fillet weld to the shell becomes a weld loaded with pressure, having some category with all the consequencies. It's really simplier to drill a hole than to go deeper into this discussion

_________________
Konrad Anikiel

Hi,

The requirement of telltale holes for saddles of nozzles is stated e. g. in:

ASME I
“PW-15.3 Compensation plates and saddles of nozzles attached to the outside of a vessel shall be provided with at least one telltale hole [maximum size 1/4 in. (6 mm) pipe tap] that may be tapped for a preliminary compressed-air and soapsuds test for tightness of welds that seal off the inside of the vessel. These telltale holes shall be left open when the vessel is in service.”

ASME VIII/1
“UG-37
…….
(g) Reinforcing plates and saddles of nozzles attached to the outside of a vessel shall be provided with at least one telltale hole [maximum size NPS 1/4 (DN tap] that may be tapped for a preliminary compressed air and soapsuds test for tightness of welds that seal off the inside of the vessel. These telltale holes may be left open or may be plugged when the vessel is in service. If the holes are plugged, the plugging material used shall not be capable of sustaining pressure between the reinforcing plate and the vessel wall.”

The reason for the above mentioned requirement exists also for similar cases e.g. saddles for supports.

_________________
Kind regards,
Juergen Fleischfresser

Simply put, if it is placed on the pressure boundary, it is a good idea, but not a Code requirement.

An example I came across was when the client required the Code nameplate to be completely seal welded in order to avoid product infiltration/contamination from the exterior.

My reply was that, if this is a concern, and plugging of the hole is not prudent, perhaps a duplicate nameplate off of the pressure boundary, or provide a means to stamp the Code information directly onto the pressure boundary and be done with it.

Granted, the Code nameplate is not a wear plate or a reinforcing element, however I still felt strongly that it is a good idea.

_________________
A question properly stated is a question half solved.