Threaded Plugs on Pressure Vessels - Cast or Forged?

[Speckworm]

I have a few (5) unused 1/2" NPT ports on my 10-Bar ASME coded vessel. I only have Section VIII of the the ASME Code so I don't know what is permitted to plug these holes. Can I use the cast pipe plugs we have here in stock (only has a "27A" marking on it) or do I need to purchase something with a specific marking and rating? What reference material would apply here so I would know where to find it?
Speckworm

 

[metengr]

If you have Section VIII, Div 1 look at UG-14 Rods and Bars.

 

[Speckworm]

Thanks Metengr, I would not have considered a threaded rod or bar to apply here. Is UG-14 just stating that basically anything under NPS4 doesn't need to be an ASME fitting? This blows my mind. For this case I assume with NPT threads I just need to call out a Class 150 or greater square head plug, we just don't identify ours in stock that way. (What we have on the shelf may very well be Class 150, I just don't know if there are markings that would prove it.) I just don't see a minimun rating required in Section VIII which is why I am confused.

 

[metengr]

Threaded bar under one of the material specifications permitted in Subsection C can be used in this application. You can use a square head pipe plug, however, it has to be material that is permitted under Subsection C, and have the proper thread engagement, see UG-43.

 

[GenB]

malleable iron fittings to an ASME std (most are) can be used to 10 bar or sometimes to 20 bar depending on temperature up to 400F. after tat forge fittings 1000 . 2000 . 3000 . 6000 lbs are available. commercially.pp

 

[brkmech1234]

Speckworm,

You can use threaded plug of ASME B16.11 which is rated to be 6000 class

 

[moltenmetal]

A 1/2" NPT threaded plug in a vessel is no different than any other piping spec item which might be inserted into that female NPT nozzle later by the user- a valve, a nipple, a level switch or other instrument etc. It is NOT a closure. If your 10 bar design pressure and design temperature (not mentioned) are within the limits of a B16.3 150# MI threaded plug, you can use it. I wouldn't use any fitting which doesn't identify the rating, so keep those fittings on the shelf- who knows what 27A means?. For the cost of some 3000# A105 threaded plugs, they'd be worth the piece of mind.