Max Size of Openings in Pressure Vessels 1

• Feb 8, 2003

• #2

apiguy

Mechanical

Mar 5, 2002

116

Would'nt that be the same as a Tee fitting ? The APIGUY....

 

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• Feb 9, 2003

• #3

prex

Structural

Jul 4, 2000

1,917

I don't find ASME VIII confusing about size of openings: UG-36 to Ug-43 apply with some limitations (UG-36(b)) and 1-7 requires for much care when higher sizes are required.
In your limit condition I think that proof testing (e.g. strain gauges) would be required to satisfy code rules. prex

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Online tools for structural design

 

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• Feb 10, 2003

• #4

Shmulik

Mechanical

Nov 19, 2001

295

Outside nozzle’s diameter shall not exceed inside shell’s diameter.
The solution ‘apiguy’ suggests is correct to my opinion. I suppose you are using 18” pipe for vessel’s shell. You may place a standard 18” Tee as a part of the shell (UCS-27: Shells Made from Pipe).

 

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• Feb 10, 2003

1
• #5

deanc

Specifier/Regulator

Sep 18, 2002

855

Take a look at Appendix 14.

 

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• Feb 10, 2003

• #6

Shmulik

Mechanical

Nov 19, 2001

295

deanc:
Please be more specific. As far as I can see, appendix 14 regards Integral Flat Heads with a Large, Single, Circular, Centrally Located Opening. The question regards perpendicular opening, it must be located on shell, isn’t it?

 

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• Feb 10, 2003

• #7

deanc

Specifier/Regulator

Sep 18, 2002

855

Sorry,did not understand your question. Prex is correct.
See UG-36 a 2 and Appendix L-7 for some help.

 

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• Feb 10, 2003

• #8

deanc

Specifier/Regulator

Sep 18, 2002

855

Also check B31.1 for pipe info.

 

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• Feb 10, 2003

• #9

twjag

Structural

Mar 28, 2002

48

Per 1-7(c), "appropriate proof testing may be advisable in extreme cases of large openings approaching full vessel diameter, openings of unusual shape, etc."
Per U-2(g, the Code acknowledges that it does not contain rules to cover all details of design & construction. Where details & design are not given, the Manufacturer, with acceptance of the inspector, may provide design details which will be as safe as those provided by the rules of the Code.
Design methods from other Codes or accepted engineering practice may be used where Section VII does not provide rules, with necessary adjustments to the factors of safety.
AWWA M11 provides rules for very large opening, approaching & equal to the shell diameter.
B31.1 & other B31 piping codes provide rules for large openings. Use of a tee is an option, using B31.1 rules.

 

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• Feb 13, 2003

• Thread starter
• #10

spike

Structural

Jun 7, 1999

46

Spike thanks everyone for the replies. The use of tee fittings is not possible. The concept is how to weld a nozzle having the same diameter as the vessel and still comply with the Code. A full penetration weld would be used, but additional reinforcement would not be possible because the diameters are the same.

 

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• Feb 13, 2003

• #11

prex

Structural

Jul 4, 2000

1,917

Note that the addition of separate reinforcement plates is not impossible, but useless, as they would have to be formed with the shape of the tee: much simpler to increase the thickness of both shells to provide the required reinforcement. prex

http://www.xcalcs.com

Online tools for structural design

 

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• Feb 21, 2003

• #12

twjag

Structural

Mar 28, 2002

48

spike,
My previous post directed you to AWWA M11, which does provide rules for design & reinforcement for large opening approaching & equal to the shell diameter.
It provides rules for "crotch plate" reinforcement.

 

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• Feb 24, 2003

• #13

deanc

Specifier/Regulator

Sep 18, 2002

855

If you use a Code that is not ASME or a different section,you must have AIA acceptance,perhaps under U-2.

 

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• Feb 25, 2003

• #14

twjag

Structural

Mar 28, 2002

48

deanc,
You are correct. The design package must be accepted by the AIA. This includes design methods within the Code, & those offered based upon good engineering practice where the Code does not offer methods or formulas.
Use of methods not contained in the Code must be adjusted to Code allowable stresses

 

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• Mar 7, 2004

• #15

hockchong

Mechanical

Dec 9, 2002

29

Hi Everyone,
Is there any limit specified in PD5500? I have a case here where the OD of nozzle 1110mm and the vessel OD 1170mm. I need a clause stated in the PD5500 code that mention that the size is violating the code as they don't accept my explanation on practical fabrication issue. Thanks and I need this urgently.

Thanks again.

Regards,
Lee

 

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