How To: Determine Openings In Shells, Headers, And Dished Heads Diagram

How To: Determine Openings In Shells, Headers, And Dished Heads

The objective of this post is to help you learn How To: Determine Openings In Shells, Headers, And Dished Heads. We will review the formula(s) required to complete the calculations. Then define the different variables in each of the formulas. Wrapping everything up with a couple of practice questions for you to work on.

All referenced page numbers are from the 2007 ASME Boiler & Pressure Vessel Code

We Will Cover The Following

  • How to determine the minimum allowable distance between the centers of two unreinforced openings
  • Review and provide variable definitions for the formulas provided in the Boiler & Pressure Vessel Code
  • Review practice questions to determine the minimum allowable distance between the centers of two unreinforced openings

Formulas

PG-32.1.3 page 19 Single Openings. Single openings are defined as openings that have a minimum center-to-center distance between adjacent openings not less than Lh or Ls. The minimum allowable distance between the centers of two unreinforced openings is determined by the following equation:

How To: Openings In Shells, Headers, And Dished Heads L Formula

The formula to determine the variable K found in the equation above is under PG-32.1.1 page 19.

How To Determine Openings In Shells, Headers, And Dished Heads K Formula 

Formula Variables

A, B = The finished opening diameters of any two finished openings under consideration, in. (mm) (see d below)

D = The outside diameter of the shell, header, or dished head containing the opening, in. (mm)

d = Diameter of a finished opening, in. (mm) (see PG-32.1.2)

K = PD/1.82St (where K shall not exceed 0.990)

Lh = The distance between centers of the two openings measured on the surface of the dished head.

Ls = The distance between centers of the two openings measured on the surface of the shell or header

P = The maximum allowable working pressure

S = The maximum allowable stress value, taken from Tables 1A and 1B of Section II, Part D

t = The nominal thickness of the head, shell, or header in. (mm)

[table id=1 /]

How To: Determine Openings In Shells, Headers, And Dished Heads Questions

Note: All code questions are to be calculated in (mm) and (MPa) unless otherwise stated. Convert accordingly and properly before the calculation.

Question #43

How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Question #43
2A1 Question #43
How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Solution #43 Part (1/2)
2A1 Solution #43 Part (1/2)
How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Solution #43 Part (2/2)
2A1 Solution #43 Part (2/2)

Question #44

How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Question #44
2A1 Question #44
How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Solution #44 Part (1/2)
2A1 Solution #44 Part (1/2)
How To: Determine Openings In Shells, Headers, And Dished Heads - 2A1 Solution #44 Part (2/2)
2A1 Solution #44 Part (2/2)

Summary

Did the practice questions provided help you understand How To: Determine Openings In Shells, Headers, And Dished Heads better? Let me know in the comment section below.

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