ASME I Flanged-In Manhole

[FabianoRibeiro]

Please, verify if my interpretation of the code is correct:

In the case of a elliptical (12x16in) flanged-in opening in a elliptical 24in head we have two options:

1- Flued opening such as indicated in Fig. UG-38;
2- Opening with ring such as Fig. PG-28.

In the first case, the thickness of the head should be computed using the equation in PG-29.1. Since it's a flued opening, the additional thickness specified in PG-29.3 is not required. Also, area reinforcement calculation is not required for configuration according to PG-34.2.

In the second case, the thickness of the head should also be calculated according to equation in PG-29.1 and the additional thickness according to PG-29.3 is required. In this case, area reinforcement calculation is also required.

 

[gr2vessels]

Fabiano,
Please correct me if I am wrong;- do you intend to calculate the ASME Sect. VIII Div 1, flued opening Fig. UG-38 using the provisions of ASME Sect I?
I suggest that use the provisions of UG-38 for the flued opening (first case). The thickness of the head should be computed as per UG-32, not as per PG-29.1. Also, the area of reinforcement calculation is not required according to PG-34.2, it is required as per UG-37.
In second case, you are correct.
Cheers,
gr2vessels

 

[FabianoRibeiro]

gr2vessels,

I intend to calculate a flanged-in manhole according to ASME I. I indicate Fig. UG-38 because I did not find in Sec. I the same figure.

Therefore, case 1 is calculation of the flued opening according to ASME Sec. I.

Best regards.

 

[FabianoRibeiro]

After thoughting a little over this issue again, I came out with another interpretation.

The manhole can be fabricated in two ways: with a flanged-in or with a welded ring.

In the case of a flanged-in, the head should be calculated according to the second part of PG-29.7 and the thickness shall be increased according to PG-29.3. No area reinforcement calculation is required and the criteria related to the flange in PG-34.2 apply.

In the case of a welded ring, area reinforcement calculation is required and PG-28 apply. However, it seems to me that the head thickness should be calculated normally according to the first part of PG-29.7 and increase in thickness is NOT required.

What do you think?

Another question is: what is "flanged opening supported by an attached flue" written in PG-29.3?

Best regards.

 

[FabianoRibeiro]

Correcting myself...

After thoughting a little over this issue again, I came out with another interpretation.

The manhole can be fabricated in two ways: with a flanged-in or with a welded ring.

In the case of a flanged-in, the head should be calculated according to the second part of PG-29.7 and the thickness shall be increased according to PG-29.3. No area reinforcement calculation is required and the criteria related to the flange in PG-34.2 apply.

In the case of a welded ring, area reinforcement calculation is required and PG-28 apply. Additionally, increase in thickness is also required.

What do you think?

Another question is: what is "flanged opening supported by an attached flue" written in PG-29.3?

Best regards.

 

[gr2vessels]

Hi Fabiano,
Refer to the thread below, this topic was debated earlier.

http://www.eng-tips.com/viewthread.cfm?qid=237870&page=1

Cheers,
gr2vessels