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.

 

[vesselfab]

I am not sure that a reverse flanged in elliptial manway is a good option in a 24" head.

 

[FabianoRibeiro]

That sounds strange to me too. I told my client to put a handhole but I could not convince him.

About the interpretation, do you think that's correct?

 

[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.

 

[GenB]

the first flanged in opening is std on cleavebrooks boilers,
nothing wrong with it if you have the machinery to make it and it will save you in welding and reinforcings.
2- flanged with flue opening is a different thing, you flange- in and then
install your tube/pipe ''flue'' or even a manhole ring or handhole.
3-you may weld the manhole and reinforce as required. not always the plate has to be thicker.
4-why to blame the customer!

 

[FabianoRibeiro]

GenB, thanks for your help.

Do you have any picture and/or drawing showing the difference between the flue and the flanged-in opening?

You say that not always the plate has to be thicker. What do you mean by not always? What are the conditions that you refer?

Best regards.

 

[GenB]

hi, look under tube fire and/or water tubes attachment and that's your answer.
i am sorry but my teachings are very conservative, requires a lot of home work.
Flues have nothing to do with manhole or handholes,
it is just form of atatching. a sample flanged flue are the cheap water heaters tank type 30 thru 50 GL capacity.in the US American standard water heaters and others sold at home-depot.