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Structural tmin per Bednar?

Structural tmin per Bednar?

Structural tmin per Bednar?

(OP)
In Bednar's Pressure Vessel Design Handbook, sec 3.3, he provides a "practical rule" for mim thickness for CS as follows:
min. t= [(Di+100)/1000] inch
for fabrication and handling purposes.
Is this STRUCTURAL tmin?
Would anyone know this basis for this formula?
Is there a formula for computing/ estimating structural tmin(or otherwise, apart form the one given in the codes) for B31.1 & B31.3 piping?

Thanks

RE: Structural tmin per Bednar?

Sure, see how much ovaling you get when you pick it up from the end points, or see how much it flattens when you drop it from a 5 meter height, or when you stack two more rows of pipe on top of it as you load it on a truck.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

RE: Structural tmin per Bednar?

Formula is wrong.  Typo, perhaps?

Gives a Tmin of 0.101 for 1-inch OK
Gives a Tmin of 0.106 for 6-inch *wrong*

RE: Structural tmin per Bednar?

(OP)
Duwe6
The formula is correct, i.e., not a typo. That's why I want to know the basis for it.

RE: Structural tmin per Bednar?

The codes do not give a formula.  They give recommended max D/t values for which you can still use the full allowable stresses, the basis of which is based on ovaling limits of a couple of % of D .. or so.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

RE: Structural tmin per Bednar?

(OP)
BigInch: I'm well aware of the intent and the provisions of the codes. You don't have to respond if you don't understand the questions or have something better to offer.
I have asked for an interpretation of what an authority said, the basis and if there are other means "apart from the ones given in the codes." Both responses from you are all but relevant to the questions.
Please let others respond.
 

RE: Structural tmin per Bednar?

No problem.  I was just trying to get some discussion going on it, but nobody seems to be very interested.  If you'd rather continue to talk to yourself about it, that attitude will ensure that you do.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

RE: Structural tmin per Bednar?

Silence is golden.
http://www.phrases.org.uk/meanings/silence-is-golden.html

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)  

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