temperature limit for leg supported vessel
temperature limit for leg supported vessel
(OP)
In almost every specification and book,the temperature limitation has been specified as 230°c.and if the temperature is above 230° leg support shall not used.
can anybody provide the reson behind this limiting temp.
is it for thermal expansion?how it affects to leg?
can anybody provide the reson behind this limiting temp.
is it for thermal expansion?how it affects to leg?





RE: temperature limit for leg supported vessel
I have never heard of such a restriction limitation.
Show me an authoritative text or report with this restriction.
Was this temperature restriction something that a customer or consultant stated at a meeting ?
Was the customer/consultant an MBA or Certified Project Management Professional ?
In these mysterious "books and reports", what type of support is suggested for vertical axis vessels operating above this temperature limit ?
RE: temperature limit for leg supported vessel
RE: temperature limit for leg supported vessel
Exactly, it is written in PIP standards and also if you refer any handbook directly or indirectly it is limited by temp.
What are the probable reason behind it??
RE: temperature limit for leg supported vessel
RE: temperature limit for leg supported vessel
RE: temperature limit for leg supported vessel
RE: temperature limit for leg supported vessel
In accordance with the code of record, he has at his disposal a multitude of methods, designs and materials available to produce a stable and code compliant design. He must check for strength as well as elastic stability under all loading combinations
He can use a variety of leg/skirt designs, select from a variety of materials, structural shapes etc.
He may use a detailed finite element analysis method of the legs and shell juncture to justify his design.
He may require fireproofing on the supporting legs or skirt of a vessel. He will note this on his design drawings
I don't care that recommendations of the PVP has somehow (subjectively) limited any and all legged vessel designs to 446F.
(230C).
There is no justification .... without a valid research paper/study/peer reviewed report....its just an opinion and its asinine
RE: temperature limit for leg supported vessel
I have asked to many of my frnds the same and maximum of them has given their opinion same as what james has given above.
RE: temperature limit for leg supported vessel
RE: temperature limit for leg supported vessel
"Fabricator always have to follow the requirements in a 50 page (or thicker) client vessel spec."
Yes, of course, but this is beside the point. If the client wants the vessel painted purple with yellow dots, you paint it purple with yellow dots.
The original question was "why do we have a 230C limit on legged vessel designs ?"
The answer to the question is "Because sombody said so.."
There is no reason based on any code, or stress analysis, or elastic stability study.
I will repeat ....... This is an arbitrary restriction placed on the fabricator by the client.
I also believe that 230C (446F not 650F) is a very low threshold
RE: temperature limit for leg supported vessel
First, is there engineering basis to limit the use of legs on hot vessels. My answer is yes based on my education and stress analysis experiences.
Second, is the threshold 450 F or 650 F? I agree 650 F is a better number. PIP may have gone extra conservative on this one. This is just like steam out case: some vessel specs do not care; some spec call for 0.25 X full vacuum; some call for half vacuum; and some ask for design for full vacuum. They all have their reasond behind these choice.