High Pressure Piping Design, B31.3, Chapter IX 1

[jserpas]

I have the following questions with regards to Chpt.IX:

* If t > D/6, must I use Chapter IX, or can I still use the formulae provided by Chapter II? If so, what are the considerations/modifications to formulae in Chapter II?

* Can someone provide a synopsis of the requirements/limitations of Chapter IX?

Thank you in advance!

 

[Cockroach]

The specifications refers to "owner of the plant" separate from "designer of the plant". As principle designer, your obligation is to ensure the specification is adhered to.

When a plant owner designates the piping as "high pressure service", then all the provisions of ASME Chapter IX B31.3 Specification apply without exception.

Some of the considerations that apply to "high pressure service" are:
a) pressures attained are greater than ANSI Class 2500
flanges for the particular material and temperature,
b) maximum allowable stresses are based upon 2/3 of the
material yield; this holds across the board for the
application temperature and material,
c) Category "M" Fluid Service.

I have always considered t>D/10 since this typically is referred to in pressure vessel textbooks.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[grampi1]

Why did you bring up category M? M is separate from K.

 

[bvi]

The answer is that it is not required to use Chapter IX of B31.3 when D/t>6. It is only required to use Chapter IX when is is specified for use by the Owner. The base code states that special considerations may be required when D/t>6, but the pressure design equation in B31.3 does remain conservative for the thicker pipe.