Pressure limitations for ASME B31.3 and B31.11 codes ?

[Marruiz]

Hi.

I was looking for the pressure limitations of those codes and I couldn't know a couple of things:

1. I found that B31.3 code has 15[psi] as a minimium pressure and the max pressure is calcuated based on the B16.5 PN 420 (Class 2500) max pressure, that consider the material and temperature to define the max pressure, but... the material that I’m using is API 5L x70 wich is not specified in the tables, the tables just consider the ASTM materials nomencalture (B16.5 Table 1A)… I asumed to consider 1.1 Material Group (which gives me 6170 psig as the max pressure) but I’m not sure whether that’s correct when i want to work with API 5L x70. Am I alright?

2. For B31.11 code I found 15[psi] as a minimium pressure but I couldn’t find any place where the max pressure is mentioned.
Do you guys know how I can get this max pressure?
Is the same that in the B32.3 case?

Thanks a lot for answering me.

 

[doct9960]

1. I found that B31.3 code has 15[psi] as a minimium pressure and the max pressure is calcuated based on the B16.5 PN 420 (Class 2500) max pressure, that consider the material and temperature to define the max pressure, but... the material that I'm using is API 5L x70 wich is not specified in the tables, the tables just consider the ASTM materials nomencalture (B16.5 Table 1A)... I asumed to consider 1.1 Material Group (which gives me 6170 psig as the max pressure) but I'm not sure whether that's correct when i want to work with API 5L x70. Am I alright?

The maximum working pressure of your API 5L Grade X70 pipe will depend on the design temperature, pipe diameter, pipe thickness, & allowances. Note that API 5L Grade X70 is not intended for high temperature service. For high pressure piping, refer to Chapter IX of ASME B31.3

 

[Marruiz]

I got your point but I don't mean that, I mean that I want to know what is the max pressure which B31.3 code is aplied (with its formulas to calculate thickness, reinforcements, etc), considering the material and the temperature.

For example, with an ASTM A515 gr.70 the code works up to 6170 psig (more than that pressure it's a high pressure piping), for higher presures you have to apply special rules(chapter IX).

In other words I want to know what is considered as a Pressure Piping, (from X?[psi] pressure and below Y?[psi] pressure it can be called "pressure piping"). For B31.3 and B31.11 codes.

 

[BigInch]

B31.3 any pressure above 15 psig is pressure piping.

Maximum pressure is whatever you can calculate for your material with its specific allowable stress, the wall thickness you're using and the temperature to which it will be exposed.

For your unlisted materials it is calculated per
323.1.2 Unlisted Materials.
.....

323.1.2 Unlisted Materials.
Allowable stresses shall be
determined in accordance with the applicable allowable
stress basis of this Code or a more conservative basis.

302.3 Allowable Stresses and Other Stress Limits
.......
(f) Unlisted Materials. For a material which conforms
to para. 323.1.2, the tensile (yield) strength at
temperature shall be derived by multiplying the average
expected tensile (yield) strength at temperature by the
ratio of ST (SY) divided by the average expected tensile
(yield) strength at room temperature.

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