Help!!! B31.3 Line Sizing Assistance
Help!!! B31.3 Line Sizing Assistance
(OP)
I posted this on the mechanical engineering forum, but got no assistance. So I thought I'd re-post here and, hopefully, get some help.
==========================================================================================================================================Can anyone explain explain the principal difference between B31.3 and B31.8. I know 3 is for plant piping while 8 is for gas transmission, but that is the extent of my knowledge.
I also created a line list based on the pipe schedule found at http://www.engineersedge.com/pipe_schedules.htm, but was told that this chart is based on B31.8. All the charts I have seen are identical to this one. Does anyone have a pipe schedule chart for B31.3? Can anyone share a pipe calculation spreadsheet for B31.3? Finally, what are the acceptable design factor and temperature correction factor for B31.3?
Thanks. Any and all assistance is appreciated.
==========================================================================================================================================Can anyone explain explain the principal difference between B31.3 and B31.8. I know 3 is for plant piping while 8 is for gas transmission, but that is the extent of my knowledge.
I also created a line list based on the pipe schedule found at http://www.engineersedge.com/pipe_schedules.htm, but was told that this chart is based on B31.8. All the charts I have seen are identical to this one. Does anyone have a pipe schedule chart for B31.3? Can anyone share a pipe calculation spreadsheet for B31.3? Finally, what are the acceptable design factor and temperature correction factor for B31.3?
Thanks. Any and all assistance is appreciated.





RE: Help!!! B31.3 Line Sizing Assistance
For any of the piping codes, they identify the formulas and any factors that need to be applied. The formulas and factors are not the same between the various codes. You should get a copy of the codes and look at the formulas and see how the required thicknesses vary for different design conditions. Under a specific code, you calculate the minimum wall thickness required to withstand the pressure. You then add any mill tolerances and corrosion allowances and then select the next available wall thickness that is greater than the minimum you calculate. You may also have clients' preferences to take into account. For example, many companies will specify minimum sch 80 pipe for 2" and below even if your calculations indicate sch 40 is adequate.
RE: Help!!! B31.3 Line Sizing Assistance
However, when I emailed my spreadsheet to the senior engineer, he said "this calculation was done using B31.8. Can you please re-do using B31.3". I have re-calculated but still get the same figures. So, I'm not sure if he meant the pipe diameters are wrong...or that the temperature correction and design factor that I used are wrong.
RE: Help!!! B31.3 Line Sizing Assistance
RE: Help!!! B31.3 Line Sizing Assistance
RE: Help!!! B31.3 Line Sizing Assistance
RE: Help!!! B31.3 Line Sizing Assistance
Good luck,
Latexman
RE: Help!!! B31.3 Line Sizing Assistance
The equations for calculating MAOP are different in each of the Standards and if you want to do a B31.8 table, you'll have to use all 5 of the different design factors available.
Both 31.3 and 31.8 have temperature deratings, but, the flanges derate for temperature different than the pipe and they normally limit the MAOP before the pipe does.
Next, B31.3 does allow much of an upgrade in MAOP based on pipe yeild strenght, but that's another topic for another day.
RE: Help!!! B31.3 Line Sizing Assistance
*I'm still reading through the standard and, as you know, it's over 450 pages. So, any assistance is appreciated.
RE: Help!!! B31.3 Line Sizing Assistance
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: Help!!! B31.3 Line Sizing Assistance
RE: Help!!! B31.3 Line Sizing Assistance