Industrial Duct Design

[TimBIS]

I am designing a hot gas duct for a boiler exhaust. I am trying to determine what allowable stress to use for the meridional stress to prevent buckling of the duct. I have purchased "The Structural Design of Air and Gas Ducts for Power Stations and Industrial Applications" published by ASCE. It seems to tell me what to do, but not how to do it. I am looking at purchasing "Round Industrial Duct Construction Standards" published by SMACNA. This book is $340 so I want to make sure it is what I need before I order it.
Is anybody familiar with this manual?

 

[JedClampett]

I think that talking to someone is going to be more beneficial than any book learning on this. I suspect that the SMACNA document is more for light gage forced air systems than for hot gas, large scale systems. The big power design companies do this all the time and what I remember from my 10 minutes of training on this was spanning the plates using one way action to the stiffeners, the stiffeners to the edges and use 21 ksi for everything (unless it was very hot, then reduce it). They combine snow with the gas pressures, which I could never figure out, but I guess there's an instant when the hot gas is blowing through the duct and the snow hasn't melted yet. Provide enough expansion for the temperatures of the gas.
I'd talk to someone who's done this before or try to pick the brain of an engineer at one of the big companies.

 

[SAIL3]

JedClampett is correct...experience trumps ploghing thru the document you reference....from your post I assume it is round duct, if it is rectangular, then it requires a different approach...if round, the design is a blend of ASME theory but with lower FS depending on the press....also allow for thermal expansion...a usefull ref..

USEFUL INFORMATION ON THE DESIGN OF PLATE STRUCTURES
Steel Plate Engineering Data-Vol 2
Published by AISI, 1979