Is it worth buying the NFBA - Post-Frame Building Design Manual, Second Edition?

[S.K.G]

I am trying to do a post-frame building design for the first time and currently using the NFBA post-frame building manual 1999 edition that I found online. I would prefer to use the more updated version (second edition) but it does not seem to be available for free so I was wondering if it is worth buying it or is the 1999 edition sufficient?

 

[lexpatrie]

I'd lean on the "did anything in the engineering change" question, which is hard to determine without both references. And were the changes conservative or were they refinements to eeek out a few more pounds of capacity? (e.g. C[sub]b[/sub] in steel construction has a more generally applicable equation, as of say 1996, but the old equation still "works" under the restrictions, if you use the old approach you'll still get a safe design, it might have one beam size larger or something, versus the current code but it wouldn't be fundamentally unsafe. By contrast the change to column strength in the 1991 NDS reduced the allowable loads on intermediate columns and left the short and slender columns relatively unaltered as to strength. If you use the old equation there and it's an intermediate column, then it could potentially be "unsafe" in the current equation, but the jumps in wood sizes might mean the capacity change won't change the design.

I mean there's a fourth edition of the Diaphragm Design manual, but what's "new" or changed since the third, second, or first?

Goes to the standard of care, too. I'm not convinced it's a code-referenced standard, (in the IBC) either, but if it is, some busybody (perhaps at Reid Middleton) would have submitted an update in the last 25 years.