Hiya,
Can anyone tell me the relationship of the design values in the Wood Handbook to the stress ratings for calculating beam sizing? In particular, if we have an species for which the Modulus of Rupture is given, can the allowable fiber stress in bending be calculated from that?

Even the Modulus of Elasticity in the Wood Handbook, given in megapascals, doesn't convert to psi and make sense with the published E values in the NDS.

I'm missing something here, so if anyone can steer me to a reference if the answer is not easily posted here, thanks.

Found the answer: ASTM D245 explains the methods used.

I think it's in this standard, ASTM D245
http://webstore.ansi.org/ansidocstore/product.asp?sku=ASTM+D245-06
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This is an example I have, not sure how much I can help you with it.
Fb=(5% exclusion limit)/(1.6 load duration factor*1.3 safety factor on 5% limit) = 5%-tile/2.1

5% exclusion limit =avg-(1.645*std deviation)

Suppose a number of 2x4's were tested in bending;
Avg=9138 psi
Std Dev=3205 psi

5%= 9138-(1.645*3205)= 3,866 psi
Fb= 5%/2.1= 1841 psi
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The "allfromr" link on this page might be of some help
http://www1.fpl.fs.fed.us/vicki/borinteractive.html

My copies of the wood handbook have psi's in table 4.2 preceeeding the metric tables. E is pretty close to those #'s. The new Emin in the 05 NDS is developed using similar methods to the above Fb example, I think.

Whoops I see you found it.