Using Ultimate load results from testing done per ASTM E330

[AJ817]

Hello,

I received testing results for gyp board sheathing that was done per ASTM E330. The average ultimate load for the system before failure was 117 psf. What safety factors need to be applied to this value to get a pressure that I can apply to my Components and Cladding wind pressure table. The manufacturer does not know and says its code related but I can not find anything specific to this. I'm told it is not the same as a Vult pressure vs a Vasd pressure where you use 60%

Thank you,

 

[JLNJ]

Back in the allowable stress days, FM used a safety factor of 2.0 to "rate" its roofs based on the tested system failure (the pressure the roof assembly could withstand for 60 seconds). (I'm not sure how to use your "average ultimate" number. Depends on the spread between tests, I suppose.) FM also used an importance factor of 1.15 regardless of building classification.

 

[SWComposites]

You also need to account for the scatter in strength properties between sheets and batches. Something like allowable strength = average - 3*sigma, probably. With enough test data to get valid estimates of the average and std deviation (sigma). Then apply the code safety factor to the allowable strength.