CIB-W18 Timber Structures – A review of meeting 1-43 2 MATERIAL ...

y assuming a normal distribution. EN 14358 follows basically the same
approach as ISO 12491, but assuming a log-normal distribution and an unknown
coefficient of variation.
The investigations show that EN 14358 and EN 384 give the same results.
If only one European standard is maintained, one suggests that EN
14358 is kept, since it is applicable to all wood-based products and that it
is much easier to i use. We should only slightly modify it in order to have
a minimum sampling (e.g. 200 specimens, made of 5 distinct samples).
Despite ISO 12491 is applicable to all building materials, we suggest
not to use it, since it gives a big scatter.
In ISO 13910, there is an equivalence factor with EN 384, which varies
from 1,0 to 1,3, depending on the strength property, the size and the quality
of timber, taking into account different test methods. Our simulations
show that the way of calculating the fifth percentiles gives another correction
factor, which encounters the previous one. By combining both factors,
we could use a straightforward correspondence between both standards.
Conclusions
The investigations show that EN 14358 and EN 384 give the same results.
If only one European standard is maintained, one suggests that EN 14358
is kept, since it is applicable to all wood-based products and that it is much
easier to use. We should only slightly modify it in order to have a minimum
sampling (e.g. 200 specimens, made of 5 distinct samples).
Despite ISO 12491 is applicable to all building materials, we suggest
not to use it, since it gives a big scatter.
In ISO 13910, there is an equivalence factor with EN 384, which varies
from 1,0 to 1,3, depending on the strength property, the size and the quality
of timber, taking into account different test methods. Our simulations
show that the way of calculating the fifth percentiles gives another correction
factor, which encounters the previous one. By combining both factors,
we could use a straightforward correspondence between both standards.
CIB-W18 Timber Structures – A review of meeting 1-43 2 MATERIAL PROPERTIES page 2.111