EN 1058-2009 pdf download.Wood-based panels – Determination of characteristic 5- percentile values and characteristic mean values.
On the basis of test results from wood-based panel products for structural purposes, this European Standard specifies a method for the determination of:
– characteristic 5-percentile values of mechanical properties under the assumption of a log-normal distribution of the test data according to EN 14358; and
charactenshc mean values (50-percentile values) of physical properties under the assumption of a normal distribution of the test data.
Test data should be determined from tests using the test methods outlined in EN 789.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (Including any amendments) applies.
EN 326-1, Wood-based panels — Sampling, cutting and inspection — Part 1: Sampling and cutting of test pieces and expression of test results
EN 789, Timber structures — Test methods — Determination of mechanical properties of wood based panels
EN 14358, Timber structures — Calculation of characteristic 5-percentile values and acceptance criteria for a
sample
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
characteristic value
value of a material property which Is defined as a fractile of the distribution of that property within the total population of that material
NOTE For all strength properties, this fractile is the fifth percentile. For stiffness properties as well as physical properties, two different characteristic values can be used: the fifth percentile and the mean value.
3.2
panel
piece of wood-based sheet material large enough to permit the cutting of test pieces
3.3
reference population
wood-based panels for which the characteristic values are relevant
3.4
production site
any single production line
3.5
sample
number of panels of one population
NOTE Unless otherwise agreed, the panels of the sampie are ijrawn at WVKiOm
3.6
shift
continuous period of production by the same group of workers
NOTE NoimaUy 8 h.
3.7
test piece
piece of panel cut to the size required for testing a specific property
4 Symbols
L Lower specification limit
i Characteristic value of a log-normal distributed property
1 Characteristic mean value of a normal distributed property
U Upper specification limit
Coefficient of vanahon of a log-normal distributed sample
VT Coefficient of variation of a normal distributed sample
5 Reference population
The reference population is in accordance with EN 326-1 defined by parameters such as type and manufacturing process, thickness range, grade, lay-up and quality dassification of wood-based panels and is consistent with the material that is or can be supplied commercially and is capable of being identified at all stages of production, supply and in service.
6 Determination of characteristic values of mechanical and physical properties
6.1 Sampling
A total of at least 32 panels of the same type, grade, thickness range andlor lay-up shall be sampled at random from the production sites. Where there are fewer than 32 shifts, the total number of panels shall be obtained by taking a maximum of four panels from each shift at each production site.
Sampling of test pieces from panels shall be In accordance with the procedures given in EN 789.
6.2 Testing
Testing shall be carried out in accordance with either EN 789 (for strength and stiffness properties) or
EN 326-1 (for physical properties).
6.3 Analysis of data
6.3.1 General
According to the distnbution of the test data, the characteristic values shall be calculated either on the basis of log-normal distribution (in case of strength properties) or normal distribution (in case of physical properties and modulus of elasticity).
If exceptionally, the number of panels is less than 32. the reasons for that have to be declared specifically in the test report.
6.3.2 Strength and stiffness properties
The procedure of calculating the characteristic value i of log.normal distributed test data with known or unknown coefficient of variation v1 according to EN 14358 is given in Annex A.
6.3.3 Characteristic mean value (50-percentile characteristic value)
The procedure of calculating the estimates of the characteristic mean value L – and i, respectively, of normal distributed test data with known or unknown coefficient of vanation V is given in Annex B.
7 Test report
The test report shall contain the following statements:
a) date and place of sampling;
b) product type sampled;
c) number of panels sampled and their dates of production:
d) method of sampling and calculation;EN 1058-2009 pdf download.