Classification and dimensions- general use plywood
Plywood is subdivided into grades based on the following: appearance of face veneers, glue bond, the degree of moisture resistance of the bond, and if sanded or not.
6.1. Selection of samples for strength and mechanical tests are done in accordance with GOST 9620. Selection of samples for formaldehyde emission tests are done in accordance with GOST 27678.
6.2. The length and width is measured at two points in the same panel, which are parallel to the edges and are located at least 100 mm from the edges. The measurements are done with a metal tape, which has an index error of 1 mm or less in accordance with GOST 7502. Measurements have to be taken twice and the actual length (width) of the sheet would be their average.
6.3. Thickness is measured at a distance of at least 100 mm from the edges.
Thickness also has to be measured at the middle of each side of the panel with a caliper as per GOST 11358, or with a micrometer with a scale division of at least 0.1 mm in accordance with GOST 6507.
Measurements of thickness have to be taken 4 times and the actual thickness would be an average of those 4 measurements.
The difference in thickness in one panel of plywood is determined as a difference between the maximum and minimum thickness from these 4 measurements.
6.4. Moisture content is determined in accordance with GOST 9621.
6.5. Shear strength along the glue line is determined in accordance with GOST
6.6. Static bending strength is determined in accordance with GOST 9625
6.7. Tensile strength is determined in accordance with GOST 9662
6.8. Formaldehyde emission is determined in accordance with GOST 27678
6.9. Roughness of the surface is determined in accordance with GOST 15612
6.10. Wood and manufacturing defects are measured in accordance with GOST 30427
6.11. Deviation from linear edges of plywood panel is determined by measurements of the maximum gap between the panel edge and metallic square edge in accordance with GOST 8925 and within an index error of 0,2 mm.
6.12. Measurements for squareness are determined in accordance with GOST 30427.