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GB/T 5849-2016 "Plywood" and ISO 13609:2014 Wood-baThe main technical differences between sed panels, Plywood, Blockboards, and battenboards are as follows:
1. Dimensional deviation
1) Flatness requirements exist in GB/T 5849-2016, but not in ISO 13609:2014;
2) For length and width deviations, GB/T 5849-2016 only allows positive deviations, while ISO 13609:2014 allows negative deviations;
3) Regarding thickness deviation, GB/T 5849-2016, being limited to solid plywood, only classifies thickness deviation into two levels based on basic thickness. ISO 13609:2014 classifies it into five levels based on basic thickness, with the thickness deviation varying depending on the basic thickness value. Taking the two commonly used plywood types in China with basic thicknesses of 12 mm and 15 mm as examples, GB/T 5849-2016 has stricter requirements for thickness deviation. As my country is a major exporter of plywood, considering the requirements for secondary processing of plywood, Chinese standards impose stricter requirements on dimensional deviations to ensure product quality and promote the sustainable development of export trade.
2. Moisture content: GB/T 5849-2016 requires the moisture content of plywood to be 6% to 14%, while ISO 13609:2014 requires 8% to 14%.
3. Gluing Quality: GB/T 5849-2016 specifies different requirements for the glued strength of plywood based on category and tree species, while ISO 13609:2014 maintains uniform technical requirements for glued strength, regardless of category or tree species. GB/T 5849-2016 requires the specimen to be immersed in water at (63±3) ℃ for 3 hours, cooled at room temperature for 10 minutes, and then tested; the pretreatment conditions are simple. ISO 13609:2014 requires the same pretreatment conditions as ISO 13608:2014, but includes additional pretreatment conditions such as vacuum pressurization and steam treatment compared to GB/T 5849-2016. GB/T 5849-2016 only allows for a reduction in the index value when the wood damage rate exceeds 80%, estimating the wood damage rate of the specimen visually. ISO 13609:2014 specifies the acceptable and unacceptable ranges for average shear strength and wood failure rate; it also requires that the sample be dried before determining the wood failure rate, and specifies the drying temperature and time, light source, incident angle, and distance between the sample and the light source. ISO 13609:2014 offers greater reproducibility in the determination of wood failure rate.
4. Formaldehyde Emission: GB/T 5849-2016 directly references GB 18580 "Formaldehyde Emission Limits in Wood-based Panels and Their Products for Interior Decoration and Renovation". This standard is a mandatory national standard. The GB 18580-2017 standard, which came into effect on May 1, 2018, stipulates that formaldehyde emission is measured using the climate chamber method, which is basically consistent with ISO 12460-1.
Source: Zheng Honglian, Liu Xudong, Gu Qiang, Deng Chao. Comparative analysis of Chinese national standards and ISO standards for plywood products [J]. Wood Industry, 2020, 34(5):44-48.