Plywood QC Inspection Checklist : Part 23 formaldehyde test types perforation extraction method, dryer method and climate box method
* After reading this article, you can get:
1. The most comprehensive environmental protection level of popular science.
2. The strictest and safest formaldehyde standard.
3. The most practical suggestions of environmental protection grade selection.
Wood-based panel is widely used in furniture manufacturing and interior decoration projects due to the advantages of easy processing and dimensional stability. However, wood-based panel will release formaldehyde, if a formaldehyde-based resin is used, and other harmful gases, causing indoor air pollution.
Since different test methods of measuring the formaldehyde emission (FE) from wood-based composite panels have been used for different countries and regions, Three test methods (i.e., 24-hour desiccator, 1 m3 chamber, and perforator) for plywood (PLW), particleboard (PB), and medium density fiberboard (MDF), particularly emphasizing on correlations between the 24-hour desiccator and the 1 m3 chamber method. Some methods for formaldehyde Emission such as desiccator, chamber, perforator and gas anal- ysis.
There are three testing methods described in the US standard for the formaldehyde emission: large chamber, small chamber, and desiccator. The US standards do not classify formaldehyde emission limitation levels. The US standard gives a limit value of formaldehyde emission by the chamber method.
What are the domestic standards for formaldehyde?
At present, in the compulsory national standard GB18580-2017, the national standard E1 level (< 0.124mg/m) is the only formaldehyde emission standard, which meets the safety standard and is easy to buy.
There are three methods to measure formaldehyde, namely, perforation extraction method, dryer method and climate box method. The former E0 grade (< 0.5mg/L) was measured by dryer method. However, after the new national standard changed to 1 m climate box method, the past E0 level and the present E1 level can not be compared horizontally, so E0 level is not mentioned in the new national standard.
Because of the different inspection methods, national standard, European standard, Japanese F4 star and California CARB can not be compared horizontally.
1.The F4 star standard comes from the Japanese Agricultural Standard (JAS) issued by the Ministry of Agriculture and Forestry of Japan. The formaldehyde emission of F4 star is less than 0.4 mg/L. The concentration of formaldehyde after dissolving in water is measured by dryer method, so the unit (mg/L) is different from that of other countries.It is very rare in China that products exported to Japan or imported from Japan can be certified by F4 star. If a product has F4 star certification, the factory must get JIS certification first. Few factories in China have got the certification, which can be found on JIS official website.
Enterprise standard E0 grade plate, in strict accordance with the new national standard formaldehyde detection test method (1m_climate box method)
There are many formaldehyde standards in the United States, among which the California Air Resources Board (CARB) has the highest standards.
CARB promotes four formaldehyde-related standards (from low to high) throughout California by enacting bills and authorizing large-scale laboratories:
CARB Phase 1 (<0.05 ppm)
CARB Phase 2 (<0.05 ppm)
ULEF (Ultra-low Formaldehyde Emission)
NAF (Formaldehyde Free)
The price of Wood-based Panels Certified by CARB P1 and P2 is closer to the people. Manufacturers use formaldehyde-containing adhesives, but they can reduce formaldehyde content by technical means, so that more people can afford it.