A Discussion on Quantitative Methods for Formaldehyde Emission from Wood-based Panels and Their Products

Introduction

Authors: Yu Haixia, Fang Chongrong, Xu Manping, Gan Meijiao, Yang Weiming, Zhuang Xiaowei

Institutions: 1. Zhejiang Academy of Forestry Sciences, Key Laboratory of Biological and Chemical Utilization of Forest Resources, Zhejiang Province; 2. Zhejiang Provincial Forest Products Quality Inspection Station

Source: Timber Industry Magazine, Issue 3, 2018

Abstract: The acetylacetone spectrophotometric method and the phenol reagent method were compared and analyzed to determine the quantitative method for formaldehyde release from wood-based panels. Results showed that at a sampling volume of 120 L, the detection limit of the acetylacetone method was 0.007 mg/m³, which had a relatively large error when testing products with formaldehyde release below 0.04 mg/m³, requiring an increase in gas flow rate or sampling time to improve detection accuracy. The detection limit of the phenol reagent method was 0.0008 mg/m³, making it more suitable for detecting wood-based panels and their products below GB 18580-2017 E1 grade (<0.124 mg/m³), with high sensitivity and shorter sampling time.

background

my country's newly revised mandatory national standard GB 18580-2017, "Formaldehyde Emission Limits in Wood-based Panels and Their Products for Interior Decoration and Renovation," officially came into effect on May 1, 2018. The new standard retains only the 1 m³ climate chamber test method used in arbitration from the original standard, specifying a formaldehyde emission limit of 0.124 mg/m³. Other methods, such as the desiccator method, perforation extraction method, and the newly added gas analysis method, are only used as testing methods for enterprise production quality control. The release of the new standard means that the formaldehyde emission requirements for interior decoration and renovation materials have been mandatorily raised to the E1 level. The implementation of the new standard will significantly improve the environmental safety indicators of wood-based panel products, while also placing higher demands on formaldehyde emission detection technology.

To address the detection limit of the formaldehyde emission quantification method using the climate chamber method in the new standard, this study employed the acetylacetone spectrophotometric method from GB/T 17657-2013 "Test Methods for Physicochemical Properties of Wood-based Panels and Decorative Wood-based Panels" and compared it with the formaldehyde quantification method using the phenol reagent (MBTH) from GB/T 18204.2-2014 "Hygienic Inspection Methods for Public Places Part 2: Chemical Pollutants". The aim was to obtain a more accurate quantitative analysis method for formaldehyde emission, providing a reference for the accurate control of formaldehyde emission from wood-based panels.

Conclusion

1) When the sampling volume is 120 L, the detection limit of the acetylacetone method (10 mm optical path cuvette) is much higher than the requirements of GB/T 17657-2013, making it unsuitable for the determination of formaldehyde release using the climate chamber method; the detection limit of the acetylacetone method (50 mm optical path cuvette) is slightly higher than the requirements of GB/T17657-2013, making it unsuitable for detecting products with formaldehyde release below 0.04 mg/m3. If this method is the only option, it is recommended to appropriately increase the gas flow rate or sampling time.

2) The detection limit of the phenol reagent method is 0.0008 mg/m3, which meets the requirement of less than 0.005 mg/m3 in GB/T17657-2013. It is suitable for the detection of products with formaldehyde release below E1 (0.124 mg/m3) level, and has the advantages of high sensitivity and shortened sampling time.