1. Preparation of test specimens

Two specimens with dimensions of length l=(500 ± 5) mm and width b=(500 ± 5) mm;

The test piece is subjected to equilibration treatment after being placed at (23 ± 1) ℃ and relative humidity (50 ± 5)% for (15 ± 2) days.

2. Sample edge sealing

After 15 days of equilibration pretreatment of the sample, the edges were sealed with formaldehyde free aluminum tape in a formaldehyde pretreatment box.

3. Formal testing

Place the two samples with sealed edges into the Huaheng formaldehyde climate chamber within 1 hour. The test piece is placed vertically in the center position of the formaldehyde climate chamber. The distance between the specimens shall not be less than 200mm.

The test piece shall be sampled twice a day from the second day of operation to the fifth day, with a sampling interval of at least 3 hours.

Sampling (air collection): During the testing period, 25mL of distilled water is absorbed using an absorption bottle device, and the air sampling system is connected to the air outlet of the climate chamber at a pumping speed of 2L/min. The air inside the chamber is extracted.

4. Quantitative analysis

Take acetylacetone solution and ammonium acetate solution for color development, measure with a spectrophotometer, and perform quantitative calculation. The principle of formaldehyde test chamber is as follows: Place a sample with a surface area of 1 square meter into a climate chamber where the temperature, relative humidity, air flow rate, and air replacement rate are controlled at certain values. Formaldehyde is released from the sample and mixed with the air inside the box. The air inside the box is periodically extracted and passed through an absorption bottle containing distilled water. All formaldehyde in the air is dissolved into the water; Measure the amount of formaldehyde in the absorption solution and the volume of extracted air, expressed in milligrams per cubic meter (mg/m3), and calculate the amount of formaldehyde in each cubic meter of air. Sampling is periodic until the formaldehyde concentration in the testing chamber reaches equilibrium.