WATER ABSORPTION COEFFICIENT - GB/T17657-1999-4.5 & GB/T 4897.2-2003 (particle board) & GB/T 11718-1999 (density board)

1. TOOLS
1.1 Constant temperature water tank
1.2 Micrometer accurate to 0.01 mm

2. SAMPLING
We cut three 400x400 mm mother samples from 1 sheet

We then cut two 50x50 (+/-1 mm) final samples from each 400x400 mm monther sample and get six 50x50 mm final samples for testing

Samples shall be free from resin wood and features such as bark, knots and resin pockets

3. ENVIRONMENTAL CONDITIONS
Temperature: 20 (+/- 2) ℃
Humidity: 65 (+/-5) %

4. TESTING PROCEDURE
4.1 Measure samples’ thickness (h1) on samples’ central points

4.2 Immerse the samples in distilled water with a pH 7+/-1 at 20(+/-2) ℃. Immersion time shall be per the standard in use

4.3 Take out the samples and, with the help of a soft cloth, remove excess water; within 30 minutes of taking the samples out of the water, measure samples’ thickness (h2) on the same central points

4.4 Calculate water absorption coefficient and fill the report

T = (h2-h1/h1) x 100

T = water absorption coefficient, expressed in %
h1 = thickness before immersion
h2 = thickness after immersion

5. ASSESSING TEST RESULTS
Passing requirement per the sales contract