JGT 396-2012 for Non-load Bearing Fiber Cement Board for Exterior Wall 3

6. 2.4 Flatness of the board
The flatness of the board should not be greater than 1.0 mm/2 m.
6. 2.5 Edge straightness
When the area of the plate is greater than or equal to 0.4 m2 or the aspect ratio is greater than 3, the straightness of the edge should not be greater than 1 mm/m
6.2.6 Edge perpendicularity
Edge perpendicularity should not be greater than 2 mm/m.
6.3 Physical Performance
The physical properties of fiber-reinforced cement board shall comply with the provisions of Table 4.

6.4
Mechanical property
6.4.1
Flexural strength in saturated water
The flexural strength of fiber-reinforced cement board under saturated water should conform to the provisions of Table 5.

6.4.2 Impact resistance
Falling ball method test impact 5 times, no through cracks on the plate surface.
7 Test methods
7.1 Test conditions
The laboratory for mechanical properties testing should meet the test environment conditions of 25 ℃±5 ℃ and 55%±5% relative humidity.
7.2 Samples and test pieces
Five sheets were taken as a group of samples, and after the permissible deviation of appearance quality and size was determined in turn, the sheets were selected as physical and mechanical properties test samples according to Table 6 and Table 7, and the specimens were cut at places greater than 100 mm away from the sheets according to the size and quantity specified in Table 6 and Table 7, and numbered for various tests.