Polymers 2021 , 13 , 709
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( a ) Example of OSB
( b ) Example of experimental sample of OSB
Figure1. Oriented strand board in ( a ) full piece and ( b ) prepared for measurement according to [24].
Samples of OSB were cut to specific dimensions (165 × 165 mm) according to ISO 5657: 1997 [24]. The density of the strand boards was determined according to Standard EN 323: 1996 [25].
Table1. Physical and chemical properties and fire technical characteristics of the OSB with thickness of 10–18 mm [13].
Parameters
Notes
Values
Density (kg.m − 3 ) Humidity (%)
630 ± 10% 5 ± 12%
Bending Strength (N.mm − 2 )
MainAxis
20 10
Secondary Axis
Modulus of Elasticity (N.mm − 2 )
MainAxis
3500 1400
Secondary Axis
Swelling (%)
15
Thermal Conductivity (W.m − 2 .K − 1 ) Formaldehyde Content (mg.100 g − 1 )
0.13
8
Flame Spread Index 1
83.3
Thickness 9 mm 2 Thickness 18 mm 3
Reaction to Fire
D-s2, d2 D-s1, d0
Class of Fire Reaction [26] E—Eoderately Flammable 1 Flame spread index was calculated from peak heat release rate (HRR), total heat release and time to sustained ignition by ASTM E 84 ([27] and [28]; 2 [29]; 3 [10]. The selected board materials were stored at a specific temperature (23 ◦ C ± 2 ◦ C) at relative humidity (50 ± 5%). Rantuch et al. [30] state that OSB moisture does not have a significant effect on the critical conditions under which they can be ignited, but significantly affects the time at which it occurs. 2.2. Experimental Procedures The methodology can be divided into three parts: 1. Verification of test equipment; a small burner flame was not used as the secondary ignition source. 2. Determination of ignition time and weight loss depending on the selected level of heat flux density and thickness of board materials and on the distance of selected board materials from the ignition source. 3. Determination of the critical temperature during ignition of an OSB with a thickness of 15mm. 2.2.1. Verification of Test Equipment The beginning of the experimental measurement entailed verification of the test equipment according to ISO 5657: 1997 [24]. The aim of this verification was to monitor
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