In comparison to oak, the charring rate of aspen samples as well as those of pine and fir were higher.
The average charring rate of oak was 0.32 mm/min, fir--0.58 mm/min, pine--0.60 mm/min, aspen--0.61 mm/min.
After 45 minutes of heating, the charring rate of oak was 0.44 mm/min, aspen--0.79 mm/min, fir--0.77 mm/min, pine--0.76 mm/min.
The regression analysis of the charring rate for different species of wood was made, equations (3)-(6) were obtained, the predicted values of the charring rate calculated using the equations (3)-(6) are presented in Fig.
The regression analysis resulted in the highest value of the correlation coefficient R = 0.9597, which was obtained in predicting the charring rate of aspen, fir R = 0.9515, oak--R = 0.9424 and pine--R = 0.9240, which was the lowest value.
To predict the charring rate of different species of wood (oak, aspen, pine and fir), the following equations (3)-(6) can be used:
The aim of this article is to study the effect of variability of charring along the members of wooden floor and wall assemblies insulated with heat-resistant mineral wools, such as stone wool and heat-resistant glass wool, and to detect the possible influence of density of wood on the charring rate.
Charring is the most important parameter in the design of timber-frame members for fire resistance.
Charring takes place mainly on the fire-exposed narrow side.
The notional charring rate of small sized timber frame members is given as
where [[beta].sub.0] is the one-dimensional charring rate for timber, given as
Coefficients [k.sub.p], [k.sub.s] and [k.sub.n] are explained as follows: The protection factor [k.sub.p] takes the influence of protective cladding on charring into account.