Mass Loss of and Temperature Distribution in Southern Pine and Douglas Fir in the Range 100 To 800°C

Abstract

Southern pine and Douglas fir test specimens were placed in an over kept at either 100, 160, 245, 400, 600, or 800 °C, and the center point temperatures and the mass losses of the specimens were measured as functions of exposure time. A model is described for calculating the temperature distribution in and the mass loss of wooden beams having rectangular cross sections. Comparisons were made between the data and the results of the model, and reasonable agreements were found between the measured and calculated temperatures and mass losses. Some tests were also performed to assess the effect of ambient oxygen concentration on the mass loss.

Model for Predicting the Mechanical Properties of Composites at Elevated Temperatures

“…The validity of the first part of the model (temperature distribution and mass loss, data Section 3) has been evaluated by comparing the results of the model to data generated using both an organic matrix composite (graphiteepoxy Fiberite T300/1034) and wood [5,1]. The measured and calculated temperature and mass losses agreed well, supporting the validity of this first part of the model.…”

“…In this paper such a model is outlined. The model has first been developed for predicting the changes in strengths and moduli of wood during fire [1][2][3]. Here the model is adapted to fiber reinforced organic matrix composites.…”

The Strength of Wooden Bends and Joints Exposed to Elevated Temperatures

“…Accordingly, knowledge of strength of load-bearing wooden structure elements exposed to elevated temperatures would be greatly helpful in designing wooden structures. The effect of temperature on the strength of wooden beams has been studied extensively [1][2][3][4][5][6][7]. It was found that, at as high a temperature as about 400°F, the strength of wood elements suffered only a slight reduction by less than 30%.…”

Failure Time of Loaded Wooden Beams During Fire

“…The loss in strength with exposure time may be obtained from the expression [3] In this equation Am,,/Am,,, is the mass loss which can be calculated by the method described in detail in ref. [4]. The exponent e is a constant.…”