- Author
-
Abu-Zaid, M.
|
Atreya, A.
- Title
- Effect of Water on Piloted Ignition of Cellulosic Materials.
- Coporate
- Michigan State Univ., East Lansing
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
-
NIST GCR 89-561,
February 1989,
189 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NBS-GRANT-60NANB5D057
- Keywords
-
cellulosic materials
|
ignition
|
droplets
|
fire extinguishment
|
thermal decomposition
|
water
|
wood
|
weight loss rate
|
thermal diffusivity
|
weight loss
- Abstract
- This experimental study is an attempt to quantify the effect of water on extinguishment; thermal decomposition and piloted ignition of wood. In the extinguishment part, cooling of hot porous and non-porous ceramic solids by water droplets was studied. These solids were used to simulate low thermal diffusivity porous and non-porous combustible building materials and were instrumented by several surface and in-depth thermocouples. Temperature measurements in the solid were used quantify the heat transfer during droplet evaporation. Thermal decomposition of wood in air was also studied as a function of sample moisture content and externally applied radiation prior to the ignition experiments. Simultaneous measurements of weight loss rate; surface, bottom and in-depth temperatures; O2 depletion and production of CO2, CO, total hydrocarbons and water were made. It was found that the presence of moisture delayed the decomposition process and diluted the decomposition products. Piloted ignition experiments were conducted on Douglas fir for four different mositure contents and at different levels of externally applied radiation. It was found that the presence of moisture increases the ignition time, surface temperature and the evolved mass flux at ignition. A single equation was derived to correlate all the ignition data. This correlation accounts for the moisture dependent thermal properties and the heat loss from the sample surface.