Accession Number:

AD0475535

Title:

IGNITION OF THICK WOOD SPECIMENS BY HIGH-TEMPERATURE THERMAL RADIATION

Descriptive Note:

Final rept. Jan 1963-May 1965

Corporate Author:

NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA

Personal Author(s):

• Brown, III, F. W.

Report Date:

1965-11-01

Pagination or Media Count:

49.0

Abstract:

An investigation was undertaken to determine the probability of ignition of thick woods by thermal radiation. A carbon-arc source was used to simulate the thermal radiation from a nuclear weapon. Measurements were made to determine the irradiance and time necessary to produce glow and flaming ignition in ponderosa pine, Douglas fir, and maple. The results of this study are presented in the form of graphs of irradiance as a function of time for several moisture contents for each type of wood. In all cases on the graphs, the locations of the areas of char, persistent glowing ignition, and persistent flaming ignition are shown. The values of Q, total thermal energy necessary to produce sustained burning with or without flame, can be easily computed from these data. They range from a minimum value of about 19 calsq cm for very dry pine to several thousand caloriessq cm for wood with a very high moisture content. It was concluded that for sound solid woods of a normal moisture content, it is almost impossible to start continued ignition with nuclear weapons of a size less than about 100 Mt at a distance where blast damage would not be severe. An appendix describes the high-intensity thermal-radiation facility used to conduct the investigation.

Descriptors:

• *IGNITION
• *THERMAL RADIATION
• *WOOD
• BLAST
• CARBON
• DENSITY
• ELECTRIC ARCS
• FIRES
• HIGH TEMPERATURE
• INTENSITY
• NUCLEAR WEAPONS
• SIMULATION
• THERMAL CONDUCTIVITY

Subject Categories:

• Wood, Paper and Related Forestry Products

Distribution Statement:

APPROVED FOR PUBLIC RELEASE