- Author
-
Wickstrom, U.
- Title
- Numerical Procedure for Calculating Temperature in Hollow Structures Exosed to Fire.
- Coporate
- California Unv., Berkeley
Lund Inst. of Tech., Sweden
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
-
CIB W14/79/38 (S); NBS GCR 77-100; Report 79-3,
August 1977,
62 p.
- Distribution
- Available from National Technical Information Service
- Contract
- GRANT-G79006
- Keywords
-
ASTM E119
|
building fires
|
ceilings
|
computer programs
|
concrete slabs
|
construction materials
|
convection
|
heat transfer
|
radiation
|
slabs (members)
|
steel beams
|
structural members
- Abstract
- An approximate theory for two-dimensional heat transfer in hollow structural elements exposed to fire is described. Radiation as well as convection heat transfer are accounted for. The theory is coded in a set of FORTRAN subroutines that can easily be adapted to most programs for analysis of solid state conduction using finite element or finite difference approximations. For voids with piecewise straight boundaries and all angles beteen surfaces less than or equal to 180 degrees, a set of equations has been programmed to calculate view factors. In calculating convection heat exchange, it is assumed that the heat capacity of enclosed air is negligible, and that a uniform effective air temperature can be calculated as a function of surrounding surface temperature only. To illustrate the method, the finite element program FIRES-T is employed. Four hollow structures exposed to ASTM E-119 fire are analyzed. For two of the examples where experimental data are available excellent agreement between measured and calculated temperature is achieved.