Estimate of the Correction Applied to Radiant Flame Measurements Due to Attenuation by Atmospheric CO2 and H2O.
Estimate of the Correction Applied to Radiant Flame
Measurements Due to Attenuation by Atmospheric CO2 and
H2O.
(210 K)
Fuss, S. P.; Hamins, A.
Fire Safety Journal, Vol. 37, No. 2, 181-190, March
2002.
Keywords:
carbon dioxide; water; uncertainty; heat flux;
attenuation; flame research
Abstract:
A narrow band statistical model has been used to
estimate the uncertainty introduced into radiative heat
flux measurements from fires which is attributable to
attenuation by atmospheric H2O and CO2. The flames were
assumed to be soot dominated with blackbody emission
characteristics. The ambient surroundings near the
flames were assumed to be homogeneous with the total
pressure being fixed at one atmosphere. Atmospheric CO2
concentrations were held constant at 0.04 kPa and the
water vapor concentrations varied between 0.55 kPa-5.63
kPa based on temperature and relative humidity. The
remaining partial pressures were accounted for by O2 and
N2. Correlations to estimate atmospheric attenuation are
given over a range of conditions that include path
length (10-200 m), ambient temperature (19-35 deg C),
source temperature (1000?-1600 deg C) and relative
humidity (0.25-1.0) as parameters. The results of these
calculations indicate that, over this range of
conditions, the radiant flux can be attenuated by as
much as 42%.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899