- Author
-
Tewarson, A.
- Title
- Scale Effects on Fire Properties of Materials.
- Coporate
- Factory Mutual Research Corp., Norwood, MA
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
-
NBS GCR 85-488; FMRC J.I. 0J4N2.RC,
February 1985,
50 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NBS-GRANT-NB83NADA4021
- Book or Conf
- International Association for Fire Safety Science. Fire Safety Science. Proceedings. 1st International Symposium October 7-11, 1985,
Hemisphere Publishing Corp., NY,
Gaithersburg, MD,
Grant, C. E.; Pagni, P. J., Editors,
451-462 p.,
1986
- Keywords
-
mathematical models
|
carbon monoxide
|
combustion
|
crib fires
|
flammability
|
fire tests
|
heat release rate
|
paper
|
plastics
|
pyrolysis
|
smoke
|
toxic gases
|
wood
- Abstract
- The objective of this study was to examine the scale effects on fire properties of materials over a range of fire sizes from 10 kW to 5000 kW-scale fires. Experiments were performed for cellulosic materials, alone and in combination with synthetic materials in box-like and crib-like configurations. Experimental results for a pool-like material configuration from our previous study and for enclosure fires of wood cribs reported in the literature were also used. For turbulent fires of various sizes with various geometrical material configurations, a chemical similarity was found for each material for each specified value of the ventilation parameter. The decomposition mode in the combustion of the cellulosic material was found to be very important for CO and particulates, but less important for CO2 and heat. The specific extinction coefficient for particulates was found to reach a maximum value of about 0.12 m(2)/g when combustion was slightly on the fuel-rich side of stoichiometric combustion of the wood cribs. For cellulosic material, the maximum possible yield of CO was estimated to be about 0.5 g/g in combustion and about 1.0 g/g in oxidative pyrolysis. The enclosure fire results for wood cribs suggest that the maximum possible values of CO yield and the specific extinction coefficient of particulates would be expected to occur with large enclosure openings and with the ratio of total exposed surface area of the wood cribs to floor area of the enclosure greater than 2.5. With decreasing size of enclosure openings, the amount of particulates would be expected to decrease and the amount of oxygenated carbon compounds and hydrocarbons would be expected to increase. The details of atom distributions in the mixture of chemical compounds leaving the material surface and among the various fire products downstream of the reaction zone of the fire are being investigated.