Daisuke Kamikawa

STUDY ON FLAME HEIGHT OF MERGED FLAME FROM MULTIPLE FIRE SOURCES

A series of experiments to study merged flame from multiple fire sources was carried out. The porous 15-cm2 burner was used as a unit burner and propane was employed as a fuel. Many burners with various heat release rates were placed in a square configuration with various separation distances. Flame height was measured using video images and temperature distribution with height was measured using thermocouples. The numerical results from the Fire Dynamics Simulator (FDS) of the National Institute of Standards and Technology was compared with the experimental data, and the comparison results show that FDS correctly simulates the merged flame from multiple fire sources. In addition, an empirical model to estimate the merged flame height was developed considering the effect of separation distance. The validity of this model was confirmed from the comparison with the simulation results, and excellent agreement is found between the calculated merged flame height from the model and the numerical ones. To study the detailed structure of merged flame, 3 × 3 fire source configuration was taken as an example to quantitatively show oxygen mass fraction profiles and velocity fields, which were also given to indicate the formation mechanism of the merged flame.

Experimental flame heat transfer correlations for a steel column adjacent to and surrounded by a pool fire

Heat flux and temperature measurements were conducted on a square steel column adjacent to and surrounded by fire sources from the interest in the application to the structural fire safety design of metal structures. The tests on the adjacent fires demonstrate a description of the heat flux profile along the column surface as a single function of the height normalized by flame height for each column-fire distance and notable decrease of surface heat flux by the increase of the column-source distance. Surface temperature of the column in this configuration was found to be notably lower than the estimate from heat flux data based on the uniform heating assumption, which suggests the significance of the conductive heat loss to unheated surfaces of the column. The tests on the surrounding fires has resulted in heat flux profile weakly dependent on heat release rate and coincidence of the measured surface temperature and its estimate from heat flux due to rather even heat flux on all surfaces of the column.

INFLUENCE OF FIRE EXPOSURE ON THE MECHANICAL PROPERTIES OF WOOD

本論文の実験の骨子及び結果の一部(ケヤキ)については,文献18)で口頭発表した。 *1 早稲田大学大学院 Graduate School, Waseda Univ. *2 早稲田大学理工学術院 教授・工博 Prof., Department of Architecture, Waseda Univ., Ph. D. *3 早稲田大学理工学研究所 招聘研究員・博士(工学) Visiting Researcher, RISE, Waseda Univ., Ph. D. *4 東京都庁 工修 Tokyo Metropolitan Government, M. Eng. (当時 早稲田大学大学院) (Former Waseda Univ.) *5 独立行政法人森林総合研究所 博士(工学) Forestry and Forest Products Research Institute, Ph. D. *6 亀山建設(株) 代表取締役社長・工修 President, Kameyama Construction, M. Eng. *7 椙山女学園大学 教授・工博 Prof., Sugiyama Jogakuen Univ., Ph. D. *8 東京大学生産技術研究所 教授・博士(工学) Prof., Institute of Industrial Science, The University of Tokyo, Ph. D. *9 独立行政法人森林総合研究所 Forestry and Forest Products Research Institute

Impregnation of laser incised wood of Douglas fir and Japanese cedar by dipping (passive impregnation) in solutions of copper azole (CuAz-B) and a fire retardant (PPC)

Abstract The performance of the passive impregnation method of CO2-laser incised lumber has been investigated concerning wood preservation against different wood-destroying agents. Copper azole type B (CuAz-B) preservative and polyphosphatic carbamate (PPC) fire retardant were impregnated into Douglas fir and Japanese cedar lumber under both green and kiln-dried conditions. Final drying of the lumber was performed by steam injection or kiln drying. The temperature and pressure change in the lumber, as well as the total chemical retention, penetration, decay resistance, fire retardancy and total treatment time were calculated according to different standards. The preservative retention was higher in the Japanese cedar for both green and kiln-dried conditions (5.32 and 5.58 kg m-3, respectively) compared to Douglas fir (5.01 and 4.81 kg m-3). Fire retardant retentions were more than 100 kg m-3 in all cases. The penetration was approximately 100% throughout the lumber. There were no significant differences in the decay resistance test between the different categories of lumber. Moreover, it was possible to treat the green lumber in less than 48 h starting from the green conditon to the final drying. Hence, the presented passive impregnation technique could be useful for industrial application.

Combustibility of fire-retardant impregnated and surface-coated wood after 5 years of natural weathering

The weatherability and combustibility of fire-retardant-impregnated wood during natural weathering for up to 60 months were evaluated. Fire-retardant chemicals used were modified guanidine phosphate with phenolic additives in order to retain chemicals against leaching. The ability of coating was also examined using four solvent-born coating systems:1 penetrating;semi-transparent(brown), 2 thin-film-forming;semi-transparent(brown), 3 film-forming;opaque(white), 4 film-forming;transparent. The systems 1 and 2 consisted of 2 or 3-coat application of each single coating composition, whereas 3 and 4 employed specific wood-sealers as an undercoat to stabilize the surface of wood prior to the application of topcoat. Phenolic additives were effective to maintain chemical retention for a certain period. After 60-month-natural weathering, coated specimens and uncoated specimen were at a quasi-non-combustible material level and a fire-retardant material level, respectively. Fire performance of specimens coated with 3 and 4 were better than 1 and 2.

Drill and laser incising of lamina for fire-resistive glulam

Abstract Conventional glued-laminated timber (glulam) was not permitted to use to a wooden building in the fire preventive district since the amendments of the Building Standards. We already developed a one-hour fire-proof glulam made of Japanese cedar. We also succeeded to give one-hour fire performance to cross laminated timber by the same concept. The both structures are composed of three parts which are load-bearing part, fire-die-out part and surface part. The fire-die-out part is made of lamina incised by CO2 laser and impregnated the fire retardant evenly. As the handling of CO2 laser is not so easy for glulam manufacturer, we felt a growing need for drill incising technology. Therefore, we made pinholes of some diameters up to 2.5 mm to lamina of Japanese cedar, by a drill and investigated differences of hole position on two sides of the lamina. The maximum off-center for length and width directions was 1.8 and 3.3 mm, respectively. These off-centers are 2.3% and 41% of distances between neighboring hole on incising patterns. As the results of impregnating performance and fire-resistive performance of lamina incised by drill, significant differences were not recognized between drill incising and laser incising.

BURNING BEHAVIOUR ON FIRE-PREVENTIVE GLUED LAMINATED TIMBER OF SEVERAL COLUMNS

The Japanese government is promoting use of wood in recent years, because of the environmental provision of carbon dioxide fixation. The authors developed “FR wood”. “FR wood” is the only technique with simply use one tree species in Japan. “FR wood” is built by three layers. The central member supports load, the second layer prevents a fire and the third layer is surface. A lot of experimental cases were conducted, and many temperature data or carbonization thickness data were accumulated. The measured maximum temperature depended on the thickness and the tree species of load supporting member.

Fire Resistance of Structural Glued Laminated Timber Treated with Wood Preservatives

There is no regulation for wood preservatives in the Japanese Agricultural Standard (JAS) for glued laminated timber. Glued laminated timber (GLT) treated with wood preservatives is not qualified as a JAS product and we cannot use it for quasi-fireproof construction material considering the charring rate during accidental fire. It is necessary to clarify that the incising process and impregnation of chemicals do not affect the fire safety of treated GLT in order to use it just the same as normal GLT. Treated GLT beams whose laminae were incised mechanically and impregnated with wood preservatives (alkyl ammonium compound (AAC) or azole neonicotinoid compound (AZN)) were made for a 45-minute-quasi-fireproof test. The beams were not destroyed during the fire test and their char depths were less than 35 mm. The fire performance was the same as of a normal GLT beam. The results of vacuum-pressure delamination tests met the requirement for use environment A.

Heating Mechanism Of Unprotect4ed Steel Beam Installed Beneath Ceiling And Exposed To A Localized Fire: Verification Using The Real-scale Experiment And Effects Of The Smoke Layer

Measurements of the heating condition of a steel beam installed beneath a ceiling and exposed to a localized fire source are made on a real-scale experiment. The data of thermal response obtained from the experiments are compared with previous small-scale experiments. The effects of the smoke layer which influences upon the heating condition of the beam are investigated through the smoke experiments setting the smoke protection soffits to the same experimental equipment. FDM-based calculation is demonstrated using the average temperature of the smoke layer for the boundary conditions to predict the thermal response of the beam. Applicability of the approximated temperature of the smoke layer is examined by comparing the numerical results of the temperature with those obtained through the experiment.