Development of Models for Charring Rate of Selected Construction Timber Species in Southwestern Nigeria

The performance of Nigeria timber species under fire exposure to prevent collapse of structure has not been adequately investigated. This study was to determine the charring rate models of some selected timber species mostly used for constructional purposes in Southwestern Nigeria. Six species out of ten identified timbers were selected for studies. They are: Afara, Iroko, Opepe, Mahogany, Mansonia, and Teak. The densities of the timber species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Samples from each of the selected species, were exposed to fire at temperature ranges of 20° to 230° C for 30 minutes; 20° to 300° C for 60 minutes; 230° to 600° C for 30 minutes. Empirical statistical model was developed for charring rate of the timber species. The models were analysed using ANOVA at . At 30 minutes fire exposure (20 to 230° C), Afara of 9.0, 12.0 and 15.0% MC had the highest mean charring rates of 0.84±0.02mm/min, 0.82±0.02mm/min and 0.82±0.02mm/min respectively, while Opepe had the lowest charring rates of 0.48±0.02 mm/min, 0.48±0.02 mm/min and 0.47±0.02 mm/min at the three MC levels. This study indicated that density was a major predictor of the charring rate of constructional timber. Opepe which had the highest density also exhibited the lowest charring rate of all the species tested and is useful and recommended to ensure the safety and comfort of occupants in case of fire outbreaks.

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Fire resistance properties of some selected tropical timber species from South-western Nigeria after fire exposure

Selected Scientific Papers - Journal of Civil Engineering ◽

10.1515/sspjce-2019-0018 ◽

2019 ◽

Vol 14 (2) ◽

pp. 61-72

Author(s):

Oluwaseun Adedapo Adetayo ◽

Bamidele Ibukunolu Olugbemi Dahunsi

Keyword(s):

Tectona Grandis ◽

Strength Properties ◽

Timber Species ◽

Fire Exposure ◽

Tropical Timber ◽

Moisture Contents ◽

Percentage Loss ◽

Temperature Ranges ◽

Density Values ◽

Nauclea Diderrichii

AbstractThe research investigated changes in post fire density and strength properties of Nigerian wood species used for construction. The selected species are: Terminalia superba (Afara), Milicia excels (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak). Densities and strength properties of the species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Species were exposed to fire at various temperature ranges. The results revealed that at 9, 12 and 15%MC, Opepe had the highest density values of 630±28.85kg/m³, 686±22.64kg/m³ and 752±17.22 kg/m³ respectively. At 9%MC, Mahogany had the lowest density (439±10.58kg/m³) while at 12 and 15%MC, Afara had the lowest density values of 444±4.18kg/m³ and 469±7.07kg/m³ respectively. Post fire exposure revealed that Afara had the highest percentage loss in density 29.2% and strength properties, while both Iroko and Mahogany exhibited the lowest percentage loss in both density and strength properties.

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Variations of Density and Compressive Strength Before and After Charring of Some Selected Construction Timber Species of Southwestern Nigeria

FUOYE Journal of Engineering and Technology ◽

10.46792/fuoyejet.v2i2.126 ◽

2017 ◽

Vol 2 (2) ◽

Author(s):

Oluwaseun A Adetayo ◽

Bamidele IO Dahunsi

Keyword(s):

Compressive Strength ◽

Tectona Grandis ◽

Percentage Change ◽

Timber Species ◽

Fire Exposure ◽

Southwestern Nigeria ◽

Before And After ◽

Density Values ◽

Nauclea Diderrichii ◽

Milicia Excelsa

This study aimed to evaluate the percentage variations of density and compressive strength of some selected timber species mostly used for constructional purposes in Southwestern Nigeria after undergoing fire exposure. The species are: Terminalia superba (Afara), Milicia excelsa (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak).The densities and the compressive strengths of the species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Nine specimen per species, were exposed to fire at various temperature ranges.The results of analysis by variance revealed that at 9% MC, Mahogany had the lowest density value of 439±10.58Kg/m³. At 12 and 15% MC, Afara had the lowest density values of 444±4.18Kg/m³ and 469±7.07Kg/m³ respectively. At 9, 12 and 15% MC, Opepe had the highest density values of 630±28.85Kg/m³, 686±22.64Kg/m³ and 752±17.22Kg/m³ respectively. Afara of 9, 12 and 15% MC had the lowest compressive strength parallel to the grain values of 9.59±1.08N/mm2, 9.59±1.08N/mm2 and 8.13±1.01N/mm2 respectively, while Mahogany had the highest compressive strength parallel to the grain values of 16.57±0.50N/mm2, 15.17±0.49N/mm2 and 12.12±0.42N/mm2 at the three MC levels. Post fire exposure revealed that Afara had the highest percentage change in density and compression in parallel values, while both Iroko and Mahogany exhibited the lowest percentage change in density and compression in parallel values. This study indicated that Mahogany and Iroko species which had lowest post fire change in density and compression in parallel values are useful and recommended to ensure the safety in case of fire outbreaks.

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The charring depth and charring rate of glued laminated timber after a standard fire exposure test

Building and Environment ◽

10.1016/j.buildenv.2008.02.010 ◽

2009 ◽

Vol 44 (2) ◽

pp. 231-236 ◽

Cited By ~ 15

Author(s):

Te-Hsin Yang ◽

Song-Yung Wang ◽

Ming-Jer Tsai ◽

Ching-Yuan Lin

Keyword(s):

Fire Exposure ◽

Exposure Test ◽

Standard Fire ◽

Glued Laminated Timber ◽

Charring Rate

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STRENGTH CHARACTERIZATION AND GRADING OF LESS-USED NIGERIAN GROWN TIMBER SPECIES FOR STRUCTURAL APPLICATIONS

Malaysian Journal of Civil Engineering ◽

10.11113/mjce.v32n1.609 ◽

2020 ◽

Vol 32 (1) ◽

Author(s):

Rahmon, R.O. ◽

Jimoh, A.A.

Keyword(s):

Developing Countries ◽

Structural Strength ◽

Testing Machine ◽

Strength Properties ◽

Timber Species ◽

British Standard ◽

Moisture Contents ◽

Universal Testing ◽

Structural Applications ◽

Strength Characterization

The demand for timber is unlimited as it continues to increase rapidly in Nigeria. There is problem of undocumented properties of unpopular timber species used locally, especially in developing countries such as Nigeria. This research therefore aimed at characterizing and grading of three (3) less-used timber species in Nigeria for structural uses. Ayunre (Albizia zygia), Eku (Brachystegia eurycoma) and Ire (Funtunia elastica) timber species were obtained from different sawmills in Ilorin, Nigeria and preparation of various test specimens are in accordance with British Standards BS 373: 1957. A total of 300 specimens were used in determining the strength characteristics of the timber species a 300 kN capacity Testometric Universal Testing Machine (UTM) at Agricultural and Biosystems Engineering Laboratory, University of Ilorin. Twenty (20) specimens for each timber species were tested for structural/strength properties according to the British Standard. Results show that the timber species had average moisture contents of 12.47, 11.78 and 12.71% for Ayunre, Eku and Ire, respectively. For density classification, Ayunre and Eku were classified as heavy wood and Ire as light wood. The results obtained provided quantitative details of the strength properties of selected timber species which can be used in determining the application of these timber species for structural applications. The timber species were, therefore graded according to NCP 2 (1973), EN 338 (2009) and BS 5268 (2002).

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Numerical model to predict the effect of wood density in wood–steel–wood connections with and without passive protection under fire

Journal of Fire Sciences ◽

10.1177/0734904119884706 ◽

2020 ◽

Vol 38 (2) ◽

pp. 122-135 ◽

Cited By ~ 1

Author(s):

Elza MM Fonseca ◽

Lino Silva ◽

Pedro AS Leite

Keyword(s):

Numerical Model ◽

Wood Density ◽

Room Temperature ◽

Steel Plate ◽

Fire Exposure ◽

Layer Depth ◽

Passive Protection ◽

Char Layer ◽

Charring Rate ◽

Wood Char

The main objective of this work is to present a numerical model to predict the effect of wood density in unprotected wood connections with an internal steel plate (wood–steel–wood), when comparing with the same connections using passive protection with gypsum plasterboard, submitted to fire conditions. Wood–steel–wood connections are made of four wood members, two on each side, with an internal steel plate that connects the pieces using steel dowel fasteners. First, analytical methodologies according to Eurocode 5 part 1-1 were used to design the connections at room temperature. After that, to predict the fire exposure and the connection ability, a numerical model was performed which permits to compare the fire resistance in wood–steel–wood connections without and with passive protection following the Eurocode 5 part 1-2. Results of the temperature and the wood char layer depth were compared using three different wood densities. The evolution of the charring rate was calculated in different locations of the connections and compared with the analytical value proposed by the Eurocode 5 part 1-2.

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