State of Structural Timber Fire Endurance

Authors

  • Erwin Schaffer

Keywords:

Fire endurance, fire resistance, timber, wood, columns, beams, walls, floors, panels, thermal properties, strength, wood assemblies, wood components

Abstract

The paper is motivated by the need for information relating to the design and behavior of wood structural components. Such information is critically reviewed. Most standard conventional components have been five tested under the sponsorship of materials suppliers or designers. However, only the fire endurance of floors and columns have both models and experimental evidence available for use. Models for the fire endurance of heavy timber, or glulam, beams are presented that are based on reduction of the cross section with duration of fire exposure and a reduction of strength of the outer fibers. Essentially no experimental information is available on model effectiveness. No models for the performance of wood-base wall systems were found, but extensive experimental ratings exist. To facilitate further research, a review of the influence of fire on wood and wood properties is given. Included are strength and deformation under load, charring of solid sections and panels, temperature distribution, and thermal properties. Research needs, in addition to filling the gaps found, include: analysis of risk based upon both variability of the "fire load" and "structural fire resistance"; and benefit/cost analyses on fire protection.

References

American Society for Testing and Materials. 1973. Fire tests of building construction and materials. ASTM Desig. E 119. ASTM, Philadelphia, PA.nAmerican Society for Testing and Materials. 1976. Standard method for evaluating allowable properties for grades of structural lumber. ASTM Desig. D 2915. ASTM, Philadelphia, PA.nAmerican Insurance Association. 1976. The National Building Code. Am. Insur. Assoc. New York, NY.nBach, L. 1965. Non-linear mechanical behavior of wood in longitudinal tension. Ph.D. Thesis, Syracuse Univ., Syracuse, NY.nBaldwin, R. 1975. The economics of structural fire protection. Build. Res. Establ. BRE Curr. Pap. CP 45-75. London.nBamford, C. H., J. Crank, and D. H. Malan. 1946. The combustion of wood. Proc. Combust. Phil. Soc.46:162-182.nBuilding Officials and Code Administrators International. 1975. The BOCA Basic Building Code (sec. 903.2.2). Build. Off. and Code Adm. Int., Chicago, IL.nCarslaw, H. S., and J. C. Jaeger. 1965. Conduction of heat in solids. Oxford Univ. Press. Oxford, England.nCommonwealth of Scientific and Industrial Research Organizations. 1962. The fire resistance of timber, Part IV—Fire-retardant-treated timber. CSIRO For. Prod. Newsl. No. 283, Melbourne, Australia.nDorn, H., and K. Egner. 1961. Fire tests on glued laminated structural timbers (glulam beams). Holz-Zentralbl.28:435-438. (Tech. Transl. 1131, Natl. Res. Counc. Canada, Ottawa.)nEickner, H. W. 1975. Fire endurance of wood-frame and sandwich wall panels. J. Fire Flammability6:155-190.nForest Products Laboratory. 1974. Wood handbook—Wood as an engineering material. Agric. Handb. No. 72. U.S. Dep. Agric. For. Serv.nChanholm, H. J. [n.d.]. Fire resistance in timber structures. Note No. 274. Chalmers Technol. U., Göteborg, Sweden.nHall, G. S. 1968. Fire resistance tests of laminated timber beams. Timber Res. and Develop. Assoc. Res. Rep. WT/RR/1. London.nHall, G. S., R. G. Saunders, R. T. Allcorn, P. E. Jackman, M. W. Hickky, and R. Fitt. 1972. Fire performance of timber. Timber Res. and Develop. Assoc. High Wycombe, Bucks, England.nHarmathy, T. Z. 1961. A treatise on theoretical fire endurance rating. ASTM Symp. on Fire Test Methods. STP NO. 301. ASTM, Philadelphia, PA.nHarmathy, T. Z. 1965. Ten rules of fire endurance rating. Fire Technol.1(2):93-102.nImaizumi, C. 1962. Stability in fire of protected and unprotected glued laminated beams. Norsk. Skogind.16(4): 140-151.nKansa, E. J., H. E. Perlee, and R. F. Chaiken. 1977. Mathematical model of wood pyrolysis including internal forced convection. Combust. Flame29(3):311-324.nKanury, A. M. 1972. Thermal decomposition kinetics of wood pyrolysis. Combust. Flame18(1):75-83.nKanury, A. M. 1973. Rate of charring combustion in a fire. Proc. 14th Symp. (Intl.) on Combust., 1131-1142. Combust. Inst., Pittsburgh, PA.nKanury, A. M. 1975. A theoretical analysis of the ASTM E 119 standard Fire Test Build. Constr. and Mater. NBS-GCR 76-50. U.S. Dep. Comm. Nat. Bur. Stand.nKnudsen, R. M., and A. P. Schniewind. 1975. Performance of structural wood members exposed to fire. For. Prod. J.25(2):23-32.nKung, H. C. 1972. A mathematical model of wood pyrolysis. Combust. Flame18(2):185-195.nLawson, D. I., and J. H. McGuire. 1953. The solution of transient heat flow problems by analogous electrical networks. Proc. Inst. Mech. Engs. A167:275.nLawson, D. I., C. T. Webster, and L. A. Ashton. 1951. Fire endurance of timber beams and floors. Nat. Build. Studies Bull. No. 13. HMSO, London.nLawson, D. I., C. T. Webster, and L. A. Ashton. 1952. Fire endurance of timber beams and floors. Struct. Eng.30(2):27-34. (Great Britain.)nLie, T. T. 1972. Fire and buildings. Appl. Sci. Publ., Ltd., London.nMalhotra, H. L., and F. W. Rogowski. 1967. Fire resistance of laminated timber columns. Pap. No. 3. Proc. Symp. No. 3 on Fire and Struct. Use Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nMeyer-Ottens, C. 1967. The behavior of load-bearing and nonloadbearing internal and external walls of wood-based materials under fire conditions. Pap. No. 8. Proc. Symp. No. 3 on Fire and Struct. Use Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nMitchell, N. D. 1947. Fire tests of untreated and treated wood walls. Proc. Am. Wood-Preserv. Assoc.43:353-360.nNational Board of Fire Underwriters. 1964. Fire resistance ratings of less than one hour. NBFU [Now part of Am. Insur. Assoc], New York.nNational Fire Protection Association. 1976. Fire protection handbook, Ch. 6. 14th ed. NFPA, Boston, MA.nNational Forest Products Association. 1961. Heavy timber construction details. Wood Construction Data No. 5. (A.I.A. File No. 19-B.) Natl. For. Prod. Assoc., Washington, DC.nOdeën, K. 1970. Fire resistance of glued laminated timber structures. Pap. No. 2:7-15, Proc. Symp. No. 3 on Fire and Struct. Use Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nOllis, W. J. B. 1968. Standard tests and caculation of fire resistance in timber. Munic. Eng. 145(June 14, 1968): 1213.nPachkis, V., and H. D. Baker. 1942. A method for determining unsteady-state heat transfer by an electrical analogy transaction. J. Am. Soc. Mech. Engs.64:105.nRobertson, A. F., and D. Gross. 1958. An electrical-analog method for transient heat flow analysis. J. Res. Nat. Bur. Stand.61:105.nRogowski, B. F. 1967. Charring of timber in fire tests. Pap. No. 4. Proc. Symp. No. 3 on Fire and Struct. Use Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nSchaffer, E. L. 1965. An approach to the mathematical prediction of temperature rise within a semi-infinite wood slab subjected to high-temperature conditions. Pyrodynamics2:117-132.nSchaffer, E. L. 1966. Review of information related to charring of wood. U.S. Dep. of Agric. For. Serv. Res. Note FPL-0145. For. Prod. Lab., Madison, WI.nSchaffer, E. L. 1967. Charring rate of selected woods —transverse to grain. U.S. Dep. of Agric. For. Serv. Res. Pap. FPL 69. For. Prod. Lab., Madison, WI.nSchaffer, E. L. 1968. A simple test for adhesive behavior in wood sections exposed to fire. U.S. Dep. of Agric. For. Serv. Res. Note FPL-0175. For. Prod. Lab., Madison, WI.nSchaffer, E. L. 1971. Elevated temperature effect on the longitudinal mechanical properties of wood. Ph.D. Thesis, Univ. Wisconsin, Madison, WI.nSchaffer, E. L. 1973. Effect of pyrolytic temperatures on the longitudinal strength of dry Douglas-fir. ASTM J. Test. Eval.1(4): 319-329.nSchaffer, E. L. 1974. Do fire-retardant treatments affect the charring rate of wood? J. Fire Flammability. Fire-Retardant Chem.1:96-109.nSchniewind, A. P. 1968. Recent progress in the study of the rheology of wood. Wood Sci. Technol.2:188-206.nSon, B. C. 1973a. Fire endurance test of plywood-faced exterior walls for single-family housing. NBSIR 73-140. U.S. Dep. Comm. Nat. Bur. Stand.nSon, B. C. 1973b. Fire endurance test of an inter-dwelling double wall construction of paper honeycomb and gypsum board. NBSIR 73-166. U.S. Dep. Comm. Nat. Bur. Stand.nSon, B. C. 1973c. Fire endurance test of a roof/ceiling construction of paper honeycomb and gypsum board. NBSIR 73-167. U.S. Dep. Comm. Nat. Bur. Stand.nSon, B. C. 1973d. Fire endurance test of a wood stud interdwelling double wall construction. NBSIR 73-169. U.S. Dep. Comm. Nat. Bur. Stand.nSon, B. C. 1973e. Fire endurance test of an interdwelling double wall constructed of polyurethane foam-filled sandwich panels. NBSIR 73-170 (NTIS PB 221-193). U.S. Dep. Comm. Nat. Bur. Stand.nSon, B. C. 1973f. Fire endurance tests of unprotected wood-floor constructions for single-family residences. NBSIR 73-263. U.S. Dep. Comm. Nat. Bur. Stand.nSteinhagen, H. P. 1977. Thermal conductive properties of wood: A literature review. U.S. Dep. of Agric., For. Serv. Gen. Tech. Rep. FPL-9. For. Prod. Lab., Madison, WI.nTenning, K. 1967. Glued laminated timber beams: Fire tests and experience in practice. Pap. No. 1. Proc. Symp. No. 3 on Fire and Struct. Use Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nTenning, K. 1976. Fire resistance in laminated timber structures. [Symposium, Kiev, USSR.] Töreboda Limtra AB.nUnderwriters' Laboratories. 1974. U.L. Fire Resistance Index. Underwriters Lab., Inc., Northbrook, IL.nU.S. Department of Housing and Urban Development. 1973. Minimum property standards. HUD, Washington, DC.nVorueiter, L. V. 1956. Combustion and heat insulating losses of wood and fiber boards. Holzforschung10:73-80.nWardle, T. M. 1966. Fire resistance of heavy timber construction. New Zealand For. Serv. Publ. Inf. Ser. No. 53. Wellington, N.Z.nWardle, T. M. 1967. Discussion on Pap. No. 2. Proc. Symp. No. 3 on Fire and Struct. Use of Timber in Builds., Minist. Technol. and Fire Off. Comm., Joint Fire Res. Org., HMSO, London.nWisconsin Department of Industry, Labor: and Human Relations. 1972. Wisconsin Administrative Code—Building, heating, ventilating, and air conditioning code. Soc. Ind. 51. WDILHR, Madison, WI.n

Downloads

Published

2007-06-05

Issue

Section

Research Contributions