The ASTM E119 is a large-scale test used to qualify assemblies for fire resistance, including heat transmission and structural integrity. The test requires specialized furnaces and full-scale assemblies that are 3.0 m (10 ft) or more on each side, making it very expensive to perform.
In this study, we investigated the feasibility of the scaling methodology for a reduced-scale fire resistance test on different types of wood-based structures, specifically commercially available intumescent coating applied onto wood and bolted lap joints in wood. We build upon a previously developed scaling methodology for wood and gypsum boards, which integrated geometric scaling, Fourier number time scaling, and furnace boundary condition matching. Intumescent coating presents a particular challenge in scaling in that it expands when exposed to fire conditions. To account for this expansion, we identified a relationship between initial dry film thickness and final expanded thickness through cone calorimeter tests and integrated it into a modified scaling methodology. This approach was then validated through fire exposure tests in furnace on wood samples painted with intumescent coating at full, half, and quarter scales. Finally, we demonstrated the scaling laws for joints under combined thermo-structural loading, by subjecting wood-based half-lap joint samples to combined bending and thermal loading at half and quarter scale. The samples were subjected to static three-point bending with the load scaled to achieve structural similitude, while simultaneously being exposed to a scaled fire exposure on the bottom surface. Our study provides insights into the practical application of scaling methodology for testing the fire resistance of joints and fire-resistant coated wood, paving the way for more cost-effective and quicker fire testing for the wood-based composite industry. / Master of Science / The ASTM E119 is a critical test standard that evaluates the fire resistance of various building materials, including wood-based structures. However, the standard tests are quite expensive due to the need for specialized equipment and large-scale samples. In this study, we explored the potential of using a scaled-down fire resistance test on different types of wood-based materials, including commercially available fire-resistant coated wood and joints.
We built on existing scaling methods for wood and gypsum boards and adapted it to account for the unique properties of intumescent coating - a fire-resistant material that expands when exposed to high temperatures. By conducting a series of tests, we developed a modified scaling approach to accommodate the expansion of the coating.
We then validated this new method by performing fire exposure tests at various scales on wood samples coated with intumescent coating. Finally, we adapted the scaling methods to account for wood based bolted joints. We tested the fire resistance of wood-based half-lap joints under combined heat and structural stress at smaller scales.
Our study offers valuable insights into a more cost-effective and efficient method for testing fire resistance in wood-based structures. By providing a reliable scaling approach for fire-resistant coated wood and joints, our work has the potential to make fire testing more accessible for the wood composite industry, ultimately leading to safer and better-performing buildings.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/115640 |
| Date | 03 July 2023 |
| Creators | Kulkarni, Akhilesh |
| Contributors | Mechanical Engineering, Lattimer, Brian Y., Case, Scott W., Huxtable, Scott T. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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