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進入《TAIPEI TIMES》 Oysters used in fire-retarding boards
An experiment to test a fire-retardant material is run at Kaohsiung Municipal Chung-Cheng Industrial High aSchool on Sunday. Photo courtesy of Kaohsiung Municipal Chung-Cheng Industrial High School
By Fang Chih-hsien and William Hetherington / Staff reporter, with staff writer
High-school students in Kaohsiung said they have found a way to slow a fire’s spread, adding that the material could be used as fire retardant.
Students at Kaohsiung Municipal Chung-Cheng Industrial High School said that burning oyster shells releases gases that help prevent fires from spreading.
The students made the discovery while preparing for an annual competition for innovations in science, school principal Kao Jui-hsien （高瑞賢） said, adding that they won first place in the structural engineering category.
Pressed wood is often used in home decor, as it is cheap to manufacture, but it burns quickly, Kao said, adding that oyster shells, which are usually discarded, can be used instead.
Oyster shells are composed of calcium carbonate, which produces calcium oxide and carbon dioxide when heated — with the latter reducing oxygen concentrations in its immediate surroundings, he said.
This property could help people escape if their home were to catch fire, he said.
Structural engineering teacher Chang Yung-hsiang （張永翔） and chemistry teacher Chang Wen-han （張文瀚） worked with five students to make six boards composed of different ratios of crushed shells and wood shavings.
The students analyzed the properties of the boards when burned.
Boards that had at least 60 percent shell content displayed fire-retardant properties and would extinguish in 3.24 to 8.85 seconds, the group said.
Because the density of carbon dioxide in the air surrounding the burning boards is 1.5 times greater than in normal circumstances, it is difficult for oxygen — which aids combustion — to reach the combustible material, second-year student Hung Yu-shan （洪宇珊） said.
The boards would be perfect for use as fire-retardant building materials in places like KTV lounges, movie theaters and other confined public spaces, Hung said, adding that the shells are abundant in Taiwan and are an environmentally friendly material.
Repurposing them would also solve the issue of what to do with the roughly 10,000 tonnes of waste shells produced annually, she said.
新聞來源：TAIPEI TIMES
