氣凝膠多孔板開發及應用於既有建築外牆防火與隔熱成效之研究

Study of the Enhancement Performance of Fire Resistance and Thermal Insulation of Silica-based Aerogel Board with Development and Application to Retrofit the Existing External Wall of Building

由於台灣30年屋齡以上的老舊建築超過400萬戶，為此，內政部於2020年訂定「都市危險及老舊建築物加速重建條例」補助民眾以都市更新方式辦理建築物重建、整建或維護，以加速推動老舊社區改善居住環境，使既有建築物透過整建活化，再賦予新的生命週期達到都市更新目的及資源再利用的永續發展目標。一般老屋外牆拉皮的工法中會設置外牆隔熱系統（External wall Insulation, EWI），此系統通常由防火材質的材料製成，但建築物外牆系統若符合建築技術規則防火構造之外牆的除外規定，或非防火構造符合外牆棟距及地界線距離之規定者，亦可能使用如聚氨酯泡沫或是發泡聚苯乙烯等可燃性材料。因此若能開發出一種除了能減少建築能耗，而且擁有高性能防火性質的EWI，必能應用在更多種類的建築上。
本文主要闡述一種創新材料―氣凝膠多孔板運用於EWI之可能性。此種材料擁有密度小、多孔洞結構、超疏水性以及低熱傳導係數之特性。本文作者利用圓錐量熱儀，參照CNS 14705-1-2013的標準，證實其防火程度可達到耐燃一級。再者，將氣凝膠多孔板應用在既有建築之外牆石材乾式工法中，更可以降低熱傳透率至1.394 W/m2-K，亦符合高性能節能綠建材標章之評定基準（1.8W/m2-K）。以氣凝膠多孔板之隔熱性質以及防火上的表現來看，除了對於既有建築物之能源效益與防火安全提升將有極大的助益之外，與市面上一般主流的外牆隔熱系統相較，也更具市場競爭力。

There are more than 4 million old buildings over 30 years old in Taiwan, thus, the Ministry of the Interior promulgated a satute to expedite the reconstruction of unsafe and old buildings within the area of urban planning, improve the living environment, and improve building safety and citizens' living conditions in response to potential disaster risk. Generally, the external wall insulation system (EWI) made of fire resistant materials is installed in the external wall of the old house retroffiting. Sometimes flammable materials such as polyurethane foam and expanded polystyrene etc. could be used in the EWI as the existing external wall system meets the requirements of the building technical regulations. Hence, a type of EWI that not only reduces the building energy demand, but also offers higher class of fire resistance would allow EWI to be more widely applied.
This paper introduces a novel material: silica-based aerogelboard which differs itself from mainstream products available in the market because of its outstanding performance, such as low density, high surface area, low thermal conductivity and superhydrophobicity. Herein, its thermal insulation and fire-resistant performance were tested and compared with commercial products. The results of a cone calorimeter analysis indicated that most of commercial foaming materials are flammable and that the proposed silica-based aerogel board can improve the fire resistance performance to achieve non-flammable class 1 in accordance with CNS 14705-1-2013. Moreover, the evaluation of thermal insulation performance conducted in this paper indicated that the application of aerogel porous board in the dry construction method of the external stone wall of the existing building can reduce the heat transmitance to 1.394 W/m2-K. It leads to this EWI system can meet the evaluation criteria of the high-performance energy-saving green building materials label (1.8 W/m2-K). In terms of thermal insulation and fire safety performance, aerogel porous board will not only greatly enhance the energy efficiency and fire safety performance of existing buildings, but also have market competitiveness.