Fire tests and thermal analyses of LSF walls insulated with silica aerogel fibreglass blanket

Abstract

Load-bearing light gauge steel framed (LSF) wall is one of the main structural elements in cold-formed steel (CFS) buildings. When cavity insulation is used to enhance the energy performance of LSF walls, their structural adequacy based fire resistance levels (FRL) decrease considerably. Hence, new insulation materials and/or different wall configurations are considered. This research study investigated the use of silica aerogel fibreglass blanket as external insulation to enhance the FRL of LSF walls. Three fire tests were conducted to determine the time-temperature profiles of different wall components and the FRL of aerogel blanket insulated LSF walls. Suitable finite element (FE) models were then developed, validated and used to further optimise the LSF wall configuration. This study shows that silica aerogel fibreglass blanket, when used as a form of external insulation, enhances the fire resistance by delaying the stud temperature development by about 20 min and reducing the stud flange temperature difference by up to 200 °C when compared with cavity insulated LSF walls. However, the aerogel blanket accelerates the temperature development of fire protective gypsum boards, which leads to an early failure of these boards. This paper presents the details of the fire tests, finite element study and their findings.