Abstract: In this paper, the effects of interlayer effect between the configuration of curtain wall and facade on flame shape, near - field temperature field and mass loss during fire propagation of insulation material were investigated experimentally. The influence of distance variation on the flame spreading was studied. The results showed that the flame front in the special confined space of the interlayer presented an "inverted V" type gradient distribution; the mass of the molten droplet decreased with the increase of curtain wall spacing; when the distance was big, the high temperature appeared at the central vertical area, and the temperature at the centerline decreased with the reduction of the distance. The study is helpful to evaluate the fire risk of building parallel glass curtain wall and the fire safety design of building external structure.

Key words: thermal safety, glass curtain wall, thermal insulation material, downward fire spread