An Experimental Study on the Impairment of Sprinkler Head Water Distribution Performance Due to Thermal Deformation of Escutcheons of Different Materials

This study investigated the deformation characteristics of sprinkler escutcheons made of different materials under fire exposure and their effects on water distribution performance. Room heat tests were conducted on escutcheons made of Acrylic Styrene Acrylonitrile (ASA), flame-retardant ABS (FR ABS), PA 66 reinforced with 30% glass fiber (PA 66 + GF 30%), and STS 304. The results showed that ASA and FR ABS underwent thermal deformation, whereas PA 66 + GF 30% and STS 304 maintained their original shapes. Subsequently, PA 66 + GF 30% and ASA were selected as representative specimens for water distribution tests. PA 66 + GF 30% satisfied the water distribution criteria, while the thermally deformed ASA caused a directional bias in the water spray and failed to meet the required criteria. These findings experimentally support the technical basis of NFPA 13, which requires sprinkler escutcheons to be metallic or listed for use with sprinklers. Accordingly, this study proposes the adoption of NFPA 13-based requirements for sprinkler escutcheons in South Korea.