Investigation of Sprayed Fire-Resistive Material and In Situ Bond Failure

This paper reviews several case studies of spray fire-resistive materials (SFRMs) and provides lessons learned over the course of the forensic investigations. ASTM E736-00 Standard Test Method for Cohesion/Adhesion of Sprayed Fire-Resistive Materials Applied to Structural Members (ASTM 2006) is used to determine the bond strength of newly cured SFRM. The International Building Code (IBC) 2015 (ICC 2014) specifies minimum acceptable bond strengths. The validity of those bond strengths as applied to in-service SFRM is considered. Discussions and suggestions are made to improve the testing method and reduce the allowable minimum bond strengths of SFRM. Recommendations to improve testing methods included measuring the angle of the applied tension force with respect to the tested surface, and minimizing the effect of surface forces by cutting the SFRM directly around the bonded disk.