Rationale

Results from recent WUI fire tests indicate that intersections between exterior walls and horizontal projections, such as soffits, can be weak points for entry of fire into the structure if both the wall and the horizontal projection are hardened but the intersection between these two surfaces is not detailed properly. Although there are standards that can be used to evaluate WUI hardening of exterior walls (ASTM E2707) and horizontal projections (ASTM E2957), there is no existing ASTM standard that explicitly addresses the intersection between these two surfaces. In order to fill this gap, revisions to ASTM E2957 are proposed to allow for simultaneous evaluation of the horizontal projection as well as the intersection between the horizontal projection and the exterior wall.