Fastener Pull-out

NZMRM wind uplift resistance testing specifically assumes fasteners are permanently fixed to the purlins and will not pull out. Because of this and, also due to the huge range of fastener/purlin material variations, the pull-out resistance of fasteners is eliminated from the uplift testing procedure. Accordingly, when designing for SED wind conditions, the engineer must make a separate calculation to determine the necessary pull-out resistance of the fastener from the purlin material to be used, which will allow the correct selection of the fasteners.