Wind uplift rating is one of the key performance requirements for single-ply mechanically attached systems. It depends on the properties of the membrane (mechanical, physical and chemical), substrate (compressive strength and dimensional stability), and deck (thickness and deflection). An attachment system (fastener, plate and seam) integrates the above components to form an assembly. Fastener pullout resistance (FPR) from the deck is one of the essential design parameters in the system specification. As well, the FPR is an indicator of the existing deck condition in reroofing/recover applications. In the field, the FPR values are obtained using pullout testers. To quantify the accuracy of the manual pullout testers under various environmental conditions, an experimental program is in progress at the National Research Council's Dynamic Roofing Facility (DRF). From this ongoing research, this paper compares the FPR data from the field pullout tester with those obtained using the laboratory universal Instron testing machine. In the manual pullout tester, consistency of the FPR data depends on the operator. Considering this variable and to generalize the data, the above experiments are performed on two decks (steel and wood) with three different fastener types. The study finds that the field manual pullout tester underestimates the FPR data in comparison to the data obtained from the laboratory machine. This trend is found true irrespective of the selected decks and fasteners. In the roofing market, automatic pullout testers are also available that function using a battery-powered source. Selected experiments were performed to identify the influence of the pull out speed on the FPR data using an automatic pullout tester.