The design, construction, demonstration, and operation of a bench-scale device capable of comparison screening the fire suppression efficiency of liquid agents are described in this paper. The apparatus is based on a well-characterized flame, a means to facilitate the introduction of liquid agents, and a way to generate liquid droplets. A porous cylinder in a counterflow diffusion configuration is used. A small-scale vertical wind tunnel, which allows for the delivery of a uniform flow of oxidizer to the burner and also assists in the delivery of liquid agent droplets to the flame, is used for the flow facility. Droplets are generated by a small glass nebulizer. The performance of the screening apparatus was evaluated using several liquid fire suppressants with different thermophysical properties. A test protocol is also proposed. Published by Elsevier Science Ltd.