A study was made of flame propagation along methane-air roof layers using a laboratory scale gallery, 8 feet long by 3 inches wide by 6 to 10 inches high. The effects of various environmental and gas layer factors on the speed of the propagating flame were determined and dimensional analysis techniques were used to develop a relationship between these factors and flame speed. The model was designed to study the early stages of flame propagation along a methane-air layer ignited at the closed end of a tunnel.