Skylab Experiment M-479: Zero Gravity Flammability

Flammability under conditions of weightlessness was investigated in Skylab 4. Thirty-seven experiments using six materials were successfully carried out to learn how a flame acts in the absence of convection. Specific objectives were to measure the extent of surface flame propagation and flash-over to adjacent materials, rates of surface and bulk flame propagation, self-extinguishment, and extinguishment by both vacuum and water spray. Data were returned in the form of crew comments on voice tapes and sixteen millimeter motion pictures taken at 24 frames per second. All experiments were performed and all hardware functioned properly, although an operational oversight caused the water in the supply tank to be less than the minimum required pressure. Burning rates were significantly reduced as anticipated from earlier aircraft tests. Some reduction of total burning was also noted. The surface burn was not followed by continued inward burning as typically experienced on Earth although some one-g tests at extremely low pressures have partially reproduced this condition. Ignition and extinguishment also appear to be similar to one-g. A soft blue flame was seen by the crew, but was not detected on the film emulsions used. Smoke patterns were also noted.