A series of large-scale tests were carried out to evaluate the effectiveness of using extinguishing powder (Purple K) to supress propane or petrol fire or to reduce emitted radiative heat flux. Three sets of different fire were carried out: a petrol leakage fire, a petrol pool fire and a liquid propane jet fire impinging a horizontal cylinder. In these tests, the powder was not able to extinguish the liquid hydrocarbons fire, but in some cases was able to extinguish the propane jet fire. In all cases, powder spray had excellent properties to reduce radiative heat flux.