Cheers Sardorian - I actually ended up using the line trace, to run custom events to deactivate the particles. I ended up using a series of them so that only certain extinguishers put out certain fires. It currently works really well! The only concern I have now is trying to sort why the motion controllers move when moving the HMD, its a right pain…Think it may have something to do with the capsule on the FPS BP?? - here is a quick video test: 
