`  == Reading the fire ==  ``Spraying water on the ceiling with a short pulse of a diffused spray (e.g., cone with an opening angle of 60°) to test the heat of the smoke: `` * I've always been taught that a diffused spray will only fill up the room with all kinds of hot steam and be detrimental to visibility and survival of anyone in the room (water->steam expansion rate is very high), and to opt for a straighter stream using a ``penciling`` technique.  Anybody else learned this way?   `