Why does smoke come from a fire? Let's say you have a nice fire going, and it has burned down to the point where what you see is a collection of hot "glowing embers." The fire is still producing a lot of heat, but it is producing no smoke at all. You might have gotten to this point either by starting with logs in a fireplace or by starting with charcoal. If you now toss a piece of wood, or even a sheet of paper, onto this fire, what you will notice is that the new fuel produces a lot of smoke as it heats up. Then, all of a sudden (often with a small pop), it bursts into flame and the smoke disappears. If you have a fireplace or wood stove, or if you have been around a lot of campfires, this little scene is very familiar to you. It tells you a lot about smoke -- let's look at what is happening. There are four things that you find in any piece of wood: * Water - Freshly cut wood contains a lot of water (sometimes more than half of its weight is water). Seasoned wood (wood that has been allowed to sit for a year or two) or kiln-dried wood contains a lot less water, but it still contains some. * Volatile organic compounds - When the tree was alive, it contained sap and a wide variety of volatile hydrocarbons in its cells. Cellulose (a chief component of wood) is a carbohydrate, meaning it is made of glucose. A compound is "volatile" if it evaporates when heated. These compounds are all combustible (gasoline and alcohol are, after all, hydrocarbons -- the volatile hydrocarbons in wood burn the same way). * Carbon * Ash - Ash is the non-burnable minerals in the tree's cells, like calcium, potassium and magnesium. Back to FAQs

FAQS       Fire News Fire extinguishers in good hands, Allstate grant funds simulators God's house catches fire thanks to a smoking butt Fair offers lessons for emergencies Indian Rocks apartment fire called suspicious Fire at Mill Valley taco shop put out by automatic extinguisher Apartment fire extinguished quickly more ...