Mineral fiber and other cementitious materials sprayed directly into the contours of beams, columns, girders, and floor/roof decks are the most often utilized fire prevention materials for structural steel. The application method can be either dry or wet. Dry applications involve the use of a hand-held nozzle to spray the fire retardant material into the desired areas. This is usually done by first marking out where the sprinkler system should go and then using the nozzle to spray the mineral wool right into those marks. The dry application process allows for more precise spreading and control of the fire retardant product than using water. Wet applications require spraying water onto the surface to be treated with the fire retardant material. This creates puddles of water that soak into the surrounding soil to help spread the fire retardant material around the column. After the puddles have soaked in for several minutes, they must be pumped away so that traffic can continue down the road. This method is less accurate than dry application but it spreads the material over a larger area so it works better for large structures like bridges. Fire proofing steel columns is an important part of bridge construction because without it, there is no way to stop a fire from spreading through the girder webbing.