71. Fire Stops

The architect who is mindful of the interests of his client should always take such precautions as he can to make his building not only strong and durable, but also as slow burning and inaccessible to vermin as may be practicable. This can be done to a considerable extent without much additional cost. One of the best preventatives to the progress of fire is to stop all spaces between the floor joists and in the partitions with soft brick or fireproof tiles laid in mortar, as shown in Figs. 59 and 60. The spaces between the ends of the first story joists and over all dropped girders should be filled with brickwork in the same way. This will prevent the rapid passage of fire between the joists from one side of the building to the other and up in the partitions. If the partitions are bridged, and one or two courses of brickwork laid on top of the bridging, an additional stop to fire rising in them is provided. If a fire can be prevented from ascending in the partitions and spreading between the joists for fifteen or twenty minutes after it is discovered it can generally be controlled without destroying the building. Partitions which rest on the floor, with no partition below, should have a piece of tin 3 or 4 inches wider than the partition placed under the sole piece, as shown in Fig. 61. If the building is balloon frame, 2x4 bridging should be cut in between the studding of the outside walls, just below the ledger board or false girt, and brickwork laid on top to at least 5 inches above the top of the joists. This will not only prevent fire from ascending in the walls, but will prevent the ledger board from being quickly burnt through. The space between the timbers around smoke flues and all similar places, where fire or mice could pass through, should be filled solid with mortar or mineral wool. In general fire will not make much headway where there is no draught, and every pains should be taken to prevent the passage of flames through the concealed portions of the building. Mineral wool is a very efficient article for stopping the progress of flames and vermin, also of sound and heat