how the codes relate to the instructions given in this manual. The requirements of local building codes must always be observed because they represent the legal requirements for an installation in a given jurisdiction. However, most local codes are based on the national model building codes. Model codes themselves do not have the force of law until they are adopted by a state or local jurisdiction. In the United States, the primary source of model codes is the International Code Council, which publishes the International Building Code (IBC) and International Residential Code (IRC). In Canada, the primary model code is the National Building Code (NBC), published by the National Research Council of Canada. Most of the model building codes, and thus the local codes based on them, recognize that the manufacturer of a product usually has a good idea of how its product should be installed in order to provide best performance. Therefore, most codes reference the manufacturer's instructions and state that the product must be installed according to the code and the manufacturer's instructions. However, any specific requirement in a local code will usually override any provision of the manufacturer's instructions, especially if the local requirement is more restrictive. Therefore, vinyl siding installations must always conform to local building codes, but the local code may also require that the installation conform to the siding manufacturer's instructions. Fire Safety Information Exterior vinyl building materials require little maintenance for many years. Nevertheless, common sense dictates that builders and suppliers of vinyl