These requirements cover oil-fired central furnaces which include forced-air furnaces of the downflow@ horizontal@ and upflow types. Floor-mounted unit heaters designed to supply heated air through ducts are covered also by these requirements. These requirements cover furnaces intended to burn standard grade fuel oils as specified in the Specifications for Fuel Oils@ ASTM D396. Requirements for the installation and use of oil-burning equipment are included in the Standard for Installation of Oil-Burning Equipment@ NFPA 31@ and in codes such as the BOCA National Mechanical Code@ the SBCC Standard Mechanical Code@ and the IAPMO Uniform Mechanical Code. The applicable requirements are to be utilized in conjunction with this standard.