9247 is a part of the Motor and Bus Structural Specifications (MBS). MBS provides details of all structural requirements for buses, including chassis, floor pan, and suspension design; fuel and exhaust systems; body types, materials, and manufacturing processes; electrical, safety, and environmental standards; and applicable National Highway Traffic Safety Administration (NHTSA) crash test requirements. The 9247 part of MBS contains application information on bus body designs, general requirements for body structure, frames, and other components, construction materials, and welding details. It also includes information on glazing and sealing, fasteners and adhesives, interior equipment and trim, and soundproofing. Additionally, this part describes structural requirements for side and rear doors, windows, exterior skin, and emergency exits. It also provides details on service life, inert gas welding, fatigue testing, and front and rear end protection.