published specifications, including tensile and yield points, which establish properties and suitability of the steel for school bus body test code and safety requirements. All Type A, C, and D bodies shall meet the requirements of FMVSS 221 and the requirements of the most current National School Bus Specifications and Procedures, Side Intrusion Test.
All welds used in construction of body shall conform to latest applicable specifications of the American Welding Society.
Welds, rivets, or high-strength bolts may be used in connecting parts of the structural body. All bolts shall have provision to prevent loosening under vibratory loads. All bolts, nuts, washers, and screws used throughout the body shall be cadmium or zinc plated, or thoroughly treated in an approved manner for prevention of rust.
All metal used in construction of the bus body shall be zinc or aluminum coated before construction, provided that for metals twelve (12) gauge or less in thickness, either zinc or aluminum coating shall be mill applied for these components:
Service door panels
Emergency door panels
All exterior body panels
Body posts and roof bows
Window visors where used
All floor section panels and floor sills
Excluded are door handles, interior decorative parts, and other interior plated parts.
All metal parts that will be painted shall be chemically cleaned, etched, zinc- phosphate-coated, and zinc-chromate or epoxy primed, or conditioned by equivalent process. Any areas from which primer is removed for any purpose, such as sanding, grinding, welds, etc., must be thoroughly cleaned and treated as specified and primer applied. Rivets used in assembly shall be zinc-phosphate treated unless coated with rust prevention material and primed as specified. In providing for these requirements, particular attention shall be given to lapped surfaces, welded connections or structural members, cut edges, metal in which holes are punched or drilled, closed or box sections not vented or drained, and surfaces subjected to abrasion during vehicle operation.
As evidence that above requirements have been met, samples of materials used in construction of the bus body, when subjected to 1,000-hour salt spray test as provided for in latest revision of ASTM, Designation: B 117, "Standard Method of Salt Spray (Fog) Testing," shall not lose, after rubbing to remove corrosion, more than ten percent (10%) of material by weight.
The front-end assembly shall be sufficiently heavy to withstand vibrations transmitted to it through chassis cowl. Windshield or corner posts must be of Section C-16