Exhaust System and Muffler

Section 442 Section 442.435  Exhaust System and Muffler a)         The exhaust pipe, muffler and tail pipe shall be outside the bus body and attached to the chassis. AGENCY NOTE:  As mandated by the United States Environmental Protection Agency (USEPA), diesel-powered engines manufactured after December 31, 2006 are required to meet stricter standards that will reduce emissions of particulate matter and nitrogen oxides into the atmosphere.  School bus manufacturers may be required to modify exhaust systems to meet the USEPA requirements, e.g., mufflers may be replaced with after-treatment devices that significantly reduce toxins released into the atmosphere.  Modifications to exhaust systems made in compliance with the USEPA requirements are acceptable provided they do not impact the safe operation of the school bus. b)         The exhaust system shall be insulated from any insulated wire, flammable material, brake hose or line, or fuel system component by a securely attached metal shield at any point where the exhaust system is 11.8 inches (300 mm) or less (four inches (101.6 mm) or less if diesel powered engine) from the components listed in this subsection. c)         The tail pipe may meet the chassis manufacturer's standard configuration.  However, the tail pipe shall not exit beneath any fuel filler location or beneath any emergency exit door. d)         The tail pipe shall extend out to, but not more than, 1 inch (25.4 mm) beyond the perimeter of the body or the bumper. e)         The shielding of engine compartment components shall be governed by the chassis manufacturer's standards. f)         Each gas conducting component that is not of stainless steel shall be of commercial heat and corrosion resistant exhaust system material and shall be nonflexible.