The exhaust system shall include the: Exhaust manifold and gaskets; and Piping leading from the flange of the exhaust manifold to and including the muffler or mufflers and exhaust pipes. The exhaust system may not extend into the body and shall be attached to the chassis. Exhaust Pipes: Shall be of nonflexible 16-gauge steel. An Original Equipment Manufacture flexible pipe or its equivalent not longer than 24 inches in length may be used at the front of the system at or near the turbocharger; Shall exit: At the rear of the bus on either the left or right side of the emergency door, or Behind the rear wheel of the bus; May not exit under the fuel filler; and May not exit through or be attached to the bumper. The complete exhaust system shall be: Tight and free from leaks; and Properly insulated from electrical wiring or any combustible part of the bus. The complete exhaust system may not pass within 12 inches of the gasoline fuel tank or its connections unless a suitable heat baffle is installed between the exhaust system and gasoline fuel tank. A shield is not required between a diesel tank and exhaust. The exhaust system noise level may not exceed the levels in COMAR 11.14.07.08. The manufacturer shall provide the proper size exhaust pipes for the vehicle. Replacement pipes shall be of the same diameter as the pipes provided by the manufacturer.