(a)

1. (1) The following specifications are applicable to all types of school buses that may be equipped with air conditioning.

2. (2) This section is divided into three (3) parts.

   1. (A) Subsection (b) covers performance specifications;
   2. (B) Subsection (c) covers test conditions; and
   3. (C) Subsection (d) covers other requirements applicable to all buses.

(b) Performance specifications.

1. (1) Standard performance.

   1. (A) The installed air conditioning system should cool the interior of the bus from one hundred degrees Fahrenheit (100˚ F) to eighty degrees Fahrenheit (80˚ F), measured at three (3) points (minimum) located four feet (4’) above the floor on the longitudinal centerline of the bus.
   2. (B) The three (3) required points shall be:

(i) Three feet (3’) above the center point of the horizontal driver seat surface;

1. (ii) At the longitudinal midpoint of the body; and

   1. (iii) Three feet (3’) forward of the rear emergency door or, for Type D rear engine buses, three feet (3’) forward of the end of the aisle.

   2. (C)

      1. (i) Note for the Type A vehicles: placement of the rear thermocouple should be centered in the bus over the rear axle.
      2. (ii) The independent temperature reading of each temperature probe inside the bus shall be within a range of plus/minus three degrees Fahrenheit (3˚ F) of the average temperature at the conclusion of the test.

2. (2) High performance.

   1. (A) The installed air conditioning system should cool the interior of the bus from one hundred degrees Fahrenheit (100 ˚F) to seventy degrees Fahrenheit (70˚ F), measured at three (3) points (minimum) located four feet (4’) above the floor on the longitudinal centerline of the bus.

   2. (B) The three (3) required points shall be:

      1. (i) Three feet (3’) above the center point of the horizontal driver seat surface;
      2. (ii) At the longitudinal midpoint of the body; and
      3. (iii) Three feet (3’) forward of the rear emergency door or, for Type D rear engine buses, three feet (3’) forward of the end of the aisle.

   3. (C)

      1. (i) The Type A vehicles’ placement of the rear thermocouple should be centered in the bus over the rear axle.
      2. (ii) The independent temperature reading of each temperature probe inside the bus shall be within a range of plus/minus three degrees Fahrenheit (3˚ F) of the average temperature at the conclusion of the test.
      3. (c) Test conditions. The test conditions under which the above performance standards must be achieved shall consist of:
3. (1) Placing the bus in a room (such as a paint booth) where the ambient temperature can be maintained at one hundred degrees Fahrenheit (100˚ F);
4. (2) Heat-soaking the bus at one hundred degrees Fahrenheit (100˚ F) at a point measured two feet (2’) horizontally from the top of the windows on both sides of the bus, with windows open for two (2) hours; and

5. (3) Closing the windows, turning on the air conditioner with the engine running at one thousand two hundred fifty (1,250) plus/minus fifty (50) RPM, and cooling the interior of the bus to eighty degrees Fahrenheit (80˚F), (standard performance) or seventy degrees Fahrenheit (70˚ F) (high performance), within thirty (30) minutes while maintaining one hundred degrees Fahrenheit (100˚ F) outside temperature.

   1. (d) Other requirements.

6. (1) Evaporator cases, lines and ducting (as equipped) shall be designed in such a manner that all condensation is effectively drained to the exterior of the bus below the floor level:

   1. (A) Under all conditions of vehicle movement; and
   2. (B) Without leakage on any interior portion of the bus.

7. (2)

   1. (A) Evaporators and ducting systems shall be designed and installed to be free of projections or sharp edges.

   2. (B) Ductwork shall be installed so that exposed edges:

      1. (i) Face the front of the bus; and
      2. (ii) Do not present sharp edges.

8. (3)

   1. (A) On school buses equipped with Type-2 seatbelts having anchorages above the windows, the ducting (if used) shall be placed at a height sufficient to not obstruct occupant securement anchorages.
   2. (B) This clearance shall be provided along the entire length (except at evaporator locations) of the passenger area on both sides of the bus interior.
9. (4) The body may be equipped with insulation, including sidewalls, roof, firewall, rear, inside body bows, and plywood or composite floor insulation to reduce thermal transfer.
10. (5) All glass (windshield, service and emergency doors, side and rear windows) may be equipped with maximum integral tinting allowed by federal, state, or American National Standards Institute standards for the respective locations, except that windows rear of the driver’s compartment, if tinted, shall have approximately twenty-eight percent (28%) light transmission.
11. (6) Electrical generating capacity shall be provided to accommodate the additional electrical demands imposed by the air conditioning system.
12. (7) Roofs may be painted white to aid in heat dissipation.
13. (8) Air intake for any evaporator assembly or assemblies except for front evaporator of Type A-1, shall be equipped with a replaceable air filter or filters accessible without disassembly of the evaporator case.
14. (9) For all buses (except Type D rear engine transit) equipped with a rear evaporator assembly, the evaporator shall not encroach upon the head impact zone, but may occupy an area of less than twenty-six and five-tenths inches (26.5”) from the rear wall and fourteen inches (14”) from the ceiling.

15. (10) For Type D rear engine transit buses equipped with a rear evaporator over the davenport, the evaporator assembly may not:

    1. (A) Interfere with the rear exit window; and
    2. (B) Extend above the rear seating row.