24:06:07:04Heating and air conditioning systems.

A school bus must contain a heating system installed in accordance with the section entitled "Heating and Air Conditioning Systems" on pages 53 to 57, inclusive, of the National School Transportation Specifications & Procedures, May 2025 Revised Edition. If an air conditioning system is installed on a school bus, it must be installed in accordance with these standards. In addition, the following standards apply to each school bus type: (1) The minimum installation for a Type A bus, as defined on page 407 of the National School Transportation Specifications & Procedures, May 2025 Revised Edition (NSTSP), is one front fresh air heater, utilizing the manufacturer's standard heater with a defroster core and a driver's deflector, and one or more rear recirculating underseat heaters with a minimum of 38,000 BTUs; (2) The minimum installation for a Type B and C bus, as defined on page 407 of the NSTSP, is one left front fresh air heater with a defroster core and a driver's deflector with a minimum of 80,000 BTUs, one right cowl recirculating heater with a minimum of 50,000 BTUs; and (a) If the bus has a capacity of less than fifty-nine passengers, a rear underseat recirculating heater with a minimum of 75,000 BTUs; or (b) If the bus has a capacity of fifty-nine or more passengers, two rear underseat recirculating heaters, or a combination of one midship heater and one rear recirculating heater. Each heater must have a minimum of 75,000 BTUs; and (3) The minimum installation for a type D bus, as defined on page 408 of the NSTSP, is one front fresh air heater with a defroster core and a minimum of 80,000 BTUs, a driver's underseat heater with a minimum of 14,000 BTUs, and (a) If the bus has a capacity of less than fifty-nine passengers, a rear underseat recirculating heater with a minimum of 75,000 BTUs; or (b) If the bus has a capacity of fifty-nine or more passengers, two rear underseat recirculating heaters, or a combination of one midship heater and one rear recirculating heater. Each heater must have a minimum of 75,000 BTUs.

Source: 22 SDR 61, effective November 9, 1995; 30 SDR 181, effective May 20, 2004; 33 SDR 152, effective April 5, 2007; 38 SDR 58, effective October 17, 2011; 44 SDR 43, effective September 13, 2017; 53 SDR 22, effective September 8, 2026.