92 Ill. Adm. Code 442.245
Heaters
Section 442
Section 442.245 Heaters
a) An inside temperature of not less than 50 degrees Fahrenheit
at average minimum January temperature as established by the U.S. Department of
Commerce, National Weather Service Office, for the area in which the vehicle is
to be operated shall be maintained throughout the bus.
b) The primary heater shall be a high output, fresh air type.
c) The secondary heater may be recirculating type, and located so
as not to interfere with aisle space. Each secondary heater shall display a
nameplate that identifies the manufacturer and the heater capacity rating.
d) The heater hoses shall be adequately supported to guard
against excessive wear due to vibration and shall not interfere with or
restrict the operation of any engine function. Any hose in the passenger
compartment shall be adequately protected to prevent injury from burns in the
event of rupture.
e) Auxiliary
fuel-fired heating systems are permitted provided they comply with the
following:
1) The
auxiliary heating system fuel shall utilize the same type of fuel as specified
for the vehicle engine;
2) The
heater or heaters may be direct hot air or connected to the engine's coolant
system;
3) An
auxiliary heating system, when connected to the engine's coolant system, may be
used to preheat the engine coolant or preheat and add supplementary heat to the
bus' heating system;
4) Auxiliary
heating systems must be installed pursuant to the manufacturer's
recommendations and shall not direct exhaust in a manner that will endanger bus
passengers (e.g., under windows);
5) Auxiliary
heating systems that operate on diesel fuel shall be capable of operating on:
A) a hot
water and/or combustion type heater; or
B) if
only one heater is used, a fresh-air or combination fresh-air and recirculation
type heater; or
C) blended
diesel fuel without the need for system adjustment.
6) The auxiliary heating
system shall be low voltage.