EMERGENCY EXIT ALARMS All emergency exit alarms shall be connected to the accessory side of ignition switch. HEATER/DEFROSTER
The heater shall be hot water.
If only one (1) heater is used, it shall be fresh-air or combination fresh-air and re- circulation type.
If more than one (1) heater is used, additional heaters may be re-circulating air type.
The heating system shall be capable of maintaining bus interior temperatures as specified in SAE test procedure J2233.
All forced air heaters installed by body manufacturers shall bear a nameplate that indicates the heater rating in accordance with SBMTC-001. The plate shall be affixed by the heater manufacturer and shall constitute certification that the heater performance is as shown on the plate.
Heater hoses shall be adequately supported to guard against excessive wear due to vibration. The hoses shall not dangle or rub against the chassis or any sharp edges and shall not interfere with or restrict the operation of any engine function. Heater hoses shall meet or exceed SAE 20R3. Heater lines on the interior of bus shall be shielded to prevent scalding of driver or passengers.
Each hot water system installed by a body manufacturer shall include one ¼ turn ball-cock shut-off valve in the pressure line and one ¼ turn ball-cock shut-off valve in the return line with both valves at the engine in an accessible location, except that on all Type A buses, the valves may be installed in another accessible location.
There shall be a water flow regulating valve or other regulating device installed in the pressure line for convenient operation by the driver while seated in the driver’s seat. A ¼ turn ball-cock type coolant flow regulating valve for the heater shall be installed so that its control is accessible to the driver, but in such a location as to discourage tampering by students. This valve may be remotely located if a suitable remote control system is used.
Accessible bleeder valves shall be installed in an appropriate place in the return lines of body company-installed heaters to remove air from the heater lines.
Access panels shall be provided to make heater motors, cores and fans readily accessible for service. An outside access panel may be provided for the driver’s heater.
Defrosting equipment shall keep the windshield, the window to the left of the driver, and the glass in the service door clear of frost, and snow, using heat from the heater and circulation from fans. All defrosting equipment shall meet the requirements of FMVSS No 103. Any circulating fan installed on the curbside of the bus front shall be mounted on the windshield header to protect the fingers, hair, and clothing of entering and departing passengers.
Note to above requirements: Type A buses shall have a fresh air type heater and defroster system as installed by the chassis manufacturer.