Loading...
Typhoon conditions place additional pressure on bus air-conditioning systems through heavy rainfall, strong winds, high humidity, flooding and sudden temperature changes.
For operators and maintenance teams, correct system use and structured inspections before and after severe weather can reduce the risk of water ingress, electrical damage, corrosion, blocked drainage and service disruption.
During periods of heavy rain, recirculation mode can help reduce the amount of humid outside air entering the passenger compartment.
However, recirculation should not be used continuously on long journeys. In a fully occupied bus, prolonged recirculation can increase carbon dioxide levels, reduce air quality and contribute to window fogging.
Operators should balance recirculation with controlled ventilation according to passenger load, visibility and the vehicle’s HVAC configuration.
High humidity can cause rapid window fogging, creating a direct safety risk.
Recommended actions include:
The correct settings will depend on the vehicle layout and the design of the HVAC and demisting systems.
If a bus has been exposed to floodwater, or if the HVAC unit, high-voltage components or electrical connections may have been submerged, the system should not be restarted.
A qualified technician should inspect the equipment before operation resumes. This should include checks for:
For electric buses, high-voltage HVAC components require particular attention.
Roof-mounted HVAC systems should be checked for damaged seals, loose joints and deteriorated mounting interfaces.
Maintenance teams should inspect:
Any signs of ageing, deformation or separation should be addressed before severe weather arrives.
Drainage performance is critical during periods of sustained rainfall.
Drain holes, pipes and collection trays should be cleared of dirt, leaves and other debris. Blocked drainage can lead to water accumulation inside the unit or leakage into the cabin.
Teams should also verify that drain hoses are correctly positioned and that water can leave the system without flowing toward electrical components.
Strong winds can damage poorly secured covers, grilles and rooftop components.
Before a storm, operators should confirm that:
After severe weather, the HVAC system should be visually inspected before it is switched on.
Any signs of standing water, damaged panels, loose components, unusual odours or visible electrical exposure should trigger a more detailed technical inspection.
Ventilation mode should only be used to dry the system after technicians have confirmed that the unit is electrically safe and free from significant water ingress.
Leaves, dust, mud and other debris can block condenser and evaporator surfaces.
Cleaning should focus on:
Restricted airflow can reduce cooling capacity and increase system load.
Humidity and water ingress can affect compressors, fans, control panels, sensors, wiring harnesses and connectors.
Technicians should check:
The system should only return to service once the relevant safety checks have been completed.
Operators in typhoon-prone regions should integrate severe-weather preparation into their regular maintenance programmes.
Recommended actions include:
When selecting HVAC systems for regions exposed to typhoons or heavy seasonal rainfall, operators and OEMs should evaluate:
Claims relating to waterproofing or harsh-weather performance should be supported by relevant test standards and application data.
Typhoon conditions require a combination of correct operation, preventive inspection and controlled restart procedures.
The most important priorities are maintaining drainage, protecting electrical systems, preserving driver visibility and avoiding restart after suspected flooding until the system has been inspected.
A structured severe-weather maintenance plan can help operators reduce avoidable failures and protect both vehicle availability and passenger comfort.
