QC/T 476-2025Requirements and test methods for rain-proof sealing performance of buses (English PDF)

3.1 Rain proof performance for bus

The ability of a bus to close all doors, windows and opening covers to prevent rainwater from entering the passenger compartment, luggage compartment and other assemblies and components when being sprayed with rainwater.

3.2 Seep

The phenomenon that water slowly emerges from the cracks and spreads around along the inner surface of the vehicle body, but does not fall.

3.3 Leakage

The phenomenon that water appears from cracks, leaves, or falls or flows along the inner surface of the vehicle body.

NOTE: "leakage" includes "drop" and "flow".

3.3.1 Drop

The phenomenon that water appears from the cracks, leaves or falls intermittently along the inner surface of the vehicle body.

3.3.2 Flow

The phenomenon that water appears from the cracks, leaves or falls or flows continuously along the inner mark of the vehicle body.

3.4 Average raining intensity

The ratio of the total volume of water sprayed by each nozzle within a given shower surface per unit time to the total shower area covered by each nozzle within that shower surface.

NOTE: Average raining intensity is measured in millimeters per minute (mm/min).

5.1 Test vehicle

The test vehicle must meet the manufacturer's specified technical requirements. Parts within the vehicle compartment that do not affect the test results may be removed to facilitate testing and inspection.

5.2 Test equipment

5.2.1 Raining simulation device

5.2.1.1 The raining area shall be larger than the vertical projection area of the vehicle under test and shall expose all tested areas, including the front, sides, rear, top, and bottom, to rain evenly.

5.2.1.2 The average raining intensity on each rain-exposed surface (hereinafter referred to as "raining intensity") shall be independently adjustable and controlled to ensure a raining intensity of 12 mm/min ± 1 mm/min on the front and 8 mm/min ± 1 mm/min on the sides, rear, top, and bottom of the vehicle.

5.2.1.3 The structural layout of the raining simulation device is provided in Appendix A.

5.2.2 Vehicle washing simulation equipment

IPX5 hose nozzles specified in GB/T 4208-2017 shall be used. The spray water flow rate during simulating vehicle washing shall be controlled within 12.5 L/min ± 0.5 L/min.

5.2.3 Equipment verification

The nozzles and pipeline of the raining simulation device and vehicle washing simulation device shall be cleaned regularly and verified in accordance with the provisions in Appendix B.

6.1 Raining simulation test

6.1.1 Before the test begins, confirm that the electrical system is fault-free and the vehicle's historical fault codes have been cleared.

6.1.2 Park the test vehicle in a designated location within the rain-proof area. Set the parking brake at the brake state, and the engine to idle (or powered on for electric buses). Start the air conditioning fan in external circulation mode and adjust the fan speed to the highest setting. The test personnel enter the passenger compartment and close all doors, windows, and opening covers.

6.1.3 Start the raining simulation device and adjust the rainfall intensity on each raining surface to the conditions specified in 5.2.1.2 using the flow control valve. After the rain stabilizes, start the wipers to the appropriate position; turn on the high beam and fog lights, and begin the test. The test duration is 15 min.

6.1.4 During the test, observe and record any leakage (e.g., seep, drop, or flow) in the passenger compartment, luggage compartment, and equipment compartment. Water accumulation along the passenger door seals and gaps at the lower edge of the passenger door onto the vehicle floor and steps during the test shall not be counted as leakage. For leakage in the luggage compartment and equipment compartment, after the rain stops, wipe away any accumulated water at the hatch joints before opening the hatch for inspection. Alternatively, use an endoscope or other auxiliary tool to conduct an inspection during the simulated rain.

6.2 Vehicle washing simulation test

6.2.1 A vehicle washing simulation test (any water stains or accumulated water in the passenger compartment and luggage compartment shall be wiped clean before the test) shall be performed as soon as possible after the raining simulation test.

6.2.2 Turn off the engine (for electric buses, power off), air conditioning fan, lighting device, and wipers.

6.2.3 Start the vehicle washing simulation device, and adjust the water flow rate to the setting specified in 5.2.2. Aim the hose nozzle at all doors (excluding sliding, folding, and inward-swinging doors), windows, opening covers, and joints between various components of the bus, spraying twice in a reciprocating motion. During spraying, the nozzle outlet shall be 300 mm to 500 mm from the joint, with the nozzle axis approximately perpendicular to the plane of the vehicle body along which the joint line is located. The nozzle movement speed shall be 0.1 m/s to 0.5 m/s.

6.2.4 During the test, observe and record any leakage (e.g., seep, drop, and flow) in the passenger compartment, luggage compartment, and equipment compartment. During the test, water that accumulates along the passenger door seals and gaps at the lower edge of the passenger door and flows into the interior floor and steps shall not be counted as leakage. For leakage in the luggage compartment and equipment compartment, wipe away any accumulated water from the hatch joints before opening the hatch for inspection when the vehicle washing simulation stops. Alternatively, use an endoscope or other auxiliary tool during the simulated vehicle washing.

6.2.5 After the vehicle washing simulation test, inspect whether the lighting device accumulates water.

6.2.6 For pure electric buses and hybrid electric buses, conduct entire vehicle insulation resistance measurements in accordance with 6.2.1 of GB 18384-2020 within 30 min of the vehicle washing simulation test.