1 Subject Content and Application Scope
This standard specifies dust proof performance test method for buses which is intended to check the dust proof performance of bus body.
This standard is applicable to various buses. Other vehicles with closed compartment may use for reference.
2 Test Conditions
2.1 The test bus shall be technically in good condition and be subjected to all the tests under no-load conditions.
2.2 Road conditions
2.2.1 The test road shall be dry and dusty earth road or gravel road.
2.2.2 The length of road shall not be less than 10km.
2.3 Meteorological conditions
Rainless and an air velocity less than 1.5m/s. Where the air velocity is larger than 1.5 m/s but less than 3m/s, the included angle between the wind direction and running direction shall not be larger than 30°.
3 Test Preparations
3.1 Apparatus
Prior to the test, the test apparatus shall be checked and calibrated as specified.
a. Dust sampler;
b. Aerovane;
c. Thermometer;
d. Hygrometer;
e. Balance (with the minimum division of 0.1mg);
f. Stopwatch;
g. Desiccator;
h. Filter paper (filtration efficiency ≥ 99%).
3.2 Vehicle preparations
3.2.1 Preparation of sample vehicle
Prior to the test, flush both the inside and outside of the sample vehicle with water and leave it dried in air, and then shut down the doors, windows and openings to keep the compartment interior clean.
3.2.2 Preparation of dust agitating vehicle
The vehicle of the same model of the tested vehicle or of approximate length shall be selected as the dust agitator.
3.3 Preparation of filter paper
Filter paper of the same model, specification and producer shall be adopted for each test. The filter paper to be used must be kept in desiccator to dry for more than 6h. An adequate quantity of filter paper to be used in the tests shall be weighed piece by piece and placed in numbered boxes before use.
4 Test Method
4.1 Mounting of sampling probe
The mounting work is carried out at the starting point of the test road. For bus less than or equal to 10m long, the inside sampling probes, totally two, are located at the first and last quartiles of the bus length in the reference plane Y of three-dimension coordinates. For bus longer than 10m, the inside sampling probes, totally three, are located at the first, middle and last sextiles of the bus length in the reference plane Y. The height to floor H: 800mm for microbus, 1000mm for light bus and 1200mm for large and extra buses, with the air intakes upwards. One outside sampling probe is located in the same section and at the same height with the front inside sampling probe, 200mm from the bus outside, on both the left and right sides, with the air intake forwards (see Figures 1 and 2).
Figure 1 Sampling Arrangement for Bus Less than or Equal to 10m Long
Key:
—mounting position of inside sampling probe;
—mounting position of outside sampling probe.
Figure 2 Sampling Arrangement for Bus Longer than 10m
Key:
—mounting position of inside sampling probe;
—mounting position of outside sampling probe.
4.2 Measurement of background dust concentration inside bus
Before the measurement, remove dust from inside the compartment with suction cleaner, damp duster or mop and keep the doors, windows and openings closed. Turn on the dust sampler for sampling after the bus inside gets dry thoroughly. The sampling position is the front inside sampling probe. Sample at the flow rate of 20 L/min for a period of 15 min. Place the sampled filter paper carefully back to the original numbered box.
4.3 To commence the test, the dust sampler shall be turned on and have the flow regulated correctly before starting the test bus. The test bus runs at 30 km/h following the dust agitator for 15min consecutively. The driver shall deliberately chase dust so that the complete bus is running in a surrounding of agitated dust.
Where the sampling flow is 20L/min, the external dust concentration shall not be less than 100 mg/m3. Where the external dust concentration is greater than 300mg/m3, the sampling flow is allowed to be reduced to 15L/min.
To end the test, the bus shall be stopped, the dust sampler turned off and the sampled filter paper carefully put back to the original numbered box.
4.4 Return test, see 4.2 and 4.3 for the process.
4.5 Drying and weighing of filter paper
The sampled filter paper is kept in desiccator for at least 6h before weighing. The weighed results are incorporated in the test record.
1 Subject Content and Application Scope
2 Test Conditions
3 Test Preparations
4 Test Method
5 Calculation of Test Result
Additional Explanation:
