Testing basis

"Highway Tunnel Ventilation and Lighting Design Specification" JTJ026·1-1999

"Highway Tunnel Design Specification" JTG D70－2004 3. Testing method

3.1 Turn on the light source to be tested as needed, and exclude the influence of other irrelevant light sources.

3.2 When measuring, the illuminance meter first uses a large range of gears, and then gradually finds a suitable gear according to the size of the indicated value. In principle, the indicated value is not allowed to read within the range of 1/10 of the maximum range.

3.3 Read the illuminance after the indication value is stable. The last digit of the digital illuminance meter is sometimes unstable, and the number that appears the most times should be recorded.

3.4 In order to improve the accuracy of the measurement, 2-3 readings can be taken at each measuring point, and then the average value is taken. 4. On-site records

4.1 The measurement results should be recorded in a pre-prepared form;

4.2 Contents of measurement records

(1) Measurement date, time, climate conditions, and name of the measurement personnel;

(2) Measurement location;

(3) Model and specifications of light sources and lamps;

(4) Installation method, spacing, height, etc. of lamps;

(5) On-site measurement conditions (environmental conditions, power supply conditions);

(6) Use time of light sources and lamps, and the last cleaning time;

(7) Layout diagram of illuminance measurement points with dimensions;

(8) Illuminance measurement values of each measurement point;

(9) Average illuminance and illuminance average calculation results;

(10) Model, number, and identification date of illuminance meter.

5. Calculation of average illumination and uniformity

5.1 Average illumination

The average value of all measuring points in the measurement area is the average illumination of the area

5.2 Uniformity

The ratio of the minimum illumination of the measurement area to the average illumination of the area is the total uniformity of illumination in the area

U0=Lmin/Lav

The ratio of the minimum brightness of the measurement area to the average brightness of the area is the total uniformity of the road surface brightness in the area

U1=Lmin/Lmax

Ratio of the minimum brightness of the center line to the maximum brightness of the center line

5.3 Conversion of brightness and illumination

L=E/C

E: Illuminance C: C=13 for concrete pavement, C=22 for asphalt pavement

6 Precautions

6.1 Tunnels less than 200m long have no intermediate lighting

6.2 When measuring, wait until the light output of the light source is stable before measuring. Therefore, before the measurement begins, the incandescent lamp should be turned on 5 minutes in advance; the fluorescent lamp should be turned on 15 minutes in advance; the high-intensity gas discharge lamp should be turned on 30 minutes in advance; for newly installed lighting systems, the measurement should also be carried out after burning for 100 hours (fluorescent lamp) and 10 hours (incandescent lamp).

6.3 The measurement personnel should wear dark clothing to prevent the shadows of the measurement personnel and onlookers from affecting the receiver.

6.4 During the measurement, the power supply voltage should be kept stable and the measurement should be maintained at the rated voltage. If this is not possible, the power supply voltage should be measured, and when it does not match the rated voltage, the luminous flux should be corrected according to the voltage deviation.