LABORATORY EXERCISE ON LIGHT MONITORING
I. Introduction
II. ObjectiveS
At the end of the session each student should be able:
1. To conduct illumination measurements
2. To analyze and interpret the results obtained
3. To give recommendations based on findings
III. Equipment and materials
1. Light meter, Extech Model EA30
IV. Methodology
A. Use of the Instrument
1. Make sure that the protective cap is on the white domed light sensor. Press the orange power button to turn power on. The meter will automatically perform a zero calibration.
2. Select the desired unit of measure (Lux or Fc). Select LUX for this experiment.
3. Remove the protective cap from the sensor and place the white domed light sensor on the surface (i.e. counter top) you would like to monitor. The light being measured must encompass the entire white sensor dome. NOTE: Do not block the light source while reading the display.
4. Read the light level on the LCD. If the light measurement is out of range, an “OL” indication will appear on the display. If the “OL” appears, select another range by pressing the RANGE button.
5. Take note of the illumination level measurements (minimum and maximum).
a. Press the MX/MN button 3 times to have the meter continue to record the highest and lowest readings (MX and MN icons is displayed on the upper left-hand portion of the LCD).
b. Press the MX/MN button once to put the meter in MX mode to display only the maximum reading (MX is displayed).
c. Press the MX/MN button again to put the meter in MN mode to display only the minimum reading (MN is displayed).
d. To exit the MX MN mode, press and hold the MX/MN button until the MX and/or MN icons disappear.
6. Press the orange power button to turn power off.
B. Illumination Monitoring
Sampling location: Laboratory
1. Perform a brief walk-through of the areas for monitoring.
2. Draw a layout of the area to be monitored.
3. Discuss and determine the location of sampling points. Measure at least 15 sampling points. Prioritize the working surfaces that are likely to be used by the lab user.
4. Perform actual illumination measurement using the light meter. Obtain the illumination levels in lux unit and slow response time.
5. Record data obtained from the monitoring and develop an illumination map.
V. Points For discussion
Note: Please use complete sentences when addressing the questions below for your discussion.
1. Describe the illumination levels in the area monitored (i.e. where the lowest and highest lighting occurs, source of lighting, etc.)
2. Are the illumination levels measured acceptable? What recommended illumination level/s did you compare your results with? Explain why you chose those levels.
3. What control measures do you recommend?
VI. RECOMMENDED ILLUMINATION LEVELS
| Activity | Illumination (lux) |
| Public areas with dark surroundings | 20 – 50 |
| Simple orientation for short visits | 50 – 100 |
| Working areas where visual tasks are only occasionally performed | 100 – 200 |
| Performance of visual tasks of high contrast or large size | 200 – 500 |
| Performance of visual tasks of medium contrast or small size | 500 – 1000 |
| Performance of visual tasks of low contrast or very small size | 1000 – 2000 |
| Performance of visual tasks of low contrast and very small size for prolonged periods of time | 2,000 – 5,000 |
| Performance of very prolonged and exacting visual tasks | 5,000 – 10,000 |
| Performance of very special visual tasks of extremely low contrast and small size | 10,000 – 20,000 |
| Activity | Minimum Illumination (lux) |
| Warehouses, homes, theaters, archives | 150 |
| Easy office work, classes | 250 |
| Normal office work, PC work, study library, groceries, show rooms, laboratories | 500 |
| Supermarkets, mechanical workshops, office landscapes | 750 |
| Normal drawing work, detailed mechanical workshops, operation theaters | 1,000 |
| Detailed drawing work, very detailed mechanical works | 1,500 – 2,000 |
VII. CONCLUSION
ILLUMINATION mAP Illumination Monitoring Worksheet
Date of Monitoring: ___________________________________________
Instrument Used: ____________________________________________
EHST 3701: Laboratory Exercise on Noise Monitoring Page 1
EHST 3701: Laboratory Exercise on Light Monitoring Page 5
