Measurement of LUX Level and Uniformity at Indoor and Outdoor Lighting (Part-2)

(3) AS per Deutsch Norm DIN 5035

• In this Method the working plane divide into a number of sections which are at least rectangular, of ratio of length to side not less than 1: 2 but which are preferably of square shape.
• A square grid of minimum size 1 meter is established within each section with a measurement point at the centre of each square.
• The grid module defining the measurement points is selected so as not to coincide with the luminaire grid in either principal direction.
• In exceptionally large interiors the grid size may be up to 5 meters. there is not any mention of accuracy limits of the method, but this is not surprising given the flexibility which the user of the method is allowed in choice of grid size.
• The DIN system is the only one of the three methods studied to give any advice concerning illuminance measurements in obstructed interiors. Areas of the working plane located between large obstructions are treated for measurement purposes as separate spaces.

(1) Nine Point Method for Determining Lux Levels in Street Lighting

•  The Lux Level of Street Light is measured by 9-point method.
• We need to make two equal quadrants between two light poles and between Pole and Rode edge.
• Two Measuring Points below Light Pole (A1,A2)  and Two opposite side of Pole at Road Edge (A3,A4).
• Two Point between Pole and Road edge (B1,B3).
• One Point Between Pole  (B2) and on One Point between opposite side of Pole at road edge (B4)
• One Point is at centre (C1).
• Average Lux = (A1+A2+A3+A4)/16 + (B1+B2+B3+B4)/8 +C1/4

• Solution
 26 Lux 27 Lux 13 Lux 12 Lux 15 Lux 14 Lux 26 Lux 32 Lux 22 Lux
• Average Lux = (A1+A2+A3+A4)/16 + (B1+B2+B3+B4)/8 +C1/4
• Average Lux = (26+26+13+22)/16 + (12+27+14+32)/8 +15/4
• Average Lux =20Lux
 MIN 12 Lux MAX 32 Lux AVG 20 Lux U1=MIN/AVG 0.58 U2=MIN/MAX 0.38

(2) As per Grid Point Set Up Measurement

• Identify a horizontal grid of measurement points on the Illumination Measurement site surface. Locate measurement points on gridlines covering the test measurement area.
• Ensure that the spacing between measurement points is uniform in both directions and is less than one-half the pole height or less than 4.5 Meter, whichever is smaller.
• For installations with lights spaced less than 4.5 Meter apart, locate measurement points no farther apart that one-half the pole height, with at least three points between poles in both directions.
• Record the location of all measurement grids and point layouts with dimensions from surrounding poles or other structures. Provide this information, including a sketch or rendering of the grid layouts.
• For open areas such as main parking, make the measurement grid large enough to cover at least four poles of this Area layout and at least two Pole are covered.
• For site perimeter open areas or areas adjacent to a building edge establish the test area measurement grid in a typical perimeter or building edge area. The depth of the test area should extend from the paved site boundary or building edge inward to the nearest line of light poles that are at least 4.5 Meter from the boundary or building edge.
• The width of the test area must cover at least two of the poles in the line that is at least 4.5 Meter from the boundary or building edge.