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Participant

Join Date: May 2009
Location: India
Posts: 4

# How to Calculate Lux Level for Street Lighting

05/19/2009 6:43 AM

Hello all,

Can somebody guide me how to calculate the lux level for street lights.

Thanks,

Mago

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Power-User

Join Date: Sep 2008
Location: Jakarta, Indonesia
Posts: 105
#1

### Re: How to Calculate Lux Level for Street Lighting

05/19/2009 9:52 AM

1. first, we must know, what is standard lux for street lighting. For example : 50 lux.

2. choose what type of Lamp will be used. whether Mercury Vapor, Metal Halide, Fluorescence.

3. How many Voltage, Wattage for this lamp.

4. How many height of the Lighting Pole.How many angel between lamp & pole (light direction)

5. Eh = IΦ x N x Cos3Φ x MF) / H2

Eh = horizontal lighting intensity level at designated point, lux

IΦ = luminous intensity of lighting fixture in the radiation direction, cd/1000

lumen (from manufacturer's photometric data)

N = lamp lumen output of lighting fixtures, Lumen

H = vertical height of lighting fixture from designated plane, feet

Φ = angle of radiation to the designated point measured against the

perpendicular to the horizontal plane, (tan -1 L/H), degrees

MH = Maintenance Factor

6. or use some software (like calculux, luxicon, chalmlite etc...).

Score 1 for Good Answer
Guru

Join Date: Apr 2007
Location: Latitude 38.701979 Longitude -90.439540 Coordinates 38.701979, -90.439540 N38°42.11874, W090°26.3724
Posts: 639
Good Answers: 15
#5
In reply to #1

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 5:55 AM

When we design parking lots or streets we have the manufacturer/supplier do the photometrics.

By zoning code we are only allowed so much light to reach past the property lines so we provide the site plan and they provide the lighting layouts.

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scotchdrnkr
Anonymous Poster
#8
In reply to #1

### Re: How to Calculate Lux Level for Street Lighting

05/21/2009 8:48 AM

hi,

i have seen the question and your reply,it is really interesting,but can u give some and example for the caluculation,i feel little bit easy to understandable for my side as well as other's.

i hope that u given some example.

Off Topic (Score 5)
Anonymous Poster
#19
In reply to #1

### Re: How to Calculate Lux Level for Street Lighting

05/25/2010 1:23 AM

thank you

Anonymous Poster
#2

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 2:57 AM

Why waste time to calculate while you can measure the lux level by lux meter or some kind of devices

Or maybe the question was wrong, it maybe meant How to design street lighting

Participant

Join Date: May 2009
Location: India
Posts: 4
#3
In reply to #2

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 3:07 AM

I have been given a project where 150W MH lights are used for street lighting.The poles are of 6m height and few of them are 8m height. The pole to pole distance is 15m. Now i need to check if this will give me 20lux as per IS standard. I am not able to do the calculation with different heights.

so please suggest me where i can get the formula to calculate the lux level considering the heights.

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Thanks, Mago
Power-User

Join Date: Nov 2006
Location: Mumbai-57
Posts: 107
Good Answers: 1
#4
In reply to #3

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 3:54 AM

Do you not see it in elect-ok's quote...?

Power-User

Join Date: Sep 2008
Location: Jakarta, Indonesia
Posts: 105
#9
In reply to #2

### Re: How to Calculate Lux Level for Street Lighting

05/22/2009 2:37 AM

yes of course,

if we just want to measure the lux, we enough use Lux-Meter.

regards

Associate

Join Date: Feb 2009
Location: Nova Scotia - Canada
Posts: 32
Good Answers: 1
#6

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 8:26 AM

Stand under the light with a light meter.

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Guru

Join Date: Feb 2007
Location: Next to the Prime Merridian (51°29'34.50"N 0°13'32.85"W)
Posts: 778
Good Answers: 1
#7
In reply to #6

### Re: How to Calculate Lux Level for Street Lighting

05/20/2009 5:13 PM

You're bloody right.

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Participant

Join Date: May 2010
Posts: 1
#18
In reply to #6

### Re: How to Calculate Lux Level for Street Lighting

05/18/2010 8:59 PM

Well as a technical person, you cannot just give a report that is only based on actual reading.. technical data must be made so you can have a good basis to your actual output this also gives you a good defense when someone disagrees with you.. haha just a thought.. :)

Guru

Join Date: Feb 2007
Location: Next to the Prime Merridian (51°29'34.50"N 0°13'32.85"W)
Posts: 778
Good Answers: 1
#10

### Re: How to Calculate Lux Level for Street Lighting

05/22/2009 6:43 AM

Just measure it!

Nothing will give you a more accurate value at any given place than that. It's like trying to determine the exact voltage, current or ohms value without a multi-meter because I cannot, can you?

Using the formulas without knowing at least one factor accurately is impossible to get the value/s right.

Your objective is more complex.

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Anonymous Poster
#11

### Re: How to Calculate Lux Level for Street Lighting

05/22/2009 8:25 PM

In practice, use the published distribution pattern for the lamp/fixture/pole height

combination you will use and try to get the required minimum over the entire area

served with the fewest fixtures practicable.

Participant

Join Date: May 2009
Location: India
Posts: 4
#12

### Re: How to Calculate Lux Level for Street Lighting

05/28/2009 1:54 AM

thanks all,

thank you for your precious replies.

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Thanks, Mago
Anonymous Poster
#13

### Re: How to Calculate Lux Level for Street Lighting

08/14/2009 5:57 AM

Point-by-point method is used to determine the illuminance value at a point on a surface that is illuminated by direct light from a luminaire or luminaries.

For Roadway:- Average Illuminance Calculation Method

Average Luminance = (lamp lumens) x (coefficient of Utilization) x(Light loss factor)/(Spacing between luminaries)x (width of roadway)

Anonymous Poster
#14
In reply to #13

### Re: How to Calculate Lux Level for Street Lighting

10/23/2009 8:40 PM

May i know why the factor of height will not be inside the average luminance formula ? Thanks !

Anonymous Poster
#15

### Re: How to Calculate Lux Level for Street Lighting

01/15/2010 5:49 AM

tHE AVERAGE LUX LEVEL IN street lighting is measured by 9 point method. you make two equal quardents between two light poles. on the lone of light poles( one side pole to road): you have 3 points p1,p2(midpoint) & p3. P1 & P2 being the points under the light pole. then p4 & p7 are points opposite pole 1 at mid of the road & opposite end of the road respectively. like wise p5 & p8 are opposite to the mid point p2 located at mid of the road & opposite side of road to p2. and p6 & p9 are mid point on road & opposite side to pole p3. the formula for avg lux = (p1+p3+p7+p9)/16+(p2+p6+p8+p4)/8+p5/4 Now there is another more accurate method 12 point has come into vouge as the 9 point assume linear distribution of lux which is not the case in reality. som derashri baroda, India

Anonymous Poster
#16
In reply to #15

### Re: How to Calculate Lux Level for Street Lighting

02/01/2010 9:49 PM

You can directly measure the intensity of light using a lux meter. Came across a good model.

http://www.industrialindia.com/catalogs/Digital_Portable_Lux_Meter/Digital-Lux-Meter-HTC-LX104.pdf

Participant

Join Date: Feb 2010
Posts: 1
#17
In reply to #15

### Re: How to Calculate Lux Level for Street Lighting

02/26/2010 10:25 AM

could anybody elobrate 12 point method for Lux calculation with a drawing?I shall be greatful Thanx

Off Topic (Score 5)
Anonymous Poster
#20
In reply to #15

### Re: How to Calculate Lux Level for Street Lighting

05/30/2010 10:27 AM

Hi som,

Cn i get a pictorial explanation fr 12 r 9 point method if two lamp pole is in the middle of the road#

Nagesh

Power-User

Join Date: Feb 2011
Location: Pakistan
Posts: 126
#21
In reply to #20

### Re: How to Calculate Lux Level for Street Lighting

02/03/2011 12:15 PM

Hi! Could you elaborate further on 12 or 9 point method, please? Assume, having five street poles on a road. The pole height is "h" and road width is "w". The first and second poles is having "S" spacing between the two. Let an observer in a car (1.5 m) on the middle of the road is about 60m from the second pole. How to calculate spacing and lux? One could use the above mentioned equation with cubic cosine law or point method? Whatever is easier :)

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Off Topic (Score 5)
Member

Join Date: May 2011
Location: Hyderabad
Posts: 6
#22
In reply to #15

### Re: How to Calculate Lux Level for Street Lighting

05/18/2011 7:10 AM

It was great... Kindly let me know the 12 point method also...

Thanks!

Surya

Member

Join Date: May 2011
Location: Hyderabad
Posts: 6
#23
In reply to #15

### Re: How to Calculate Lux Level for Street Lighting

11/17/2011 2:15 AM

tHE AVERAGE LUX LEVEL IN street lighting is measured by 9 point method. you make two equal quardents between two light poles. on the lone of light poles( one side pole to road): you have 3 points p1,p2(midpoint) & p3. P1 & P2 being the points under the light pole. then p4 & p7 are points opposite pole 1 at mid of the road & opposite end of the road respectively. like wise p5 & p8 are opposite to the mid point p2 located at mid of the road & opposite side of road to p2. and p6 & p9 are mid point on road & opposite side to pole p3. the formula for avg lux = (p1+p3+p7+p9)/16+(p2+p6+p8+p4)/8+p5/4 Now there is another more accurate method 12 point has come into vouge as the 9 point assume linear distribution of lux which is not the case in reality. som derashri baroda, India

---------------------------------------------------

Thank you very much.

But I have some doubts, Why is 16, 8, 4 used in the formula? Is there any derivation for the same?

Also why is P5 considered separate? I am really confused... Kindly give me a detailed idea.

Also I am attaching two images with two representations. Kindly clarify which one is correct, also if possible, kindly state a standard where we can get these data in details.

FIG - 1:

FIG - 2:

Thanks!!!!!!!!!!!!

Surya.

Participant

Join Date: Aug 2013
Posts: 1
#24
In reply to #23

### Re: How to Calculate Lux Level for Street Lighting

08/16/2013 12:00 AM

Figure 1 is correct for formula

avg lux = (p1+p3+p7+p9)/16+(p2+p6+p8+p4)/8+p5/4

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### Users who posted comments:

abasins (1); Anonymous Poster (9); elect-ok (2); Isti80 (2); mago (2); Nachi (1); naresh_varshney (1); polpraning (1); ramman (1); scotchdrnkr (1); suryakumar (2); Tobin HRG (1)

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