the impact of cie 140 on streetlighting in south africa

THE IMPACT OF CIE 140 ON STREETLIGHTING IN SOUTH AFRICA

AMEU CONVENTION: DURBAN: 14-17 OCTOBER 2007

AUTHOR:-

MURRAY CRONJE, BEKA (PTY) LTD

The CIE 140..., what for ?

To update and replace CIE 30.2 (1982),

Calculation and measurements of illuminance and

luminance in road lighting

It gives the methods which CIE 115 (1995) and

CIE 136 (2000) require for their recommendations

Was there a real need to update

CIE 30.2?

YES

CIE 30.2 came out just after the luminance concept was

accepted: there was very little experience with it.

And this is the CIE 140 major improvement: all the

things that experience has revealed during the past 20

years.

What are the most significant changes ?

Road surfaces characteristics are not dealt with any more

in this document

Luminous intensity data for luminaires are reviewed:

shorter angular intervals for I-tables

Interpolation methods for I-tables and r-tables are

reviewed and more completely developed

Calculation grids for both luminance and illuminance are

changed

New observer for TI

10° and 15° steps

10° and 15° steps

5° steps

5° steps2.5° steps

2.5° steps10 and 5° steps

Values of luminous intensities are required over the range of angular intervals

1° steps

Calculations will be more accurate, because we have more detailed information.

Interpolation of luminous intensity data

Linear Interpolation

C C Cm m+1

j+1

j

In the case of I, where we have measured values

in shorter angular intervals.

C C Cm m+2

j+1

j

j+2

Cm+1

Quadratic Interpolation

In the case of I, where we have measured

values in wider angular intervals.

S

D

D5m, N=10D=S/N

CIE 30.2

S

D

D/2

D3m, N=10D=S/N

CIE 140

For Luminance calculation

Before S = 50 m. Now S = 30 m.

D/2

For luminance calculations

x

x

x

x x xx x xx x x

Wl d =Wl/3

d /2

x

x

x

x x xx x xx x x

Before S = 50 m. Now S = 30 m.

d/2

For illuminance calculations

Wr/3

Wr standing for “Width of relevant area”

For Luminance calculation

W

W/4 Wt/2

WtWt/2

h=1,5m

60m

CIE 30.2 CIE 140

o : observer for Lave and Uo

x : observer for UL

ooo

oo

o

oo

The Lave

and U o re

tained are

the lowest

ones of th

e

three la

nes

TI Calculation

(%)28.0

aveL

EkTI

Before, k = 650

Now we do take the observer age into account

4

4.661641

Agek

TI calculations

2,75 (H-1,5m)

Before - only one observer position for TI calculations

Now - observer in the initial position and repeated with the observer moved forwards in increments which are the same in number and distance as are used for the longitudinal spacing D of luminance calculation points.

Example

- highway - 3 traffic lanes (Wt=3,5m), central reservation (5.5m)

- class A1 (SANS10098-1), Lav(2cd/m2), Uo(40%), Ul(70%), TI (15%)

- central pole position, H=13m, overhang 0m

- class R3, Qo=0,07

- BEKASTRADA SUPRA 400W HPS/T

l

v

l

l(m)

v(m)

2.5m

0.5m

57m

Results

S L Uo Ul TI E Uoe

CIE 30.2

60 2.28 40.2 79.4 12.2 27.6 0.42

CIE 140 57 2.82 40.1 82.4 11.8 34.1 0.46

2.59 40.0 77.7

2.33 42.0 79.9

Practical implications

• No more SABS 098 program for street lighting calculations

• Slightly shorter spacings• No more encrypted data• SABS to change their measurement methods• Municipalities to change their specifications to

exclude references to ;-• Data on 3.5 inch diskettes• Encrypted data• Designs to be done with SABS 098 program

Conclusion

• RSA now in line with the rest of the world

• Street lighting calculations now more accurate ensuring greater safety for motorists

• Users and suppliers now have a choice of which software to use

Thank you for your attention !