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: http://star.arm.ac.uk/~csj/essays/lmagill/survey.htm
Дата изменения: Unknown Дата индексирования: Tue Oct 2 07:57:47 2012 Кодировка: Поисковые слова: р п р п р п р р п п р п п р п п р п п р п п р п п р п п р п п р п п р п п р п |
Survey of Armagh
A survey of Armagh was to be carried out in order to better determine how much money is wasted each year in Armagh on bad lighting. To do this a code for different lights had to be made, to facilitate the survey. This code is shown in the table below:
Lighting for Signs (Sg) |
Streetlights (St) |
Floodlighting (Fl) |
Foot Path Lights (Fp) |
Security Lights (Sc) |
Petrol Station Lights (Ps) |
|
1 |
Up Lights |
Full Cut-Off |
Bad Up Light |
Circular Cut-Offs |
Bad Box |
Bad |
2 |
Down Lights |
Semi Cut-Off |
Good Up Light |
Antique Low Bulb |
Desk |
Good |
3 |
Square |
Bad Down Light |
Bad Standard |
|||
4 |
Cobra-Head |
Good Down Light |
Bad Conical |
|||
5 |
Long LPS |
Glare Buster |
||||
6 |
Antique, High Bulb |
To clarify this code photographs were produced to show the lights.
Up-Lights (Sg1)-
Down-Lights (Sg2)-
Fully Cut-Off
(St1)-
Semi Cut-Off
(St2)-
‘Square’ Light (St3)-
Cobra Head Fixture (St4)-
Long Low Pressure Sodium Fixture (St5)-
‘Antique’ Lights (St6)-
Badly Directed Up-Lighting (Fl1)-
Well Directed Up-Lighting (Fl2)-
Badly Directed Down-Lighting (Fl3)-
Well Directed Down-Lighting (FL4)-
Circular Cut-Off (Fp1)-
Antique Low Bulb (Fp2)-
Bad Box Light (Sc1)-
‘Desk’ type (Sc2)-
Bad ‘Standard’ Light (Sc3)-
Bad Conical (Sc4)-
Good Standard
(Sc5)-
Bad Lights (Ps1)-
Good Lights (Ps2)-
Next, a route had to be planned which could be followed. A map of Armagh is shown below. The route taken went down College Hill, right on Lonsdale Road, back down Railway Street, then right onto Cathedral Road. A sharp left was taken onto Callan Bridge Road, which turned into Nursery Road then into Friary Road. A left ws taken onto Barrack Street, then another left onto the Mall West, back to the beginning.
A tally was made of the different lights on each street, shown in this table:
College Hill |
Lonsdale Rd |
Railway St |
Cathedral Rd |
Callan Bridge Rd |
Nursery Rd |
Friary Rd |
Barrack St |
Mall West |
|
Sg1 |
1 |
3 |
4 |
7 |
|||||
Sg2 |
2 |
1 |
2 |
9 |
4 |
||||
St1 |
|||||||||
St2 |
3 |
4 |
5 |
12 |
|||||
St3 |
23 |
5 |
8 |
7 |
15 |
2 |
5 |
2 |
2 |
St4 |
5 |
4 |
10 |
8 |
2 |
1 |
|||
St5 |
3 |
1 |
1 |
3 |
26 |
||||
St6 |
8 |
2 |
6 |
||||||
Fl2 |
|||||||||
Fl3 |
2 |
2 |
16 |
2 |
7 |
||||
Fl4 |
23 |
||||||||
Fp1 |
1 |
3 |
1 |
2 |
|||||
Fp2 |
3 |
3 |
10 |
2 |
32 |
||||
Sc1 |
|||||||||
Sc2 |
|||||||||
Sc3 |
1 |
||||||||
Sc4 |
|||||||||
Sc5 |
|||||||||
Ps1 |
6 |
14 |
|||||||
Ps2 |
This information allowed more accurate estimates to be made of how much light is wasted in Armagh, and therefore how much money and coal is wasted, as well as how much carbon dioxide produced. This information was calculated using spreadsheets, seen below.
College Hill |
Lonsdale Rd |
Railway St |
Cathedral Rd |
Callan Bridge Rd |
Nursery Rd |
Friary Rd |
Barrack St |
Mall West |
|
Total No. Lights |
42 |
20 |
23 |
59 |
46 |
27 |
72 |
20 |
27 |
Distance (m) |
950 |
340 |
210 |
1100 |
340 |
480 |
1000 |
200 |
500 |
Lights per metre |
0.04 |
0.06 |
0.11 |
0.05 |
0.14 |
0.06 |
0.07 |
0.10 |
0.05 |
No. Streetlights |
31 |
15 |
15 |
24 |
28 |
7 |
32 |
7 |
14 |
Streetlights per metre |
0.03 |
0.04 |
0.07 |
0.02 |
0.08 |
0.01 |
0.03 |
0.04 |
0.03 |
It can be seen that some streets have many more streetlights than necessary. Callan Bridge Road, which is located outside the town, and not a busy road has 0.08 streetlights per metre. Compare this to the main road into Armagh, College Hill, which has only 0.03 streetlights per metre. Surely there are more lights than necessary in these areas of high lighting.
The spreadsheet below shows the estimates for the loss of money, useage of coal and production of carbon dioxide for Armagh, N. Ireland and UK. Assumptions made in the table were based on figures from the Roads Service, Department of Regional Development.
Let |
N |
denote the number of streetlights |
|||||||||
P |
denote the average wattage per light |
||||||||||
G |
denote the average wattage lost per light in gear losses |
||||||||||
H |
denote the number of hours of operation per year |
||||||||||
W |
denote the average percentage of light wasted per luminaire, wasted meaning ineffective lighting (up, to the sides etc.) |
||||||||||
c |
denote the cost of electricity consumed per "unit", i.e. cost (in pence) per kW-hour |
||||||||||
C |
denote the annual cost of wasted electricity |
||||||||||
Then the total amount of energy consumed per year is: |
|||||||||||
L = N*(P+G)*H |
and a percentage W of this is "Light Waste" |
||||||||||
Area and/or Region |
N |
P |
G |
H |
W |
L |
L_Wasted |
c |
C |
||
(W) |
(W) |
(hours/yr) |
(%) |
(GW-hours/yr) |
(GW-hours/yr) |
(p/kWh) |
(ё/yr) |
||||
Total UK Streetlighting |
6,200,000 |
80 |
10 |
4100 |
30 |
2287.80 |
686.34 |
9.85 |
67,604,490 |
||
Total for Northern Ireland |
250,000 |
80 |
10 |
4100 |
30 |
92.25 |
27.68 |
9.85 |
2,725,988 |
||
Total for Armagh |
7,077 |
80 |
10 |
4100 |
30 |
2.61 |
0.78 |
9.85 |
77,167 |
||
So, assuming a growth rate of |
2.5 |
percent per year, the total cost of wasted light over a total of |
10 |
years is: |
757,398,911 |
UK |
|||||
30,540,279 |
NI |
||||||||||
864,534 |
Armagh |
As can be seen from the above spreadsheets over ё75,000 per annum is being wasted in Armagh, enough to pay the salaries of 5 staff nurses. In the UK it would be enough money to employ about 4500 nurses, more than half the national shortfall.
There are many other uses this money could be put to, which would be far better than continuing to use dated, poorly designed lighting. If these lights were replaced with full cut-off fixtures no light would be lost and the improvements would pay for themselves within about 2 years. If, however Armagh continues to install streetlights in the way it has been doing the money lost in 10 years will be about ё850,000.
The survey of Armagh allowed figures for Armagh to be calculated with greater accuracy and brought up the fact that there were no fully cut-off streetlights in Armagh. It is little wonder when we consider this that the Armagh Observatory is so concerned about reducing light pollution. It can only be hoped that in years to come more places will follow after Flagstaff’s example: the World’s first Dark Sky City.