Calculate Motor Pump Size


  • Calculate Size of Pump having following Details
  • Static Suction Head(h2)=0 Meter
  • Static Discharge Head (h1)=50 Meter.
  • Required Amount of Water (Q1)=300 Liter/Min.
  • Density of Liquid (D) =1000 Kg/M3
  • Pump Efficiency (pe)=80%
  • Motor Efficiency(me)= 90%
  • Friction Losses in Pipes (f)=30%

Calculations:

  • Flow Rate (Q) =Q1x1.66/100000 =300×1.66/100000= 0.005 M3/Sec
  • Actual Total Head (After Friction Losses) (H) = (h1+h2)+((h1+h2)xf)
  • Actual Total Head (After Friction Losses) (H)=50+(50×30%)= 65 Meter.
  • Pump Hydraulic Power (ph) = (D x Q x H x9.87)/1000
  • Pump Hydraulic Power (ph) = (1000 x 0.005 x 65 x9.87)/1000 =3KW
  • Motor/ Pump Shaft Power (ps)= ph / pe = 3 / 80% = 4KW
  • Required Motor Size: ps / me =4 / 90% = 4.5 KW
  • Required Size of Motor Pump = 4.5 HP or 6 HP

Calculate Size of Cable for Motor (As NEC)


NEC Code 430.22 (Size of Cable for Single Motor):

  • Size of Cable for Branch circuit which has Single Motor connection is 125% of Motor Full Load Current Capacity.
  • Example: what is the minimum rating in amperes for Cables supplying 1 No of 5 hp, 415-volt, 3-phase motor at 0.8 Power Factor. Full-load currents for 5 hp = 7Amp.
  • Min Capacity of Cable= (7X125%) =8.75 Amp.

 NEC Code 430.6(A) (Size of Cable for Group of Motors or Elect. Load).

  • Cables or Feeder which is supplying more than one motors other load(s), shall have an ampacity not less than 125 % of the full-load current rating of the highest rated motor plus the sum of the full-load current ratings of all the other motors in the group, as determined by 430.6(A).
  • For Calculating minimum Ampere Capacity of Main feeder and Cable is 125% of Highest Full Load Current + Sum of Full Load Current of remaining Motors.
  • Example:what is the minimum rating in amperes for Cables supplying 1 No of 5 hp, 415-volt, 3-phase motor at 0.8 Power Factor, 1 No of 10 hp, 415-volt, 3-phase motor at 0.8 Power Factor, 1 No of 15 hp, 415-volt, 3-phase motor at 0.8 Power Factor and 1 No of 5hp, 230-volt, single-phase motor at 0.8 Power Factor?
  • Full-load currents for 5 hp = 7Amp.
  • Full-load currents for 10 hp = 13Amp.
  • Full-load currents for 15 hp = 19Amp.
  • Full-load currents for 10 hp (1 Ph) = 21Amp.
  • Here Capacity wise Large Motor is 15 Hp but Highest Full Load current is 21Amp of 5hp Single Phase Motor so 125% of Highest Full Load current is 21X125%=26.25Amp
  • Min Capacity of Cable= (26.25+7+13+19) =65.25 Amp.

 NEC Code 430.24 (Size of Cable for Group of Motors or Electrical Load).

  • As specified in 430.24, conductors supplying two or more motors must have an ampacity not less than 125 % of the full-load current rating of the highest rated motor +  the sum of the full-load current ratings of all the other motors in the group or on the same phase.
  •  It may not be necessary to include all the motors into the calculation. It is permissible to balance the motors as evenly as possible between phases before performing motor-load calculations.
  • Example:what is the minimum rating in amperes for conductors supplying 1No of 10 hp, 415-volt, 3-phase motor at 0.8 P.F and 3 No of 3 hp, 230-volt, single-phase motors at 0.8 P.F.
  • The full-load current for a 10 hp, 415-volt, 3-phase motor is 13 amperes.
  • The Full-load current for single-phase 3 hp motors is 12 amperes.
  • Here for Load Balancing one Single Phase Motor is connected on R Phase Second in B Phase and third is in Y Phase.Because the motors are balanced between phases, the full-load current on each phase is 25 amperes (13 + 12 = 25).
  • Here multiply 13 amperes by 125 %=(13 × 125% = 16.25 Amp). Add to this value the full-load currents of the other motor on the same phase (16.25 + 12 = 28.25 Amp).
  • The minimum rating in amperes for conductors supplying these motors is 28 amperes.

 NEC 430/32 Size of Overload Protection for Motor:

  • Overload protection (Heater or Thermal cut out protection) would be a device that thermally protects a given motor from damage due to heat when loaded too heavy with work.
  • All continuous duty motors rated more than 1HP must have some type of an approved overload device.
  • An overload shall be installed on each conductor that controls the running of the motor rated more than one horsepower. NEC 430/37 plus the grounded leg of a three phase grounded system must contain an overload also. This Grounded leg of a three phase system is the only time you may install an overload or over – current device on a grounded conductor that is supplying a motor.
  • To Find the motor running overload protection size that is required, you must multiply the F.L.C. (full load current) with the minimum or the maximum percentage ratings as follows;

Maximum Overload

  • Maximum overload = F.L.C. (full load current of a motor) X allowable % of the maximum setting of an overload,
  • 130% for motors, found in NEC Article 430/34.
  • Increase of 5% allowed if the marked temperature rise is not over 40 degrees or the marked service factor is not less than 1.15.

Minimum Overload

  • Minimum Overload = F.L.C. (full load current of a motor) X allowable % of the minimum setting of an overload,
  • 115% for motors found in NEC Article 430/32/B/1.
  • Increase of 10% allowed to 125% if the marked temperature rise is not over 40 degrees or the marked service factor is not less than 1.15

 

How to Design efficient Street lighting-(Part-6)


(3) Light trespass:

  • Light trespass is condition when spill (Unwanted or Unneeded) light from a streetlight or floodlight enters a window and illuminates an indoor area.

 How to Reduce Trespass

  • Select luminaries, locations, and orientations to minimize spill light onto adjacent properties.
  • Use well-shielded luminaries.
  • Keep floodlight aiming angles low so that the entire beam falls within the intended lighted area.

 Difference between full cutoffs and fully shielded:

  • The full cutoff has is luminaries that have no direct up light (no light emitted above horizontal) and 10% of light intensity between 80° and 90°.
  • The term full cutoff is often substituted for the term fully shielded.
  • The both terms are not equivalent. Fully shielded luminaires emit no direct up light, but have no limitation on the intensity in the region between 80° and 90°
  • Luminaires that are full cutoff, cutoff, semi cutoff, and non cutoff , may also qualify as fully shielded.

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  • There is also a confusing assumption that a luminaire with a flat lens qualifies as a full cutoff luminaries. While this may be true or not in some Lighting Fixtures case.

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  • Fully shielded means, a lighting fixture constructed in such a manner that the bulb should be fully recessed into Fixture so that all light is directed downward below the horizontal.
  • The fixture is angled so the lamp is not visible below the barrier (no light visible below the horizontal angle).

(G) Selection of Luminas:

(1) Types of Lighting Source

  • Street Lights are mostly Low-pressure sodium (LPS), High-pressure sodium (HPS), Metal halide and Light emitting diodes (LED).
  • LPS is very energy efficient but emits only a narrow spectrum of pumpkin-colored light that some find to be undesirable.
  • LPS is an excellent choice for lighting near astronomical observatories and in some environmentally sensitive areas.
  • HPS is commonly used for street lighting in many cities. Although it still emits an orange-colored light, its coloring is more “true to life” than that of LPS.
  • Where it’s necessary to use white light, there are metal halide and LEDs.

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  • High-pressure sodium lamps should be used for expressways, main roads, secondary roads and branch roads.
  • Low-power metal halide lamps should be used in mixed traffic roads for motor vehicles and pedestrians in residential areas.
  • Metal halide lamps can be used for motor vehicle traffic, such as city centers and commercial centers, which require high color identification.
  • Metal halide lamps, CFL lamps are used at Pedestrian streets in industrial areas, sidewalks in residential areas, and sidewalks on both sides of motorway traffic.
  • LED streetlights are more durable, longer lasting, efficiency, dimmable capacity and cost effective than traditional lights.
  • LED also enhances public safety by delivering superior visible light while providing the environmental advantage of using less energy.

 (2) Color Rendering Index (CRI):

  • CRI Measures the ability of the artificial light to show or reproduce the colors of the road or objects on the road, relative to a natural light source.
  • The natural light source (the sun) has CRI of 100. The higher
  • This index the better the visibility will be. For all types of road CRI ≥ 70 is recommended.

(3) Efficacy

  • At the low end LED efficacy starts at 70 lumens per watt (lm/W) and reaches as high as 150 lm/W.
  • While the mean efficacy for outdoor area fixtures is slightly lower than common indoor fixtures such as troffers and linear lighting about 100 lm/W for area lights compared to about 110 lm/W for troffers and linear fixtures this difference is not significant. It may be the result of outdoor area lights requiring more precise luminous intensity distributions and other factors unique to outdoor lighting.

(4) Fixture Protection:

  • When using sealed road lighting, the protection level of the light source cavity should not be lower than IP54.
  • For roads and places with dangerous environmental pollution and heavy maintenance, the protection level of the light source cavity should not be lower than IP65.
  • The degree of protection of the lamp electrical appliance cavity should not be lesser than IP43.
  • Lamps with excellent corrosion resistance should be used in areas or places with high levels of corrosive gases such as acid and alkali in the air.

(H) Effective Road Lighting:

  • Sufficient illumination.
  • Good uniformity.
  • No Glare.
  • Low consumption.
  • No Color Temperature abnormalities
  • No Zebra effect
  • Shielded lighting to ensure light is pointed downwards
  •  Completely uniform illuminance.
  • No requirement for over lighting to obtain sufficient average illumination.
  • Absence of glare.
  • Absence of low angle radiation that causes sky glow.
  • Control of light trespass.
  • High redundancy.

 Effective Lightning

Features Benefits
Proper pole height & spacing  Provide uniform light distribution
Proper Luminaire aesthetics  Blends in with the surroundings
Good maintenance Reduce problems in lightning
High lamp efficiency  Minimize energy cost
Life of Luminaire Reduce lamp replacement cost
Good color rendering  Helps object appear more natural
Proper light distribution  Provide required light on roads
Cost effectiveness  Lowers operating cost
Minimizing light pollution & glare  Reduce energy use

 

Effective Energy-efficient Street Lighting Systems (NYSERDA, 2002)

Features Benefits
Proper pole height and spacing Provides uniform light distribution, which improves appearance for safety and security Meets recommended light levels Minimizes the number of poles, reducing energy and maintenance costs
Proper luminaire aesthetics Blends in with the surroundings
High lamp efficacy and Luminaire efficiency Minimizes Energy cost
Life of the luminaire and other components Reduces lamp replacement costs
Cost effectiveness Lowers operating cost
High Lumen Maintenance Reduces lamp replacement costs
Good color rendering Helps object appear more natural and pleasing to the public Allows better recognition of the environment, improves security
Short lamp Re strike Allows the lamp to quickly come back after a power interruption
Proper light distribution Provides required light on the roads and walkways
Proper Cutoff Provides adequate optical control to minimize light pollution
Minimizing light pollution and Glare Reduces energy use
Automatic Shutoff Saves energy and maintenance costs by turning lamps off when not needed

 

Minimum Value of Street Light Designing

Descriptions Min Value
Watt 400
Lumens Per Watt 80 To 140
Voltage 230Volt
Frequency 50 To 60Hz
Power Factor   More than 95
THD  < 20%
Life Hours 70,000 hours
Color Temperature 4000K  To  5000K
CRI More than 75
Beam Angle / Beam Pattern  Type 2,3,4,5
Operating Temperature (-)25°C To (+)50°C
Working Humidity 10% To 90% RH
IP Rating  IP67
Dimmable 0-10V
Optic Lens Material High Polycarbonate (PMMA)
Forward Current >600mA
Housing IP65 – Aluminum Alloy and PC Lens
Dimension  18.23″ X 13.58″ X 4.57″
Weight  15.30 lbs – 34.39 lbs
Warranty 10 Years

How to Design efficient Street lighting-(Part-5)


(2) Surround Ratio (SR):

  • Road lighting should be illuminate not only the road, but also the adjacent areas so motorists can see objects in the periphery and anticipate potential road obstructions (e.g., a pedestrian about to step onto the road).
  • The SR is the visibility of the road’s periphery relative to that of the main road itself.
  • As per industry standards, SR should be at least 50.
  • Figure show how road lighting should illuminate both the main road and its periphery.

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(F) Lighting Pollutions

  • Light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass, and glare. 
  • 30 to 50% of all light pollution is produced by roadway lighting that shines wasted light up and off target.

(1) Glare:

  • Glare is the condition of vision in which there is discomfort or a reduction in the ability to see significant objects. Glare affects human vision and it is subdivided into four components, Disability Glare, Discomfort Glare, Direct Glare and Indirect Glare.
  • By origin
  1. Direct Glare
  2. Indirect (reflected) Glare
  • By effect on people
  1. Disability Glare
  2. Discomfort Glare
  • Disability glare:
  • Disability glare is the glare that results in reduced visual performance and visibility.
  • Since disability glare reduces the ability to perceive small contrasts.
  • It can impair important visual tasks in traffic such as detecting critical objects, controlling headlights, and evaluating critical encounters, making glare a potential danger for road users.
  • LED light sources can provide very high luminance lev­els which may cause glare. For this reason, LED lamps are commonly equipped with diffusers to reduce this luminance.
  • Disability glare may vary for dif­ferent individuals and it can be calculated objectively.
  • In a particu­lar illuminated environment, the human eye will be able to detect differences in luminance down to a certain threshold. This threshold can be compared for a situa­tion in the same environment when a source of glare is added. By comparing these thresholds, the threshold increment can be derived.
  • Discomfort glare:
  • Discomfort glare is the glare producing discomfort. It does not necessarily interfere with visual performance or visibility.
  • As vertical light angles increase, discomforting glare also increases
  • Discomfort glare, on the other hand, is a subjective phenomenon and there is no method for its Rating.
  • Although the 9-point De Boer scale (ranging from “1” for “unbearable” to “9” for “unno­ticeable”) is the most widely used in the field of auto­motive and public lighting.
  • Direct Glare:
  • Direct glare is caused by excessive light entering the eye from a bright light source. The potential for direct glare exists anytime one can see a light source. With direct glare, the eye has a harder time seeing contrast and details.
  • A system designed solely on lighting levels, tends to aim more light at higher viewing angles, thus producing more potential for glare.
  • Exposed bright light source, for example a dropped lens cobra head or floodlight causes of direct glare.
  • Direct glare can be minimized with careful equipment selection as well as placement.

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  • Figure illustrates two examples of exterior lighting that results in glare.

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  • Fig shows how full cutoff luminaries (Shielded Luminaires) can minimize this direct glare. In exterior applications, use fully shielded luminaires that directs light downwards towards the ground.
  • Indirect Glare: Indirect glare is caused by light that is reflected to the eye from surfaces that are in the field of view – often in the task area.
  • Indirect Glare can be minimized with the type and layout of lighting equipment. Direct the light away from the observer with the use of low glare, fully shielded luminaries.
  • As the uniformity ratio increases (poor uniformity), object details become harder to see.
  • For roadway lighting, good uniformity shows evenly lighted pavement. However, to meet small target visibility criteria, a non uniform roadway surface may be better.
  • There should be a balance between uniform perception and detecting objects on the road. Also, emphasis is put on horizontal surface uniformity. In reality, vertical surfaces may require more lighting in order to improve guidance.

How to Reduce Glare:

  • Glare and light trespass are more concern when installing floodlights.
  • Use shielded Light should be use to reduce Glare.
  • Higher mounting heights can more effective in controlling spill light, because floodlights with a more controlled light distribution (i.e., narrower beam) may be used, and the floodlights may be aimed in a more downward direction, making it easier to confine the light to the design area.
  • Lower mounting heights increase the spill light beyond the property boundaries. To illuminate the space satisfactorily, it is often necessary to use floodlights with a broader beam and to aim the floodlights in directions closer to the horizontal than would occur when using higher mounting heights.
  • Lower mounting heights make bright parts of the floodlights more visible from positions outside the property boundary, which can increase glare.

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(2) Sky glow:

  • Sky Glow is brightening of the night sky caused by outdoor lighting.
  • Light that is emitted directly upward by luminaries or reflected from the ground is scattered by dust and gas molecules in the atmosphere, producing a luminous background. It has the effect of reducing one’s ability to view the stars in Night.

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How to Reduce Sky Glow

  • While it is difficult to accurately model sky glow, at this point it is presumed that the most important factors are light output and lamp spectral characteristics, light distribution from the luminaire, reflected light from the ground, and aerosol particle distribution in the atmosphere.
  • If the quantity of light going into the sky is reduced, then sky glow is reduced. Thus, to reduce sky glow by
  • By using full cutoff luminaires to minimize the amount of light emitted upward directly from the luminaire.
  • Reduce Lighting Level.
  • Make practice to Turn off unneeded lights
  • Limited Lighting hours in outdoor sales areas, parking areas, and signages
  • Installing Low-Pressure Sodium light sources, which allow astronomers to filter the line spectra from telescopic images.

How to Design efficient Street lighting-(Part-4)


(C) Lighting Factor:

(1) Maintenance Factor (Light Loss Factors) (MF)

  • The Maintenance Factor (Light loss factor) is the combination of factors used to denote the reduction of the illumination for a given area after a period of time compared to the initial illumination on the same area.
  • The efficiency of the luminaire is reduced over time. The designer must estimate this reduction to properly estimate the light available at the end of the lamp maintenance life.
  • Luminaire maintenance factors vary according to the intervals between cleaning, the amount of atmospheric pollution and the IP rating of the luminaire.
  • However, it is proposed to consider maintenance factor of not less than 0.5 for LED Road lighting installations for IP66 rated luminaires.
  • The maintenance factor may range from 0.50 to 0.90, with the typical range between 0.65 To 0.75
  • These maintenance factor values shall be adopted for the purposes of producing the lighting simulation design.
  • The maintenance factor is the product of the following factors.
  • LLF = LLD x LDD x EF
  • Mostly We consider Maintenance factor from 0.8 to 0.9
  • We have to choose Maintenance factor carefully by increasing maintenance factor 0.5 the spacing of pole increasing 2 meter to 2.5 meter.
Maintenance Factor Max. Spacing of Pole (Meter)
0.95 43
0.9 40.5
0.85 38
0.8 36

(A) Lamp Lumen Depreciation Factor (LLD)

  • As the lamp progresses through its service life, the lumen output of the lamp decreases. This is an inherent characteristic of all lamps. The initial lamp lumen value is adjusted by a lumen depreciation factor to compensate for the anticipated lumen reduction.
  • This assures that a minimum level of illumination will be available at the end of the assumed lamp life, even though lamp lumen depreciation has occurred. This information should be provided by the manufacturer. For design purposes, a LLD factor of 0.9 to 0.78 should be used.

(B) Luminaire Dirt Depreciation Factor (LDD).

  • Dirt on the exterior and interior of the luminaries and to some on the lamp reduces the amount of light reaching the roadway.
  • Various degrees of dirt accumulation may be anticipated depending upon the area in which the luminaire is located. Industry, exhaust of vehicles, especially large diesel trucks, dust, etc, all combine to produce the dirt accumulation on the luminaries.
  • Higher mounting heights, however, reduce the vehicle-related dirt accumulations.
  • LDD factor of 0.87 to 0.95 should be used. This is based on a moderately dirty environment and three years exposure time.

(C) Equipment Factor (EF).

  • Allows for variations inherent in the manufacture and operation of the equipment (i.e., luminaries, system voltage and voltage drop).
  • It is generally assumed to be 95%.

(2) Coefficient of Utilization (CU):

  • Coefficient of Utilization is the ratio of the luminous flux from a luminaire received on the surface of the roadway to the lumens emitted by the luminaire’s lamps alone.
  • Coefficient of Utilization should be maximum.
  • Coefficient of Utilization differs with each luminaire type, and depends upon mounting height, road width, and overhang.
  • The coefficient of utilization (K) should be over 30% or the utilance above 40% for the road, highway, square or enclosure. Luminaires or floodlights should not by placed far from the area to be lit or, where appropriate, light projection beyond the useful zone should be minimized (K = average maintained illuminance multiplied by the surface calculation and divided by the lumens installed).

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Type Luminaries Dirt Depreciation Luminaire Lumen Depreciation Total Light Loss Factor
LED 0.9 0.85 0.765
HPS 0.9 0.9 0.81
LPS 0.9 0.85 (0.7 for 180W) 0.765 (0.63 for 180W)

 

Light Loss Factors

Type of Lamp Laminar Dirt description Light Loss Factor
HPS 0.88 0.74
Induction 0.88 0.62
LED 0.88 0.72

 

Maintenance factors

Cleaning intervals (months) Pollution category
High Medium Low
12 0.53 0.62 0.82
18 0.48 0.58 0.8
24 0.45 0.56 0.79
36 0.42 0.53 0.78

 

Maintenance Factors for 36 month cleaning interval

Factors IP5X IP6X
Pollution category Pollution category
Low Medium High Low Medium High
LMF 0.88 0.82 0.76 0.9 0.87 0.83
LLMF 0.89 0.89 0.89 0.89 0.89 0.89
MF 0.78 0.73 0.68 0.80 0.77 0.74

 (E) Lighting Uniformities

(1) Lighting Uniformities

  • Uniformity is a description of the smoothness of the lighting pattern or the degree of the intensity of bright and dark areas on the road.
  • Uniformity is a measure of how evenly distributed the light on the road is, which can be expressed as Overall Uniformity (UO) and Longitudinal Uniformity (UL).
  • The uniformity ratio shall not exceed 4:1 and preferably should not exceed 3:1 except on residential streets, where 6:1 may be acceptable.

(A) Overall uniformity:

  • In design, the overall uniformity (UO) is expressed as a ratio of the minimum to the average luminance on the road surface of the carriageway within the calculation area.
  • UO=Lmin / Lave

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  • It is a measure of how evenly or uniformly illuminate on the road surface.
  • A good overall uniformity ensures that all spots and objects on the road are sufficiently lit and visible to the motorist.
  • The industry accepted value for UO is 30 to 0.40.

(B) Longitudinal uniformity:

  • The longitudinal uniformity (UL) is expressed as the ratio of the minimum to maximum luminance along the center line of a lane within the calculation area.
  • UL=Lmin / Lmax.
  • Longitudinal uniformity is a measure to reduce bright and dark bands of light appearing on road lit surfaces. The effect can be somewhat hypnotic and present confusing luminance patterns.

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  • It is a measure to reduce the intensity of bright and dark banding on road lit surface.
  • A good level of longitudinal uniformity ensures comfortable driving conditions by reducing the Pattern of high and low luminance levels on a road (i.e. zebra effect).
  • It is applicable to long continuous roads.

 Combination of Overall Uniformity and Longitudinal Uniformity:

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  • The picture on the left shows a road with good UO while the picture on the right has low level of UO. The Road is more visible in the road with higher UO. Having higher UO allows the motorist to see the road clearly and anticipate potential road hazards (e.g. open manholes, road excavations, sharp objects on the road, people crossing the street).
  • The picture on the right shows a road with low level of UL demonstrating the ‘Zebra Effect’ while the picture on the left has high level of UL without ‘Zebra Effect’.
  • The ‘zebra effect’ can cause discomfort to motorists, posing a risk to road safety. Ensuring good level of uniformity can reduce the luminance level needed. 
Lighting levels
Category Eave ( LUX) Emin  LUX) Uniformity ratios
Emax : Emin Eave : Emin
Express & Main street 30 15 3:01 2.5:1
Suburban shopping street 25 10 5:01 3:01
Subsidiary street 15 10 5:01 3:01
Other streets 15 5 10:01 5:01

 

Road Classification Area Classification Average  Lux Uniformity Ratio (Aver./Min.)
Arterial (Minor & Major) Commercial 12 3 to 1
Intermediate 9
Residential 6
Collector (Minor & Major) Commercial 8
Intermediate 6 4 to 1
Residential 4
Local Commercial 6
Intermediate 5 6 to 1
Residential 3
Alleys Commercial 4
Intermediate 3 6 to 1
Residential 2
Sidewalks (Roadside) Commercial 3 3 to 1
Intermediate 6 4 to 1
Residential 2 6 to 1
Pedestrian Ways 15 3 to 1

  

Illumination for Intersections

Functional Classification Average Maintained Illumination at Pavement by Pedestrian Area Classification in Lumen Uniformity
High Medium Low Eavg/Emin
Major/Major 37 28 19 32
Major/Collector 31 24 16 32
Major/Local 28 22 14 32
Collector/Collector 26 19 16 43
Collector/Local 23 17 11 43
Local/Local 19 15 9 65

 

Illumination for Pedestrian Areas

Maintained Illuminance Values for Walkways
Area Classification Description E avg (Lux) EV min (Lux) E avg/Emin
High Pedestrian Conflict Mixed Vehicle and Pedestrian 22 11 43
Areas Pedestrian Only 11 5 43
Medium Pedestrian Pedestrian Areas 5 2 43
Conflict Areas
Low Pedestrian Rural/Semi-Rural Areas 2 1 108
Conflict Areas Low Density Residential (2 or fewer dwelling units per acre) 3 1 65
Medium Density Residential (2.1 to 6.0 dwelling units per acre) 4 1 43
Pedestrian Portion of Pedestrian/Vehicular Underpasses Day 108 54 43

How to Design efficient Street lighting-(Part-3)


(C) Lighting Fixture:

(1) Fixture’s Mounting Height:

  • Higher mounting heights used in conjunction with higher wattage luminaries enhances lighting uniformity and typically reduces the number of light poles needed to produce the same illumination level.
  • In general, higher mounting heights tend to produce a more cost-effective design. For practical and aesthetic reasons, the mounting height should remain constant throughout the system.
  • The manufacturer’s photometric data is required to determine an appropriate mounting height.
  • Typical mounting heights for highway lighting purposes range from 30 ft to 55 ft (9.1 meter to 16.8 meter).
  • Mounting heights for light towers or High mast is typically 80 ft (24 m) or greater.
  • The installation height is too low, the glare of the lamp increases.
  • As the installation high increase, glare decreases, but the lighting utilization rate decreases.

 

(2) Fixtures Classification:

  • The Illuminating Engineering Society of North America (IESNA, IES or BIS1981) provides classifications for luminaires according to their glare control and high-angle brightness.

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(A) Full Cutoff (F):

  • A luminaire light distribution is designated as full cutoff (F) when Zero intensity at or above horizontal (90° above nadir) and Less than 10% of lamp lumens at or above 80°.
  • Full-cutoff fixtures reduce glare dramatically and eliminate direct up light by sending all their light toward the ground .This efficiency should translate into lower bulb wattages if the existing poles are used. However, some lighting engineers believe that to achieve the same illumination uniformity as their semi-cutoff counterparts, full-cutoff fixtures need to be mounted either on taller poles or closer together
  • Benefits:
  • Limits spill light on to adjacent property, reduces glare. No light is emitted directly from the luminaries into the sky.
  • Reduce Lighting Pollution.
  • Limitations:
  • May reduce pole spacing to maintain uniformity and increase pole and luminaire quantities.
  • Application:
  • Use for roadway, parking, and other vehicular lighting applications. Minimizes glare and light pollution and light trespass.

 (B) Cutoff (C):

  • A luminaries light distribution is designated as cutoff (C) when Less than 2.5% Intensity at or above horizontal (90° above nadir) and Less than 10% of lamp lumens at or above 80°.
  • The direction of maximum intensity may vary but should be below 65º.
  • Benefits:
  • Small increase in high-angle light allows increased pole spacing.
  • Cutoff system is the reduction of glare.
  • Limitations:
  • May allow some up light (Sky Light) from luminaries. Typically a small overall impact on sky glow.
  • Application:
  • Interchange lighting and rural intersections due to the ability to reduce glare.
  • Use in applications where pedestrians are present. Provides more vertical illuminance than Full Cutoff luminaires.
  • Lamp rating should be less than 3200 lumens.
  • The cutoff design is where the luminaire light distribution is less than 25,000 lm at an angle of 90° above nadir (vertical axis) and 100,000 lm at a vertical angle of 80° above nadir.

 (C) Semi Cutoff (S) (Medium Beam Angle):

  • A luminaire light distribution is designated as Semi cutoff (S) when Less than 5% Intensity at or above horizontal (90° above nadir) and Less than 20% of lamp lumens at or above 80°.
  • The direction of maximum intensity may vary but should be below 75º.
  • Benefits:
  • High-angle light accents taller vertical surfaces such as buildings. Most light is still directed downward.
  • Limitations:
  • Little control of light at property line.
  • Potential for increased glare when using high wattage luminaries. Typically directs more light into the sky than cutoff.
  • Application:
  • Used for standard road lighting. Adequate glare control is obtained with reasonable spacing.
  • The principal advantage of the semi-cutoff system is a greater flexibility in sitting.
  • Use in pedestrian areas. If using in residential areas, provide with house side shields to minimize light trespass. Lamp rating should be less than 3200 lumens.
  • For the semi-cutoff design, the luminous flux numbers become 50,000 lm for 90° above nadir and 200,000 lm at a vertical angle of 80° above nadir.
  • Semi-cutoff fixtures create broad cones of light that permit wide spacing between poles. But such fixtures create harsh glare and send some light directly into the sky.

(D) Non Cutoff (N) (Higher Beam Angle):

  • A luminaries light distribution is designated as Non Cutoff (N) when Emit light into all directions.
  • No limitations on light distribution at any angle.
  • There is considerable output near the horizontal plane.
  • Benefits:
  • Uniform luminous surfaces such as internally illuminated signs or globes. Wattage should be limited. Suitable for sports lighting, facade, landscape or other applications where luminaires are tilted due to limitations in pole or fixture locations
  • Limitations:
  • Location and aiming are critical. Most likely of all categories to produce offensive brightness and sky glow.
  • Application:
  • Used in areas with a lot of background light. Non-cutoff luminaries shall not be used at lower mounting heights because of glare.
  • Use for decorative applications only. Lamp rating should be less than 3200 lumens.
  • “Full cut off” fixtures must be installed properly, so that the bottom of the fixture is level with the ground.
  • “Fully Shielded” fixtures do not allow any light to be emitted above the lowest light emitting
  • part, but do not restrict light output in the “glare” zone, 90-80 degrees below horizontal.

1

  (3) Fixtures Distributions (Optical System):

  • The Illuminating Engineering Society classified series of Fixture distribution patterns as Types I, II, III, IV, and V.

1

(A) Type I (Two-way):

  • The lateral distribution having a preferred lateral width of 15 degrees in the cone of maximum Lumen.
  • Illumination Pattern: Narrow, symmetric luminance pattern.
  • Fixture Location: This type is generally applicable to a luminaire location near the center of a roadway where the mounting height is approximately equal to the roadway width.
  • Type of Road: The luminaire is placed on the side of the street or edge of the area to be lighted. Most 1or 2 Lane Road

(B) Type II (Two Way) :

  • Light distributions have a preferred lateral width of 25 degrees.
  • Illumination Pattern: Slightly wider illuminance pattern than Type I.
  • Fixture Location: They are generally applicable to luminaires located at or near the side of relatively narrow roadways, where the width of the roadway does not exceed 1.75 times the designed mounting height.
  • Type of Road: The luminaire is placed on the side of the street or edge of the area to be lighted. It produces a long, narrow, oval-shaped lighted area which is usually applicable to narrower streets.

(C) Type III (Bat Wing) :

  • Type III light distributions have a preferred lateral width of 40 degrees.
  • Illumination Pattern: It produces an oval-shaped lighted
  • Fixture Location: This distribution is intended for luminaires mounted at or near the side of medium width roadways, where the width of the roadway does not exceed 2.75 times the mounting height.
  • Type of Road: The luminaire is placed on the side of the street or edge of area to medium width streets.

(D) Type IV (Forward throw “Asymmetric”):

  • Type IV light distributions have a preferred lateral width of 60 degrees.
  • Illumination Pattern: Widest luminance pattern.
  • Fixture Location: This distribution is intended for side-of-road mounting and is generally used on wide roadways where the roadway width does not exceed 3.7 times the mounting height.
  • Type of Road: very wide roadway (4 to 6 Lane)
  • Applications: Type IV often use at perimeters where Spill Light is required and there is no place to add Pole.

(E) Type V:

  • Type V light distributions have a circular symmetry of candlepower that is essentially the same at all lateral angles.
  • Illumination Pattern: It produces a circular, wider lighted area and is usually applicable to wide streets.
  • Fixture Location: The luminaries are mounting at or near center of roadways, center islands of parkway, and intersections.
  • Type of Road: very wide roadway (4 to 6 Lane)
  • Applications: Type V often applies to high-mast lighting.

GUIDE FOR LUMINAIRE LATERAL LIGHT TYPE AND PLACEMENT

Pole Arrangement Road Width Type of Distribution
One Side or Staggered up to 1.5 x Mounting Height Types II-III-IV
Staggered or Opposite Beyond 1.5 x Mounting Height Types III & IV
Center of the Roadway Mounting up to 2 x Mounting Height Type I

 

Type of Classification

AREA CLASSIFICATION  CUTOFF TYPE
Commercial Full Cutoff or Semi Cutoff
Intermediate Full Cutoff or Semi Cutoff
Residential Full Cutoff

 

THE SELECTION OF LUMINAIRE MOUNTING HEIGHTS

Lamp Lumens Mounting Height
≤20,000 Lumen  ≤35 Foot
20,000 To 45,000 Lumen 35 To 45 Foot
45,000 To 90,000 Lumen 45 To 60 Foot

 

Type of LED Luminaries Type of Road Lamp mounting height from the floor level (Meters) Minimum Illumination Level (Lux) at centre of road Color of Illumination
250-260W Above 18 (20 To 22) 5000K-6500K
190W A1 Between 11 To 15 (20 To 22) 5000K-6500K
140-170W A1 Between 9 To 15 (18 To 20) 5000K-6500K
90-120W A2/B1 07 To 11 (15 To 18) 4300K-5600K
70-120W A2/B1 07- To 11 (15 To 18) 4300K-5600K
70-120W B1/B2 06 To 09 (15 To 18) 4300K-5600K
70-50W B1/B2/C1 7 To 9 (12 To 15) 4300K-5600K
45-50W B1/B2/C1 5 To 7 (12 To 15) 4300K-5600K
25-30W B1/B2/C1 5 To 7 (10 To 12) 4300K-5600K

 

Relationship between mounting height and spacing

Mounting Height Width of road 6 Meter to 7 Meter 9 Meter to 10.5 Meter 12 Meter to 14 Meter
Pole  arrangement Cut-off Type Semi Cutoff Type Cut-off Type Semi Cutoff Type Cut-off Type Semi Cutoff Type
8 Meter Single side 24 28
Staggered 24 28
Opposite 28 28
10 Meter Single side 30 30
Staggered 35 35 30 35
Opposite 35 40 30 35
12 Meter Single side 42 48 36 42
Staggered 36 42 36 42
Opposite 42 48 42 48

 

GUIDE FOR LUMINAIRE LATERAL LIGHT TYPE AND PLACEMENT

SIDE OF THE ROADWAY MOUNTING            CENTER OF THE ROADWAY MOUNTING
One Side
or Staggered
Staggered
or Opposite
Local
Street Intersection
Single Roadway Twin Roadways
(Median Mounting)
Local
Street Intersections
Road Width up to 1.5 x Mounting Height Road Width beyond1.5 x Mounting Height Road Width up to 1.5x Mounting Height Road Width up to 2x Mounting Height Road Width up to 1.5x Mounting Height (each pavement) Width up to 2.0x Mounting Height
Types Types Type Type Types Types
II, III, IV III & IV II (4-way) I II & III I (4-way) & V

 

How to Design efficient Street lighting-(Part-2)


(2) Proper Placement of Pole:

1

(A) Setback

  • Set back is the horizontal distance between the face of a light pole and the edge of traveled way.
  • Placing luminaries too close to a vertical surface results in hotspots at its base.
  • A setback of 3 foot to 4 foot works well for many applications.
  • Light from luminaires at extremely short setbacks grazes the surface and enhances its texture.
  • Light from luminaries at Long setbacks (Luminaries too far from a vertical surface) cause shadows at low levels.
  • Longer setbacks may be required for taller surfaces.
  • Scallops between fixtures become more noticeable as setback increases.
  • As setback (or spacing) distance increases, Light levels and uniformity decrease.

Set Back (BS 5489)

Design Speed Pole Set Back
50 Km/Hr 0.8 Meter
80 Km/Hr 1 Meter
100 Km/Hr 1.5 Meter
120 Km/Hr 1.5 Meter

(B) Overhang

  • Overhang is the horizontal distance between the center of a luminaries mounted on a bracket (Nadir) and the adjacent edge of a carriage way or traveled way.
  • In general, overhang should not exceed one fourth of the mounting height to avoid reduced visibility of curbs, obstacles, and footpaths.

(C) Outreach

  • Outreach is the horizontal distance between the center of the column and the center of the luminaries and is usually determined for architectural aesthetic considerations.

(D) Pole Boom(Arm) Length:

  • The use of an arm places the light source closer to the traveled way while allowing the pole to be located further from the edge of the traveled way.
  • Depending on the application, Pole arms may be single and/or double mast arms or davit arms at the top of the pole.
  • There are several different arm lengths and styles of arms that are used.
  • Arm Type:
  • Type A bracket an arm has a single member arm. It is used when the Arm length is less than 3.5 Meter.
  • Type B bracket arm has a two member truss arm design. Type B arms are used when the Arm length is more than 3.5 Meter.
  • Arm Lengths:
  • The length of the bracket arm is dependent upon a street width, pole location in relation to the curb and the presence of a median.
  • Type A (Single member bracket) arms are available in 2 Meter and 2.5 Meter lengths.
  • Type B (Twin member bracket) arms are available in 3.5 Meter, 4 Meter and 5 Meter Lengths.
  • Pole Height is 10 Meter: On typical streets that are 12 Meter’ wide from curb to curb, either a 2 Meter or 2.5 Meter arm is used. Depending on whether the pole is located behind the sidewalk or in the grass parkway between the sidewalk and the curb, the arm length may need to be increased to 4 Meter.
  • Pole Height is 13 Meter: On an undivided street, generally Meter, 2.5 Meter or 4 Meter arms are used.
  • Pole Height is 13 Meter: divided Street, typically have a 8 Meter wide center median to divide opposing lanes of traffic. On streets where the light poles are installed in a raised median, two 4 Meter arms oriented 180° apart are used.

(E) Boom Tilt Angle (Boom Angle)

  • When the angle of tilt is larger, a uniformity ratio is increasing. Otherwise discomfort glare is increasing because strong light comes into driver’s eyes. So the angle of tilt shall be kept from 15° to 30°.
Tilt Angle
Pole Height Arm Length Arm Tile Angle
6 Meter 0.5 Meter 5°,10°,15°
8 Meter 1 Meter 5°,10°,15°
10 Meter 1.5 Meter 5°,10°,15°
>=12 Meter 2 Meter 5°,10°,15°

(F) Pole Height:

  • Light poles for conventional highway lighting applications support luminaire mounting heights ranging from approximately 30 ft to 50 ft (9.1 m to 15.2 m).
  • Light towers for high-mast lighting applications generally range from 80 ft to 160 ft (24.4 m to 48.8 m) and are designed in multiple sections.
  • Weathering steel is a common material choice for light towers.
  • Ornamental light Poles used for local streets generally range in height for 8 ft to 15 ft (2.4 m to 4.5 m).
Pole Height Application
< 6 Meter Majority of side streets or alleys, Public gardens and parking Area to make people feel safe
8 Meter Urban traffic route , the multiplicity of road junctions
10 Meter Urban traffic routes
12 Meter Heavily used routes
18 Meter High mast lighting poles shall be installed at large-scale area such as airports, dockyards, large industrial areas, sports areas and road Intersections.

 (G) Poles distance from Curb (Offset):

  • The lighting poles should not be installed very close to the pavement edge, because the capacity of the roadway is decreased and the free movement of traffic is obstructed.
  • For roads with raised curbs (as in urban roads) =Min. 0.3 meter and desirable 0.6 meter from the edge of raised curb.
  • For roads without raised curbs (as in rural roads)=Min. 1.5 meter from the edge of the carriageway, subject to min. 5.0 meter from the center line of the carriageway.
  • Height and overhang of mounting
  • The glare on eyes from the mounted lights decreases with increases in the height of mounting. Usually, mounting height range from 6 to 10m.
  • Overhangs on the lighting poles would keep the poles away from the pavement edges, but still allow the lamp to be held above the curb or towards the pavements.

 (H) Pole to Pole Spacing

  • Spacing is the distance, measured along the center line of the road, between successive luminaries in an installation.
  • To preserve longitudinal uniformity, the space height ratio should generally be greater than 3.
  • Placing luminaries too far apart creates scallops at the base of the surface.
  • Spacing distances that are equal to 3 to 4 times the setback work well for many applications.
  • Placing luminaries closer together eliminates scallops.
  • Uniformity and light levels increase as spacing (or setback) distances decrease.
  • Spacing of luminaires normally does not exceed five to six mounting heights.
  • The span must not be more than 45 meters and for an average of 20-30 meters.

Lighting Pole details as per Road

Road Road Width (Meter) Pole Arrangement Lamp (Watts) Pole to Pole Spacing (Meters) Mounting Height, (Meters) Arm Length, (Meters)
Expressway 10 Twin Central 250 25 To 35 12 1.5
15 250 20 To 35 12 3.0
20 Opposite 250 20 To 45 12 1.5
25 250 20 To 40 12 1.5
30 250 20 To 30 12 1.5
36 250 20 To 25 12 1.5
40 250 20 To 22 12 1.5
Major 10 One-side 250 10 To 40 10 1.5
15 250 10 To 45 12 3.0
10 Twin Central 150 20 To 37 10 1.5
15 250 20 To 43 12 3.0
20 Opposite 150 20 To 40 10 3.0
25 250 20 To 45 10 1.5
30 250 20 To 45 10 1.5
36 250 20 To 45 12 3.0
40 250 20 To 45 2 3.0
Collector 10 One-side 150 10 To 40 10 1.5
15 250 10 To 50 12 3.0
10 Twin Central 150 20 To 40 10 1.5
15 150 20 To 37 12 3.0
20 Opposite 150 20 To 47 10 1.5
25 250 20 To 48 10 1.5
Rural
Highway
8 One-side 150 10 To 38 8 1.5
10 150 10 To 37 8 3.0
15 150 15 To 38 10 3.0
10 Twin Central 150 20 To 45 10 3.0
15 150 20 To 39 12 3.0
20 1.5
Minor 4 One-side 70 10 To 40 8 1.5
6 70 10 To 40 8 1.5
8 70 10 To 40 8 1.5
10 70 10 To 39 8 1.5
10 Twin Central 70 20 To 35 8 1.5
15 Staggered 70 10 To 20 8 1.5
15 Opposite 70 20 To 40 8 1.5

 

Illumination Level
Classification  Average Illumination (lux) Ratio Minimum to average illumination
Class A1 30 0.4
Class A2 15 0.4
Class B1 8 0.3
Class B2 4 0.3

 

Relationship between Mounting Height and Spacing of Fixtures

Pole Arrangement Cut-off type Semi cutoff type
Height Spacing Height Spacing
Single side >=0.7 X Width of Road <=3 X Fixture Mounting Height >=0.8 X Width of Road <=3.5 X Fixture Mounting Height
Both Side Staggered >=1.5 X Width of Road <=3.5 X Fixture Mounting Height >=1.7 X Width of Road <=4 X Fixture Mounting Height
Both Side Opposite >=0.5 X Width of Road <=3 X Fixture Mounting Height >=0.6 X Width of Road <=3.5 X Fixture Mounting Height
Twin central >=0.7 X Width of Road <=3.5 X Fixture Mounting Height >=0.8 X Width of Road <=4 X Fixture Mounting Height

 

 Pole to Pole Distance vs Lux Level

Pole Height Lamp Pole to Pole Distance Max. Illumination (Lux) Average (Lux)
4 Meter 15 watt 12 to 18 Meter 25 18
5 Meter 18 watt 14 to 20 Meter 30 18
6 Meter 30 watt 18 to 24 Meter 32 20
7 Meter 50 watt 21 to 28 Meter 32 20
8 Meter 100 watt 24 to 32 Meter 40 22
9 Meter 110 watt 27 to 35 Meter 34 20
10 Meter 140 watt 30 to 40 Meter 35 22
12 Meter 180 watt 30 to 40 Meter 33 23
14 Meter 200 watt 30 to 40 Meter 30 21

 

Lux Vs Mounting Height

Fixtures (Lux) Mounting Height
3000 to 10000 Lux 6 to 7 Meter
10000 to 20000 Lux 7 to  9 Meter
More than 20000 Lux More than 9 Meter

 

 
Road Road Type Type of Pole positions Individual Carriageway Width (Meter) Central Verge (Meter) Pole Height above Ground (Meter) Maximum Pole to Pole Spacing (Meter) Clearance from Road Edge (Meter) Bracket Length (Meter) Tilt Angle Lighting Specifications Lamp (Watt)
A1 Dual Carriage Central Verge 10 1.2 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Dual Carriage Central Verge 11 1.2 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Dual Carriage Central Verge 12 1.2 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Dual Carriage Central Verge 14 1.2 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Dual Carriage Central Verge 16 1.2 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Single Carriage Opposite 12 0 12 35 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 250W
A1 Single Carriage Opposite 14.5 0 12 35 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 250W
A1 Single Carriage Opposite 16 0 12 40 0.6 Around one meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Single Carriage Opposite 18 0 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Single Carriage Opposite 21 0 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
Single Carriage Opposite 25 0 12 40 0.6 1 meter  10° 35 lux
/0.4/ 0.33
HP SV 400W
A1 Single Carriage Opposite 31 0 12 40 0.6 1 meter  10° 35 lux/ 0.4/
0.33
HP SV 400W
A2 Single Carriage Single Sided 10 11 30 0.6 < 1.0 meter  10° 25 lux
/0.4/ 0.33
HP SV 250W
A2 Single Carriage Single Sided 9 11 30 0.6 < 0.5 meter  10° 25 lux
/0.4/ 0.33
HP SV 250W
A2 Single Carriage Single Sided 7 11 30 0.6 < 0.5 meter  10° 25 lux
/0.4/ 0.33
HP SV 250W
A2 Single Carriage Single Sided 7 11 30 0.6 < 0.5 meter  10° 25lux
/0.4/ 0.33
HP SV 250W
A3 Single Carriage Single Sided 7 8 20 0.6 < 0.5 meter  10° 20lux
/0.4
HP SV 150W
Pedestrian Pathway Single Carriage Single Sided 3m-6m 7.5 20-25 0.6 <0.5 meter  10° 20 lux
/0.4
HP SV 150W

 

Poles (Meter) Top Dia (mm) Bottom Dia (mm) Thickness (mm) Base plate (mm) Single Arm Bracket (mm) Double Arm Bracket (mm)
3 70 130 3 200x200x12 1000 NA
3 70 130 3 200x200x12 NA 1000
4 70 130 3 200x200x12 1000 NA
4 70 130 3 200x200x12 NA 1000
4 70 130 3 200x200x12 1000 NA
5 70 130 3 200x200x12 NA 1000
5 70 130 3 200x200x12 1000 NA
6 70 130 3 200x200x12 NA 1000
6 70 130 3 200x200x12 1000 NA
7 70 135 3 225x225x16 1000 NA
7 70 135 3 225x225x16 NA 1000
8 70 135 3 225x225x16 1000 NA
8 70 135 3 225x225x16 NA 1000
9 70 155 3 260x260x16 1000 NA
9 70 155 3 260x260x16 NA 1000
9 70 175 3 275x275x16 1000 NA
9 70 175 3 275x275x16 NA 1000
10 70 175 3 275x275x16 1000 NA
10 70 175 3 275x275x16 NA 1000
10 70 200 3 290x290x16 1000 NA
10 70 200 3 290x290x16 NA 1000
11 70 210 3 320x320x20 1000 NA
11 70 210 3 320x320x20 NA 1000
12 70 230 3 325x325x20 1000 NA
12 70 230 3 325x325x20 NA 1000

 

Recommended Levels of Illumination (BIS 1981) (IS 1944)

Type of Road Road Characteristics Road Width (Meter) Average Level of Illumination on Road Surface in Lux Ratio of Minimum/Average Illumination Ratio of Minimum/Max Illumination Type of Luminaire Preferred Luminas Mounting Height
A-1 Important traffic routes carrying fast traffic >10.5,12,14,16,18,20,30 30 0.4 33 Cutoff 9 To 10 Meter
A-2 Main roads carrying mixed traffic like city main roads/streets, arterial roads, throughways > 7 m up to 10 m 15 0.4 33 Cutoff 9 To 10 Meter
B-1 Secondary roads with considerable traffic like local traffic routes, shopping streets < 7m Colony Roads 8 0.3 20 Cutoff or semi-cutoff 7.5 To 9 Meter
B-2 Secondary roads with light traffic 4m,5m, 6m 4 0.3 20 Cutoff or semi-cutoff 7.5 To 9 Meter

 

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