Design Basics : BS EN13201 : 2003 BS 5489-1 : 2003 The European Norm for Road Lighting provides the lighting designer with a basis for specifying lighting quality for a given scheme. Here we discuss the basic principles and outline the various standards adopted. The European Norm is divided into 3 as follows:

• BS EN 13201-2: Performance Requirements • BS EN 13201-3: Calculation of Performance • BS EN 13201-4: Methods of Measuring Lighting Performance

Performance Requirements The classes we are most concerned with in the package are ME (Luminance), S (Illuminance) and CE (Conflict areas). Design for Traffic Routes This part of the standard covers recommendations for the lighting of all-purpose traffic routes, where the predominant user is motorised vehicles, and the speed of the user is moderate to fast, using a luminance specification. The recommendations are divided into 6 categories (excluding sub-categories of ME3 and ME4) as shown in Figure (1).

Class Luminance of road surface in dry condition

Lav (cd/m2)

Uo (%)

Ul (%)

TI (%)

ME1 2.0 40 70 10

ME2 1.5 40 70 10

ME3a 70

ME3b 60

ME3c

1.0 40

50

15

ME4a 60

ME4b 0.75 40

50 15

ME5 0.5 35 40 15

ME6 0.3 35 40 15

Figure (1): Recommended specifications for luminance, uniformity ratios and threshold increment for ME classes. The most stringent of these categories is ME1, which is likely to be used on major trunk roads with a high traffic speed and capacity. The other specifications are designed more for use where there is a lower requirement, for example on dual carriageways, single carriageways, feeder or estate roads or in rural areas.

Figure (2): Provides guidance on the selection of ME lighting classes for traffic routes (taken from Appendix B, Table B2 of BS 5489-1 : 2003). Hierarchy description

Type of road /general description

Detailed description Traffic flow ADT (Average Daily Traffic)

Lighting class

Motorway Limited Access

Routes for fast moving long distance traffic. Fully grade-separated and restrictions on use. Main carriageway in complex interchange areas Main carriageway with interchanges <3km Main carriageway with interchanges ≥3km Emergency lanes

≤ 40 000 > 40 000 ≤ 40 000 > 40 000 ≤ 40 000 > 40 000 -

ME1 ME1 ME2 ME1 ME2 ME2 ME4a

Strategic route

Trunk and some principal “A” roads between primary destinations

Routes for fast moving long distance traffic with little frontage access or pedestrian traffic. Speed limits are usually in excess of 40mph and there are few junctions. Pedestrian crossings are either segregated or controlled and parked vehicles are usually prohibited. Single carriageways Dual carriageways

≤ 15 000 > 15 000 ≤ 15 000 > 15 000

ME3a ME2 ME3a ME2

Main distributor

Major urban network and inter-primary links Short- to medium- distance traffic

Routes between strategic routes and linking urban centres to the strategic network with limited frontage access. In urban areas speed limits are usually 40mph or less, parking is restricted at peak times and there are positive measures for pedestrian safety reasons. Single carriageways Dual carriageways

≤ 15 000 > 15 000 ≤ 15 000 > 15 000

ME3a ME2 ME3a ME2

Secondary distributor

Classified Road (B and C class) and unclassified urban bus route, carrying local traffic with frontage access and frequent junctions

Rural areas (Zone E1/2d) These roads link the larger villages and HGV generators to the Strategic and Main Distributor Network. Urban areas (Zone E3d) These roads have 30 mph speed limits and very high levels of pedestrian activity with some crossing facilities including zebra crossings. On street parking is generally unrestricted except for safety reasons.

≤ 7000 > 7000 ≤ 15000 > 15000 ≤ 7000 > 7000 ≤ 15000 > 15000

ME4a ME3b ME3a ME3c ME3b ME2

Link road Road linking between the Main and Secondary Distribution Network with frontage access and frequent junctions

Rural areas (Zone E1/2d) These roads link the smaller villages to the distributor network. They are of varying width and not always capable of carrying two-way traffic. Urban areas (Zone E3d) These are residential or industrial inter-connecting roads with 30 mph speed limits random pedestrian movements and uncontrolled parking

Any Any With high pedestrian or cyclist traffic

ME5 ME4b or S2 S1

The new standards allow for different lighting levels (figure 3) to be adopted at different times of the night, if the traffic flow varies significantly. However it is just the luminance level that can change, the uniformities should retain the values used for the peak period. The standard describes how to construct the grid and the positioning of the luminaires for performing an ME calculation, and TURBO Light 2 adheres to these guidelines. If you are using Solution Finder or Quick Light, you can be sure of getting results accurately to comply with the standard. However, in Super Light you have complete control of these parameters, so care is needed when setting up the grid from scratch in this module. Of course, if you copy a project across from Quick Light, then the grid and luminaire positions will be set-up for you automatically. The diagram in Figure (3) shows how the grid is set up correctly for an ME luminance calculation. Notice the following details about the diagram:

• The carriageway is all that is included in the calculation; there are no footpaths or verges included.

• The grid points are located inside the edges of the lanes, by a distance of WL /6 on both sides. The gap between the grid points in the Y direction is WL /3.

• For S ≤ 30m, there are ten points spaced S/10 apart in the X direction, (where S is the standard spacing between columns), for S > 30m the number of points is the smallest integer giving D ≤ 3m.

• The calculation points are evenly spaced within the field of calculation. • Staggered arrangements are a special case, because here the grid is between

columns on the same side of the road.

Figure (3): Diagram of calculation grid for ME classes (Luminance method). Example shows a single sided column configuration.

A) In the longitudinal direction for S ≤ 30m, N = 10;

for S > 30m, the smallest integer giving D ≤ 3m

B) In the transverse direction The spacing (d) is determined from the equation:

D = WL /3

D = S/N

D =

WL /3

wL

Centre-line of lane

S60m

Observation direction

First luminaire in calculation field

Last luminaire in calculation field

Field of calculation

Edge of lane

Edge of lane

d/2

Design for Subsidiary Roads S classes deal with the road lighting of minor roads, where traffic speed and density are lower, and the predominant users are pedestrians, slow moving vehicles, or cyclists, for example in residential areas. It is divided into seven separate classes for dealing with different requirements. They are detailed in Figure (4).

Class Horizontal Illuminance

Eav (lux)

Emin (lux)

S1 15 5

S2 10 3

S3 7.5 1.5

S4 5 1

S5 3 0.6

S6 2 0.6

S7 Performance

not determined

Performance not

determined

Figure (4): Recommended specifications for illuminance in S classes. Average illuminance Eav does not exceed more than 1.5 times the minimum value of Eav indicated for the specified lighting class. For any lighting system, this requirement should be applied at the maximum design spacing, at the actual average design spacing of the lighting system, and to any group of three consecutive luminaires. The table below (figure 5) gives selection guidance for S-classes according to traffic flow, crime rate, environmental zone, and colour rendering.

Lighting class

Low traffic flowa Normal traffic flowb High traffic flowc

Crime rate Ra value

E1/E2d E3/E4d E1/E2d E3/E4d E1/E2d E3/E4d

Low Ra < 60 S5 S4 S4 S3 S3 S2

Ra ≥ 60 S6 S5 S5 S4 S4 S3

Moderate Ra < 60 S4 S3 S3 S2 - S1

Ra ≥ 60 S5 S4 S4 S3 - S2

High Ra < 60 S2 S2 S2 S1 - S1

Ra ≥ 60 S3 S3 S3 S2 - S2

NOTE 1 Crime rates are relative to the local area, and not national. Assistance can be obtained from the local crime prevention officer.

NOTE 2 The lighting levels shown in this table may be increased by one lighting class in the vicinity of traffic calming measures. a Low traffic flow refers to areas where the traffic usage is of a level equivalent to a residential road and solely associated with the

adjacent properties. b Normal traffic flow refers to areas where the traffic usage is of a level equivalent to a housing estate access road and can be

associated with local amenities such as clubs, shopping facilities, public houses, etc. c High traffic flow refers to areas where the traffic usage is high and can be associated with local amenities such as clubs, shopping

facilities, public houses, etc. d Environmental zone, as given in the ILE publication Guidance notes for reduction of light pollution [16].

Figure (5): BS5489-1 : 2003 Table B.4 - Lighting classes for subsidiary roads (pedestrians and cyclists)

It should be noted that the lighting level may be increased by 1 class in the vicinity of traffic calming measures. Implications of implementing the new standards TURBO Light 2 sets out the grid and luminaires correctly for an S class calculation in Solution Finder and Quick Light. The correct method for setting out an S class grid is shown in Figure (6). Notice that the relevant area extends to the furthest edges of the road under consideration, which includes any footpaths that are present. Generally, the rules are as follows:

• The area for calculation includes the carriageway and the footpaths. • The number of points (n) transversely should be greater than or equal to 3 and is

the smallest integer such that the distance between points d ≤ 1.5m • The grid is located inside the relevant area, by a distance of Wr /2n on both sides.

The gap between the grid points in the Y direction is Wr /n. • For S ≤ 30m, there are ten points spaced S/10 apart in the X direction, (where S

is the standard spacing between columns), for S > 30m the number of points is the smallest integer giving D ≤ 3m.

• The calculation points are evenly spaced within the field of calculation.

A) In the longitudinal direction for S ≤ 30m, N = 10;

for S > 30m, the smallest integer giving D ≤ 3m

Figure (6): Diagram of calculation grid for S class (Illuminance method). Example shows a single sided column configuration.

B) In the transverse direction for n > 3;

the smallest integer giving d ≤ 1.5m

Luminaire Luminaire Field of calculation

Edge of relevant area

W

d/2

D

=Wr /n

D/2 D = S/N

S

Designing for Conflict Areas This part of the standard provides recommendations for the lighting of conflict areas, road junctions and major/minor priority junctions where at least one road is lit as a traffic route in accordance with an ME class. It is therefore beyond the scope of this Appendix to give all possible junction layouts. BS5489-1 Appendix J provides such road junction information. The sizes and forms of roundabouts vary so widely that it is difficult to give a simple rule relating mounting height and light output. As the lighting technique is directed towards revealing the kerbs, obstructions, vehicles, etc., by direct lighting rather than by silhouette, we express the minimum requirements in terms of average horizontal illuminance and uniformity. The following table gives lighting classes for conflict areas on traffic routes, using the CE lighting classes related to the lighting class on the roads approaching the conflict area.

Traffic route lighting class

Conflict area lighting class

ME1 ME2 ME3 ME4 ME5

CE0 CE1 CE2 CE3 CE4

Figure (7): Taken from BS5489-1 : 2003 Table B.3 - Lighting classes for conflict areas For traffic routes within the road categories defined by an ME class, the maintained illuminance should be not less than the values given in Figure (8).

Class Horizontal Illuminance

Eav (lux)

Uo (%)

CE0 50 40

CE1 30 40

CE2 20 40

CE3 15 40

CE4 10 40

CE5 7.5 40

Figure (8): Recommended specifications for conflict areas.

Designing for Urban Centres (CE Classes) The table below gives selection guidance on lighting classes for pedestrian areas and mixed vehicle and pedestrian areas in city and town centres.

Lighting Class

Type of Traffic Normal Traffic Flow High Traffic Flow

E3 E4 E3 E4

Pedestrian only CE3 CE2 CE2 CE1

Mixed vehicle and pedestrian with separate footways CE2 CE1 CE1 CE1

Mixed vehicle and pedestrian on same surface CE2 CE1 CE1 CE1

Figure (9): Taken from BS5489-1 : 2003 Table B.5 - Lighting classes for city and town centres The selection of these classes for a specific city or town centre may be varied up or down from the classes shown in the table, taking account of vehicular traffic use, street parking, level of crime, etc.