MAINTENANCE OFOUTDOOR LIGHTINGSYSTEMS

CIE 15x:2003

UDC: 628.971 Descriptor: Exterior lighting

ISBN 3 901 906 xx x

Deadline for BA and D5 votes:10.06.2003

THE INTERNATIONAL COMMISSION ON ILLUMINATION

The International Commission on Illumination (CIE) is an organisation devoted to international co-operation and exchange ofinformation among its member countries on all matters relating to the art and science of lighting. Its membership consists ofthe National Committees in 37 countries and one geographical area and of 5 associate members.

The objectives of the CIE are:1. To provide an international forum for the discussion of all matters relating to the science, technology and art in the fields

of light and lighting and for the interchange of information in these fields between countries.2. To develop basic standards and procedures of metrology in the fields of light and lighting.3. To provide guidance in the application of principles and procedures in the development of international and national

standards in the fields of light and lighting.4. To prepare and publish standards, reports and other publications concerned with all matters relating to the science,

technology and art in the fields of light and lighting.5. To maintain liaison and technical interaction with other international organisations concerned with matters related to the

science, technology, standardisation and art in the fields of light and lighting.The work of the CIE is carried on by seven Divisions each with about 20 Technical Committees. This work covers subjectsranging from fundamental matters to all types of lighting applications. The standards and technical reports developed bythese international Divisions of the CIE are accepted throughout the world.A plenary session is held every four years, at which the work of the Divisions and Technical Committees is reviewed, reportedand plans are made for the future. The CIE is recognised as the authority on all aspects of light and lighting. As such itoccupies an important position among international organisations.

LA COMMISSION INTERNATIONALE DE L’ECLAIRAGE

La Commission Internationale de l'Eclairage (CIE) est une organisation qui se donne pour but la coopération internationale etl'échange d'informations entre les Pays membres sur toutes les questions relatives à l'art et à la science de l'éclairage. Elleest composée de Comités Nationaux représentant 37 pays plus un territoire géographique, et de 5 membres associés.

Les objectifs de la CIE sont :1. De constituer un centre d'étude international pour toute matière relevant de la science, de la technologie et de l'art de la

lumière et de l'éclairage et pour l'échange entre pays d'informations dans ces domaines.2. D'élaborer des normes et des méthodes de base pour la métrologie dans les domaines de la lumière et de l'éclairage.3. De donner des directives pour l'application des principes et des méthodes d'élaboration de normes internationales et

nationales dans les domaines de la lumière et de l'éclairage.4. De préparer et publier des normes, rapports et autres textes, concernant toutes matières relatives à la science, la

technologie et l'art dans les domaines de la lumière et de l'éclairage.5. De maintenir une liaison et une collaboration technique avec les autres organisations internationales concernées par des

sujets relatifs à la science, la technologie, la normalisation et l'art dans les domaines de la lumière et de l'éclairage.Les travaux de la CIE sont effectués par 7 Divisions, ayant chacune environ 20 Comités Techniques. Les sujets d'étudess'étendent des questions fondamentales, à tous les types d'applications de l'éclairage. Les normes et les rapports techniquesélaborés par ces Divisions Internationales de la CIE sont reconnus dans le monde entier.Tous les quatre ans, une Session plénière passe en revue le travail des Divisions et des Comités Techniques, en fait rapportet établit les projets de travaux pour l'avenir. La CIE est reconnue comme la plus haute autorité en ce qui concerne tous lesaspects de la lumière et de l'éclairage. Elle occupe comme telle une position importante parmi les organisationsinternationales.

DIE INTERNATIONALE BELEUCHTUNGSKOMMISSION

Die Internationale Beleuchtungskommission (CIE) ist eine Organisation, die sich der internationalen Zusammenarbeit unddem Austausch von Informationen zwischen ihren Mitgliedsländern bezüglich der Kunst und Wissenschaft der Lichttechnikwidmet. Die Mitgliedschaft besteht aus den Nationalen Komitees in 37 Ländern und einem geographischen Gebiet und aus 5assoziierten Mitgliedern.

Die Ziele der CIE sind:6. Ein internationaler Mittelpunkt für Diskussionen aller Fragen auf dem Gebiet der Wissenschaft, Technik und Kunst der

Lichttechnik und für den Informationsaustausch auf diesen Gebieten zwischen den einzelnen Ländern zu sein.7. Grundnormen und Verfahren der Meßtechnik auf dem Gebiet der Lichttechnik zu entwickeln.8. Richtlinien für die Anwendung von Prinzipien und Vorgängen in der Entwicklung internationaler und nationaler Normen

auf dem Gebiet der Lichttechnik zu erstellen.9. Normen, Berichte und andere Publikationen zu erstellen und zu veröffentlichen, die alle Fragen auf dem Gebiet der

Wissenschaft, Technik und Kunst der Lichttechnik betreffen.10. Liaison und technische Zusammenarbeit mit anderen internationalen Organisationen zu unterhalten, die mit Fragen der

Wissenschaft, Technik, Normung und Kunst auf dem Gebiet der Lichttechnik zu tun haben.Die Arbeit der CIE wird in 7 Divisionen, jede mit etwa 20 Technischen Komitees, geleistet. Diese Arbeit betrifft Gebiete mitgrundlegendem Inhalt bis zu allen Arten der Lichtanwendung. Die Normen und Technischen Berichte, die von dieseninternational zusammengesetzten Divisionen ausgearbeitet werden, sind von der ganzen Welt anerkannt.Tagungen werden alle vier Jahre abgehalten, in der die Arbeiten der Divisionen überprüft und berichtet und neue Pläne für dieZukunft ausgearbeitet werden. Die CIE wird als höchste Autorität für alle Aspekte des Lichtes und der Beleuchtungangesehen. Auf diese Weise unterhält sie eine bedeutende Stellung unter den internationalen Organisationen.

Published by the

COMMISSION INTERNATIONALE DE L'ECLAIRAGECIE Central Bureau

Kegelgasse 27, A-1030 Vienna, AUSTRIATel: +43(01)714 31 87 0, Fax: +43(01)713 08 38 18

e-mail: ciecb@ping.atWWW: http://www.cie.co.at/

CIE 2003

MAINTENANCE OFOUTDOOR LIGHTINGSYSTEMS

CIE 15x:2003

UDC: 628.971 Descriptor: Exterior lighting

ISBN 3 901 906 xx x

CIE 15x:2003

II

This Technical Report has been prepared by CIE Technical Committee 5-14 of Division 5“Exterior and other lighting applications” and has been approved by the Board ofAdministration of the Commission Internationale de l'Eclairage for study and application. Thedocument reports on current knowledge and experience within the specific field of light andlighting described, and is intended to be used by the CIE membership and other interestedparties. It should be noted, however, that the status of this document is advisory and notmandatory. The latest CIE proceedings or CIE NEWS should be consulted regarding possiblesubsequent amendments.

Ce rapport technique a été préparé par le Comité Technique CIE 5-14 de la Division 5“Eclairage extérieur et autres applications” et a été approuvé par le Bureau d'Administrationde la Commission Internationale de l'Eclairage, pour étude et application. Le document traitedes connaissances courantes et de l'expérience dans le domaine spécifique indiqué de lalumière et de l'éclairage, et il est établi pour l'usage des membres de la CIE et autresgroupements intéressés. Il faut cependant noter que ce document est indicatif et nonobligatoire. Pour connaître d'éventuels amendements, consulter les plus récents comptesrendus de la CIE ou le CIE NEWS.

Dieser Technische Bericht ist vom CIE Technischen Komitee 5-14 der Division 5“Aussenbeleuchtung und andere Lichtanwendungen” ausgearbeitet und vom Vorstand derCommission Internationale de l'Eclairage gebilligt worden. Das Dokument berichtet über denderzeitigen Stand des Wissens und Erfahrung in dem behandelten Gebiet von Licht undBeleuchtung; es ist zur Verwendung durch CIE-Mitglieder und durch andere Interessiertebestimmt. Es sollte jedoch beachtet werden, daß das Dokument eine Empfehlung und keineVorschrift ist. Die neuesten CIE-Tagungsberichte oder das CIE NEWS sollten im Hinblick aufmögliche spätere Änderungen zu Rate gezogen werden.

Any mention of organisations or products does not imply endorsement by the CIE. Whilstevery care has been taken in the compilation of any lists, up to the time of going to press,these may not be comprehensive.

Toute mention d'organisme ou de produit n'implique pas une préférence de la CIE. Malgré lesoin apporté à la compilation de tous les documents jusqu'à la mise sous presse, ce travail nesaurait être exhaustif.

Die Erwähnung von Organisationen oder Erzeugnissen bedeutet keine Billigung durch dieCIE. Obgleich große Sorgfalt bei der Erstellung von Verzeichnissen bis zum Zeitpunkt derDrucklegung angewendet wurde, ist es möglich, daß diese nicht vollständig sind.

CIE, 2003 – All rights reserved

CIE 15x:2003

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The following members of TC 5-14 "Maintenance of outdoor lighting systems", took part in thepreparation of this Report. The committee comes under Division 5 "Exterior Lighting andOther Lighting Applications”.

N. Pollard (Chair) United KingdomE. Bjelland NorwayP. Chan Hong KongP. Rombauts BelgiumL. di Fraia ItalyK. Iizuka JapanS. Lain United KingdomE. Manzano ArgentinaC. A. Oerkvitz USAJ. Roberge CanadaA . Stockmar GermanyP. Szilas HungaryN. Tharyani IndiaR. Yates South Africa

The style and layout of this standard has been taken from that of Publications CIE 97-1992"Maintenance of Indoor Electric Lighting Systems" from which it was felt important that the twodocuments should have a similar framework.

TABLE OF CONTENTS

SUMMARY V

RESUME V

ZUSAMMENFASSUNG V

1. INTRODUCTION 1

2. NEED FOR MAINTENANCE 1

2.1 Influencing factors 2

2.2 Inspection and recording intervals 2

2.3 Cleaning schedules and environmental pollution categories 3

3. ANALYSIS OF DEPRECIATION 3

3.1 Lamp lumen maintenance 3

3.2 Lamp survival 4

3.3 Dirt on lamps and luminaires 4

3.4 Long term depreciation of reflector and diffuser materials 5

3.5 Dirt on light reflecting surfaces, e.g. arcades, tunnels and underpasses 6

3.6 Corrosion of luminaire supports 6

4. ECONOMICS OF SERVICING 7

4.1 Lamp replacement 7

4.2 Cleaning of luminaires 8

4.3 Luminaire supports 8

4.4 Electrical components 9

4.5 Monitoring/patrolling for lighting defects 9

4.6 Obstruction of light by trees 9

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5. MAINTENANCE FACTOR 9

5.1 Determination of maintenance factor 10

6. SERVICING LIGHTING SYSTEMS 11

6.1 Safety of personnel 11

6.2 Access 11

6.3 Cleaning luminaires 11

6.4 Cleaning agents 11

6.5 Relamping 12

6.6 Equipment disposal 12

7. APPENDICES 12

7.1 Example of cost effectiveness of patrolling for road lighting. 12

7.1.1 Patrol viability calculations 137.1.2 Patrol interval viability formulae 13

7.2 Example of maintenance factor estimation 14

7.3 Example of optimum group maintenance interval estimation 14

7.4 Maintenance equipment 15

7.5 Terminology 16

7.5.1 Definitions 167.5.2 Abbreviations 16

8. BIBLIOGRAPHY 17

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MAINTENANCE OF OUTDOOR LIGHTING SYSTEMS

SUMMARY

During the life of a lighting installation, the light available progressively decreases. Thereduction rates are a function of environmental, operating and age conditions. In lightingdesign we must take account of this fall by the use of a maintenance factor and plan suitablemaintenance schedules to limit the decay. This guide provides information on suggestedmaintenance factors and the selection of suitable equipment. It describes the parametersinfluencing the depreciation process and develops the procedure for estimating the economicmaintenance cycles for outdoor electric lighting installations and gives advice on servicingtechniques.

MAINTENANCE D’UNE INSTALLATION D’ECLAIRAGE EXTERIEUR

RESUME

Au cours de la vie utile d'une installation d'éclairage, la quantité de lumière disponible décroîtprogressivement. Les taux de décroissance dépendent des facteurs environnement,conditions d'opération et âge. Le concepteur de projet doit donc tenir compte de cettediminution en déterminant un facteur de maintenance approprié et en établissant un pland'entretien précis pour limiter toute dégradation. Ce guide décrit la façon d'établir des facteursde maintenance réalistes et de choisir les équipements adéquats. Il décrit aussi lesparamètres affectant le processus de dépréciation, propose une marche à suivre pouroptimiser les cycles d'entretien des installations d'éclairage électrique, et conseille lestechniques d'entretien les plus appropriées.

GERMAN TITLE

ZUSAMMENFASSUNG

Translation requested

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1. INTRODUCTION

The luminance/illuminance initially provided by a lighting installation will decrease graduallythroughout the life of the installation. Several terms to describe the factor which accounts forthis reduction have been used. In the current International Lighting Vocabulary (CIE 17.4 -1987) the English term “Light loss factor” is given with “Maintenance factor” shown asobsolete. The equivalent term in French is “Facteur de dépréciation”. For the purposes of thisreport it has been decided to retain the term “Maintenance factor” as this is the morecommonly used and understood term. The definition is given in publication CIE 17.4 - 1987(845-09-59) as:

“Ratio of the average luminance/illuminance on the working plane after a certainperiod of use of a lighting installation to the average luminance/illuminance obtained under thesame conditions for the installation considered conventionally as new.”

Note: The term depreciation factor has been formerly used to designate the reciprocal of theabove ratio.

The recommended parameters for lighting design are now generally based on“maintained” values which are the average luminance/illuminance at the “certain period” of theabove definition, when maintenance has to be carried out. The exceptions are for glare andobtrusive light ratings e.g. TI, when the initial values are taken.

Lighting systems have different maintenance characteristics and this should be one ofthe important assessments made in the early stages of project design.

This guide discusses the various influencing factors and gives data based on practicalsolutions which enable the maintenance factor for types of systems and environments to bederived. The derived maintenance factor should be applied to all formulae used for lightingscheme calculations, such as luminance/illuminance on areas or at points. Methods forestimating economic maintenance periods and advice on cleaning techniques are also given.

The maintenance of the mechanical fixtures supporting the luminaires is also covered.This is because in most outdoor situations this is of considerable importance to the overallinstallation performance and quite often has major safety factors of its own. Correct luminairealignment is also an important factor in this aspect regarding both task and environmentalconsiderations.

The guide also provides a limited selection of typical data to allow the calculationmethods to be explained. However, to take advantage of the continuing development oflighting products, up-to-date data should be obtained from manufacturers.

The bibliography contains a list of publications used as the basis for this guide wherefurther information may be obtained.

2. NEED FOR MAINTENANCE

All lighting schemes will deteriorate progressively from the moment they are put into use. Thelosses are due to the accumulation of dust and dirt on all exposed surfaces of lamps andluminaires - reducing the transparency or reflecting power - and to the decay in lamp-lumenoutput and failing lamps. For the luminaires within the installation, if this process is unchecked,it will result in their light output falling to very low values as shown in Figure 2.1, and thescheme becomes poor and dangerous. As the decay in light output is gradual, the loss maynot be noticed immediately. But over a period this gradual reduction will cause problemsrelevant to the tasks at hand including, for sports such as ice hockey, a danger of not seeingthe puck, or in road lighting of causing a vehicle accident.

Regular maintenance is, therefore, most important for an effective lighting installation.The lighting system should not only be cleaned correctly and thoroughly but the cleaningshould be carried out at regular intervals. A well designed maintenance programme willmaintain the required luminance/illuminance, reduce capital and operating costs and run thesystem safely. It will ensure a satisfactory appearance, security and safety for the users.

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However, even with a well designed and operated maintenance programme some lossof light level is inevitable through equipment deterioration. This loss has to be estimated, atthe time the lighting scheme is planned, and an allowance in the form of maintenance factorshould be included in the scheme design calculations.

In outdoor lighting situations, surfaces, other than the walls and ceilings of pedestrianor vehicular tunnels or underpasses, are not normally within the control of the lightingmaintenance engineer. This guide will therefore concentrate on that part of the installationwhich is under control.

2.1 Influencing factors

There are several factors which can reduce the light output. These are grouped under non-recoverable and recoverable depreciation.

Non-recoverable factors, such as ageing, are inherent in the installation and itsenvironment and cannot be improved during normal maintenance or are uneconomical toovercome. At the specification stage of a lighting installation, these factors should be takeninto account together with the planning of a maintenance programme.

If the influence of other factors such as voltage, frequency, temperature and ballast,are permanent and significant then at the design stage the magnitude of these effects shouldbe estimated and an allowance similar to the maintenance factor should be made in thecalculations. The influence of random occurrences may be ignored, provided they do not harmthe operation of the lighting system.

Recoverable factors of lamp lumen maintenance, lamp survival and luminairemaintenance can be made good during routine maintenance by relamping, cleaning andreplacement of components.

The value of such maintenance programme is indicated as an example in Figure 2.1.Clearly the depreciation in the unserviced scheme will fall to around 20 % of the initial valuewithin 3 years and will continue to decline. But by comprehensive cleaning the decline ischecked at under 10 % depreciation.

Figure 2.1 The effect of maintenance program.

Once the non-recoverable reductions by ageing or soiling have occurred they cannotbe brought back to their original condition and replacement of the bowl or complete luminairemay be necessary. This is the case with luminaires if they are in, say, dusty or oilyatmospheres. In such cases it is well worth considering at the design stage, the use of sealedluminaires of high IP ratings, e.g. IP 6X.

2.2 Inspection and recording intervals

A regular inspection and performance recording of lighting installations is advisable and isdiscussed further in Sections 4.1 & 4.2. While having cost, it may well eventually bring cost

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savings due to a more refined maintenance requirement for the environment concerned.While having a cost, such inspections may lead to required adjustments in the maintenanceprocedures, in order to ensure that minimum required lighting performance is maintained at alltimes.

2.3 Cleaning schedules and environmental pollution categories

A regular cleaning schedule of lighting installations, of both internal and external surfaces, isadvisable, the frequency of which will depend on:

(a) type of environment;(b) equipment used;(c) design parameters.

Within many countries luminaires are classified by IP ratings (IEC 529), against theirability to deter the ingress of moisture and water. The first integer indicates the particle sizei.e. fine dust or large grit, the higher the number the smaller the particle. The second integerindicates the degree of protection to moisture from indirect spray through high pressure jet tototal immersion. The higher the number the higher the seal.

The optical compartments of luminaires used in medium/high pollution environmentsshould be of a rating IP4X or higher.

3. ANALYSIS OF DEPRECIATION

Several factors contribute to light losses and the effect and magnitude vary with the type oflamp, luminaire, its installation geometry and the environment. For example, areas vary as tothe amount and type of dirt in the air; the amount of dirt in the centre of an industrial city isgreater than that found in a rural village. But the type of dirt is also important. The dry dustfrom a stone quarry is very different from the crop spray and insects on a rural traffic route. Itis important to be able to recognise these variations when assessing luminaire types andcleaning requirements.

3.1 Lamp lumen maintenance

The output of all lamps decreases during use. The exact rate, however, depends on the lamp typeand ballasting system. The losses due to this effect can be reduced by more frequent lampreplacement, perhaps by group replacement. Table 3.1 shows typical examples. It is thereforevery important to obtain up-to-date data from the manufacturers for estimating the maintenancefactor and the maintenance programme, particularly when using a new type of lamp.

Table 3.1 Lamp Lumen Maintenanace Factors (LLMF).

Operating time (thousands of hours)Lamp type

4 6 8 10 12S 0,98 0,97 0,94 0,91 0,90M 0,82 0,78 0,76 0,74 0,73Q 0,87 0,83 0,80 0,78 0,76L 0,98 0,96 0,93 0,90 0,87FD* (Tph) (Hph)

0,950,82

0,940,78

0,930,74

0,920,72

0,910,71

FS* 0,91 0,88 0,86 0,85 0,84H - - - - -Note. The lamp abbreviations given in the table relate to the following lamps:

S High Pressure Sodium FD Tubular fluorescentM Metal Halide FS Compact fluorescentQ High Pressure Mercury H Tungsten halogenL Low Pressure Sodium Tph TriphosphorHph Halophosphate* Relates to value at an ambient temperature of 25° C, therefore check location.

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For specific lamp data always consult the manufacturers.

3.2 Lamp survival

Lamp survival is the probability of lamps continuing to operate for a given time. The survivalrate depends on lamp type and particularly, in the case of discharge lamps, the wattage,frequency of switching and the ballasting system. Failed lamps cause reduction in illuminanceand uniformity, but the effect can be minimised by spot replacement of lamps. Table 3.2shows typical examples.

Table 3.2 Lamp Survival Factors (LSF).

Operating time (thousands of hours)Lamp type

4 6 8 10 12S 0,98 0,96 0,94 0,92 0,89M 0,98 0,97 0,94 0,92 0,88Q 0,93 0,91 0,87 0,82 0,76L 0,92 0,86 0,80 0,74 0,62FD (Tph) (Hph)

0,990,99

0,990,98

0,990,93

0,980,86

0,960,70

FS* 0,98 0,94 0,90 0,78 0,50H - - - - -Note. The lamp abbreviations given in the table relate to the following lamps:

S High Pressure Sodium FD Tubular fluorescentM Metal Halide FS Compact fluorescentQ High Pressure Mercury H Tungsten HalogenL Low Pressure Sodium Tph TriphosphorHph Halophosphate

For specific lamp data consult the manufacturers.

3.3 Dirt on lamps and luminaires

Dirt on lamps and luminaires will generally cause the greatest loss of light. The amount of lightloss depends on the nature and density of airborne dirt, luminaire design and lamp type. Dirtaccumulation on reflecting surfaces can be minimised by sealing the lamp compartmentagainst entry of dust and moisture. Significant benefits can be obtained with the luminaireoptical compartment sealed to at least IP5 - protection.

Table 3.3 shows typical data for a range of luminaires.

Table 3.3 Luminaire Maintenance Factors (LMF).

Exposure time (years)OpticalcompartmentIP Rating

PollutionCategory

1,0 1,5 2,0 2,5 3,0

IP2X High 0,53 0,48 0,45 0,43 0,42Medium 0,62 0,58 0,56 0,54 0,53Low 0,82 0,80 0,79 0,78 0,78

IP5X High 0,89 0,87 0,84 0,80 0,76Medium 0,90 0,88 0,86 0,84 0,82Low 0,92 0,91 0,90 0,89 0,88

IP6X High 0,91 0,90 0,88 0,85 0,83Medium 0,92 0,91 0,89 0,88 0,87Low 0,93 0,92 0,91 0,90 0,90

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Definition of pollution categories

Low: No nearby smoke or dust generating activities and a low ambient contaminant level.Light traffic. Generally limited to residential or rural areas. The ambient particulatelevel is no more than 150 micrograms per cubic metre.

Medium: Moderate smoke or dust generating activities nearby. Moderate to heavy traffic. Theambient particulate level is no more than 600 micrograms per cubic metre.

High: Smoke or dust plumes generated by nearby activities are commonly enveloping theluminaires.

3.4 Long term depreciation of reflector and diffuser materials

Glazing bowls / Diffusers:

Glass

Glass is easily cleaned to restore the original finish.

A lack of long term cleaning can lead to surfaces being more difficult to restore,especially prismatic, or in extreme cases surface damage may result (e.g. etching).

Lack of cleaning leads to reduced light output and change in the light distribution bydiffusion of the light, resulting in reduced lighting levels and degraded distribution.

Plastics - Acrylic (PMMA – polymethyl methacrylate) and Polycarbonate (PC)

Degradation is generally from dirt and atmospheric contaminants, and materialageing. Inappropriate use of, or exposure to solvents can produce rapid degradationas the plastic structure is attacked.

Regular cleaning with mild detergent and water will restore clarity. Remove intensegrime with white spirit or other cleaners specifically formulated for PMMA or PC, andrinse well. Abrasives and scourers will damage the surface and add diffusion.

Adhesives used in construction or fixings must be compatible otherwise degradation(short to long term) may occur.

Acrylic

Performs well with UV present. Over the long term (of the order 10 years +) the plasticwill have begun to deteriorate by crazing with gradual loss of strength; the componentshould be regarded as a replaceable item.

Its principal drawback is its relative brittleness – lack of impact resistance – wherevandalism, for example, may be a problem, although toughened versions are availablethat improve this characteristic.

Polycarbonate

Its principal advantage over PMMA is its (initially) higher strength and resistance toimpact. However the material degrades in the presence of UV – daylight, and UV-emitting lamps. The effect is accelerated by temperature. It is important therefore tokeep the material service temperature below around 90°C - 100°C, particularly whenUV is present (e.g. by ensuring the lamp wattage used in the luminaire is limitedappropriately). The degradation can be rapid, so the material is normally protected byUV absorbers – either additives integral with the raw material or applied as a surfacetreatment. These absorbers are used up gradually and only delay degradation – butnormally allow a service life of several years.

Degradation results in embrittlement – loss of strength and impact resistance – andyellowing – loss of light transmission. The component should be regarded as areplaceable component.

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Opal polycarbonate is usually more susceptible to UV as the diffusing additive canincrease the radiation absorbed. Surface UV-absorber treatment is particularlyrecommended.

Cleaning is as above, but PC is softer than acrylic and has a poor resistance toabrasion.

Reflectors:

Aluminium

The reflecting surface of aluminium will degrade by oxidation unless protected. Theusual method is by anodising (a controlled sealed oxide surface) – either performedas a separate operation after the reflector is formed, or as a treatment during theproduction of the aluminium sheet. The film thickness can typically be from 1 µ to 25 µthick – the thicker the film the more protection it gives, but the more it diffuses thefinish. Lighting grades have anodic films of typically around 2 µ - 3 µ to balancecorrosion resistance with a wide range of high-reflectance surface finishes.

Exposure to a moist atmosphere will lead to surface pitting and a gradual reduction inreflectance/specularity. Dirt ingress will lead to significant loss of reflectance andspecularity with consequent loss of light output and degradation of the shape of thelight distribution, leading to poorer light levels and uniformity for example. Protectioninside a sealed enclosure is necessary for an acceptable life. Cleaning is then largelyunnecessary. If cleaning is necessary, low surface tension water with a specialbonded fibre fabric cloth, or chamois leather, can be used.

Metallised plastic

Protection is usually by lacquering the aluminium surface, applying the lacquer byspraying and then curing it by heat. The lacquer may eventually degrade to someextent by yellowing. Operating at too high a temperature (by an excessive lampwattage for example) will accelerate degradation, and may also damage the bondbetween the metallised coating and the substrate.

Cleaning, if necessary, should be gentle without abrasives or solvents to avoiddamaging the protective lacquer. In a sealed fitting this should be unnecessary.

Glass

Silvered glass is little used now except in specialist applications. The backing on thereflecting surface protects the silver from oxidation; the edges are vulnerable todegradation from moisture – particularly marine – and using such reflectors within asealed luminaire is appropriate. Cleaning the glass will maintain the reflectiveproperties providing care is taken not to damage the protective backing.

3.5 Dirt on light reflecting surfaces, e.g. arcades, tunnels and underpasses

Dirt on structural surfaces tends to reduce the amount of inter-reflected light which in bothpedestrian and vehicular tunnels and underpasses, plays an important part in the visualscene. Structural proportions and the distribution of light from luminaires determines theamount of light which strikes the walls and ceiling. Regular maintenance of all reflectingsurfaces is advisable in all such installations. Clean surfaces will also maintain the luminancebalance in the environment.

Note: For reference to Tunnels and Underpasses, see “Section 8 – Maintenance” of CIE 88-1990 Guide for the lighting of road tunnels and underpasses.

3.6 Corrosion of luminaire supports

Whilst recognising that most supports are chosen for their design strengths, aesthetic factorsand overall suitability, it must be recognised that during the life of a structure, periodicmaintenance may be necessary.

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In many countries, modern supports have generally been protected from the date ofmanufacture against corrosion. However, the problems of environmental degradation andaccidental damage can significantly affect the life and therefore their structural integrity.

A regular programme of inspections should be made where visual and possiblyelectronic studies are recorded to ensure that appropriate remedial action is taken in advanceof any structural decay. Particular attention should be paid to welded steel structures and toplanted steel structures and to internal surfaces where corrosion may go undetected. Woodensupports can equally be susceptible to damage from vehicles and inspections should be madeat frequencies which coincide with electrical and luminaire maintenance visits and correctiveaction taken where appropriate.

4. ECONOMICS OF SERVICING

During the design of a lighting installation it is often possible to choose components, systemsand finishes that will result in the maintenance being kept to a minimum:

• Choosing luminaires in which the optical compartment is easy to clean and/or has ahigh IP rating.

• Reducing the number of variants on a scheme.• Using luminaires having few components, which, when requiring service, can be

easily handled or removed for off-site servicing.• Where applicable, recommending surface finishes that remain clean for long periods

and are easily cleanable.

Other ways the designer can help the maintenance and thus improve theeffectiveness of maintenance are:

• Planning for ease of maintenance - consider access, types of tools needed forservicing, ensuring availability of spare lamps, optics or even luminaires. Early liaisonwith maintenance engineers to ensure understanding of requirements and proceduresis also advantageous.

• Preparing a comprehensive maintenance schedule with instructions.• Organising effective information feed back of mistakes, failures or difficulties and use

these to avoid a repetition in future projects.• Concrete plinths that keep steel structures away from the corrosive effects of the

ground.

4.1 Lamp replacement

The total lamp replacement costs comprise the cost of lamps and the cost of labour involvedincluding cost of ordering, stocking, installation, disposal, etc. The labour cost depends on thelamp change system adopted and on the accessibility of the luminaire. The alternatives are“Spot” replacement where each failed lamp is changed or “Group” replacement where all thelamps (failed or good) are changed at some time which is less than the rated average lamplife. In most projects a combined spot/group lamp replacement programme is practised. It isvery important that in places where loss of a lamp may lead to unsafe movements the failedlamp is replaced immediately. Installation of multi lamp luminaires are least affected byrandom lamp failures.

With lamp lumen depreciation, it can also become a waste of energy resources tooperate lamps well past their most efficient life cycle.

Costs assessed as follows:

Cost of spot replacement per socket Cs is:

Cs = L + S + E + D (4.1)

where L = cost of lamp;S = cost of labour (incl. initial sighting costs);E = cost of access equipment;D = cost of disposal.

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Cost of group replacement per socket Cg is:

Cg = L +B + E + D ..(4.2)

where L = cost of lampB = cost of labour for group replacement per lamp.E = cost of access equipment.D = cost of disposal

Cost of combined group and spot replacement per socket, Ct is:

Ct = Cg + FCs (4.3)

where F = fraction of lamps failed and replaced prior to the re-lamping interval.

Note: Lamps may be bulk purchased and stored for spot replacement. Also spares can bepart of initial scheme purchase.

If the good lamps (i.e. those which were used as spot replacements in the second half ofthe group replacement) are used for subsequent spot replacement, then FCs simplifies to FS.

The economy of group replacement depends on lamp lumen depreciation and heavilyon survival rates. The more lamps survive the replacement interval the fewer costly spotreplacements are needed.

It is important to note that lamp replacement intervals very much depend on the lampoperating hours. Examples of annual burning hours are given in Table 4.1.

Table 4.1 Examples of typical annual lamp operating hours.

Installation hours/yearContinuous 8760

All Night (Sunset to sunrise 4200Sunset to 24:00 hr 2600

Sunset to 22:00 (5 nights/week) 13004 hrs/week 208

4.2 Cleaning of luminaires

The optimum cleaning interval T for a luminaire is reached when the cost of the lost lightoutput equals the cost of cleaning.

The optimum cleaning interval T can be determined from the expression:

T = - Cc / Ca + 2 Cc / DELTA Ca years (4.4)

where T = optimum cleaning interval;Cc = cost of cleaning the luminaire once;Ca = annual cost of owning and operating the luminaire without cleaning;DELTA = annual average rate of luminaire dirt depreciation. Values are given in

Table 3.3.

Note1: Cc - cost of cleaning includes the cost of any cleaning agent, special tool, platforms orequipment and the labour. The labour costs may also be affected by the timing atwhich the cleaning is done (during normal working hours or not).

Note2: Ca - cost of operating includes the amortization installation cost (proportion of capitalwritten off per year), the annual energy cost (derived from energy used in kWh x costof energy per unit) and relamping cost (cost of lamps and replacement labour perannum).

4.3 Luminaire supports

In many outdoor lighting installations, particularly road lighting, the care and maintenance ofthe luminaire supports is an important part of the overall maintenance responsibility.

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For fixed poles, towers or wall brackets, frequent inspections and painting will benecessary, together with occasional monitoring of below ground conditions.

For structures over 20 years old, thought should be given to overall structural stabilityand to eventual, planned replacement.

Where hinged or winched poles or masts are installed, regular inspection of the ropesand pulleys by a special competent person should be included. The cleaning and lubrication ofall moving parts should be a part of the routine maintenance schedule.

Where the accurate alignment of luminaires is of task and/or environmentalimportance, this too should be checked and corrected as necessary.

4.4 Electrical components

Any electrical installation is a potential safety hazard and its regular inspection, maintenanceand testing of great importance, which in many countries is required by law.

The replacement of any components must be judged on the potential hazard to thesafe operation of the installation. As lighting technology is constantly making advancementsthere are many instances where old installations, although operating safely, will benefit fromnew types of lamps or control systems or even to change the whole installation. In these casesthe investment can be estimated against the potential savings in energy cost and service cost.Another benefit could be in the improvements in the visual environment.

In some situations the group replacement of Photo-electric control units (PECU’s),may be considered beneficial, especially when combined with a group lamp change.

4.5 Monitoring/patrolling for lighting defects

As forms of “Remote Monitoring” of lighting schemes become more practicable, and theirrelative expense more cost effective, simple patrolling is likely to decline in use.

However, the cost benefit of remote monitoring or direct patrolling for lighting defectsis difficult to assess. In cases where non illumination is a major safety risk then routinemonitoring or patrolling is a necessity. In other cases where it could be interpreted as more ofa public relations exercise, then other factors must be considered such as encouraging thepublic to notify the authority concerned. A very effective method is to establish a toll-freetelephone number or pre-paid postcard for the public to use. The local police and/or securityforces can also be asked to help in this respect. However for this to work it is even moreimportant to have a clear and simple identification system for the various lighting points.

An example of how to establish the optimum frequency of professional patrolling forlighting defects in road lighting installations is given in Appendix 7.1.

4.6 Obstruction of light by trees

Tree branches and foliage can pose a continuing problem in achieving proper outdoor lighting.Periodic trimming of trees becomes essential to keep up with growth. Field personnel mustwork closely with forestry organisations and property owners to achieve lighting requirementswith minimum visual and horticultural damage to the trees.

In road lighting, the presence of low overhanging foliage may seriously obstruct thelight delivered to road as well as impede traffic movement. Judicious pruning can reduce oreliminate the screening effect. There are instances where pruning increases the averagelighting effectiveness approximately one third, and approximately doubled the lightingeffectiveness in the critical areas of low visibility.

5. MAINTENANCE FACTOR

In any lighting design calculations an appropriate maintenance factor has to be included toallow for depreciation. The magnitude of the maintenance factor can significantly affect thelamp wattage and number of luminaires needed to produce the specifiedluminance/illuminance. High maintenance factors are beneficial for achieving minimum safety

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levels, and can be achieved by careful choice of equipment and electing to clean theinstallation more frequently.

Maintenance factor is defined as the ratio of the luminance/illuminance produced bythe lighting system after a certain period to the luminance/illuminance produced by the systemwhen new.

Maintenance factor:

MF = Em / Ein (5.1)

where Em = maintained luminance/illuminance;

Ein = initial luminance/illuminance.

By calculating the maintenance factor for different luminaires and environmentalconditions, and taking into account the proposed maintenance schedule, it is possible topredict the pattern of illuminance in an installation over a period of time.

The maintenance factor is a multiple of factors.

Maintenance factor

MF = LLMF x LSF x LMF (x SMF)* (5.2)

where LLMF = the lamp lumen maintenance factor;LSF = the lamp survival factor;LMF = the luminaire maintenance factor;

* and where appropriate (e.g. pedestrian subways):

SMF = the surface maintenance factor.

5.1 Determination of maintenance factor

The magnitude of each of these factors varies with lamp, luminaire, environment and time.

For an accurate assessment of LLMF, the manufacturers data should be used.However, some typical data are shown in Table 3.1.

For an accurate assessment of LSF, the manufacturers data should be used.However, some typical data are shown in Table 3.2.

For LMF, considerable research has been done with reference to the degree ofsealing (i.e. IP rating) of luminaires which is shown in Table 3.3.

The total maintenance factor can be determined by the following step-by-step procedure.

Step 1 Select lamp and luminaire for the application.

Step2 Determine group replacement interval of lamps (if applicable). (See Table 4.1)

Step 3 Obtain LLMF from Table 3.1 for period established in Step 2.

Step 4 Obtain LSF from Table 3.2 (if applicable).

Step 5 Determine cleaning interval of luminaires (and surrounding surfaces ifapplicable - see CIE 97 - 1992).

Step 6 From an assessment of the luminaire IP rating, environmental pollutioncategory and cleaning interval from step 5, obtain the LMF from Table 3.3.

Step 7(if applicable)

Obtain SMF from for period established in Step 5.

Step 8 Calculate MF = LLMF x LMF (x SMF)*.

* If applicable. Calculate maintenance factor to not more than two significantfigures.

Step 9 It is advisable to repeat Steps 1 to 7, by adjusting the various components, sothat a range of maintenance programme options are considered at the initialdesign stage.

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6. SERVICING LIGHTING SYSTEMS

6.1 Safety of personnel

In some countries certain procedures and cleaning agents may not be permitted for use underenvironmental health regulations. It is always advisable to consult the authorities.

Servicing live lighting equipment should be avoided if possible and if necessary onlycarried out by well trained persons.

6.2 Access

It is important that provision is made for access to luminaires for relamping and cleaning.Equipment to help in servicing is discussed in Section 7.4.

The maintenance engineers will need to determine how to get at the luminaire, i.e. whatequipment will be needed, hydraulic platforms, staging, ladders, safety harnesses, etc. andwhether the general public will have to be protected. It is vital to ensure that access equipment isso located that the operators can work comfortably and safely on the luminaires. Their armsshould not be fully stretched and all vehicles should have suitable safety coning arrangements.

6.3 Cleaning luminaires

Extreme caution should be exercised when cleaning all surfaces. Some surfaces are verysusceptible to abrasion; for example, polished (unanodised) aluminium is very sensitive, asare some plastics, acrylic and polycarbonate in particular.

The maintenance engineers should experiment on a small test area with a methodbefore starting the whole job.

The maintenance engineers should be instructed to take care in handling plastics asthey tend to get brittle with age. Depending on the actual material, the environment andaltitude of the site (higher altitudes have an increased ultra-violet content), the light sourceand the temperature at which the unit operates, plastics may also yellow badly and will need tobe replaced.

Aluminium reflectors should be washed with a warm, soapy solution and rinsedthoroughly before being air dried. Plastic opal or prismatic lenses should be cleaned with adamp cloth (using non-ionic detergent and water) and treated with anti-static polish or sprayand allowed to dry. Vitreous enamel, stove enamel and glass optics should be wiped with adamp cloth using a light concentration of detergent in water.

Care should be taken not to seal up luminaires before they are totally dry.

6.4 Cleaning agents

Choice of cleaning materials and methods is determined by the type of dirt to be cleaned andthe type of material to be cleaned. For plastic materials a final treatment with anti-staticsubstance is recommended.

General cleaning - The first and most commonly used is a chemical detergent withadditives in different concentration levels. It is an advantage to use compounds that require norinsing after the wash.

Heavy duty cleaning of oil concentrations - The second type of cleaner is a heavy dutyliquid cleaner which may contain detergents, solvents and abrasives. It is useful for theremoval of oily dirt. These must be tested to ensure that they do not damage materials orleave deposits.

Excessive oily industrial conditions - In some heavy oily applications, such as roadtunnels, the use of a high-pressure steam cleaner is practical provided the installation hasbeen designed with this cleaning technique in mind.

Ultra-sonic cleaning - This is a system in which the items to be cleaned are normallyremoved from the site and placed within special tanks containing the cleaning liquid and a

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series of “transducers”. These “transducers” produce sound waves that in turn createmicroscopic bubbles that provide an intense cleaning action over a small area. Normalcleaning times are between 2-10 minutes. If the item is extremely dirty a pre clean may benecessary and rinsing afterwards is also required. Its main use is in the cleaning of glassrefractor bowls. Care needs to be taken to ensure that this system does not damage thematerials being cleaned.

6.5 Relamping

The maintenance personnel will require instruction on the removal of the lamps so as not todamage the sockets or any components of the luminaire in any way.

If the luminaire’s aiming position has to be disturbed, care must be taken to note and/ormark its original position so that this can be reset when the relamping has been carried out.

When new lamps are not being put in the luminaires after the cleaning process, theold lamps should be carefully examined and any lamp showing age should be replaced at thattime with the lamp specified by the designer. Lamps must be replaced with care so that nodamage is caused to the luminaire.

Relamping with new lamps should be done after the luminaire has been cleaned.Generally the replacement lamps should be only those that are recommended by the design ofthe scheme. However, consideration should be given to potential use of improved lamps andcontrol gear, but their suitability for the luminaire and application must be checked with theinstallation designer.

6.6 Equipment disposal

Disposal of lamps

Discarded lamps may be disposed of through landfill at suitably licensed and contained sites.Incineration is not a recommended disposal route.

Crushing of lamps to reduce bulk or allow materials recovery may be undertaken bythe producer or subsequent manager of the waste, although uncontrolled breakage orcrushing should be avoided whenever possible.

Low pressure sodium lamps

Low-pressure sodium lamps contain sodium metal, which reacts with water. Hazardsto be considered are the potentially corrosive sodium hydroxide solution and the extremelyflammable and explosive hydrogen gas, which result from reacting sodium with water. Theselamps should be broken and reacted with water under controlled conditions prior to disposal asfollows:

Working in a dry atmosphere not more than 20 lamps should be carefully brokeninto a large dry container. When the container is not more than one quarter full oflamp debris the operator should fill it with water from a distance, i.e. by the use ofa hose. The water will react with the sodium and may be disposed of as a weakcaustic soda solution and the glass debris as a normal controlled waste. Theseinstructions are supplied with each individual lamp. Again the breaking of lampsshould only be carried out under controlled and approved conditions after carryingout a full risk assessment.

7. APPENDICES

7.1 Example of cost effectiveness of patrolling for road lighting.

The following formulae have been taken from the UK Institution of Lighting EngineersTechnical Report No.14 “The Cost Effectiveness of Night-time Patrolling” (1984), for which asurvey was taken of patrolling methods and frequencies in an attempt to establish theoptimum frequency, and hence optimum cost, of providing the task of recording faults for

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repair. The Report looks at many different facets associated with the provision of patrollingand draws conclusions based on data obtained. Given below are the Patrol Viability Formulaewithin the Report together with an explanation of some of the factors involved.

7.1.1 Patrol viability calculations

The formulae below have been devised to help calculate the most cost effective patrolintervals for a road lighting installation. They incorporate cost factors not directly associatedwith, but affected by, the frequency of night patrolling.

• Patrol costs are likely to vary pro-rata to any change in patrol interval.• Repair costs are affected by the patrol interval. Extending the interval increases the

number of repairs to be carried out in a given area, thus increasing the working/travellingtime ratio. In effect an optimum is reached at about 2,5% outages.

• Social Cost Factor (SCF):Patrolling is undertaken primarily to reduce the period of time between failure andsubsequent repair of a lighting unit. The cost effectiveness of patrolling can, therefore,only be assessed when a value is assigned to the cost of a unit being inoperative. In theabsence of a recognised formula, the Panel have determined that such a cost is equal tothe sum of the costs of providing, financing, energising and maintaining the unit. The costhas been termed the Social Cost Factor (SCF).

• Out of Schedule Repair (OSR):Much of the theoretical saving achieved by prolonged patrol intervals is, in practice,absorbed by response to sporadic, individual public complaints. Such Out of ScheduleRepairs (OSR) increase administration and operational costs and reduce the number ofrepairs available for the routine repair visit. The cost effectiveness of that visit is,therefore, reduced.

7.1.2 Patrol interval viability formulae

• PATROL COSTS per unit period =

period in hour per patrolled Unitspatrols of No. hour per cost ×

7.1(1)

• REPAIR COST per unit per period =

100period per outage %

day per repaired Unitsdayper Cost × 7.1(2)

• SOCIAL COST FACTOR (SCF)

(i) Annual cost =

capitalonInteresteMaintenancEnergy(Yrs)lifedAnticipate

CostCapitalAvg. +++ 7.1(3)

(ii) Unit cost per outage per period =

100period in Outage %

periodinweeksNo. weeksin time Outage Avg.

100period in Hours Burning %

CostAnnual

×

××7.1(4)

Notes: Period usually summer or winter, but could be whole year or any part.Avg. outage time = half patrol interval + Avg. repair time.(Avg. repair time includes material and cable fault delays.)

• AVERAGE COST OF OUT OF SCHEDULE REPAIRS (OSR) per outage =

(Cost of each unscheduled repair x % of repairs done out of schedule)+ (Cost of each scheduled repair x % of repairs done in schedule)

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Subtracting the cost of a scheduled repair gives the average increased cost peroutage due to undertaking OSR’s.

This value can be related to a period of time by multiplying by the relevant totalpercentage outage over that period.

7.2 Example of maintenance factor estimation

• Location

Urban motorway on the outskirts of a large industrial city.(Medium Pollution)

• Lighting system

12 m twin arm columns equipped with IP65 luminaires utilising high pressure sodiumlamps.

• Operation conditions: operating hours

4000 hrs (Sunset to Sunrise) per year.

• Maintenance schedule

Cleaning and relamp every three years.

From: Table 3.1 LLMF = 0,90 for 12000 hours of replacement time

From: Table 3.3LMF = 0,87 for three yearly cleaning of IP 65 luminaire

Therefore:MF = 0,90 x 0,87 = 0,783 = 0,78

If cleaning is carried out annually, the LMF = 0,92 and MF = 0,90 x 0,92 = 0,828 =0,83. This makes the installation 5 % more efficient. This could result in over 5 % saving in thelighting installation size and the energy consumed whilst maintaining the design luminance /illuminance.

Note: 1. To achieve a specified maintained illuminance various maintenance schedules canbe considered and the appropriate factors obtained from the data. All factors relateinitial to maintained conditions.

2. It is common practice to carry out lamp change and cleaning at the same time butcleaning of lamp and luminaire between relamping may be beneficial in dirty locationsor when a longer lamp replacement period is used.

3. Luminaire Maintenance Factor is not related to lamp burning hours.

7.3 Example of optimum group maintenance interval estimation

Worked examples (Costs are in US$):

Note : (1) Taking 1 x 250W SON-E lamp on 10 m galvanised column as an example.

(A) Lamp replacement From formula 4.1,

(a) Cost of spot replacement per lamp Cs

Cs = L + S + EL = $14,77 S = $36,07 E = $7,89Cs = $14,77 + $36,07 + $7,89 = $58,73

(b) Cost of group replacement per lamp Cg From formula 4.2,Cg = L + B + E B + E = $2,45

= $14,77 + $2,45 = $17,22

(c) Cost of combined group and spot replacement per lamp per rated lamp life Ct.

From formula 4.3,

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I)CFC(100

Csg

t+= F = 20 I = 80

where F = percentage of lamps failed and replaced prior to the re-lamping interval,say 20%I = percentage of rated lamp life at group re-lamp interval, say 80%

8073,85$x2022,71$x(100

Ct+= = $36,21

In this example, it is thus more economical to implement combined group and spotreplacement.

(B) Cleaning of luminaires From formula 4.4,

The optimum cleaning interval T can be determined as follows:

DELTAC

C2

C

C

a

c

a

c+=T

Cc = cost of cleaning the luminaire once = $7,50Life expectancy of column = 20 yearsLife expectancy of luminaire = 10 yearsGroup lamp replacement interval = 3 yearsInstallation cost for column and wiring = $2030,79Installation cost for luminaire and lamp = $110,88Annual energy cost = $85,54Cost for group lamp replacement = $17,22Cost for spot lamp replacement = $58.73

Ca = amortised installation cost for column, wiring, luminaire andlamp + annual energy cost + lamp replacement cost per year.

=3

$58,73)x(0,2$17,22$85,54

10$110,88

20$2030,79 ++++ =$207,83

take DELTA = annual average rate of luminaire dirt depreciation = 0,2

T = 2,083,207

5,7283,207

5,7x

x+ = 0,397 years (or 4.8 months)

7.4 Maintenance equipment

Time, labour and expense of maintaining a lighting system can be greatly reduced bychoosing maintenance equipment with features most suited to the system requirements. Manydifferent kinds of maintenance devices are available to facilitate the cleaning task. The choiceof equipment will depend on several factors such as mounting height, size of area, size ofdoors, lifts and stairs leading to area, accessibility of lighting units and obstacles in the area.Some available maintenance equipment are:

Ladders: Ladders are often used in lighting maintenance because their low weight,low cost and simplicity make them desirable for simple tasks. However, safety and mobilityrestrictions limit their use in some cases.

Hydraulic truck: Often the quickest and most efficient maintenance device is thehydraulic lift truck or hoist. Although there are different types available the method of operatingis basically the same. The platform can be raised or lowered automatically. Where suchequipment is required for off-roadway works, it is important to check that the surface can takethe weight of the vehicle.

Scaffolding: Portable scaffolding generally has greater safety and mobility thanladders. More equipment can be carried and the maintenance man has a firm platform fromwhich to work. In general, scaffolds should be light, sturdy, adjustable, mobile, and easy to

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assemble and dismantle. Special requirements often dictate the type of scaffolding which canbe used, for example, for mounting on uneven surfaces or for clearance of obstacles.

Telescopic scaffolding: The telescopic scaffold provides a quick means for reachinglighting equipment at a variety of mounting heights. This equipment comes in various sizesthat have platforms which can be raised and lowered either manually or electrically.

Hinged columns: (and other raising and lowering devices): lowering lighting units to aconvenient work level, enabling the worker to maintain them with a minimum of equipment.When a lighting unit is raised into place, the luminaire unit makes the proper electrical circuitconnection automatically. An additional safety feature of this type of device is that theelectrical circuit is disconnected when the luminaire is lowered. However, installation andmaintenance of winches, pullies and line can be a major item.

Catwalks, cranes, cages, etc.: Lighting maintenance can be incorporated as anintegral part of the lighting system. This can be accomplished in many ways. For many sportsstadiums, luminaires can be maintained from catwalks, within the stands or in the case ofsome high masts from maintenance cages.

Vacuum cleaners and blowers: A blower or vacuum cleaner is sometimes used toremove dust from lighting units. While some of the dirt can be removed in this way, the unitsstill have to be washed at sometime. The periodic use of a vacuum cleaner or blower can,however, prolong the cleaning interval.

7.5 Terminology

7.5.1 Definitions

Cleaning agent: material used to aid the removal of dirt.

Group replacement (lamps): replacement of a large number of lamps at one chosen time in aninstallation.

Initial illuminance: the average illuminance on the reference surface, based on initial lamplumens, when the installation is new and the room surfaces are clean.

Initial luminous flux: the luminous flux (lumens) measured after an initial ageing period inreference conditions.

IP Code: Ingress Protection Code of enclosures against the entry of dust and moisture.

Maintained luminance/illuminance: the average luminance/illuminance on the referencesurface below which an installation is not allowed to fall. It is the luminance/illuminance atwhich maintenance must be carried out.

Maintenance cycle: repetition of relamping and/or cleaning intervals.

Rated average lamp life: the period over which the lamp survival factor falls to 50% inreference conditions.

Spot replacement (lamps): replacement of individual lamps as they fail.

7.5.2 Abbreviations

LLMF Lamp Lumen Maintenance FactorRatio of luminous flux of lamp at a given time in the life to the initial luminous flux. Initialluminous flux of lamps is usually declared at 100 hours for discharge lamps.

LSF Lamp Survival FactorFraction of the total number of lamps which continue to operate at a given time under definedconditions and switching frequency.

LMF Luminaire Maintenance FactorRatio of efficiency of luminaire at a given time to the initial efficiency value.

MF Maintenance FactorRatio of maintained luminance/illuminance to initial luminance / illuminance.

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SMF Surface Maintenance FactorRatio of surface reflectance at a given time to the initial reflectance value.

8. BIBLIOGRAPHY

BJELLAND, E.M. “Telemanagement” of lighting installations, Proceedings Lux Europa,Reykjavik, 58, 2001.

BSI BS 5489. Road Lighting [Specifically Part 2 ,Table 4.], 1992.

CIBSE LG1. The Industrial Environment. [Section 5.4]. 1989.

CIBSE LG4. Sports. [Section 6]. 1990.

CIBSE LG6. The Outdoor Environment. [Section 7]. 1992.

CIE 88-1990. Guide for the lighting of road tunnels and underpasses. [Section 8].

CIE 94-1993. Guide for Floodlighting. [Section 11].

CIE 97-1992. Maintenance of Indoor Electric Lighting Systems.

CSS (UK). Model Document for the Maintenance of Public Lighting and Signs by CompetitiveTendering. 1985.

DI FRAIA, L. The Optimisation of Road Lighting. CIBSE National Lighting Conference. Latepaper No. 6. 1992.

IEC 598-1. Safety of Luminaires, [Chap. 9 Degrees of Protection of Enclosures]. 1977.

IESNA. Design Guide for Roadway Lighting Maintenance, 1993.

ILE. Road Lighting in Developing Countries.[Section 7.0]. 1987.

ILE TR. No. 14. The Cost Effectiveness of Night-time Patrolling. 1984.

ILE TR. No.18. Planned Replacement of Lighting Columns. 1988.

ILE TR. No.19. The Effectiveness of Lantern Cleaning. 1989.

ILE, TR. No. 22. Lighting Columns and Sign Posts: Planned Inspection Regime, 1997.

MANZANO, E.R., SAN MARTIN, R. Procedure for continuous urban lighting managementevaluation. CIE 24th Session Proceedings, CIE 133-1999, 234.

MARSDEN. A.M., The Economics of Outdoor Lighting Maintenance, ILE Lighting Journal. Vol.58, No.1, 11. 1993.

SABS. Guidelines for Installation and Maintenance of Street Lighting. (Project 7:Maintenance). Issue 2, 1993.

UK Dept. of Transport, Std. TD 23/86. Trunk Roads and Trunk Road Motorways -Maintenance of road lighting. 1986.

US Dept. of Transportation. Roadway Lighting Handbook. [Ch. 8]. 1978.

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CIE PUBLICATIONSRecommendations

17.4 International lighting vocabulary, 4th ed. (Jointpublication IEC/CIE), 1987.

23 International recommendations for motorwaylighting, 1973.

39.2 Recommendations for surface colours forvisual signalling, 2nd ed., 1983.

Standards and Draft Standards

ISO 10526/CIE S005 CIE standard illuminants forcolorimetry, 1999.

ISO/CIE 10527 Colorimetric observers, 1991(S002, 1986).

CIE S 004-1998 Colours of light signals (Draftstandard), 1998.

ISO 16508/CIE S006 Road traffic light — 200 mmroundel signals photometric properties, 1998.

ISO 17166/CIE S007 Erythema reference actionspectrum and standard erythema dose, 1998.

ISO 8995/CIE S 008-2000 Lighting of indoor workplaces.

CIE S 009-2000 Photobiological safety of lampsand lamp systems.

CIE S 011:2003 Spatial distribution of daylight –CIE standard general sky, 2003.

CIE DS 010.2-2001 Photometry – The CIE systemof physical photometry.

CIE DS 012.2:2002 Standard method of assessingthe spectral quality of daylight simulators forvisual appraisal and measurement of colour.

CIE DS 013.2:2002 International Standard Global UVIndex.

Technical Committee Reports

1 Guide lines for minimising urban sky glow nearastronomical observatories (Joint publicationIAU/CIE), 1980.

13.3 Method of measuring and specifying colourrendering of light sources, 1995.

15.2 Colorimetry, 2nd ed., 1986.16 Daylight, 1972.18.2 The basis of physical photometry, 2nd

ed., 1983.19.21 An analytic model for describing the influence

of lighting parameters upon visualperformance, 2nd ed., Vol.1.: Technicalfoundations, 1981.

19.22 An analytic model for describing the influenceof lighting parameters upon visualperformance, 2nd ed., Vol.2.: Summary andapplication guidelines, 1981.

23 International recommendations formotorlighting, 1973..

31 Glare and uniformity in road lightinginstallations, 1976.

32 Lighting in situations requiring specialtreatment (in road lighting), 1977.

33 Depreciation of installation and theirmaintenance (in road lighting), 1977.

34 Road lighting lantern and installation data:photometrics, classification andperformance, 1977.

38 Radiometric and photometric characteristics ofmaterials and their measurement, 1977.

40 Calculations for interior lighting: Basicmethod, 1978.

41 Light as a true visual quantity: Principles ofmeasurement, 1978.

42 Lighting for tennis, 1978.43 Photometry of floodlights, 1979.44 Absolute methods for reflection

measurements, 1979.45 Lighting for ice sports, 1979.46 A review of publications on properties and

reflection values of material reflectionstandards, 1979.

47 Road lighting for wet conditions, 1979.48 Light signals for road traffic control, 1980.49 Guide on the emergency lighting of building

interiors, 1981.51.2 A method for assessing the quality of daylight

simulators for colorimetry, 1981.

52 Calculations for interior lighting: Appliedmethod, 1982.

53 Methods of characterising the performance ofradiometers and photometers, 1982.

54.2 Retroreflection: Definition andmeasurement, 1982.

55 Discomfort glare in the interior workingenvironment, 1983.

57 Lighting for football, 1983.58 Lighting for sports halls, 1983.59 Polarisation: Definitions and nomenclature,

instrument polarisation, 1984.60 Vision and the visual display unit work

station, 1984.61 Tunnel entrance lighting: A survey of

fundamentals for determining the luminance inthe threshold zone, 1984.

62 Lighting for swimming pools, 1984.63 The spectroradiometric measurement of light

sources, 1984.64 Determination of the spectral responsivity of

optical radiation detectors, 1984.65 Electrically calibrated thermal detectors of

optical radiation (absolute radiometers), 1985.66 Road surfaces and lighting (joint technical

report CIE/PIARC), 1984.67 Guide for the photometric specification and

measurement of sports lightinginstallations, 1986.

69 Methods of characterising illuminance metersand luminance meters: Performance,characteristics and specifications, 1987.

70 The measurement of absolute luminousintensity distributions, 1987.

72 Guide to the properties and uses ofretroreflectors at night, 1987.

73 Visual aspects of road markings (joint technicalreport CIE/PIARC; French translation: Aspectsvisuels des marquages routiers is availablefrom PIARC), 1988.

74 Roadsigns, 1988.75 Spectral luminous efficiency functions based

upon brightness matching for monochromaticpoint sources, 2° and 10° fields, 1988.

76 Intercomparison on measurement of (total)spectral radiance factor of luminescentspecimens, 1988.

77 Electric light sources: State of the art -1987, 1988.

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78 Brightness-luminance relations: Classifiedbibliography, 1988.

79 A guide for the design of road trafficlights, 1988.

80 Special metamerism index: Change inobserver, 1989.

81 Mesopic photometry: History, special problemsand practical solutions, 1989.

82 CIE History 1913 - 1988, 1990.83 Guide for the lighting of sports events for

colour television and film systems, 1989.84 Measurement of luminous flux, 1989.85 Solar spectral irradiance, 1989.86 CIE 1988 2° spectral luminous efficiency

function for photopic vision, 1990.87 Colorimetry of self-luminous displays - A

bibliography, 1990.88 Guide for the lighting of road tunnels and

underpasses, 1990.89 Technical Collection 1990:

89/1 Results of a CIE detector response intercomparison

89/2 Photobiological effects of sunlamps89/3 On the deterioration of exhibited

museum objects by optical radiation89/4 Guide for the measurement of

underground mine lighting.90 Sunscreen testing (UV.B), 1991.93 Road lighting as an accident countermeasure,

1992.94 Guide for floodlighting, 1993.95 Contrast and visibility, 1992.96 Electric light sources - State of the art, 1992.97 Maintenance of indoor electric lighting

systems, 1992.98 Personal dosimetry of UV radiation, 1992.99 Lighting education (1983-1989), 1992.100 Fundamentals of the visual task of night

driving, 1992.101 Parametric effects in colour-difference

evaluation, 1993.102 Recommended file format for electronic

transfer of luminaire photometric data, 1993.103 Technical Collection 1993:

103/1 Colour appearance analysis103/2 Industrial lighting and safety at work103/3 Reference action spectra for ultraviolet

induced erythema and pigmentation ofdifferent human skin types

103/4 Biologically effective emissions andhazard potential of desk-topluminaires incorporating tungstenhalogen lamps

103/5 The economics of interior lightingmaintenance

103/6 Clarification of maintained illuminanceand associated terms.

104 Daytime running lights (DRL), 1993.105 Spectroradiometry of pulsed optical radiation

sources, 1993.106 CIE Collection in Photobiology and

Photochemistry, 1993:106/1 Determining ultraviolet action spectra106/2 Photokeratitis106/3 Photoconjunctivitis106/4 A reference action spectrum for

ultraviolet induced erythema in humanskin

106/5 Photobiological effects in plant growth106/6 Malignant melanoma and fluorescent

lighting106/7 On the quantification of environmental

exposures: limitations of the concept ofrisk-to-benefit ratio

106/8 Terminology for photosyntheticallyactive radiation for plants.

107 Review of the official recommendations of theCIE for the colours of signal lights, 1994.

108 Guide to recommended practice of daylightmeasurement, 1994.

109 A method of predicting corresponding coloursunder different chromatic and illuminanceadaptation, 1994.

110 Spatial distribution of daylight - Luminancedistributions of various reference skies, 1994.

111 Variable message signs, 1994.112 Glare evaluation system for use within outdoor

sports- and area lighting, 1994.113 Maintained night-time visibility of retroreflective

road signs, 1995.114 CIE Collection in photometry and radiometry,

1994:114/1 Survey of reference materials for

testing the performance ofspectrophotometers and colorimeters

114/2 International intercomparison ontransmittance measurement - Report ofresults and conclusions

114/3 Intercomparison of luminous fluxmeasurements on HPMV lamps

114/4 Distribution temperature and ratiotemperature

114/5 Terminology relating to non-selectivedetectors

114/6 Photometry of thermally sensitivelamps.

115 Recommendations for the lighting of roads formotor and pedestrian traffic, 1995.

116 Industrial colour-difference evaluation, 1995.117 Discomfort glare in interior lighting, 1995.118 CIE Collection in colour and vision, 1995:

118/1 Evaluation of the attribute ofappearance called gloss

118/2 Models of heterochromatic brightnessmatching

118/3 Brightness-luminance relations118/4 CIE guidelines for co-ordinated

research on evaluation of colourappearance models for reflection printand self-luminous display imagecomparisons

118/5 Testing colour appearance models:Guidelines for co-ordinated research

118/6 Report on color difference literature118/7 CIE guidelines for co-ordinated future

work on industrial colour-differenceevaluation.

121 Photometry and goniophotometry of luminaires,1996.

122 The relationship between digital andcolorimetric data for computer-controlled CRTdisplays, 1996.

123 Low Vision - Lighting needs for the partiallysighted, 1997.

124 CIE Collection in Colour and Vision, 1997:124/1 CIE TC 1-31 Report: Colour notations

and colour order systems124/2 CIE TC 1-18 Chairman's Report: On

the course of the disability glarefunction and its attribution tocomponents of ocular scatter

124/3 Next step in industrial colour differenceevaluation, Report on a colourdifference research meeting.

125 Standard erythemal dose — A review, 1997.126 Guidelines for minimizing sky glow, 1997.127 Measurement of LEDs, 1997.128 Guide to the lighting for open-cast mines,

1998.129 Guide for lighting exterior work areas, 1998.130 Practical methods for the measurement of

reflectance and transmittance, 1998.

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131 The CIE 1997 interim colour appearancemodel (simple version), CIECAM97s, 1998.

132 Design methods for lighting of roads, 1999.134 CIE Collection in Photobiology and

Photochemistry, 1999.134/1 CIE TC 6-26 Report: Standardization of

the terms UV-A1, UV-A2 and UV-B134/2 CIE TC 6-30 Report: UV protection of

the eye134/3 CIE TC 6-38 Report: Recommendation

on photobiological safety of lamps. Areview of standards

135 CIE Collection 1999: Vision and colour,physical measurement of light and radiation.135/1 Disability Glare135/2 Colour rendering, closing remarks135/3 Virtual metamers for assessing the

quality of simulators of CIE illuminantD50 (Supplement 1-1999 to CIE 51-1981)

135/4 Some recent developments in colour-difference evaluation

135/5 Visual adaptation to complexluminance distribution

135/6 45°/0° Spectral reflectance factors ofpressed polytetrafluoroethylene (PTFE)power (Reprint of NIST Technical Note1413)

136 Guide to the lighting of urban areas, 2000.137 Conspicuity of traffic signs in complex

backgrounds, 2000.

138 CIE Collection 2000: Photobiology andPhotochemistry.138/1 Blue-light photochemical retinal hazard138/2 Action spectrum for photocarcino-

genesis (non-melanoma skin cancers)138/3 Standardized protocols for

photocarcinogenesis safety testing138/4 A proposed global UV index.

139 The influence of daylight and artificial light ondiurnal and seasonal variations in humans. Abibliography, 2001.

140 Road lighting calculations, 2000.141 Testing of supplementary systems of

photometry, 2001.142 Improvement to industrial colour-diffence

evaluation, 2001.143 International recommendations for colour

vision requirements for transport, 2001.144 Road surface and road marking reflection

characteristics, 2001.145 The correlation of models for vision and visual

performance, 2002.146/147Collection on Glare, 2002

146 CIE equations for disability glare147 Glare from small, large and complex

sources.148 Action spectroscopy of skin with tunable

lasers, 2002.149 The use of tungsten filament lamps as

secondary standard sources, 2002.150 Guide on the limitation of the effects of

obtrusive light from outdoor lightinginstallations, 2003.

Proceedings of the Sessions:

1921 Paris1924 Genèva1927 Bellagio1928 Saranac1931 Cambridge1935 Berlin1939 Scheweningen1948 Paris1951 Stockholm1955 Zürich1959 4-7 Bruxelles (Vol. A,B,C,D)

1963 11 Vienna (Vol. A,B,C,D)1967 14 Washington (Vol. A,B)1971 21 Barcelona (Vol. A,B,C)1975 36 London1979 50 Kyoto1983 56 Amsterdam1987 71 Venice, Vol.1-21991 91 Melbourne, Vol.1-21995 119-120 New Delhi, Vol. 1-21999 133 Warsaw, Vol. 1-2

Discs and other publications

D001 Disc version of CIE Colorimetric Data (S001and S002 Tables), 1988.

D002 Disc version of CIE Colorimetric and ColourRendering Data (Publ. 13.2 and 15.2 Tables),1991.

D005 A method for assessing the quality of D65daylight simulators for colorimetry (based onCIE 51-1981) 1994.

D006 Automatic quality control of daylightmeasurement - Software for IDMP stations(computer program to CIE 108- 1994), 1994.

D007 A computer program implementing the "Methodof predicting corresponding colours underdifferent chromatic and illuminance adaptation"(described in CIE 109-1994), 1994.

D008 Computer program to calculate CRIs(according to CIE 13.3-1995), 1995.

x004 Symposium on light and radiationmeasurement '81, Hajdúszoboszoló (CIE-Hungarian NC).

x005 Proceedings of the CIE Seminar '92 onComputer programs for light and lighting.

x006 Japan CIE Session at PRAKASH 91.x007 Proceedings of the CIE Symposium '93 on

Advanced Colorimetry.

x008 Urban sky glow - a worry for astronomy(Proceedings of a Symposium of CIE TC 4-21),1994.

x009 Proceedings of the CIE Symposium '94 onAdvances in Photometry.

x010 Proceedings of the CIE Expert Symposium '96Colour Standards for Image Technology.

x011 Special volume, 23rd Session, New Dehli ’95,Late papers.

x012 NPL — CIE-UK Visual Scales Conference.x013 Proceedings of the CIE LED Symposium ’97 on

Standard Methods for Specifying andMeasuring LED Characteristics, 1998.

x014 Proceedings of the CIE Expert Symposium ’97on Colour Standards for Imaging Technology,1998.

x015 Proceedings of the First CIE Symposium onLighting Quality, 1998.

x016 Proceedings of the CIE/ICNIRP Conference onMeasurements of Optical Radiation Hazards,1998.

x017 Special volume, 24th Session, Warsaw ’99,Late papers, 2000.

x018 Proceedings of the CIE Symposium ’99 “75Years of CIE Photometry”.

x019 Proceedings of three CIE workshops onCriteria for Road Lighting, 2001.

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x020 Proceedings of the CIE Symposium 2001“Uncertainty Evaluation, Methods for Analysisof Uncertainties in Optical RadiationMeasurement”, 2001.

x021 Proceedings of the CIE Expert Symposium2000 “Extended Range Colour Spaces”, 2001.

x022 Proceedings of the 2nd CIE Expert Symposiumon LED measurement ”Standard methods for

specifying and measuring LED and LED clustercharacteristics, 2001.

x023 Proceedings of two CIE Workshops onphotometric measurement systems for roadlighting installations (1994, 1996), 2002.

x024 Proceedings of the CIE/ARUP Symposium onVisual Environment, 2002

CIE publications on CD-ROM

A CD-ROM with all current CIE Technical Reports and Standards is available from IHS,Information Handling Services, 15 Inverness Way East, M/S B203 Englewood, Colorado 80112-5776 USA.

CIE-Journal Vol.1 - Vol.8 1982 - 1989. CIE NEWS No. 1 - No. 64 1986 - 2002.

For latest information on CIE publications see the CIE Home Page on the World Wide Web:

http://www.cie.co.at/