Conservation of Cultural Heritage - Guidelines and procedures for choosing appropriate lighting for indoor exhibitions

CEN/TS 16163 defines the procedures as well as the means to implement adequate lighting, with regard to the conservation policy. It takes visual, exhibition and conservation aspects into account and it also discusses the implications of the lighting design on the safeguarding of cultural property. This Technical Specification gives recommendations on values of minimum and maximum illumination levels. It aims to provide a tool for setting up a common European policy and a guide to help curators, conservators and project managers to assess the correct lighting that can assure the safeguarding of the exhibits. This Technical Specification covers lighting for heritage objects on exhibition in both public and private sites and does not consider lighting in other cultural heritage contexts such as open-air collections, etc.

Erhaltung des kulturellen Erbes - Leitlinien und Verfahren für die Auswahl geeigneter Beleuchtung für Innenausstellungen

Die vorliegende Norm legt sowohl die Verfahren als auch die Mittel zur Umsetzung guter Beleuchtung im Hinblick auf Grundsätze der Konservierung, ohne dabei die Bedingungen für Sichtbarkeit und Ausstellungsgestaltung zu vernachlässigen, fest. Ziel ist die Bereitstellung eines Hilfsmittels zur Aufstellung gemeinsamer europäischer Grundsätze und einer Anleitung, um Kuratoren, Konservatoren und Projektleitern zu helfen, den Architekten und Gestaltern ein richtiges Beleuchtungsprogramm mit einem Europäischen Referenzdokument anzubieten.

Conservation du patrimoine culturel - Lignes directrices et procédures concernant le choix d'un éclairage adapté pour les expositions en intérieur

Le présent document définit les modes opératoires ainsi que les moyens pour mettre en oeuvre un éclairage
adéquat tenant compte de la politique de conservation, mais également des conditions de visibilité et de
scénographie d'exposition. Son objectif est de fournir un outil qui permettra d'élaborer une politique
européenne commune et un guide pour aider les conservateurs, les restaurateurs et les chargés de projet à
présenter aux architectes et aux concepteurs un programme d'éclairage convenable suivant une référence
européenne.

Ohranjanje kulturne dediščine - Smernice in postopki za izbiro ustrezne razsvetljave za razstave v zaprtih prostorih

CEN/TS 16163 določa postopke in načine uporabe ustrezne razsvetljave v skladu s politiko ohranjanja. Upošteva vizualne, razstavne vidike in vidike ohranjanja ter obravnava posledice načrtovanja razsvetljave na ohranjanje kulturne dediščine. Ta tehnična specifikacija daje priporočila glede največje in najmanjše ravni osvetljenosti. Prizadeva si zagotoviti orodje za oblikovanje skupne evropske politike in vodnika za pomoč kuratorjem, konservatorjem in vodjem projektov pri ocenjevanju ustrezne razsvetljave, ki bi zagotovila ohranjanje eksponatov. Ta tehnična specifikacija obravnava razsvetljavo predmetov kulturne dediščine, ki so razstavljeni v javnih in zasebnih prostorih, ter ne vključuje razsvetljave v drugih okoliščinah kulturne dediščine, kot so razstave na prostem itd.

General Information

Status
Published
Public Enquiry End Date
24-Dec-2010
Publication Date
29-May-2014
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
14-May-2014
Due Date
19-Jul-2014
Completion Date
30-May-2014

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Standards Content (sample)

SLOVENSKI STANDARD
SIST-TS CEN/TS 16163:2014
01-julij-2014
2KUDQMDQMHNXOWXUQHGHGLãþLQH6PHUQLFHLQSRVWRSNL]DL]ELURXVWUH]QH
UD]VYHWOMDYH]DUD]VWDYHY]DSUWLKSURVWRULK

Conservation of Cultural Heritage - Guidelines and procedures for choosing appropriate

lighting for indoor exhibitions

Erhaltung des kulturellen Erbes - Leitlinien und Verfahren für die Auswahl geeigneter

Beleuchtung für Innenausstellungen

Conservation du patrimoine culturel - Lignes directrices et procédures concernant le

choix d'un éclairage adapté pour les expositions en intérieur
Ta slovenski standard je istoveten z: CEN/TS 16163:2014
ICS:
91.160.10 Notranja razsvetljava Interior lighting
97.195 Umetniški in obrtniški izdelki Items of art and handicrafts
SIST-TS CEN/TS 16163:2014 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 16163:2014
TECHNICAL SPECIFICATION
CEN/TS 16163
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
April 2014
ICS 97.195
English Version
Conservation of Cultural Heritage - Guidelines and procedures
for choosing appropriate lighting for indoor exhibitions

Conservation du patrimoine culturel - Lignes directrices et Erhaltung des kulturellen Erbes - Leitlinien und Verfahren

procédures concernant le choix d'un éclairage adapté pour für die Auswahl geeigneter Beleuchtung für

les expositions en intérieur Innenausstellungen

This Technical Specification (CEN/TS) was approved by CEN on 14 October 2013 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their

comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available

promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)

until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 16163:2014 E

worldwide for CEN national Members.
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Contents Page

Foreword ..............................................................................................................................................................4

Introduction .........................................................................................................................................................5

1 Scope ......................................................................................................................................................6

2 Normative references ............................................................................................................................6

3 Terms and definitions ...........................................................................................................................6

4 Symbols ............................................................................................................................................... 11

5 Sensitivity of cultural property to light ............................................................................................. 12

5.1 General ................................................................................................................................................. 12

5.2 Mechanisms of damage ..................................................................................................................... 12

5.2.1 General ................................................................................................................................................. 12

5.2.2 Photochemical .................................................................................................................................... 12

5.2.3 Radiant heating ................................................................................................................................... 13

5.2.4 Biological effects ................................................................................................................................ 13

5.3 Sensitivity and classification for cultural property ......................................................................... 14

5.4 Limitations for total luminous exposure .......................................................................................... 14

6 Light measurement ............................................................................................................................. 15

6.1 Measurement of illuminance ............................................................................................................. 15

6.2 Measurement of UV radiation ............................................................................................................ 16

7 Exhibition lighting............................................................................................................................... 16

7.1 General ................................................................................................................................................. 16

7.2 Viewing conditions ............................................................................................................................. 16

7.3 Visual adaptation ................................................................................................................................ 16

7.4 Contrast ratios .................................................................................................................................... 17

7.5 Colour appearance ............................................................................................................................. 17

7.6 Colour rendering ................................................................................................................................. 17

7.7 Backgrounds to exhibits .................................................................................................................... 18

7.7.1 General ................................................................................................................................................. 18

7.7.2 Luminance of backgrounds ............................................................................................................... 18

7.7.3 Colour of backgrounds ...................................................................................................................... 18

7.8 Glare ..................................................................................................................................................... 19

7.9 Modelling ............................................................................................................................................. 20

7.10 Historic furnishings & interiors ......................................................................................................... 21

7.11 Simulation and mock-ups .................................................................................................................. 21

Annex A (informative) Characteristics of light sources ............................................................................. 22

A.1 Daylight ................................................................................................................................................ 22

A.2 Electric sources .................................................................................................................................. 22

A.2.1 General ................................................................................................................................................. 22

A.2.2 Incandescent lamps ........................................................................................................................... 23

A.2.3 Fluorescent lamps .............................................................................................................................. 24

A.2.4 Solid State Lighting ............................................................................................................................ 24

A.2.5 Metal Halide lamps.............................................................................................................................. 26

Annex B (informative) Glasses and films characteristics .......................................................................... 27

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B.1 Glasses ................................................................................................................................................. 27

B.2 Window films ....................................................................................................................................... 27

B.3 Other protection .................................................................................................................................. 27

Annex C (informative) Filters ......................................................................................................................... 28

Annex D (informative) Relative damage ........................................................................................................ 29

Annex E (informative) Lamps and lighting attachments ............................................................................. 30

Bibliography ...................................................................................................................................................... 31

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Foreword

This document (CEN/TS 16163:2014) has been prepared by Technical Committee CEN/TC 346

“Conservation of Cultural Heritage”, the secretariat of which is held by UNI.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,

Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

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Introduction

Lighting is needed for many specific functions in museums and other cultural heritage buildings, for example,

for research, conservation and permanent or temporary exhibitions. Lighting is one of the most important

factors enabling visitors to fully enjoy works of art and other cultural property. In fact, lighting is a key medium

in which visitors interpret and appreciate cultural heritage. Enough light is needed to see well but this may

present a challenge when what is being viewed will deteriorate in the presence of light. Where cultural

heritage is judged to be worth preserving for future generations it is essential to consider the controlled use of

light. Indeed, light is an environmental factor, which is a threat to many objects. Alone or in combination with

other environmental factors (temperature, humidity, pollution, etc.) light causes fading, discoloration and

embrittlement of a wide range of materials. This damage is cumulative and irreversible: no conservation

treatment can restore change of colour or loss in strength of materials damaged by light. Therefore, the

challenge of museum exhibition lighting is to find an appropriate compromise between the long term

preservation of the exhibit and the needs of visitors to view them within a suitable exhibition design. As an

integral part of exhibition lighting, the following aspects should be considered:

— the conservation aspect, related to the sensitivity of the exhibit at different wavelengths of the incident

radiant energy, the spectral composition of the light source and the total luminous exposure,

— the visual aspect, related to the impact of lighting on the visitor experience: lighting has to allow visitors to

see exhibits on display, with the correct colour perceptions without glare, reflections or insufficient

illumination,

— the design aspect related to the concept and position of the exhibition architecture, the point of view of

the curator and all others involved in the scenographic and/or didactic objectives of the exhibition.

Due to its non-technical nature the last mentioned aspect cannot be dealt with in this Technical Specification.

This Technical Specification uses terms defined in European (EN 12665 and EN 15898) and International

(CIE International lighting vocabulary) terminology standards, but their definitions have been adapted to the

intended users of this specification.
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CEN/TS 16163:2014 (E)
1 Scope

This Technical Specification defines the procedures as well as the means to implement adequate lighting, with

regard to the conservation policy. It takes visual, exhibition and conservation aspects into account and it also

discusses the implications of the lighting design on the safeguarding of cultural property. This Technical

Specification gives recommendations on values of minimum and maximum illumination levels. It aims to

provide a tool for setting up a common European policy and a guide to help curators, conservators and project

managers to assess the correct lighting that can assure the safeguarding of the exhibits. This Technical

Specification covers lighting for heritage objects on exhibition in both public and private sites and does not

consider lighting in other cultural heritage contexts such as open-air collections, etc.

2 Normative references
Not relevant.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
accent lighting
lighting focused on an exhibit or a group of exhibits to emphasize them
[SOURCE: CIE S 017/E:2011]
3.2
annual luminous exposure
total luminous exposure per year (unit: lux hours per years, lx h / a)

Note 1 to entry: One year of museum display is approximately 3 000 h. See also 3.35.

3.3
blue wool test: test for light fastness

certified set of eight pieces of wool each dyed with a different specific blue dye graded to fade after a set

exposure to light
[SOURCE: ISO 105-B08:1995]

Note 1 to entry: This system is usually referred as Blue Wool Standard (BWS) and it is used in museums to assess the

radiation exposure of materials. The eight wool pieces are numbered #1 to #8, each about 2 to 3 times as sensitive as the

next. High sensitivity is defined as materials rated #1, #2, or #3; medium as #4, #5, or #6; and low as #7, #8. A panel of

selected blue wool samples is left at the measurement point and after a period it can be seen which samples have faded

and the dose of light received determined.
3.4
colour rendering

effect of an illuminant on the colour appearance of exhibits by conscious or subconscious comparison with

their colour appearance under a reference illuminant
[SOURCE: CIE S 017/E:2011 or IEC-IEV:1987, 845-02-059]
3.5
colour rendering index

derived from the colour rendering indices for a specified set of 8 test colour samples

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CEN/TS 16163:2014 (E)

Note 1 to entry: Ra has a maximum of 100, which generally occurs when the spectral distributions of the light source

and the reference light source are substantially identical.
[SOURCE: CIE S 017/E:2011 or IEC-IEV:1987-845-02-61 and CIE 015:2004]
3.6
colour temperature

temperature of a Planckian radiator whose radiation has the same chromaticity as that of a given stimulus

(unit: kelvin, K)
[SOURCE: CIE S 017/E:2011 or IEC-IEV:1987, 845-03-049; see also CIE 015:2004]
3.7
cultural heritage

tangible and intangible entities of significance to present and future generations

Note 1 to entry: The term “exhibit” is used in this standard for cultural heritage. In specific professional contexts, other

terms are used: e.g. "artefact", “cultural property", “item”.
[SOURCE: EN 15898]
3.8
damage potential
Pdm

ratio of effective damaging irradiance and the illuminance at a point on the surface for a specific light source

(unit : W/lm)
3.9
daylight
visible part of global solar radiation

Note 1 to entry: When dealing with actinic effects of optical radiation, this term is commonly used for radiations

extending beyond the visible region of the spectrum.
[SOURCE: IEC-IEV:1987, 845-09-84]
3.10
daylighting
lighting for which daylight is the light source
[SOURCE: CIE S 017/E:2011]
3.11
daylight factor

ratio of the illuminance at a point on a given plane due to the light received directly or indirectly from a sky of

assumed or known luminance distribution, to the illuminance on a horizontal plane due to an unobstructed

hemisphere of this sky, excluding the contribution of direct sunlight to both illuminances

Note 1 to entry: Glazing, dirt effects, etc. are included.

Note 2 to entry: When evaluating the lighting of interiors, the contribution of direct sunlight needs to be considered

separately.
[SOURCE: CIE S 017/E:2011 and IEC-IEV, 1987, 845-09-087]
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3.12
dosimeter
indicator measuring total irradiant exposure during a given time

Note 1 to entry: The above definition is valid in the context of the present Technical Specification and concerns with

the light measurement only.
3.13
effective damaging irradiance

radiant flux per unit area at a point on the surface weighted by the relative damage action spectrum (unit: watt

per square metre, W m ²)
3.14
effective irradiance
E : E = ∫ Ε s(λ) dλ
eff eff e,λ

irradiance weighted on the spectral sensitivity of the materials constituting the exhibit

3.15
exhibit
object on display illuminated by natural and/or artificial light
3.16
filter
any device that modifies or reduces a portion of the electromagnetic spectrum

Note 1 to entry: Common filters are: coloured and neutral filters, conversion temperature blue (CTB) and conversion

temperature orange (CTO) filters, UV or IR absorbing filters. Neutral-density filters decrease the transmitted light by a

known amount without selecting any particular wavelength.
3.17
illuminance (at a point of a surface)

ratio of the luminous flux dΦ incident on an element of the surface containing the point, to the area dΑ of that

element (unit: lux, lx = lm⋅m )
Note 1 to entry: It represents the quantity of light impinging on a surface.
[SOURCE: IEC-IEV, 1987, 845-01-038]
3.18
infrared radiation

part of the electromagnetic spectrum with wavelength longer than those of the visible radiation, from about

780 nm to tens of micrometres
3.19
irradiance

radiometric quantity; the radiant flux per unit area at a point on the surface (unit: watt per square metre, W m ²)

3.20
lamp
source made in order to produce an optical radiation, usually visible

Note 1 to entry: This term is also sometimes used for certain types of luminaires (see below).

[SOURCE: CIE S 017/E:2011 and IEC-IEV, 1987, 845-07-003]
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3.21
light

radiation that is considered from the point of view of its ability to excite the visual system

Note 1 to entry: It corresponds to the so-called visible radiation in the range between 380 nm and 780 nm.

Note 2 to entry: In the field of conservation, this term sometimes extends the range outside the visible portion,

including parts of the ultraviolet (UV) and near infrared (IR) regions.
[SOURCE: CIE S 017/E:2011]
3.22
luminaire

apparatus which distributes, filters or transforms the light transmitted from one or more lamps and which

includes, except the lamps themselves, all the parts necessary for fixing and protecting the lamps and, where

necessary, circuit auxiliaries together with the means for connecting them to the electric supply

[SOURCE: CIE S 017/E:2011 or IEC-IEV 1987-845-10-001]
3.23
luminance
quantity defined by the formula:
dAcosϑdΩ
where
is the luminance in a given direction or at a given point of a surface

is the luminous flux transmitted by an elementary beam passing through the given point and propagating in the

solid angle dΩ containing the given direction
is the area of a section of that beam containing the given point
is the solid angle
is the angle between the normal to that section and the direction of the beam
–2 –2 –1
(unit: cd·m = lm·m ·sr )
Note 1 to entry: It corresponds to the light coming from a surface.
[SOURCE: CIE S 017/E:2011 or IEC-IEV, 1987, 845-01-035]
3.24
luminous flux

photometric quantity derived from the radiometric quantity radiant flux (radiant power) by evaluating the

radiation according to the spectral sensitivity of the human eye (as defined by the CIE standard photometric

observer) (unit: lumen, lm)

Note 1 to entry: It is the luminous power emitted by a source or received by a surface.

Note 2 to entry: For the practical use of this document, in this definition, the values used for the spectral sensitivity of

the CIE standard photometric observer are those of the spectral luminous efficiency function V(λ) (photopic vision).

Note 3 to entry: See CIE S 017/E:2011 or IEC-IEV, 1987, 845-01-22 for the definition of spectral luminous efficiency,

845-01-23 for the definition of the CIE standard photometric observer and 845-01-56 for the definition of luminous efficacy

of radiation and ISO 23539:2005(E)/CIE S 010/E:2004.
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3.25
luminous intensity

luminous flux per unit solid angle in that direction (unit: candela, cd = lm sr ; sr = steradian)

Note 1 to entry: It is the luminous flux on a small surface, divided by the solid angle that the surface subtends at the

source (CIE S 017/E:2011 or IEC-IEV, 1987, 845-01-31).

Note 2 to entry: The candela is the base SI photometric unit. For its definition, see CIE S 17/E:2011 or IEC-IEV, 1987,

845-01-050 or the BIPM SI Brochure.
3.26
lux
symbol lx; SI unit of illuminance

Note 1 to entry: For more information see CIE S 17/E:2011 or IEC-IEV, 1987, 845-01-052 or the BIPM SI Brochure.

3.27
photometric quantities

quantities that are based on the perception of radiation by the human eye and are valid only for visible

radiation
3.28
radiant flux

radiometric quantity representing the radiant energy transported per unit time into a region of space by

electromagnetic waves (unit: watt, W)
3.29
reflectance

ratio of the reflected radiant or luminous flux to the incident flux in the given conditions

[SOURCE: IEC-IEV, 1987, 845-04-058]
3.30
relative damage potential

ratio of the damage potential of a specific light source and the damage potential of the CIE standard Illuminant

A (2 856 K) (equals to the incandescent lamp); it is dimensionless and assumes values between 0 and 1

3.31
relative damage action spectrum
s(λ)
dm,rel

describes the wavelength dependence of the photochemical damage properties, such as fading; it is

dimensionless and assumes values between 0 and 1
s(λ) =α(λ)⋅ ⋅ f(λ)
dm,rel
where
is the spectral absorbance
α(λ)
is a function of wavelength determined by the receiving material
f(λ)

Note 1 to entry: It is normalised at 300 nm so that s(λ) = 1 for λ = 300 nm (see also Figure 1).

dm,rel
[SOURCE: CIE 157:2004]
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3.32
sensitive exhibits

museum exhibits, which can be more or less affected by electromagnetic radiations and/or other

environmental factors
3.33
source
object that produces light or other radiant flux
[SOURCE: CIE S 17/E:2011]
3.34
spectral sensitivity
s(λ)

describes the wavelength dependence of the material properties, such as fading; it is dimensionless and

assumes values between 0 and 1
3.35
total luminous exposure

photometric quantity; it is the product of the illuminance by the time of the exhibit exposure; it is measured in

lux·hours [lx·h]
3.36
ultraviolet radiation
part of the electromagnetic spectrum with wavelengths from 10 nm to 380 nm

Note 1 to entry: In the museum context UV is usually considered to include wavelengths up to 400 nm.

4 Symbols
The notations adopted in this TS are summarized below.
Table 1 — Symbols
Symbol Quantity
Unit
H lux-hours per year, lx⋅h per year Annual luminous exposure
R 1 Colour Rendering Index
T kelvin, K Colour temperature
P watt/lumen, W/lm Damage potential
D 1 Daylight factor
E watt per square metre, W⋅m Effective damaging irradiance
E watt per square metre, W⋅m Effective irradiance
eff
E lux, lx=lm⋅m Illuminance
E watt per square metre, W⋅m Irradiance
-2 -2 -1
L candela per square metre, cd⋅m =lm⋅m ⋅sr Luminance
Φ lumen, lm Luminous flux
I Luminous intensity
candela, cd= lm⋅sr
Φ watt, W Radiant flux
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ρ 1 Reflectance
s(λ) 1 Relative damage action spectrum
dm,rel
s(λ) 1 Spectral sensitivity
H lux⋅hours, lx⋅h Total luminous exposure
non dimensional units are indicated by 1
5 Sensitivity of cultural property to light
5.1 General

Light is one of several environmental factors to be considered in establishing a conservation policy.

A prerequisite for optimal lighting is good knowledge of present environmental conditions in the exhibition

area. This can be obtained by regularly monitoring lighting conditions by means of regular measurements to

account for daily and seasonal variations. Regular monitoring is recommended also after the first set up to

provide information on the environmental conditions, so that corrective actions can be taken if necessary.

5.2 Mechanisms of damage
5.2.1 General
Light may damage vulnerable exhibits by three mechanisms:
— Photochemical,
— Radiant heating effect,
— Growth of biological organisms.

The extent to which materials deteriorate under given lighting conditions depends on their chemical

composition, the characteristics of the light source, the illuminance levels and the length of exposure.

5.2.2 Photochemical

The absorption of light by a molecule or an ion can induce chemical changes, which result in changes of the

mechanical properties and the colour of the material, thus altering the exhibit in an irreversible way. For the

majority of light sensitive exhibits the damage is caused by the quantity of light (luminous exposure) and its

spectral distribution. The effectiveness of damage exponentially increases with the decreasing wavelength.

This means that usually the energy radiation of UV is much more damaging than blue light; blue light is more

damaging than green light, and so on (see Figure 1).

Accordingly, it is recommended to minimize the presence of UV in display lighting. The maximum acceptable

relative level of UV is 75μW/lm. This figure was originally chosen as it represented the amount of UV

produced by tungsten lamps which were at that time regarded as safe for lighting exhibits. Indeed, lower

relative levels of UV (such as 10μW/lm) can be attained either by using UV absorbers, on windows and

electric light sources, or by employing sources with minimal or zero UV output, such as most white LEDs.

However, the elimination of UV for sensitive exhibits is not sufficient to avoid damage if visible light is not

controlled and maintained below the values given in Table 3.
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Key
X wavelength in nm
-0.012 (λ/[nm] -300)
Y s(λ) = e
dm,rel

Figure 1 — Relative damage Y to photochemically sensitive surfaces versus wavelength X of incoming

radiation

NOTE This graph is applicable for all Cat 2,3 and 4 exhibits (except newspapers), see also Table 2.

It has to be stressed that molecules, which make up th
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.GLãþLQHErhaltung des kulturellen Erbes - Beleuchtung von Ausstellungen des kulturellen ErbesConservation des biens culturels - Eclairage d'exposition des biens culturelsConservation of cultural property - Exhibition lighting of cultural property97.195Umetniški in obrtniški izdelkiItems of art and handicrafts91.160.10Notranja razsvetljavaInterior lightingICS:Ta slovenski standard je istoveten z:prEN 16163oSIST prEN 16163:2010en,fr,de01-december-2010oSIST prEN 16163:2010SLOVENSKI

STANDARD
oSIST prEN 16163:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
DRAFT prEN 16163
October 2010 ICS 97.195 English Version
Conservation of cultural property - Exhibition lighting of cultural property

Erhaltung des kulturellen Erbes - Beleuchtung von Ausstellungen des kulturellen Erbes This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 346.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. prEN 16163:2010: EoSIST prEN 16163:2010

prEN 16163:2010 (E) 2 Contents Page Foreword ..............................................................................................................................................................3Introduction .........................................................................................................................................................31 Scope ......................................................................................................................................................42 Normative references ............................................................................................................................43 Terms and definitions ...........................................................................................................................44 Damage to cultural property caused by optical radiations ...............................................................74.1 Mechanisms of damage ........................................................................................................................74.1.1 Photochemical action of optical radiation ..........................................................................................74.1.2 Radiant heating effect of optical radiation ..........................................................................................74.2 Sensitivity and classification for cultural property ............................................................................74.3 Total luminous exposure ......................................................................................................................85 Optical radiations measurement ..........................................................................................................85.1 Visible radiation measurement .............................................................................................................85.2 UV measurement....................................................................................................................................96 Visual ergonomics rules for exhibition lighting .................................................................................96.1 Quality of light ........................................................................................................................................96.2 Illumination level ....................................................................................................................................96.3 Visual noise ......................................................................................................................................... 107 Exhibition lighting design .................................................................................................................. 117.1 Natural or artificial lighting ................................................................................................................ 117.2 Content of exhibition lighting design ............................................................................................... 117.2.1 Types of lighting for exhibition (room, hall or gallery) ...................................................................... 117.2.2 Lighting project stages ...................................................................................................................... 117.3 Preventive conservation on lighting project .................................................................................... 117.3.1 Illumination levels ............................................................................................................................... 117.3.2 UV protection ...................................................................................................................................... 127.3.3 Heating ................................................................................................................................................. 12Annex A (informative)

Characteristics of the light sources ......................................................................... 13A.1 Daylight ................................................................................................................................................ 13A.2 Artificial sources ................................................................................................................................. 13A.2.1 Incandescent lamps ........................................................................................................................... 13A.2.2 Fluorescent lamps .............................................................................................................................. 13Annex B (informative)

Glasses and films typology and characteristics .................................................... 15B.1 Glasses ................................................................................................................................................ 15B.2 Window films ....................................................................................................................................... 15B.3 Other protection .................................................................................................................................. 17Annex C (informative)

Lamps and lighting attachments .............................................................................. 18Annex D (informative)

Filters .......................................................................................................................... 19Bibliography ..................................................................................................................................................... 20 oSIST prEN 16163:2010

prEN 16163:2010 (E) 3 Foreword This document (prEN 16163:2010) has been prepared by Technical Committee CEN/TC 346 “Conservation of cultural property”, the secretariat of which is held by UNI. This document is currently submitted to the CEN Enquiry. Introduction Lighting is needed for many specific functions in museums and other cultural heritage organisations, for example for research, conservation and permanent or temporary exhibition. This standard deals only with lighting for permanent and temporary exhibitions in museums and galleries and does not consider lighting in other cultural heritage contexts such us hypogeal sites. Lighting is one of the most important factors enabling visitors to fully enjoy works of art and other cultural property. In fact, light is the key element for the links with our environment: humans need light and their need increases with ageing. On the other hand conservation consideration must be taken to care for the objects for future generations since light is an environmental factor, which is a threat to many objects. Alone or in combination with other environmental factors (temperature, humidity, pollution, etc.) light causes fading, discoloration and embrittlement to a wide range of materials. This damage is cumulative and irreversible: no conservation treatment can restore change of colour or loss in strength of materials damaged by light. Accordingly, the challenge of museum display lighting is to find an appropriate compromise between the requirements of the conservation and the needs of visitors and of a suitable exhibition design. As an integral part of an exhibition, display lighting contains both objective and subjective aspects:  the conservation aspect – sensitivity of the object, spectral composition of the light source and total luminous exposure,  the visual aspect – the impact of lighting on the visitor experience: lighting must give visitors a good view of presented objects, without glare, reflects or insufficient illumination,

 the exhibition design aspect – the lighting design must participate with the interpretation and be meaningful. oSIST prEN 16163:2010

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1 Scope This document defines the procedures as well as the means to implement good lighting, with regard to the conservation policy, but still regarding the conditions of visibility and exhibition design. It aims at providing a tool for setting up a European common policy and a guide for help curators, conservators and project managers to give to the architects and designers a correct lighting program with a European reference. 2 Normative references Not applicable. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 annual light exposue illuminance level multiplied by the time for which the object is exposed at that level. It is expressed in lux-hours per year (lxh/y). One year of museum display is approximately 3000 hours. See also total luminous exposure 3.2 blue wool scale scale of light-fastness, which comprises eight categories of standard dyed wools. The first is the most responsive to light; the second is approximately half as responsive as the first; and so on to the eighth, which is the least responsive 3.3 colour rendering index (CRI) measure of the degree to which the psychophysical colour of an object illuminated by the test source conforms to that of the same object illuminated by the reference illuminant, suitable allowance having been made for the state of chromatic adaptation NOTE The general colour rendering index (Ra) is calculated on eight Munsell samples, all of which have low to moderate chromatic saturation. Theoretically, CRI spans between 100 (best conditions) and 0 (worst conditions). Usually for white sources CRI spans between 100 and 60. 3.4 colour temperature temperature of a Planckian radiator whose radiation has the same chromaticity as that of given stimulus NOTE The reason this measurement is called a "temperature" is because it was derived from a theoretical ideal object called a "black body radiator". When the radiator is heated, it changes from black to red to yellow to white to blue. The lower the Kelvin rating, the "warmer" or more yellow the light, while the higher the rating, the "cooler" or more blue the light. The unit is the Kelvin (K). 3.5 daylight part of global solar radiation capable of causing a visual sensation. Daylight colour temperature can span from about 2500 K (at sunrise and sunset) to 20000 K (blue sky) and depends on day hour and season of the year oSIST prEN 16163:2010

prEN 16163:2010 (E) 5 3.6 daylighting lighting for which daylight is the light source. Formerly the term “natural light” was used, but “daylighting” is now in use in analogy with the term “electric lighting” 3.7 daylight factor ratio of the illuminance at a point on a given plane due to the light received directly and indirectly from a sky of assumed or known luminance distribution, to the illuminance on a horizontal plane due to an unobstructed hemisphere of this sky. The contribution of direct sunlight to both illuminances is excluded 3.8 dosimeter device or apparatus for total luminous exposure measurement during a given period of time 3.9 effective irradiance results from weighting the irradiance with the spectral sensitivity at the different wavelengths 3.10 exhibition design spatial interpretation of the curatorial purpose. It contains the design of showcases, colour setting, panels, sound and lighting 3.11 filter any device that selects a more or less wide portion of the electromagnetic spectrum (coloured and neutral filters, conversion temperature blue (CTB) and conversion temperature orange (CTO) filters, anti-UV or anti-IR filters). Neutral-density filters decrease the transmitted light by a known amount without selecting any wavelength 3.12 illuminance photometric quantity that corresponds to the radiometric quantity irradiance. Ratio between the luminous flux d - incident on an element of the surface containing the point, and the area dA of that element. It is measured in lux (lx) 3.13 illuminant radiation with a relative spectral power distribution defined over the wavelength range that influences object colour perception. It is a mathematical function, which defines a specific spectral power distribution incident on the object. It cannot always be exactly realized with a source 3.14 infrared radiations (IR) part of the electromagnetic radiation with wavelengths longer than those of the visible radiation, from about 780 nm to tens of micrometers 3.15 irradiance radiometric quantity that is the ratio between the radiant flux d -e incident on an element of the surface containing the point, and the area dA of that element. It is measured in watt per square meter W/m2 3.16 light light is the portion of the electromagnetic radiation to which the human eye is sensitive (c. 380 nm – 780 nm). In the field of conservation, this term extends the range outside the visible portion, including the ultraviolet (UV) and near infrared (IR) regions oSIST prEN 16163:2010

prEN 16163:2010 (E) 6 3.17 lighting art, devices or techniques used for illumination 3.18 light meter apparatus for illuminance measurement 3.19 luminous flux photometric quantity that corresponds to the radiometric quantity radiant flux. It is measured in lumen, lm 3.20 lux lx. Unit of illuminance. Illuminance produced on a 1 m2 surface by a luminous flux of 1 lumen uniformly distributed over that surface. 1 lx = 1 lm.m-2 3.21 lux meter see light meter 3.22 photometric quantities quantities that are based on the perception of radiation by the human eye and are valid only for visible radiations 3.23 optical radiation see light 3.24 radiant flux radiometric quantity. It is the radiant energy transported per unit time into a region of space by the electromagnetic wave. It is measured in Watt, W 3.25 radiometric quantities quantities that are based on purely objective physical measures 3.26 source object that produces a radiant flux, visible (light) and/or not visible (e.g. UV, IR) 3.27 Spectral Reflectance Factor characteristic of a material surface. It is the ratio of spectral reflected light by the object to spectral irradiance emitted by the illuminating source 3.28 spectral sensitivity describes the wavelength dependence of the material properties as the result of a radiant exposure under otherwise equivalent conditions of exposure. It is dimensionless and assumes values between 0 and 1 3.29 total luminous exposure photometric quantity. It is the sum of the illuminance level over a given period of time. It is measured in lux hours [lxh] oSIST prEN 16163:2010

prEN 16163:2010 (E) 7 3.30 ultraviolet radiation (UV) part of the electromagnetic radiations with wavelengths shorter than those of the visible radiation, from 10 nm to 380 nm 4 Damage to cultural property caused by optical radiations 4.1 Mechanisms of damage Light may damage vulnerable objects with two mechanisms:  photochemical action,  radiant heating effect. Moreover, optical radiations, particularly in combination with high relative humidity, can favour the growth of biological organisms, such as mould. 4.1.1 Photochemical action of optical radiation The absorption of light by a molecule or an ion can induce chemical changes, thus changing the mechanical properties and colour of the material, altering the object in an irreversible way. The activation energy for the change is supplied by the absorbed light, which brings the physical system to an excited state. The start does not depend on the surrounding environment, but the subsequent chemical processes can be affected by environmental factors such as temperature, relative humidity and possible presence of photo sensitizers. 4.1.2 Radiant heating effect of optical radiation The energy supplied by light raises the temperature of the surface on which light impinges, depending on the amount of light that is absorbed, heat diffusivity within the object, and convective exchanges. Apart from thermal stress induced on the artefact, and desiccation, which can be caused by a decrease in local relative humidity due to the temperature rise, the higher temperature level accelerates chemical reactions and photochemical processes. 4.2 Sensitivity and classification for cultural property The table below lists materials in four categories according to their sensitivity to light. Table 1 — Classification of sensitive cultural property from CIE 157:2004 Category Description 1.

No sensitivity The object is entirely composed of materials that are insensitive to light. Examples; most metals, stone, most glass, genuine ceramic, enamel, most minerals. 2.

Low sensitivity The object includes durable materials that are slightly light responsive.

Examples; oil and tempera painting, fresco, undyed leather and wood, horn, bone, ivory, lacquer, some plastics. 3. Medium sensitivity The object includes fugitive materials that are moderately light responsive.

Examples; most textiles, watercolours, pastels, prints and drawings, manuscripts, miniatures, paintings in distemper media, wallpaper, and most natural history objects, including botanical specimens, fur and feathers. 4.

High sensitivity The object includes highly light responsive materials.

Examples; silk, colorants known to be highly fugitive, graphic art and photographic documents. oSIST prEN 16163:2010

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4.3 Total luminous exposure The photochemical effect is closely related to the cumulative radiation received by the object.

According to the reciprocity law, the net photochemical effect is the result of the total exposure which an object receives. In other words, it is the total energy hitting the object in its lifetime, which matters: Total luminous exposure = illuminance x time expressed as lx hours/year (photometric units) The following table gives the recommended values of maximum total luminous exposure for the different classes of light sensitive objects. Table 2 — Total luminous exposure for different classes of light sensitive object interpreted from CIE 157:2004 Material classification Blue wool scale Total luminous exposure 1. Insensitive - no limit (for conservation) 2. Low sensitivity 7 & 8 600 000 lxh/y 3. Medium sensitivity 4, 5 & 6 150 000 lxh/y 4. High sensitivity 1, 2 & 3 15 000 lxh/y

When more classes of materials are simultaneously present, the limit to be considered corresponds to the most protected class. It should be taken into account that other physical or chemical factors (relative humidity, temperature, pollutants) can enhance the effects of light, so that in adverse environmental conditions the reported limits are mandatory. 5 Optical radiations measurement 5.1 Visible radiation measurement The illuminance shall be measured with lux-meters sensitive in the 380 - 760 nm range.

Several types of devices are available to measure indoor light levels. The measuring range shall be from 0.1 lx to 106 lx. When measuring light, the lux-meter should be placed as close as possible to the most light exposed part of the object’s surface. The sensor surface is oriented parallel to the object. If the object is not flat, the sensor should be parallel to the most exposed or vulnerable surface.

The effective illuminance on a surface depends on its orientation to the light source, being proportional to the cosine of the angle of incidence of light on the surface (Cosine law). When light comes from different sources, or when the surface of the object is not perpendicular to the incoming light, measurements should be performed with lux-meters having the cosine correction function, so as to provide a correct evaluation of actual illuminance on the target. If the room is lit with artificial light only, one run of measurements is sufficient. Special lighting during cleaning works and similar must also be measured and taken account of in the total luminous exposure.

If the room is lit with natural light, one set of measurements is not enough, because light levels change with the weather, time of day and season. It is essential to position the lux-meter exactly and always in the same sampling points, in order to avoid distortion of the information. The monitoring should be done during one year to take into account the daily and seasonal variations.

oSIST prEN 16163:2010

prEN 16163:2010 (E) 9 Many devices can supply instantaneous illuminance as well as total luminous exposure by integrating the data over time, so called data loggers. Moreover, a semi-quantitative evaluation of the total luminous exposure can be obtained by disposable sensors such as Blue Wool Standard or similar dosimeters, which fade or change their colour when exposed to light. These allow a user-friendly and satisfactory indication of the light dose received, expressed in terms of lxh/y. Alternatively, it is possible to use the concept of prevision of the quantity of light over one year or over the duration of the exhibition. It can be evaluated by the method of the "daylight factor". An annual illuminance is available by the weather agency of each country. In order to predict the quantity of light indoors, it is necessary to measure, at the same time, illumination both outdoors and indoors. 5.2 UV measurement Ultraviolet (UV) radiation is more energetic than visible light. It cannot be perceived by the human eye and is therefore not needed for our vision. As it can cause objects to deteriorate, it must be eliminated or, at least, reduced at the lowest possible level. There are two ways to measure, or more precisely, to prove the presence of UV.

The first method is using a UV-meter, a device which gives quantitative values in microwatt per square centimetre (µw/cm2). Different manufacturers produce their own UV sensors. The result is a multitude of UV sensors showing different curves. For UV measurements, the only choice is 365 nm at the maximum of the sensibility curve. The second method is using the “UV monitor” especially developed for museum use. It measures the proportion of UV radiation present in the light. It is measured in microwatts per lumen (µw/lm) which is not part of the international system of measurements.

To verify the presence of UV radiation with an ultraviolet meter, two measurements are necessary. The first with a UV filter in front of the sensor, the second without. If the difference is significant (i.e. not less than 50%), the light source contains UV and shall be eliminated.

With the special “UV monitor” for museum use, the elimination of the UV source is necessary if the value exceeds 75 µw/lm (value measuring on incandescent light source).

The elimination of UV for vulnerable objects and collections will have effect only if at the same time visible light is controlled. 6 Visual ergonomics rules for exhibition lighting 6.1 Quality of light The choice of a source for museum lighting should provide a good colour rendering. Usually the CIE colour rendering index (CRI) is adopted to classify light sources. The best sources are daylight and incandescent lamps with a CRI close to 100. It is possible to use luminescence lamps, specially fluorescent lamps with

95-98 CRI. If the colour of the object is not an important factor it is possible to use lamps with 80-85 CRI. In general, the spectral irradiance of the source should carry all wavelengths that are reflected from the object with an intensity as wide as that perceived by the human eye. The colour temperature of the source is another factor that influences object vision. Generally, low level of illumination request low colour temperature, about 3000 K and high level of illumination request high colour temperature. 6.2 Illumination level To see displayed objects properly, not only an excellent quality of light is required, but also a certain level of illumination. The necessary level is subjective and related to the age of the observer, because the performance of the human vision diminishes with increasing age. However, it also depends on the background illumination level (contrast), i.e. a clear detail appears more luminous on a dark background compared to a oSIST prEN 16163:2010

prEN 16163:2010 (E) 10 pale one. In the former case a lower level of illumination is needed. Moreover, human vision adjusts its sensibility when passing from a high to a low illumination level. However, in no case illuminance levels higher than 200 lux are allowed. 6.3 Visual noise Visual noise can be caused by reflections on surface varnish or protection glass, or by a bright source or a big contrast of luminance dazzling the viewer. In the most cases a good position of the spotlight (see Figure 1.) is the solution. If still dazzling occurs, antireflection glasses or indirect illumination must be used. Another more significant visual noise is ambient light levels or light levels in adjacent spaces which affect the ability of the viewer to perceive colour and details. Accordingly, proper adjustment of the surrounding illumination can markedly modify the light levels that are needed for the best perception of the objects.

Figure 1 — Spotlight good position
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prEN 16163:2010 (E) 11 7 Exhibition lighting design 7.1 Natural or artificial lighting This choice is linked to architecture. In a classical setting, galleries are lit from the top by glass roofs and the galleries of sculptures by lateral windows. A recommended design with natural lighting must be the result of a study of illumination including solar and UV protection, and knowledge of the daylight factor. The choice of natural illumination does not exempt us from artificial illumination. It must be added and complemented as the light of the day changes. Daylight has a high content of UV and IR radiation and its irradiance strongly depends on the hour and season. Devices such as filters, films, variable transparency glasses, curtains and so on, must be used, to

control the visible and infrared components and eliminate, as much as possible, the UV component. 7.2 Content of exhibition lighting design 7.2.1 Types of lighting for exhibition (room, hall or gallery) Exhibition lighting contains also the following components:

 work lighting, for exhibition installation, cleaning and maintenance,

 safety lighting, compulsory for all public spaces, contains:  emergency exit lighting,  circulation lighting, for the safety of visitors,

must be turned on during opening hours,  display lighting for ambient exhibition and visual design, intended to highlight individual or a group of objects, and display cases. 7.2.2 Lighting project stages The illumination of an exhibition, as any design project, includes three stages:  lighting conception, the draft to be validated by an exhibition designer,  construction planning, drawing of plans and request for quotes,  implementation, which has two parts: 1) electrical

installation before

arrival of the objects and 2) light adjustments, once the objects are installed. 7.3 Preventive conservation on lighting project 7.3.1 Illumination levels When different types of materials are simultaneously present, the limitation for the most vulnerable type should be applied. With a proper control of the surrounding environment, 200 lx is generally sufficient to provide an adequate visibility for visitors. In cases where low illuminance (about 50 lux) is required (for example during a long-term exhibition of objects in the high sensitivity category) visibility of the exhibit can be enhanced by lighting the background to a lower level. This has the effect of reducing visual adaptation and making the exhibit the brightest part of the field

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