oSIST prEN 15999-2:2023

SLOVENSKI STANDARD
oSIST prEN 15999-2:2023
01-april-2023
Ohranjanje kulturne dediščine - Smernice za načrtovanje vitrin za razstavljanje in
hranjenje predmetov - 2. del: Tehnični vidiki
Conservation of cultural heritage - Guidelines for design of showcases for exhibition and
preservation of objects - Part 2: Technical aspects
Erhaltung des kulturellen Erbes - Leitfaden für die Konstruktion von Schauvitrinen zur
Ausstellung und Erhaltung von Objekten - Teil 2: Technische Aspekte
Conservation du patrimoine culturel - Lignes directrices pour la conception de vitrines
destinées à exposer et préserver des biens culturels - Partie 2 : Aspects techniques
Ta slovenski standard je istoveten z: prEN 15999-2
ICS:
97.195 Umetniški in obrtniški izdelki. Items of art and handicrafts.
Kulturne dobrine in kulturna Cultural property and
dediščina heritage
oSIST prEN 15999-2:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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DRAFT
EUROPEAN STANDARD
prEN 15999-2
NORME EUROPÉENNE

EUROPÄISCHE NORM

February 2023
ICS 97.195
English Version

Conservation of cultural heritage - Guidelines for design of
showcases for exhibition and preservation of objects - Part
2: Technical aspects
Conservation du patrimoine culturel - Lignes Erhaltung des kulturellen Erbes - Leitfaden für die
directrices pour la conception de vitrines destinées à Konstruktion von Schauvitrinen zur Ausstellung und
exposer et préserver des biens culturels - Partie 2 : Erhaltung von Objekten - Teil 2: Technische Aspekte
Aspects techniques
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-CENELEC
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

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

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15999-2:2023 E
worldwide for CEN national Members.

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Contents . Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Symbols and abbreviated terms . 8
5 Specification of properties of a showcase . 8
5.1 Environmental factors . 8
5.1.1 Airtightness (3.1) and air exchange rate . 8
5.1.2 Air exchange rate measurements . 11
5.1.3 Protection against adverse climate . 12
5.1.4 Protection against pollution . 16
5.1.5 Protection against UV radiation . 17
5.2 Security and safety . 17
5.2.1 General . 17
5.2.2 Resistance against theft . 17
5.2.3 Electronic security . 18
5.2.4 Structural stability . 18
5.2.5 Fire resistance . 18
5.2.6 Resistance against splashing water . 19
5.3 Showcase relocations . 19
5.3.1 General . 19
5.3.2 Disassembly of showcase . 20
5.3.3 Transport of showcase . 20
5.4 Marking . 20
Annex A (informative) Assessment procedure for showcases from non-serial production . 21
Annex B (normative) Test method for certified safety showcases . 24
Annex C (informative) Physics of showcase air exchange . 31
Annex D (informative) Leak detection . 36
Annex E (informative) Example of air exchange rate measurement procedure by tracer gas decay38
Annex F (informative) Example of air exchange rate measurement procedure by constant air
pressure difference . 40
Annex G (informative) Protection against pollution . 43
Annex H (informative) Emission- and impact-testing of showcase materials . 46
Annex I (informative) Examples for the calculated approximation of the hygrometric half-time . 47
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Annex J (informative) Numerically calculating hygrometric half-time from internal and
environmental relative humidity (3.7) data . 51
Bibliography . 52

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European foreword
This document (prEN 15999-2:2023) has been prepared by Technical Committee CEN/TC 346
“Conservation of cultural heritage”, the secretariat of which is held by UNI.
This document is currently submitted to the CEN Enquiry.
EN 15999 consists of the following parts, under the general title “Conservation of cultural heritage –
Guidelines for showcases for exhibition and preservation of objects”:
— Part 1: General requirements,
— Part 2: Technical aspects.
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Introduction
The main purpose of a showcase for cultural heritage objects on exhibition is to reduce the risks of
total loss, physical damage, chemical and biological deterioration (e.g. by accidents, theft, vandalism,
natural disasters, humidity, temperature, dust, pollutants, light, pests). A showcase adapted for its
tasks is expected to have properties which have been selected and specified with regard to its specific
use, requirements, value of object(s), and (projected) exhibition environment.
This document specifies how the performance of the showcase ⁠— as derived from needs identified
during the risk assessment approach described in prEN 15999-1⁠— can be technically specified by
using classified properties. These classes characterize, determine or measure the performance of the
showcase. The specification of the properties of a showcase can be used in the procurement phase or
in the operating phase; e.g. to define showcase properties for objects on loan.
prEN 15999-2 is for stakeholders who are expected to understand the properties of a showcase,
including end-users (such as collection managers, conservators, curators, registrars, installers,
technical agents), designers (architects, persons in charge of scenography or museography),
manufacturers, and contracting authorities who are in charge of the cultural institutions.
This document should facilitate both dialogue and collaboration between stakeholders who are
engaged in projects which involve showcases. It provides technical information about conservation,
safety and security, use and management of the showcase.
While recognizing that aesthetics of showcases are very important, the present document
emphasizes functional design of the showcase, the practical needs of the user and the requirements
of the objects for better preservation.
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1 Scope
This document defines and classifies properties of passive showcases for the safe and secure display
of cultural heritage objects for better preservation. It applies to most uses of the showcase:
showcases for so called permanent or temporary exhibitions, historical or modular showcases,
showcases in uncontrolled ambient environment, etc. Aspects of active showcases (those using
electricity to directly condition their microclimates) and anoxic showcases (those containing inert
atmospheres instead of air) are mentioned in this document, but their properties are not defined, nor
classified.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
EN 1023-3:2000, Office furniture - Screens - Part 3: Test methods
EN 15898:2019, Conservation of cultural heritage - Main general terms and definitions
EN 1630:2021, Pedestrian doorsets, windows, curtain walling, grilles and shutters - Burglar resistance
- Test method for the determination of resistance to manual burglary attempts
EN 410, Glass in building - Determination of luminous and solar characteristics of glazing
EN 50131 (all parts), Alarm systems - Intrusion and hold-up systems
EN 60529, Degrees of protection provided by enclosures (IP Code)
EN ISO/IEC 17025:2017, General requirements for the competence of testing and calibration
laboratories (ISO/IEC 17025:2017)
EN 60332-1-2:2004, Tests on electric and optical fibre cables under fire conditions - Part 1-2: Test for
vertical flame propagation for a single insulated wire or cable - Procedure for 1 kW pre-mixed flame
(IEC 60332-1-2:2004)
EN IEC 60332-3-24:2018, Tests on electric and optical fibre cables under fire conditions - Part 3-24:
Test for vertical flame spread of vertically-mounted bunched wires or cables - Category C
(IEC 60332-3-24:2018)
ISO 20653:2013, Road vehicles — Degrees of protection (IP code) — Protection of electrical equipment
against foreign objects, water and access
ISO 21348:2007, Space environment (natural and artificial) — Process for determining solar
irradiances
prEN 15999-1: Conservation of cultural heritage – Guidelines for design of showcases for exhibition and
preservation of objects – Part 1: General instructions
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3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 15898:2019 and in
prEN 15999-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
airtightness
capacity of an envelope to limit the entrance or escape of air or other gas
3.2
end-user
person with assigned responsibility for cultural heritage on display in showcases or for the
showcases themselves
3.3
environment
physical, chemical and biological conditions surrounding the showcase
3.4
humidity buffering
smoothing of the peaks and troughs in relative humidity, whilst not changing the average relative
humidity
3.5
humidity control
maintaining a relative humidity value different from the average relative humidity value of the
environment (3.3)
3.6
pollution sorbent
material that captures some specific gaseous pollutants to reduce their concentration
3.7
relative humidity
ratio of the actual vapour pressure to the saturation vapour pressure
[SOURCE: EN 15757:2010, 3.9]
3.8
volatile organic compound
VOC
volatile organic compound, including VVOC (very volatile organic compound) and SVOC (semi
volatile organic compound)
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3.9
security personnel
those people in the organisation in the supply chain that have been assigned security related duties
Note 1 to entry: These people may or may not be employees of the organisation.
[SOURCE: ISO 28001:2007, 3.22]
4 Symbols and abbreviated terms
AER – air exchange rate,
RH – relative humidity (3.7),
T – temperature,
VOC – volatile organic compound (3.8),
UV – ultraviolet,
IR – infrared
5 Specification of properties of a showcase
5.1 Environmental factors
Showcases can enhance the physical protection of objects from environmental risks arising from
incorrect humidity and temperature, pollutants, pests, UV and/or IR radiation.
5.1.1 Airtightness (3.1) and air exchange rate
The protective capacity of the showcase against the environmental factors listed below is mainly
determined by its airtightness (3.1). This allows it to:
— limit entry of gaseous pollutants present in the showcase's environment (3.3) (e.g. external use
of corrosive cleaning products, penetration of outdoor gaseous pollutants);
— reduce water vapour exchanges and improve microclimate control (e.g. moisture exchange due
to low airtightness (3.1) limits the effectiveness and useful lifetimes of added moisture sorbent
and decreases hygrometric control of buffering showcases, which rely on high loading of
moisture sorbent in conjunction with higher airtightness (3.1));
— limit entry of particulate matter present in the room coming from indoor and outdoor sources
(e.g. smoke, dust, sporae, pest eggs) that deposit on objects or infest them, and to decrease
cleaning frequency of showcase interior.
When pollution comes from a source inside the showcase (e.g. an object releasing VOCs (3.8)), and
objects made of vulnerable materials are present, higher airtightness (3.1) is unfavourable for object
preservation. Intentional leaks (vents) should be created using natural or forced ventilation, or a
material able to absorb and retain the pollution should be added.
Airtightness (3.1) of showcases generally decreases with time due to ageing and wear of sealing
materials (e.g. joint adhesives, door-gaskets) and misalignment of the showcase with its openings
(e.g. doors, technical compartments) and its joints due to deformation of glass and metal sheets.
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Showcase airtightness (3.1) is quantifiable by the air exchange rate (AER). Categories of AER and
showcase performance affected by the air exchange rate are indicated in Table 1. Different classes of
AER are characterized by different levels of airtightness (3.1) from low airtightness (3.1) (AER ≥ 5
−1 −1
day ) to high airtightness (3.1) (AER < 0,4 day ).
Table 1 — Class labels according to AER with indicative capacity to maintain a suitable
environment (3.3)
Class AER Capacity to Capacity to maintain Capacity to Pollutant
−1
Label [day ] buffer against internal hygrometric provide accumulation
external (RH) conditions (RH) protection from off-
fluctuation against the gassing
ingress of showcase
b
materials
pollutants
and/or objects
   Passive Active
control control
AE 0 ≥ 5,0 Can significantly no Yes with Slight. Some Least build-up
reduce daily, high capacity protection
but not weekly, systems offered against
fluctuations external
with very large pollution, but not
amounts of recommended.
moisture
a
sorbent ; RH
can be
controlled with
active systems
AE 1 < 5,0 to Can significantly will struggle Yes Some. Between Very low risk of
3,0 reduce weekly, to control RH most stringent build-up
but not depending on recommended
monthly, room levels (in rooms
fluctuations environment with low
with large pollution
(3.3)
amounts of background
moisture values) up to
a
~25 %
sorbent ; RH
protection
can be
compared to the
controlled with
environment
active systems
(3.3)
AE 2 < 3,0 to Can significantly may struggle Yes Good. Between Low risk of
1,0 reduce monthly, for part of the most stringent build-up
but not seasonal year, recommended
variations with depending on levels up to
medium environment ~50 %
amounts of (3.3) protection
moisture compared to the
a
environment
sorbent
(3.3)
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Class AER Capacity to Capacity to maintain Capacity to Pollutant
−1
Label [day ] buffer against internal hygrometric provide accumulation
external (RH) conditions (RH) protection from off-
fluctuation against the gassing
ingress of showcase
b
materials
pollutants
and/or objects
   Passive Active
control control
AE 3 < 1,0 to Can significantly may work for Suitable with Very good. Large Moderate risk
0,4 reduce monthly, most most control showcases, of build-up
and most environments systems for and/or with hard
seasonal (3.3) most and smooth
variations with situations materials (e.g.
medium glass and
amounts of aluminium),
moisture might not satisfy
a
most stringent
sorbent
recommended
levels.
AE 4 < 0,4 to can significantly Yes Yes Very good. High risk of
0,1 reduce monthly, Nearly always build-up
and seasonal satisfy most
variations with stringent
medium recommended
amount of levels. Large
moisture showcases in
a
naturally
sorbent
ventilated
buildings or in
conditioned
buildings with
insufficient
chemical filtering
in urban
environments,
might not satisfy
most stringent
levels.
AE 5 < 0,1 unlikely to be Excellent. Very Highest risk of
Yes Yes
required for RH few showcases build-up
buffering or need this low
control, except AER.
in most extreme
situations
a
3 3
very high loading of moisture sorbent: e.g. 10 kg/m ; high loading of moisture sorbent: e.g 6 kg/ m ;
3
medium loading of moisture sorbent: e.g. 3 kg/ m .
b
protection levels are based on showcases placed in indoor environment (3.3)
Active climate conditioning systems may offer an alternative. However, the risk of technical failure
should be considered. The performance of many active systems is very temperature dependent.
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Experience has shown that the air exchange rate influences active conditioning (see Table 1). Many
manufacturers give indicative showcase volumes and air exchange rates that a certain active climate
conditioning unit will work with and requirements for space around the unit, which should be
adhered to. Humidifiers and dehumidifiers have large capacities and can successfully condition large
showcases with high air exchange rates. If both humidifiers and dehumidifiers are used together,
correct hysteresis settings on the control sensor are essential. Mixing chambers can be used for
smoothening RH fluctuations induced by humidifiers and dehumidifiers units that run alternately. It
comprises a space between the display volume and humidifier or dehumidifier units. For greater
effect, a mixing chamber is possibly equipped with moisture sorbent. Several units based on Peltier
coolers and water reservoirs are available. Many have limited dehumidification capacity and can
struggle at high room RH or high temperatures.
5.1.2 Air exchange rate measurements
Two methods adapted from building measurement standards are suitable for measuring showcase
air exchange rates. They measure:
— tracer gas concentrations,
— air pressure differences.
Measuring showcase airtightness (3.1) to estimate protection against the environmental factors
outlined in the previous section (see 5.1.1) is typically achievable with the tracer gas decay method.
This is because it measures air exchanges resulting from the complex interplay between the
construction of the showcase, and a variety of environmental contributions that often vary over time
(see C – Physics of showcase air exchange). As a consequence, air exchange rates measured by tracer
gas decay vary according to the changing ambient environmental conditions. For this reason, tests
running over periods longer than one day are recommended to obtain an average air exchange rate;
arriving at results representative of eventual exhibition conditions. See E for an example of air
exchange rate measurement procedure by tracer gas decay.
Measuring the extent of showcase air exchange via gaps is typically achievable with air pressure
difference methods, e.g. air pressure difference decay, constant air pressure difference. With these
methods air exchange is measured under a consistently controlled test environment (3.3) which
dominates over ambient environmental conditions. As a result, air exchange rates measured by air
pressure methods are less subject to changing ambient environmental conditions; according to the
unchanging construction/geometries of the showcase and its gaps. This high test repeatability stems
from its mechanically-induced air exchange, which also enable tests to be completed in minutes. See
Annex F.
Before taking air exchange rate measurements, the objective/s shall be clearly defined. This can help
to choose the suitable measurement method/s; especially in terms of the test duration, equipment
and environmental conditions. Unless preliminary tests are being undertaken, showcases shall be
tested as part of their final assessment, with all features installed, e.g. security/lighting devices and
wiring. Sealing surfaces and seals on all openings should be cleaned, and openings properly shut with
all locks engaged.
The objectives may be to determine the:
— construction quality of showcases versus targets from specifications in procurement contracts
with showcase suppliers, or from ad hoc exhibition needs,
— lifetime/amount of sorbent needed for buffering RH (see also Annex G, G.2)
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— lifetime/amount of sorbent needed for controlling RH to a limit/threshold (see also G.3)
— protection of objects from externally generated pollutants (see also G.2)
— accumulation of internally generated pollutants (see also G.4)
— venting of internally generated pollutants (see also G.4)
— remedial alterations to airtightness (3.1) made during maintenance or retrofitting of door-
gaskets, hinges, joints, gas struts, vertical lift systems and joints resealing around
lighting/cableruns, etc. on existing showcases,
— alterations to airtightness (3.1) made after relocating existing showcases,
— influences of ageing and wear on alterations to airtightness (3.1) of existing showcases.
Active microclimate conditioning systems will interfere with accuracy of airtightness (3.1)
measurements, so should be turned off and have any plumbing connections closed.
Before or after taking air exchange rate measurements, searching for leaks might be appropriate (see
Annex D).
Further information can be found in the Annexes:
— the physics of showcase air exchange (Annex C),
— the influence of showcase design on air exchange (see prEN 15999-1:2023, Annex B),
— Example of air exchange rate measurement procedure by tracer gas decay (Annex E),
— Example of air exchange rate measurement procedure by constant air pressure difference
(Annex F).
5.1.3 Protection against adverse climate
5.1.3.1 General
Showcases can be designed to provide appropriate climate conditions for the long term preservation
of objects. Relative humidity (3.7) and temperature are the principal climate parameters, but
pollution shall be considered for many materials as well. Relative humidity (3.7) of air is linked to the
air temperature. A temperature increase of 1°C can make the relative humidity (3.7) decrease about
2 % to 3 %.
NOTE An enthalpy-entropy chart, a so-called Mollier-diagram, can be consulted to determine such
changes. For example: the relative humidity (3.7) in air with a temperature of 25 °C and a constant humidity
mixing ratio of 9,9 g/kg, will drop from 50 % to 47 % when the temperature rises to 26 °C.
Four different qualities of showcases are described below to control its microclimate performances:
— Hygrometric half-time,
— Buffering against external relative humidity (3.7) fluctuation,
— Capacity to maintain internal hygrometric conditions (RH), and
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— Thermal performance.
Whilst humidity buffering (3.4) is suitable if the room average relative humidity (3.7) is acceptable,
there are often occasions when it is desired to keep the showcase average relative humidity (3.7)
significantly different to the room.
The targeted relative humidity (3.7) conditions for an object are obtained by selecting a showcase
with a suitable hygrometric half-time (5.1.3.2) and corresponding replacement cycle of the moisture
sorbent.
5.1.3.2 Hygrometric half-time
The capacity of a showcase to buffer against fluctuations in room relative humidity (3.7), or to
maintain a microclimate relative humidity (3.7), is most easily expressed as the hygrometric half-
time. The hygrometric half-time depends on two chief factors: (1) airtightness of the showcase
envelope, and (2) the type, amount (loading for the moisture sorbent) and buffering material/s in the
display
...