EN 17655:2022

SLOVENSKI STANDARD
01-september-2022
Ohranjanje kulturne dediščine - Določanje absorpcije vode z metodo kontaktne
gobice
Conservation of cultural heritage - Determination of water absorption by contact sponge
method
Erhaltung des kulturellen Erbes - Bestimmung der Wasseraufnahme durch
Kontaktschwamm-Methode
Conservation du patrimoine culturel - Détermination de l'absorption d'eau par la méthode
de l'éponge de contact
Ta slovenski standard je istoveten z: EN 17655:2022
ICS:
97.195 Umetniški in obrtniški izdelki. Items of art and handicrafts.
Kulturne dobrine in kulturna Cultural property and
dediščina heritage
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 17655
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2022
EUROPÄISCHE NORM
ICS 97.195
English Version
Conservation of cultural heritage - Determination of water
absorption by contact sponge method
Conservation du patrimoine culturel - Détermination Erhaltung des kulturellen Erbes - Bestimmung der
de l'absorption d'eau par la méthode de l'éponge de Wasseraufnahme durch Kontaktschwamm-Methode
contact
This European Standard was approved by CEN on 29 May 2022.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17655:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviated terms . 6
5 Principle . 6
6 Test equipment . 6
7 Procedure. 8
7.1 General . 8
7.2 Methodology A - in the laboratory . 9
7.3 Methodology B - In situ . 10
7.3.1 With weighing in situ . 10
7.3.2 Without weighing in situ . 10
8 Expression of results . 11
8.1 Calculation of the amount of water absorbed . 11
9 Test report . 11
10 Warning . 11
11 Guidelines for comparative evaluation . 12
Bibliography . 13

European foreword
This document (EN 17655:2022) has been prepared by Technical Committee CEN/TC 346 “Conservation
of cultural heritage”, the secretariat of which is held by UNI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2023, and conflicting national standards shall
be withdrawn at the latest by January 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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, Turkey and the United
Kingdom.
Introduction
This test method can be applied if it does not adversely affect any of the values of the object and following
ethical codes of conservation practice.
The test measurements are generally used during effective evaluation of conservation treatments;
different specific evaluation campaigns can be compared only when the same sponge material is used.
There is another non invasive method, EN 16302, recommended to measure water absorption at low
hydrostatic pressure of porous inorganic materials either untreated or subjected to any treatment or
ageing applied both in laboratory and in situ.
1 Scope
This document establishes the methodology to measure the quantity of water absorbed by a defined
surface of a porous inorganic material used for and constituting cultural property, by contact sponge
method.
This test describes the water absorption behaviour of the near-surface zone.
The method can be used on porous inorganic materials, which are untreated or have undergone any
treatment or ageing.
The method can be used both in the laboratory and in situ on flat vertical and/or horizontal surfaces
NOTE 1 Treated materials are those which have been subjected to cleaning; to the application of water repellent,
consolidating and/or biocidal products; to artificial aging tests, etc.
NOTE 2 The test is not intended to be used on surfaces which are severely deteriorated, where application of the
sponge is likely to cause material loss. The operator is expected to ensure good contact with the perimeter of the
container. The test is not accurate when applied to rough surfaces.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
porous inorganic material
materials including natural stones e.g. sandstone, limestone, marble, granite, gneiss, gypsum as well as
artificial materials, such as mortar, plaster, brick, ceramics, concrete and others
[SOURCE: EN 15801:2009, 3.1 modified]
3.2
water absorption by sponge method
amount of water (mg) transferred from the sponge through a defined test area (cm ) after a fixed time,
expressed as mg/cm min
3.3
test surface area
location where the measurement is carried out
3.4
specimen
part considered representative of the material constituting an object
Note 1 to entry: The specimen can have different origins and can be taken from:
— materials similar to those constituting the object under study (e.g. stone quarries);
— specifically, prepared comparative materials e.g. reference materials;
— available materials from the object.
Note 2 to entry: The number and dimension of the specimens can be different depending on constraints
encountered in sampling the required amount of material.
[SOURCE: EN 16302:2013, 3.3]
4 Symbols and abbreviated terms
W = water absorbed per surface unit per minute (mg / cm⋅min);
a
t = contact time (minutes);
mi = initial weight (mg);
m = final weight (mg);
f
m = weight of foreign material (where necessary), (mg);
e
S = contact surface of the sponge (cm ).
5 Principle
Determination of the amount at which water is absorbed through the test surface that is put in contact
with a sponge wet with water at given times.
6 Test equipment
6.1 Deionized water (with max. conductivity of 6 μS/cm).
6.2 Chronometer with an accuracy of 1s.
6.3 Container capable of holding the contact sponge
The base and lid of the container should be made of non-corrosive material (such as aluminium, glass,
PVC, PMMA) impermeable to liquid water and other forms of moisture. The dimensions of the container
should be as shown in Figure 1.
The standard container has a diameter of 60 mm (sponge of 55 mm, see Note). When working on objects
where it is difficult to find large flat surfaces, it is possible to use a container with a reduced diameter of
26 mm (sponge of 25 mm, see Note).
NOTE The diameters of 55 mm or 25 mm refer to the dimensions obtained by hollow punch cutting the raw
material before wetting.
Key
a) Base
b) Lid/top
Figure 1 — Size of the lidded container
Table 1 — Size of the lidded container
Container
Size (cm) Standard (mm) Small (mm)
A 66 33
B 57 26
C 1 1
D 60 29
E 10 10
F 3 3
G 4 4
6.4 Contact sponge
When the comparison of results is needed the tests shall be done with the same sponge.
The contact sponge shall be made of the honeycomb type of inert material (cellulose or polyester) with a
dry weight of 420 ± 50 g/m and have a water absorption capacity equivalent to 10 to 15 times its dry
weight. A contact sponge of standard dimensions (diameter 55 mm) or reduced dimensions (diameter
25 mm) can be used. The dimensions of the dry and wet sponge vary and shall be according to the values
shown in Figure 2.
Key
a) Dry sponge
b) Wet sponge
Figure 2 — Size of the sponge
Table 2 — Size of the standard sponge (left); size of the small sponge (right)
Standard sponge (mm) Small sponge (mm)
Dry Wet Dry Wet
a 55 a’ 58 a 25 a’ 27
b 2,5 b’ 5,5 b 2,5 b’ 5,5
6.5 Scale ideally should have an accuracy of 0,1 mg, however taking into account the work conditions
in field, scales with accuracy of 1 mg could be acceptable for on-site measurements.
6.6 Syringe or pipette maximum capacity 5 ml graduated.
7 Procedure
7.1 General
The tested surface areas shall be representative of the material under investigation. In order to avoid
discrepancies in water absorption, the test surface area should ideally be flat and continuous.
The number and dimensions of test surface area are dependent on the heterogeneity of the material and
shall be adapted to obtain statistically representative values.
Each series shall consist of at least three measurements. In case of anisotropy, each series shall always be
tested according to the same orientation, if any. In case of non-homogeneous materials, such as mortars,
containing coarse aggregates, the diameter of the measurements area shall be at least three times (and
preferably five times) the largest grain size.
In the case of surfaces which are heavily deteriorated it is necessary to evaluate the possibility of loss of
material due to the contact with sponge which would entail both a problem to the surface itself and to the
reliability of the test.
In the laboratory, the test shall be performed at temperature between 20 °C to 25 °C. Field temperatures
should be noted, and it is recommended the test should not be
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