prEN 16306

Natural stone test methods - Determination of resistance of marble to thermal and moisture cycles

This document specifies a laboratory method for determining the resistance to thermal and moisture cycling of marble intended for the external cladding of building facades.
For scientific definition of marble, reference is made to EN 12670 Terminology: 2.1.243 a.
NOTE   Bowing and rapid strength loss is known to occur in some marbles when used as exterior cladding.

Prüfverfahren für Naturstein - Bestimmungen der Beständigkeit von Marmor bei zyklischer Belastung mit Wärme und Feuchtigkeit

Dieses Dokument legt ein Laborverfahren zur Bestimmung der Beständigkeit von Marmor, der zur Außenverkleidung von Gebäudefassaden vorgesehen ist, bei zyklischer Belastung mit Wärme und Feuchtigkeit fest.
Für eine wissenschaftliche Definition von Marmor wird auf EN 12670, Begriff 2.1.243 a, verwiesen.
ANMERKUNG   Das Auftreten von Wölbung und schnellem Festigkeitsverlust ist für einige Marmorsorten bekannt, wenn sie als Außenverkleidung verwendet werden.

Méthodes d'essai pour pierres naturelles - Détermination de la résistance du marbre aux cycles thermiques et d'humidité

Le présent document spécifie une méthode de détermination en laboratoire de la résistance aux cycles thermiques et d’humidité du marbre destiné au revêtement extérieur des façades de bâtiments.
Pour la définition scientifique du marbre, se référer à la définition 2.1.243 a de la norme de terminologie EN 12670.
NOTE   Certains marbres sont connus pour présenter un gauchissement et une perte de résistance rapide lorsqu’ils sont utilisés comme revêtements extérieurs.

Preskušanje naravnega kamna - Ugotavljanje odpornosti marmorja proti cikličnim toplotnim in vlažnostnim obremenitvam

General Information

• Status: Not Published
• ICS: 73.020 - Mining and quarrying
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: CEN/TC 246 - Natural stones
• Drafting Committee: CEN/TC 246/WG 2 - Test methods
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 24-Feb-2022
• Completion Date: 24-Feb-2022
• Ref Project: oSIST prEN 16306:2021 - Natural stone test methods - Determination of resistance of marble to thermal and moisture cycles

RELATIONS

• Revised: EN 16306:2013 - Natural stone test methods - Determination of resistance of marble to thermal and moisture cycles
• Effective Date: 05-Jun-2019

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 16306:2021
01-november-2021
Nadomešča:
SIST EN 16306:2013
Preskušanje naravnega kamna - Ugotavljanje odpornosti marmorja proti cikličnim
toplotnim in vlažnostnim obremenitvam

Natural stone test methods - Determination of resistance of marble to thermal and

moisture cycles
Prüfverfahren für Naturstein - Bestimmungen der Beständigkeit von Marmor bei
zyklischer Belastung mit Wärme und Feuchtigkeit

Méthodes d'essai pour pierres naturelles - Détermination de la résistance du marbre aux

cycles thermiques et d'humidité
Ta slovenski standard je istoveten z: prEN 16306
ICS:
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
oSIST prEN 16306:2021 en,fr,de

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

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oSIST prEN 16306:2021
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oSIST prEN 16306:2021
DRAFT
EUROPEAN STANDARD
prEN 16306
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2021
ICS 73.020; 91.100.15 Will supersede EN 16306:2013
English Version
Natural stone test methods - Determination of resistance
of marble to thermal and moisture cycles

Méthodes d'essai pour pierres naturelles - Prüfverfahren für Naturstein - Bestimmungen der

Détermination de la résistance du marbre aux cycles Beständigkeit von Marmor bei zyklischer Belastung mit

thermiques et d'humidité Wärme und Feuchtigkeit

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 246.

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, Turkey 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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16306:2021 E

worldwide for CEN national Members.
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oSIST prEN 16306:2021
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Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 4

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 4

4 Symbols ............................................................................................................................................................... 5

5 Principle ............................................................................................................................................................. 5

6 Apparatus ........................................................................................................................................................... 5

7 Preparation of specimens ......................................................................................................................... 10

7.1 Sampling .......................................................................................................................................................... 10

7.2 Test specimens .............................................................................................................................................. 10

7.3 Reference marks on the specimens ....................................................................................................... 10

7.4 Drying the specimen ................................................................................................................................... 10

8 Test procedure .............................................................................................................................................. 10

8.1 Control measurements before cycling .................................................................................................. 10

8.2 Procedure for bowing measurement .................................................................................................... 10

8.3 Readings, exposure and duration of test ............................................................................................. 11

8.4 Measurements after exposure ................................................................................................................. 12

9 Calculation of results .................................................................................................................................. 12

9.1 Bowing magnitude ....................................................................................................................................... 12

9.2 Flexural strength .......................................................................................................................................... 13

10 Precision .......................................................................................................................................................... 13

11 Test report ...................................................................................................................................................... 13

Annex A (informative) Guidance on limit values ............................................................................................. 15

Annex B (informative) Non-destructive testing ............................................................................................... 16

Annex C (informative) Enhanced petrographic analysis .............................................................................. 17

Bibliography ................................................................................................................................................................. 20

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oSIST prEN 16306:2021
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European foreword

This document (prEN 16306:2021) has been prepared by Technical Committee CEN/TC 246 “Natural

stones”, the secretariat of which is held by UNI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 16306:2013.

In comparison with the previous edition, the following technical modifications have been made:

— Inclusion of a more detailed description of the test procedure and several clarifications.

— Annex C has been amended with the recommendation to increase the number of measurement points

in heterogeneous marble.
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1 Scope

This document specifies a laboratory method for determining the resistance to thermal and moisture

cycling of marble intended for the external cladding of building facades.

For scientific definition of marble, reference is made to EN 12670 Terminology: 2.1.243 a.

NOTE Bowing and rapid strength loss is known to occur in some marbles when used as exterior cladding.

2 Normative references

The following referenced documents are indispensable for the application 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 12372, Natural stone test methods — Determination of flexural strength under concentrated load

EN 12670, Natural stone — Terminology

EN 14146, Natural stone test methods — Determination of the dynamic modulus of elasticity (by measuring

the fundamental resonance frequency)

EN 14579:2004, Natural stone test methods — Determination of sound speed propagation

ISO 4892-1:2016, Plastics — Methods of exposure to laboratory light sources — Part 1: General guidance

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bowing

change in shape from flat and planar to a curved or dished shape in a convex or concave direction

Note 1 to entry: Other terms commonly used for the same phenomenon are dishing and warping.

Note 2 to entry: Convex bowing is quantified by positive values, concave bowing by negative values.

3.2
convex
centre part of the specimen is bowing upwards, away from the moist substratum
3.3
concave
centre part of the specimen is bowing downwards, away from the applied heat
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4 Symbols
T Temperature
H Initial height of the specimen at the measuring point [mm]

H Difference between the initial height and the height after a defined number of cycles [mm]

H The normalized height difference, related to L = 1 m [mm]
N N
B H / L = The normalized bowing value [mm/m]
N N
B Bowing values after n cycles [mm/m]
L Distance between the supports under the specimen = 0,35 [m]
L Normalized length = 1 [m]
5 Principle

Bowing is measured on test samples placed within a test chamber, exposed to cycles of heat applied to

one face while the reverse face is subjected to moisture. The temperature interval is from 20 °C to 80 °C,

one cycle lasts 24 h. The temperature is measured on a black reference plate, placed on the surface of one

specimen, to control the climate within the test chamber.

The strength loss shall be measured according to EN 12372 on reference and exposed specimens

(Annex A) and the results compared.
6 Apparatus
All measuring equipment shall be calibrated.

6.1 A non-corrosive test chamber (Figure 1) of sufficient capacity to hold the required number of

specimens, laid horizontally. The container shall be designed in a way that specimens receive continuous

moisture from one side (the underside) and are exposed to cyclic heating on the other side (the upper

side). The container shall be furnished with a device that ensures a constant water level for the duration

of the test. Lying on the bottom of the container is a grating, which is covered by a sheet of heat stable

filter cloth.

6.2 A non-corrosive grating that fits within the length and width of the container and has a height of at

least 1 cm. The function of the grating is to ensure a water reservoir beneath the filter cloth.

6.3 A soft, heat stable, dimensionally stable, non-hygroscopic needle filter cloth of thickness

approximately 5 mm and without any water soluble substances or chemicals. The cloth (e.g. Polyester or

PTFE (Polytetrafluoroethylene (PTFE)) needle felt) is to be placed on top of the grating. The function of

the cloth is to deliver moisture to and a uniform support for the specimen.

6.4 Heating panels of sufficient sizes/and numbers to cover the container. The panels shall be capable

of providing a uniform heat flow, heating the black reference plate from 20 °C to 80 °C at average rate of

0,25 °C ± 0,1 per minute. The maximum permissible temperature difference within the test chamber,

during heating exposure, is 3 °C. Panels of insulating material should preferably be placed around the

container (Figure 1), to avoid unwanted cooling or air circulation. Before the system is approved for use,

trial measurements of the temperature shall be performed at 9 surface points widely distributed within

the heating frame (Figure 2). The temperature is measured on a uniform surface preferably with an

infrared thermometer or a surface measuring thermometer. The temperature readings shall be taken on

the surface of the black reference plate.
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The heating rate may be adjusted by changing the distance between the heating device and the samples,

or by controlling the effect of the heater. The heating curve is displayed in Figure 5.

6.5 A black reference plate, according to ISO 4892-1 (Figure 3), to ensure proper temperature

development and the maximum surface temperature at 80 °C. A thermocouple (cable type K), attached to

the black reference plate, is connected to a high stability temperature and process controllers. A simple

data logger is also possible.

NOTE The black reference plate is placed on the surface of a sample, preferably near the middle of the

container. The temperatures for the experimental exposure are programmed in advance. The heating elements are

controlled by the process controller. The temperature of the black reference plate is read and the signal is sent to

the process controller that adjusts the heating. The whole system can thus be computer controlled and the surface

temperature can be monitored online.

6.6 An infrared thermometer or other thermometer capable of measuring the surface temperature of

the specimens. If an infrared thermometer is used it shall be checked against a material similar to marble,

since the response of such a thermometer is influenced by the density and other parameters of the

measured surface.

6.7 A bow-test rig for bowing measurements (Figure 4). The rig comprises a steel plate, having three

supporting points upon which the specimen is placed, and three cylinders which guide the edges of the

specimen. The supporting points are situated (350 ± 5) mm apart from each other and shall be well

rounded and smooth in order to accommodate for eventual irregularities in the sawn surface of the

specimens. Above the centre of the specimen a gauge is mounted, which shall be readable to 0,001 mm.

The whole system shall have an accuracy better than ± 0,01 mm.

6.8 A reference cylinder (co-planar bases with an accuracy better than ± 0,005 mm) consisting of a

material with a low linear expansion coefficient (e.g. quartz glass or invar steel).

6.9 A ventilated oven capable of maintaining a temperature of (40 ± 5) °C.

6.10 A weighing instrument which has an accuracy of at least 0,01 % of the mass to be weighed.

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Key
1 Heating device
2 Insulation
3 Water level
4 Filter cloth
5 Grating
NOTE The front wall is omitted here for a better view of the interior.

Figure 1 — Principle sketch and an example of exposure equipment for testing the potential

bowing properties of marble
Figure 2 — Location of temperature control points
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Key
1 Black reference plate
2 Thermocouple
3 Test specimen
Figure 3 — Black reference plate (ISO 4892-1:2016) for T-measurements
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Dimensions in millimetres
Key
1 Stand
2 Gauge
3 Reference piece
4 Support
5 Steel plate (corrosion resistant)
6 Rubber or polychloroprene studs
7 Guide
Figure 4 — Schematic drawing of the bowing test rig
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7 Preparation of specimens
7.1 Sampling

Sampling is not the responsibility of the test laboratory except where specially requested to undertake

this.

At least 6 specimens are to be exposed to thermal cycling within the test chamber and a similar number

of specimens from the same batch are to be used as references for measuring the flexural strength

measurement of untreated material. Samples shall be chosen in order to be representative of the material

to be tested. For identification testing, any foliation shall be taken into consideration; 6 specimens with

...