Slate and stone for discontinuous roofing and external cladding - Part 3: Specifications for schist and schistose stones

This document specifies characteristics of schist and schistose stones (see 3.1) intended to be used for assembly into discontinuous roofing and external cladding.
This document specifies procedures for assessment and verification of constancy (AVCP) of performance of characteristics of schist and schistose stones.
This document does not cover the following:
-   slate and carbonate slate products (see EN 12326-1:2014 and EN 12326-2:2011);
-   schist and schistose products, used as wall cladding, which are either bonded with adhesive or fixed with dowels and cramps (see EN 1469:2015);
-   treated products;
-   installation or construction specific requirements.

Schiefer und Naturstein für überlappende Dachdeckungen und Außenwandbekleidungen - Teil 3: Anforderungen für Schiefer und schistose Natursteinarten

Dieses Dokument legt die Merkmale von Schiefer und schistosen Natursteinen (siehe 3.1) fest, die für den Einbau in überlappende Dachdeckungen und Außenwandbekleidungen vorgesehen sind.
Dieses Dokument legt Verfahren zur Bewertung und Überprüfung der Leistungsbeständigkeit (AVCP) der Merkmale von Schiefer und schistosen Natursteinen fest.
Dieses Dokument gilt nicht für:
-   Schiefer- und carbonathaltige Schieferprodukte (siehe EN 12326-1:2014 und EN 12326 -2:2011);
-   Schiefer- und schistose Produkte, die als Wandbekleidung verwendet werden, die entweder mit Klebstoff verklebt oder mit Ankerdornen und Klammern befestigt werden (siehe EN 1469:2015);
-   behandelte Produkte;
-   installations- oder konstruktionsspezifische Anforderungen.

Ardoises et pierres pour toiture et bardage extérieur pour pose en discontinu - Partie 3 : Spécifications pour schiste et pierres schisteuses

Le présent document spécifie les caractéristiques du schiste et des pierres schisteuses (voir 3.1) destinés à être utilisés pour l'assemblage en toiture et bardage extérieur pour pose en discontinu.
Le présent document spécifie les procédures d'évaluation et de vérification de la constance des performances (EVCP) des caractéristiques du schiste et des pierres schisteuses.
Le présent document ne couvre pas ce qui suit :
-   les produits en ardoise et ardoise carbonatée (voir l'EN 12326-1:2014 et l'EN 12326-2:2011) ;
-   les produits en schiste et schisteux utilisés comme bardage, fixés à l'aide d'un adhésif ou fixés par des goujons et des crampons (voir l'EN 1469:2015) ;
-   les produits traités ;
-   les exigences spécifiques à l'installation ou à la construction.

Skrilavec in naravni kamen za pokrivanje streh in oblaganje zunanjih zidov - 3. del: Specifikacije za skrilavce in skrilaste naravne kamne

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Due Date
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SLOVENSKI STANDARD
oSIST prEN 12326-3:2021
01-julij-2021

Skrilavec in naravni kamen za pokrivanje streh in oblaganje zunanjih zidov - 3. del:

Specifikacije za skrilavce in skrilaste naravne kamne

Slate and stone for discontinuous roofing and external cladding - Part 3: Specifications

for schist and schistose stones
Schiefer und Naturstein für überlappende Dachdeckungen und Außenwandbekleidungen
- Teil 3: Anforderungen für Schiefer und schistose Natursteinarten

Ardoises et pierres pour toiture et bardage extérieur pour pose en discontinu - Partie 3 :

Spécifications pour schiste et pierres schisteuses
Ta slovenski standard je istoveten z: prEN 12326-3
ICS:
91.060.10 Stene. Predelne stene. Walls. Partitions. Facades
Fasade
91.060.20 Strehe Roofs
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
oSIST prEN 12326-3:2021 en,fr,de

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

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oSIST prEN 12326-3:2021
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oSIST prEN 12326-3:2021
DRAFT
EUROPEAN STANDARD
prEN 12326-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2021
ICS 91.100.15
English Version
Slate and stone for discontinuous roofing and external
cladding - Part 3: Specifications for schist and schistose
stones
Schiefer und schistose Natursteinarten für
überlappende Dachdeckungen - Anforderungen und
Prüfverfahren

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

CEN/TC 128.

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 12326-3:2021 E

worldwide for CEN national Members.
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oSIST prEN 12326-3:2021
prEN 12326:3:2021 (E)
Contents Page

European foreword ...................................................................................................................................................... 4

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

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

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

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

4 Characteristics ................................................................................................................................................. 9

4.1 Dimensional variation .................................................................................................................................. 9

4.2 Water permeability ........................................................................................................................................ 9

4.3 Mechanical resistance ................................................................................................................................... 9

4.4 Durability against freeze–thaw .................................................................................................................. 9

4.5 Durability against thermal cycles ........................................................................................................... 10

4.6 Reaction to fire............................................................................................................................................... 10

4.7 External fire performance ......................................................................................................................... 10

4.8 Release of dangerous substances ............................................................................................................ 10

5 Testing, assessment and sampling methods ....................................................................................... 10

5.1 Dimensional variation ................................................................................................................................ 10

5.1.1 General.............................................................................................................................................................. 10

5.1.2 Nominal and individual thickness .......................................................................................................... 11

5.1.3 Length and width, rectangularity and flatness .................................................................................. 11

5.1.4 Format of irregular stones and special shaped products ............................................................... 11

5.2 Water permeability ...................................................................................................................................... 11

5.3 Mechanical resistance ................................................................................................................................. 12

5.4 Durability against freeze–thaw ................................................................................................................ 12

5.5 Durability against thermal cycles ........................................................................................................... 12

5.6 Reaction to fire............................................................................................................................................... 13

5.7 External fire performance ......................................................................................................................... 13

5.8 Release of dangerous substances ............................................................................................................ 13

6 Assessment and verification of constancy of performance – AVCP ............................................ 13

6.1 General.............................................................................................................................................................. 13

6.2 Assessment of performance ...................................................................................................................... 13

6.2.1 General.............................................................................................................................................................. 13

6.2.2 Test samples, testing and assessment criteria ................................................................................... 14

6.3 Verification of constancy of performance ............................................................................................ 15

6.3.1 Factory production control (FPC) ........................................................................................................... 15

7 Product designation ..................................................................................................................................... 17

7.1 Classification................................................................................................................................................... 17

7.2 Denomination................................................................................................................................................. 18

7.3 Petrographic description ........................................................................................................................... 18

7.4 Appearance ..................................................................................................................................................... 18

7.4.1 General.............................................................................................................................................................. 18

7.4.2 Reference sample, visual inspection and acceptance criteria ...................................................... 18

7.5 Typical formats for roofing stones ......................................................................................................... 18

8 Marking, labelling and packaging ........................................................................................................... 19

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Annex A (normative) Sampling procedures ....................................................................................................... 21

A.1 General ............................................................................................................................................................. 21

A.2 Principles of sampling ................................................................................................................................ 21

A.3 Taking bulk samples .................................................................................................................................... 21

A.4 Sampling and a sampling plan ................................................................................................................. 21

A.5 Sampling apparatus and methods .......................................................................................................... 22

A.5.1 General ............................................................................................................................................................. 22

A.5.2 Sampling from quarries (solid rock) ..................................................................................................... 22

A.5.3 Sampling from production plants, consignments etc ...................................................................... 22

A.6 Marking, packaging and dispatch of the samples ............................................................................. 22

A.7 Sampling report ............................................................................................................................................ 23

Annex B (normative) Statistical evaluation ..................................................................................................... 24

B.1 Scope ................................................................................................................................................................. 24

B.2 Symbols and definitions ............................................................................................................................. 24

B.3 Calculation of Lower Expected Value .................................................................................................... 25

B.4 Calculation of Higher Expected Value ................................................................................................... 25

B.5 Student t-test .................................................................................................................................................. 26

Annex ZA (informative) Relationship of this European Standard with Regulation (EU) No 305/2011

............................................................................................................................................................................. 28

ZA.2 System of Assessment and Verification of Constancy of Performance (AVCP) ...................... 29

ZA.3 Assignment of AVCP tasks ......................................................................................................................... 29

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

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oSIST prEN 12326-3:2021
prEN 12326-3:2021 (E)
European foreword

This document (prEN 12326-3:2021) has been prepared by Technical Committee CEN/TC 128 “Roof

covering products for discontinuous laying and products for wall cladding”, the secretariat of which is

held by NBN.
This document is currently submitted to the CEN Enquiry.

This document has been prepared under two standardization requests to CEN by the European

Commission and the European Free Trade Association.

For relationship with Regulation (EU) No. 305/2011 on construction products (CPR), see informative

Annex ZA, which is an integral part of this document.

This document prEN 12326-3 is one of a series of standards for specification of roofing slate products

which includes the following:

— EN 12326-1:2014, Slate and stone for discontinuous roofing and external cladding — Part 1:

Specifications for slate and carbonate slate

— EN 12326-2:2011, Slate and stone for discontinuous roofing and external cladding — Part 2: Methods

of test for slate and carbonate slate

EN 12326-1 and this document are product standards, while EN 12326-2 is the standard that specifies

test methods that are applicable for both product standards.
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prEN 12326-3:2021 (E)
Introduction

The performance of a roof or wall constructed with these products depends not only on the properties of

the product as required by this document, but also on the design, construction and performance of the

roof or wall as a whole in relation to the environment and conditions of use.
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oSIST prEN 12326-3:2021
prEN 12326-3:2021 (E)
1 Scope

This document specifies characteristics of schist and schistose stones (see 3.1) intended to be used for

assembly into discontinuous roofing and external cladding.

This document specifies procedures for assessment and verification of constancy (AVCP) of performance

of characteristics of schist and schistose stones.
This document does not cover the following:
— slate and carbonate slate products (see EN 12326-1:2014 and EN 12326-2:2011);

— schist and schistose products, used as wall cladding, which are either bonded with adhesive or fixed

with dowels and cramps (see EN 1469:2015);
— treated products;
— installation or construction specific requirements.
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 12326-2:2011, Slate and stone for discontinuous roofing and external cladding — Part 2: Methods of

test for slate and carbonate slate
EN 12407:2019, Natural stone test methods — Petrographic examination
EN 12440:2017, Natural stone — Denomination criteria
EN 12670:2019, Natural stone — Terminology

EN 13373:2020, Natural stone test methods — Determination of geometric characteristics on units

3 Terms and definitions

For the purposes of this document, the following terms and definitions given in EN 12670:2019 and the

following apply.
3.1
schistose stones

schist (3.2) and other foliated metamorphic rocks, composed of nearly parallel arranged mica, chlorite,

quartz, feldspar and/or other typical minerals with well-developed fissility that allows an easy split

Note 1 to entry: These rock types belong petrographically to metamorphic formations that start at the epizonal-

metamorphic phyllite formations, i.e. where EN 12326-1:2014 ends, see Table 4.
3.2
schist

foliated rock composed of nearly parallel arranged mica, chlorite, quartz and other typical mineral

Note 1 to entry: Commercial definition: natural stone possessing a well-developed fissility that allows an easy

split, i.e. phyllite, mica schist and quartzite schist.
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3.3
phyllite

schist (3.2) mainly consisting of glittering layers of micas, chlorite, quartz, feldspar and other minor

minerals

Note 1 to entry: It is a fine grained to medium grained, dark grey metamorphic rock with evenly distributed

layers with mica, and where these layers appear up to 10 mm apart. Typically, mica is the main constituent of the

rock.
Note 2 to entry: The rock is formed by low grade metamorphism of clay stone.
[SOURCE: EN 12670:2019, 3.1.382, modified — feldspar is added]
3.4
mica schist

schist (3.2) with glittering layers of micas, consisting of these, biotite, quartz and other minerals

Note 1 to entry: It is a medium to coarse grey to dark grey metamorphic rock with evenly distributed layers of

mica, and where these layers appear up to 10 mm apart. In addition, the rock contains quarts and/or feldspar and

other minerals. Typically, mica is the main constituent of the rock.
Note 2 to entry: The rock is formed by medium grade metamorphism of clay stone.
3.5
quartzite schist
schist (3.2) enriched in quartz and with cleavage along planes in mica

Note 1 to entry: It is a fine to medium grained, light grey to grey, metamorphic quartz-feldspar rich rock

containing rhythmically distributed planar lamina (less than 1 mm thick) of mica (muscovite and/or biotite). The

rock can be split along the lamina to slabs varying from 5 mm to more than 100 mm in thickness.

Note 2 to entry: The rock is formed by low to medium grad metamorphism of sandstone.

Note 3 to entry: Other terms used are schistose quartzite or schistose flagstone.

3.6
paragneiss

gneiss with mineralogy and texture indicating derivation from a sedimentary rock protolith

Note 1 to entry: Typically consists of abundant quartz, mica, or calcsilicate minerals; aluminosilicate minerals or

garnet commonly present.
3.7
layer
bed or stratum of rock
[SOURCE: EN 12670:2019, 3.1.260]
3.8
vein

mineral body, thin in relation to its other dimensions, which cuts the older country rock

[SOURCE: EN 12670:2019, 3.1.521]
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prEN 12326-3:2021 (E)
3.9
lineation

general descriptive term for any kind of linear (one dimensional) feature in the fabric of a rock

[SOURCE: EN 12670:2019, 3.1.270]
3.10
shouldering

removal of corner(s) (when installed) of a roofing or external cladding stone to facilitate laying or for

aesthetic reasons
3.11
irregular stones
stones of random plan dimensions
3.12
natural riven
stone with natural split faces
3.13
nominal thickness
thickness of stone declared by the manufacturer
3.14
lower expected value

value that corresponds to the 5 %-quantile of a logarithmic normal distribution for a confidence level of

75 %
Note 1 to entry: See Annex B.
3.15
higher expected value

value that corresponds to the 95 %-quantile of a logarithmic normal distribution for a confidence level of

75 %
Note 1 to entry: See Annex B.
3.16
Student's t-test

standard parametric statistical test used to test hypotheses about population means when the variance(s)

are known
Note 1 to entry: See ISO 3534-1 [3].

Note 2 to entry: In this document, the Student's t-test is used to test for significant differences between the means

of two populations.
Note 3 to entry: See Annex B.
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prEN 12326-3:2021 (E)
4 Characteristics
4.1 Dimensional variation

Dimensional variations in thickness, length and width of schist and schistose stones shall be determined

according to 5.1.
All dimensions shall be expressed in mm.
4.2 Water permeability

Water permeability is expressed through water absorption of schist and schistose stones and shall be

determined in accordance with 5.2.

The performance of water absorption shall be expressed with combined indication of mean value,

together with the highest expected value (both expressed as a mass percentage % to two decimal places).

4.3 Mechanical resistance

Mechanical resistance is expressed through modulus of rupture of schist and schistose stones and shall

be determined in accordance with 5.3.

The performance of modulus of rupture shall be expressed with the mean value and the lower expected

value (in N/mm ) and with specification of test direction in relation to eventual any visual lineation.

4.4 Durability against freeze–thaw

Durability is expressed through freeze–thaw resistance of schist and schistose stones and shall be

determined in accordance with 5.4. The durability performance against freeze–thaw shall be expressed

by:

— the mean value and higher expected value of water absorption (in mass percentage %) before and

after exposure, see Annex B;
— the change in water absorption (in %) based on Student's t-test;

— visual appearance by comparison of reference specimens and the exposed specimens, focusing on

the following aspects:
— colour changes, including oxidation of metallic minerals;
— tendency of exfoliation, splitting or other major structural changes.
The following requirements apply:

— the schist or schistose stone shall not show significant increase in water absorption when a Student's

t-test is applied,

— the schist or schistose stone shall not exhibit exfoliation (opening of cleavage plane).

Schist or schistose stone that does not satisfies the above requirements should not be used without

documented good service life experiences.

If the sample water absorption after the freeze–thaw cycling is equal to or less than the value before the

freeze–thaw cycling, the t-test shall not be carried out.
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prEN 12326-3:2021 (E)
4.5 Durability against thermal cycles

Durability is expressed through thermal cycle resistance of schist and schistose stones and shall be

determined in accordance with 5.5.
The durability performance against thermal cycles shall be expressed by:

— the mean value and higher expected value of water absorption (in weight%) before and after the

thermal cycle test, see Annex B;
— the change in water absorption (in %) based on Student's t-test;

— visual appearance by comparison of reference specimens and the exposed specimens, focusing on

the following aspects:
— colour changes, including oxidation of metallic minerals;
— tendency of exfoliation, splitting or other major structural changes.
The following requirements apply:

— the schist or schistose stone shall not show significant increase in water absorption when a Student's

t-test is applied,

— the schist or schistose stone shall not exhibit exfoliation (opening of cleavage plane).

Schist or schistose stone that does not satisfies the above requirements should not be used without

documented good service life experiences.

If the mean water absorption after the thermal cycle test is equal to or less than the value before the

freeze–thaw cycling, the t-test shall not be carried out.
4.6 Reaction to fire

The reaction to fire performance of schist and schistose stones, shall be expressed as Class A1, according

to 5.6.
4.7 External fire performance

The external fire performance of schist and schistose stones, intended to be used in buildings as

discontinuously laid roof covering, shall be expressed as Class B , according to 5.7.

ROOF
4.8 Release of dangerous substances

Release of dangerous substances of products of schist and schistose stones shall be determined as

specified in 5.8.
5 Testing, assessment and sampling methods
5.1 Dimensional variation
5.1.1 General

All measurements shall be determined in accordance with EN 13373:2020, Clause 7, and all measured

values of individual units shall be within the specified tolerances.

Measurements of rectangular, square and scallops stones are specified in 5.1.2 and 5.1.3. See also 7.5.

Other shapes and irregular stones are specified in 5.1.4.
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Sampling shall be in accordance with Annex A.
5.1.2 Nominal and individual thickness

The nominal thickness range for each product format shall be given in millimetres (e.g. thickness 8 mm –

20 mm), and the eventual thickness sorting within the nominal thickness range.

The thickness of individual schist and schistose stones shall be within the declared nominal thickness

range and eventual thickness category within this range.

Schist and schistose stones covered by this standard shall have a minimum thickness as listed in Table 1.

Table 1 — Minimum thickness of schist and schistose stones covered by this standard,

depending on plan dimensions
Plan dimensions Minimum thickness
mm mm
≤ 500 8
> 500 10
5.1.3 Length and width, rectangularity and flatness

Rectangular stones shall not deviate from the declared length or width by more than ± 8 mm. For scallops

this will apply according to the nominal gross measurement of length and width supplied by the

manufacturer.

Rectangular stones which have not been shouldered shall not deviate from rectangularity in any corner

by more than ± 1 % of their length.

NOTE Shouldering of roofing stone is permitted provided it does not adversely affect the performance of the

roof with respect to wind uplift resistance and driving rain. Further guidance on shouldering can be found in the

reference documents listed in the Bibliography list of this document.

Complementary stones may be considered as having the same tolerances as the ones they are assembled

with. For example, if the normal stones are shouldered, the assessorial stones may be considered as

having the same tolerances as these stones.

Curved roofing stones shall be manufactured so that the bevelled edges are applied to the convex face of

the stone.
Other parameters regarding deviations from flatness shall be specified.
5.1.4 Format of irregular stones and special shaped products

The format of products with shapes other than rectangular, square or scallop shall be specified. Eventual

tolerances shall be specified.
5.2 Water permeability

Performance of schist and schistose stones related to the water absorption shall be determined in

accordance with EN 12326-2:2011, Clause 11, with the following modifications:
— number of specimens: 10;
— specimen dimension: 125 mm × 200 mm × thickness.
Sampling shall be in accordance with Annex A.
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5.3 Mechanical resistance

Performance of schist and schistose stones related to the modulus of rupture shall be determined in

accordance with EN 12326-2:2011, Clause 10, with the following amendments:
— number of specimens: 10;
— specimen dimension: 125 mm × 200 mm × thickness.

Test direction may be selected based on visually identified direction of lineation, if possible, e.g. in

direction normal to, parallel to undefined with respect to lineation. The test direction shall be stated

together with the declared values.
NOTE Lineation in is not always visible to the naked eye.

Calculation of the mean value and the lower expected value shall be done according to B.3.

Sampling shall be in accordance with Annex A.
5.4 Durability against freeze–thaw

When the schist or schistose stone is intended to be used in areas subjected to freeze and thaw cycles,

and the mean water absorption of the schist or schistose stone is > 0,3 %weight, the freeze–thaw

resistance shall be determined using the test method in EN 12326-2:2011, Clause 12, with the following

amendments:
— number of specimens: 20 (+ 1 reference);
— specimen dimension: 125 mm × 200 mm × thickness;

— use water absorption to compare the specimens before and after exposure (see 5.4);

— number of freeze–thaw cycles: 100;

— q student t-test, see B.4, using a one-sided Student's t-test at a 2,5 % significance level shall be

performed to compare water absorption before and after the frost test.
Sampling shall be in accordance with Annex A.
5.5 Durability against thermal cycles

A thermal cycle test shall be performed in accordance with EN 12326-2:2011, with the

...

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