EN 520:2004+A1:2009

SLOVENSKI STANDARD
01-december-2009
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Gypsum plasterboards - Definitions, requirements and test methods
Gipsplatten - Begriffe, Anforderungen und Prüfverfahren
Plaques de plâtre - Définitions, spécifications et méthodes d'essai
Ta slovenski standard je istoveten z: EN 520:2004+A1:2009
ICS:
01.040.91 Gradbeni materiali in gradnja Construction materials and
(Slovarji) building (Vocabularies)
91.100.10 Cement. Mavec. Apno. Malta Cement. Gypsum. Lime.
Mortar
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 520:2004+A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 01.040.91; 91.100.10 Supersedes EN 520:2004
English Version
Gypsum plasterboards - Definitions, requirements and test
methods
Plaques de plâtre - Définitions, spécifications et méthodes Gipsplatten - Begriffe, Anforderungen und Prüfverfahren
d'essai
This European Standard was approved by CEN on 16 August 2004 and includes Amendment 1 approved by CEN on 20 July 2009.

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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 520:2004+A1:2009: E
worldwide for CEN national Members.

Contents
page
Foreword .3
Introduction .4
1 Scope .7
2 Normative references .7
3 Terms and definitions .8
4 Requirements . 12
5 Test methods . 17
6 Evaluation of conformity . 34
7 Designation of plasterboards . 36
8 Marking, labelling and packaging . 37
Annex A (informative)  Sampling procedure for testing . 38
A.1 General . 38
A.2 Sampling procedure . 38
A.2.1 Random sampling . 38
A.2.2 Representative sampling . 38
Annex B (normative) !Conditions for reaction to fire classification of gypsum plasterboards without
further testing . 40
B.0 Introduction . 40
B.1 End use application . 40
B.1.1 General . 40
B.1.2 (Method 1) Mechanically fixed to a supporting substructure . 40
B.1.3 (Method 2) Mechanically fixed to a solid wood-based substrate . 41
B.1.4 (Method 3) Mechanically fixed or bonded to a solid substrate (dry lining system)" . 41
Annex C (normative)  Mounting and fixing in the test according to EN 13823 (SBI test) . 42
C.0 Introduction . 42
C.1 General applications . 42
C.2 Limited applications regarding joint filling . 44
C.3 Limited applications regarding wood based substrates" . 44
Annex ZA (informative)  Clauses of this European Standard addressing provisions of EU Construction
Products Directive . 46
ZA.1 Scope and relevant characteristics . 46
ZA.2 Attestation and declaration of conformity of gypsum plasterboards . 47
ZA.3 CE marking and labeling . 51
Bibliography . 54
Foreword
This document (EN 520:2004+A1:2009) has been prepared by Technical Committee CEN/TC 241 “Gypsum and
gypsum based products”, the secretariat of which is held by AFNOR.
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 February 2010, and conflicting national standards shall be withdrawn at the latest
by February 2010.
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.
This document includes Amendment 1, approved by CEN on 2009-07-20.
This document supersedes EN 520:2004.
The start and finish of text introduced or altered by amendment is indicated in the text by tags!"͘
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, 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.

Introduction
Gypsum plasterboards are composed of a plaster core encased in, and firmly bonded to paper liners to form flat
rectangular boards. !This composition allows them properties which make gypsum plasterboards particularly
suitable for use in situations where fire protection, sound and thermal insulation are required."
Gypsum plasterboards may be fixed by various methods e.g. nailing, screwing or sticking with gypsum based or
other adhesives. They may also be inserted in a suspended ceiling system.
Gypsum plasterboards are selected for use according to their type, size, thickness and edge profile. The boards
may be used for example to provide dry lining finishes to walls, to fixed and suspended ceilings, to partitions, or as
cladding to structural columns and beams. Other uses may be for flooring and sheathing application.
Diagrams 1 and 2 show the relationship between this standard and the package of standards prepared to support
the families of gypsum and ancillary products.

!
"
Diagram 1 — Family of gypsum products
!
.
"
Diagram 2 — Family of ancillary products
1 Scope
This document specifies the characteristics and performance of gypsum plasterboards intended to be used in
building construction works including those intended for secondary manufacturing operations. It includes boards
designed to receive either direct surface decoration or gypsum plaster.
This document covers the following product performance characteristics: reaction to fire, water vapour permeability,
flexural strength (breaking load), impact resistance and thermal resistance.
The following performance characteristics are linked to systems assembled with plasterboards: shear strength, fire
resistance, impact resistance !," direct airborne sound insulation and acoustic absorption to be measured
according to the corresponding European test methods. If required, tests should be done on assembled systems
simulating the end use conditions.
This document covers also additional technical characteristics that are of importance for the use and acceptance of
the product by the Construction Industry and the reference tests for these characteristics.
It provides for the evaluation of conformity of the product to this document.
This document does not cover plasterboards, which have been subject to any secondary manufacturing operations
(e.g. insulating composite panels, plasterboards with thin lamination, etc.).
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 336, Structural timber — Sizes, permitted deviations
EN 338, Structural timber — Strength classes
EN 1995-1-1, Eurocode 5 — Design of timber structures
EN 12114, Thermal performance of buildings — Air permeability of building components and building elements —
Laboratory test method
EN 12524, Building materials and products — Hygrothermal properties — Tabulated design values
EN 12664, Thermal performance of building materials and products — Determination of thermal resistance by
means of guarded hot plate and heat flow meter methods — Dry and moist products of medium and low thermal
resistance
EN 13501-1, Fire classification of construction products and building elements — Part 1: Classification using test
data from reaction to fire tests
EN 13501-2, Fire classification of construction products and building elements — Part 2: Classification using data
from fire resistance tests, excluding ventilation services
EN 13823, Reaction to fire tests for building products — Building products excluding floorings exposed to the
thermal attack by a single burning item
!EN 13963", Jointing materials for gypsum plasterboards — Definitions, requirements and test methods
EN 14195, Metal framing components for gypsum plasterboard systems — Definitions, requirements and test
methods
!EN 14566", Mechanical fasteners for gypsum plasterboard systems — Definitions, requirements and test
methods
EN ISO 140-3, Acoustics — Measurement of sound insulation in buildings and of building elements — Part 3:
Laboratory measurements of airborne sound insulation of building elements (ISO 140-3:1995)
EN ISO 354, Acoustics — Measurement of sound absorption in a reverberation room (ISO 354:2003)
EN ISO 536, Paper and board — Determination of grammage (ISO 536:1995)
EN ISO 717-1, Acoustics — Rating of sound insulation in buildings and of building elements — Part 1: Airborne
sound insulation (ISO 717-1:1996)
EN ISO 12572, Hygrothermal performance of building materials and products — Determination of water vapour
transmission properties (ISO 12572:2001)
EN ISO 20535, Paper and board — Determination of water absorptiveness — Cobb method (ISO 535:1991)
ISO 7892, Vertical building elements — Impact resistance tests — Impact bodies and general test procedures
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 gypsum plasterboard
product composed of a plaster core encased in, and firmly bonded to strong durable paper liner to form a flat
rectangular board. The paper surfaces may vary according to the use of the particular type of board and the core
may contain additives to impart additional properties. The longitudinal edges are paper-covered and profiled to suit
the application
3.1.2
edge
paper-covered longitudinal side
3.1.3
end
side transverse to the edges, showing exposed core
3.1.4
face
surface on which the paper extends continuously to cover the edges
3.1.5
back
surface opposite to the face
3.1.6
width
shortest distance between the edges of the board
3.1.7
nominal width (w)
width stated by the producer
3.1.8
length
shortest distance between the ends of the board
3.1.9
nominal length (l)
length stated by the producer
3.1.10
thickness
distance between the face and the back, excluding edge profiles
3.1.11
nominal thickness (t)
thickness stated by the producer
3.1.12
squareness (s)
rectangularity of the board
3.2 Types of gypsum plasterboards

3.2.1 General
The performance of the types of gypsum plasterboards defined below may be combined in one board in which case
the letter identifying each type of performance satisfied shall be given in the designation.
3.2.2
gypsum plasterboard Type A
plasterboard with a face to which suitable gypsum plasters or decoration may be applied. For the purposes of
identification these boards are designated Type A
3.2.3
gypsum plasterboard Type H (plasterboard with reduced water absorption rate)
types of boards which have additives to reduce the water absorption rate. They may be suitable for special
applications in which reduced water absorption properties are required to improve the performance of the board.
For the purposes of identification, these boards are designated Type H1, H2 and H3, with different water absorption
performance
3.2.4
gypsum plasterboard Type E (gypsum sheathing board)
boards specially manufactured to be used as sheathing board in external walls. They are not intended to receive
decoration. They are not designed to be permanently exposed to external weather conditions. This type of
wallboard has reduced water absorption rate. They shall have a minimum water vapour permeability. For the
purposes of identification these boards are designated Type E
3.2.5
gypsum plasterboard Type F (gypsum plasterboard with improved core adhesion at high temperature)
plasterboard with a face to which suitable gypsum plasters or decoration may be applied. These boards have
mineral fibres and/or other additives in the gypsum core to improve core cohesion at high temperatures. For the
purposes of identification these boards are designated Type F
3.2.6
!gypsum plasterboard Type P
boards which have a face intended to receive gypsum plaster or to be combined by collage with other materials in form of
boards or panels. In case of boards intended to receive gypsum plaster, the edges are either square or round
NOTE For the purpose of identification these boards are designed Type P."
3.2.7
gypsum plasterboard Type D (gypsum plasterboard with controlled density)
These boards have a controlled density, with a face to which suitable gypsum plasters or decoration may be
applied. This enables improved performance in certain applications to be obtained. For the purposes of
identification these boards are designated Type D
3.2.8
gypsum plasterboard Type R (gypsum plasterboard with enhanced strength)
These boards for special applications where higher strength is required have both increased longitudinal and
transverse breaking loads. They have a face to which suitable gypsum plasters or decoration may be applied. For
the purposes of identification these boards are designated Type R
!3.2.9
gypsum plasterboard Type I (gypsum plasterboard with enhanced surface hardness)
boards which are used for applications where higher surface hardness is required. They have a face to which
suitable gypsum plasters or decoration may be applied. For the purposes of identification these boards are
designated Type I
3.3 Edge and end profiles of gypsum plasterboards"
The paper-covered edges of gypsum plasterboard are square, bevelled, tapered, half-rounded or rounded, or a
combination of each (see examples in Figures 1 to 6).
!deleted text"
!
Key
1 face
2 back
Figure 1 — Square edge
Key
1 face
2 back
Figure 2 — Bevelled edge
Key
1 face
2 back
Figure 3 — Tapered edge
Key
1 face
2 back
Figure 4 — Half-rounded edge
Key
1 face
2 back
Figure 5 — Half-rounded tapered edge

Key
1 face
2 back
Figure 6 — Rounded edge"
3.4 !Symbols and abbreviations
For the purpose of simplification in product marking and performance information characteristics may be identified
through the symbols and abbreviations given in Table 1.
Table 1 — Symbols and abbreviations
Requirement Sub-clause Symbol or abbreviation
Reaction to fire 4.2.1 R2F
Shear strength 4.1.1 ↑↓
Water vapour factor 4.4
µ
Thermal conductivity 4.7 λ
Fire resistance 4.2.2 FR
Impact resistance 4.3 →I
Flexural strength 4.1.2 F
Acoustic absorption 4.6.2
α
Sound insulation 4.6.1 R
See literature  www.company.com
"
4 Requirements
4.1 Mechanical characteristics
4.1.1 Shear strength (strength of board/substructure connection)
When the intended use of plasterboards is for stiffening timber framed building assemblies (i.e. walls, partitions,
roof truss structures, etc.), the conventional shear strength of the plasterboard shall be determined in accordance
with the test method described in 5.13.
NOTE It should be noted that this test does not measure the actual shear strength of the board but rather the strength of
the board/substructure connection that is the relevant property for this application.
4.1.2 Flexural strength (expressed as flexural breaking load)
4.1.2.1 The flexural breaking load of gypsum plasterboard types A, D, E, F, H, I determined in accordance with
the test method described in 5.7, shall not be less than the values given in !Table 2".
Additionally, no individual test shall demonstrate the product to be more than 10 % below the values given
in !Table 2".
!Table 2" — Flexural breaking load of gypsum plasterboards (Types A, D, E, F, H, I)
Nominal board thickness Flexural breaking load
Thickness mm N
Transverse direction Longitudinal direction
9,5 160 400
Common 12,5 210 550
15,0 250 650
t
Other thickness 16,8 ⋅ t 43 ⋅ t
4.1.2.2 The flexural breaking load of enhanced strength gypsum plasterboard type R, or combined determined
in accordance with the test method described in 5.7, shall not be less than the values given in !Table 3".
Additionally, no individual test shall demonstrate the product to be more than 10 % below the values given
in !Table 3".
!Table 3" — Flexural breaking load of enhanced strength gypsum plasterboards (Type R or combined)
Nominal board thickness Flexural breaking load
Thickness mm N
Transverse direction Longitudinal direction
12,5 300 725
Common
15,0 360 870
Other thickness t 24 ⋅ t 58 ⋅ t
4.1.2.3 The flexural breaking load of gypsum baseboards (type P) determined as described in 5.7, shall not be
less than the values given in !Table 4".
In addition, no individual test shall demonstrate the product to be more than 10 % below the values given
in !Table 4".
!Table 4" — Flexural breaking load of gypsum baseboards (Type P)
Nominal board thickness Flexural breaking load
mm N
Transverse direction Longitudinal direction
9,5 125 180
12,5 165 235
4.1.3 Deflection under load
When required, the deflection under load shall be determined in accordance with the test method described in 5.8.
4.2 Fire behaviour
4.2.1 Reaction to fire
Where subject to regulatory requirements, the plasterboard shall either be Classified Without Further Testing
according to the provisions of Annex B or it shall be tested and classified according to EN 13501-1.
Plasterboards tested according to EN 13823 (SBI test) shall be mounted and fixed in accordance with Annex C or
when the producer wishes to claim performance for a specific intended use, the mounting and fixing shall be
representative of that intended use.
When required, the paper grammage shall be determined according to EN ISO 536.
4.2.2 Resistance to fire
NOTE Resistance to fire is a characteristic dependent on an assembled system and not of the product in isolation.
When required, the fire resistance of a system including gypsum plasterboard shall be classified in accordance with
EN 13501-2.
4.3 Impact resistance
NOTE Impact resistance is a characteristic dependent on an assembled system and not of the product in isolation.
When required, the impact resistance of a system including gypsum plasterboard shall be determined in
accordance with ISO 7892.
4.4 Water vapour permeability (expressed as water vapour resistance factor)
When the intended use of gypsum plasterboards is for moisture diffusion control, tabulated design values of water
vapour resistance factor for gypsum plasterboards given in EN 12524 may be used.
Alternatively, the water vapour resistance factor shall be determined using the method given in EN ISO 12572.
4.5 Air permeability
When the intended use of gypsum plasterboards is sheathing in external walls, a design value of
-6 3 2
1,4 x 10 m /m ·s·Pa may be used for air permeability of gypsum plasterboards.
When required, air permeability shall be determined in accordance with EN 12114.
4.6 Acoustic properties
4.6.1 Direct airborne sound insulation
NOTE Direct airborne sound insulation is a characteristic dependent on an assembled system and not of the product in
isolation.
When required, the direct airborne sound insulation of a system including gypsum plasterboard shall be determined
in accordance with EN ISO 140-3 and EN ISO 717-1.
4.6.2 Acoustic absorption
NOTE Acoustic absorption is a characteristic dependent on an assembled system and not of the product in isolation.
When plasterboards are intended to be used for acoustic conditioning, acoustic absorption shall be measured
according to EN ISO 354.
4.7 Thermal resistance (expressed as thermal conductivity)
When the intended use of plasterboards is to contribute to thermal resistance in building construction works (walls,
partitions, ceilings, etc.), the design values of thermal conductivity for gypsum plasterboards given in EN 12524
may be used.
When required, thermal conductivity shall be determined in accordance with EN 12664.
4.8 Regulated substances
Materials used in products shall not release any regulated substances in excess of the maximum permitted levels
specified in a relevant document for the material or permitted in the national regulations of the member state of
destination.
4.9 Dimensions and tolerances
4.9.1 !Gypsum plasterboards (Type P)"
4.9.1.1 Width
NOTE Common nominal widths are 400 mm, 600 mm, 900 mm and 1 200 mm. Other widths are also possible.
The width shall be measured as described in 5.2 and compared to the nominal width.
The tolerance shall be mm.
−8
4.9.1.2 Length
NOTE Common nominal lengths are 1 200 mm, 1 500 mm, 1 800 mm and 2 000 mm. Other lengths are also possible.
The length shall be measured as described in 5.3 and compared to the nominal length.
The tolerance shall be mm.
−6
4.9.1.3 Thickness
NOTE The nominal thicknesses are normally 9,5 mm and 12,5 mm.
The thickness shall be measured as described in 5.4 and compared to the nominal thickness.
+0,6
!The tolerance shall be mm."
−0,6
4.9.2 Gypsum plasterboards Types A, H, D, E, F, I, R or combined
4.9.2.1 Width
NOTE Common nominal widths are 600 mm, 625 mm, 900 mm, 1 200 mm and 1 250 mm. Other widths are also possible.
The width shall be measured as described in 5.2 and compared to the nominal width.
The tolerance shall be mm for each individual measurement.
−4
4.9.2.2 Length
The length shall be measured as described in 5.3 and compared to the nominal length.
The tolerance shall be mm for each individual measurement.
−5
4.9.2.3 Thickness
NOTE Common nominal thicknesses are 9,5 mm, 12,5 mm and 15 mm. Other nominal thicknesses are also possible.
The nominal thickness shall be at least 6,0 mm.
The thickness shall be measured as described in 5.4 and compared to the nominal thickness.
+0,5
!Tolerances for nominal thicknesses below 18 mm shall be mm."
−0,5
+0,04
!For boards of nominal thickness equal to or greater than 18 mm, the tolerance shall be × thickness in mm
−0,04
rounded to the nearest 0,1 mm."
The difference between individual thickness measurements on any individual board shall not exceed 0,8 mm.
4.9.2.4 Squareness of ends
The deviation from squareness measured as described in 5.5 shall not exceed 2,5 mm per metre of width.
4.9.2.5 Edge and end profiles
The edge and end profiles may vary widely depending upon the jointing system and decorative and aesthetic
considerations. The exception is the tapered edge and the half-rounded tapered edge profile.
For the tapered edge and the half-rounded tapered edge profile, when measured as described in 5.6, each
individual reading shall be between the following limits:
 depth of taper: between 0,6 mm and 2,5 mm;
 width of taper: between 40 mm and 80 mm.
4.10 Additional requirements for gypsum plasterboards Types H1, H2, H3 (with reduced water
absorption)
!The surface water absorption of the board determined by the method described in 5.9.1 for the face of the
board shall not be greater than the values shown in Table 5.
The total water absorption of boards, determined by the method described in 5.9.2, shall not be greater than the
values shown in Table 5.
Table 5 — Water absorption classes
Surface water absorption Total water absorption
Water absorption classes
g/m %
H1 180
≤ 5
H2 220 ≤ 10
H3 300
≤ 25
"
4.11 Additional requirements for gypsum plasterboards Type E (sheathing boards)
This type of boards shall conform to type H1, H2 or H3 requirements.
The water vapour resistance factor of boards type E determined in accordance with the method described in
EN ISO 12572 shall not be greater than 25.
4.12 Additional requirements for gypsum plasterboards Type F (with improved core cohesion at
high temperature)
When a type F plasterboard (or combined) is subjected to the test described in 5.10, none of the 6 specimens shall
break.
4.13 Additional requirements for gypsum plasterboards Type D (with controlled density)
The density of gypsum plasterboard type D (or combined) determined as described in 5.11, shall be at least
3 3
0,8 x 10 kg/m .
4.14 Additional requirements for gypsum plasterboards Type I (with enhanced surface hardness)
The surface hardness of gypsum plasterboard type I (or combined) is characterised by the diameter of the
depression produced in the surface according to the test method described in 5.12.
The diameter of the depression shall not be greater than 15 mm.
5 Test methods
5.1 Sampling
Testing shall require three boards of each type and thickness on which tests as described in 5.2 to 5.6 to be carried
out.
Tests according to 5.7 to 5.12 shall be carried out on specimens cut out from the same three boards.
5.2 Determination of width
5.2.1 Principle
The width shall be measured at 3 positions along the length of the board.
5.2.2 Apparatus
A metal rule or tape permitting readings to 1 mm.
5.2.3 Procedure
Take three measurements between the extremities of the boards (see Figure 7) to the nearest 1 mm, one near
each end and one near the middle of the board.
Figure 7 — Determination of width
5.2.4 Expression of results
Each measured value expressed in mm shall be recorded.
5.3 Determination of length
5.3.1 Principle
The length shall be measured at 3 positions across the width of the board.
5.3.2 Apparatus
A metal rule or tape permitting readings to 1 mm.

Figure 8 — Determination of length
5.3.3 Procedure
Take three measurements between the extremities of the board (see Figure 8) to the nearest 1 mm, one near each
edge end and one near the middle of the board.
5.3.4 Expression of results
Each measured value expressed in mm shall be recorded and compared to the nominal length of the board.
5.4 Determination of thickness
5.4.1 Principle
The thickness of the board shall be measured at 6 points near to one end of the board.
5.4.2 Apparatus
A micrometer, dial gauge, or callipers with an anvil diameter not less than 10 mm and permitting readings to
0,1 mm.
5.4.3 Procedure
Take six measurements (see Figure 9) to the nearest 0,1 mm across one end at approximately equal intervals
across the width and at least 25 mm from the end and 100 mm from the edges. For boards of nominal width not
greater than 600 mm, three measurements shall be sufficient.
Dimensions in millimetres
Figure 9 — Determination of thickness
5.4.4 Expression of results
Record to the nearest 0,1 mm the average of the values obtained for each board.
5.5 Determination of squareness of ends
5.5.1 Principle
Two boards shall be compared with each other and the squareness measured.
5.5.2 Apparatus
A metal rule or tape permitting readings to 1 mm.
5.5.3 Procedure
Place one board on top of another so that they coincide along one edge and at one corner (circled in Figure 10).
Measure to the nearest 1 mm the distance ∆ (see Figure 10) between the ends of the opposite edges.
Turn the top board over so that the same ends are together as for the first measurement and ensure that the corner
of the top board coincides with that corner of the lower board used in the first measurement (circled in Figure 10).
Measure the new distance ∆ between the ends of the opposite edges.

There are three boards, so one shall be used twice.

Figure 10 — Determination of squareness of ends
5.5.4 Expression of results
∆ + ∆
1 2
The squareness is characterised for one of the boards by the half sum and for the other by the half
2w
∆ − ∆
2 1
difference expressed in millimetres per metre.
2w
5.6 Determination of taper profile
5.6.1 Taper width
5.6.1.1 Principle
A flat metal rule shall be applied to the face of the board and over the taper area.
5.6.1.2 Apparatus
A flat metal rule at least 250 mm long permitting readings to 1 mm.
5.6.1.3 Procedure
Measure the taper width on each edge (300 ± 50) mm from each end.
Determine the taper width (AB) by applying a metal rule to the face of the board parallel to the end as shown in
Figure 12 for tapered edge boards and in Figure 11 for half-rounded tapered edge boards.

Key
1 Face
2 Back
Figure 11 — Determination of taper width - Half-rounded tapered edge
Key
1 Face
2 Back
Figure 12 — Determination of taper width - Tapered edge
5.6.1.4 Expression of results
Record the distance in millimetres between the edge of the board (point A) and the point B at which the rule
touches the face of the board as the taper width (two measurements on each board).
5.6.2 Taper depth
5.6.2.1 Principle
The taper depth shall be measured with a special gauge.
5.6.2.2 Apparatus
A dial gauge mounted on a special measuring device as shown in Figure 13 permitting readings to 0,01 mm.
Dimensions in millimetres
Key
1 Width to be 25 mm minimum
2 Grip
3 Diameter 2 mm to 5 mm with hemispherical tip
Figure 13 — Device for determination of taper depth
5.6.2.3 Procedure
Measure the taper depth on each edge (300 ± 50) mm from each end. Place the board on a flat surface. Place the
measuring device on the face of the board, with the gauge 150 mm from the edge and adjust the scale to zero.
Move the device towards the edge and take the reading (10 ± 1) mm from the edge, for the tapered edge board
and (20 ± 1) mm from the edge for the half-rounded tapered edge board.
5.6.2.4 Expression of results
Record each measurement of taper depth to the nearest 0,1 mm.
5.7 Determination of flexural strength (flexural breaking load)
5.7.1 Principle
The flexural strength of plasterboards shall be characterised by the flexural breaking load.
Specimens (400 x 300) mm cut off the boards shall be subjected to a load which is increased at a controlled rate
until failure occurs.
5.7.2 Apparatus
A loading machine capable of being read to 2 % and capable of applying the necessary load with a rate of
(250 ± 125) N/min.
5.7.3 Procedure
5.7.3.1 Preparation of specimens
Cut two specimens from each board measuring [(400 ± 1,5) x (300 ± 1,5)] mm with all edges square from each
board (as shown in Figure 14).
One specimen is taken in the longitudinal direction (designated L) and the other in the transverse direction
(designated T) (see Figure 14).
Cut the specimens at least 100 mm from ends and edges of the board, except in the case of boards of less than
600 mm width where the distance from the edge may be reduced and shall be equal on either side of the sample.
1)
Dry the specimens to constant mass at (40 ± 2) °C and perform the test within 10 min of removal from the drying
oven.
5.7.3.2 Testing
Place each specimen into the loading machine, face down in the case of longitudinal specimens and face up in the
case of transverse specimens, on two parallel supports rounded to a radius between 3 mm and 15 mm, with the
centres (350 ± 1) mm apart.
Apply the load at a rate of (250 ± 125) N/min at the centre ± 2 mm of the span parallel to the supports, by means of
a platen with a rounding radius between 3 mm and 15 mm. Record each failure value to the nearest 1 Newton.
The time from the application of the load to the failure of the specimen shall exceed 20 s.

1) Constant mass is defined as two successive weighings 24 h apart, differing by less than 0,1 %.
Dimensions in millimetres
Key
1 Zone for sampling other specimens
Figure 14 — Sampling of specimens for determination of flexural breaking load
(example for a 1 200 mm wide board)
5.7.4 Expression of results
Record each individual value and calculate the flexural breaking load as the mean of the 3 longitudinal specimen
values (L) or of the three transverse specimen values (T).
5.8 Determination of deflection under load
The test shall be the same as the one used for flexural breaking load but a continuous record of deflection
produced by the applied load shall be made.
Calculate the mean deflection under load of the 3 longitudinal specimens (L) and also the 3 transverse specimens
(T) as the average of the recorded values for any given load.
5.9 Determination of water absorption
5.9.1 Surface water absorption
5.9.1.1 Principle
The surface of a conditioned specimen shall be exposed to water at (23 ± 2) °C for a fixed time and the increase in
mass shall be determined.
5.9.1.2 Apparatus
a) Balance permitting readings to 0,01 g;
b) clock or watch permitting readings to 1 min;
c) Cobb apparatus in accordance with EN 20535 with a cylinder height of 25 mm.
5.9.1.3 Procedure
Cut two specimens measuring [125 ± 1,5) x (125 ± 1,5)] mm from each board, one for a test on the face and the
2)
other for a test on the back. Condition the specimens to constant mass at (23 ± 2) °C and (50 ± 5) % relative
humidity and carry out the test immediately.
Weigh a specimen to within 0,01 g and place it in the Cobb apparatus (100 cm ) which has previously been
conditioned at (23 ± 2) °C, with the side to be exposed to the water tap uppermost. Fill the ring of the apparatus
with water at (23 ± 2) °C until the test surface of the specimen is covered by 25 mm of water.
Leave the specimen for 2 h ± 2 min in the apparatus and then pour the water out of the apparatus and remove the
specimen.
Immediately remove excess water by blotting with dry absorbent paper and re-weigh the specimen to the nearest
0,01 g.
5.9.1.4 Expression of results
Calculate the difference (in grams) between the dry mass and the wet mass of each specimen.
Calculate for the face and for the back the average difference in mass and multiply this by 100. Record this value
as the surface absorption of the face or of the back of the gypsum plasterboard expressed in g/m .
5.9.2 Total water absorption
5.9.2.1 Principle
Conditioned specimens (as in 5.9.1.3) are immersed in water at (23 ± 2) °C and the percentage increase in mass is
determined.
5.9.2.2 Apparatus
a) Balance permitting readings to 0,1 g;
b) water bath at (23 ± 2) °C large enough to hold the specimen.
5.9.2.3 Procedure
Cut a specimen measuring [(300 ± 1,5) x (300 ± 1,5)] mm from each board, approximately half-way between the
edges and at least 150 mm from the ends. !deleted text"
3)
Condition the specimens to constant mass at (23 ± 2) °C and (50 ± 5) % relative humidity, weigh to the nearest
0,1 g and carry out the test immediately.
Immerse the specimen in a water bath at (23 ± 2) °C covered with 25 mm to 35 mm of water for 2 h ± 2 min.
Place the specimen horizontally but not resting flat on the bottom of the container.
After removal from the bath, wipe excess water from the surface and edges of the specimen and weigh
immediately to the nearest 0,1 g.

2) Constant mass is defined as two successive weighings 24 h apart, differing by less than 0,1 %.
3) Constant mass is defined as two successive weighings 24 h apart, differing by less than 0,1 %.
5.9.2.4 Expression of results
Calculate increase in mass of each specimen as a percentage of the initial mass. Record the average percentage
increase in mass as the water absorption of the gypsum plasterboard.
5.10 Determination of core cohesion at high temperature
5.10.1 Principle
A bending moment shall be applied to a specimen that is heated between two burner flames. On heating, the
bending moment causes the sample to deflect. When deflection is complete the specimen shall be examined for
breakage.
5.10.2 Apparatus
5.10.2.1 Meker burners
The nozzle diameter shall be (29 ± 1) mm with a gas orifice diameter of (0,75 ± 0,05) mm.

Key
1 Burners
2 Specimen
3 Alignment
Figure 15 — Alignment of specimens with respect to burners
5.10.2.2 Thermocouples
Insulated chromelalumel (Type K) with a diameter of 1,5 mm.
5.10.2.3 Mounting device
Any form of device capable of supporting the specimen with weight in the horizontal plane.
Dimensions in millimetres
Key
1 Mounting sleeve
2 Burner
3 Load
Figure 16 — Side view of the apparatus for determination of core cohesion
5.10.2.4 Specimen support
The specimen shall be mounted between the burners with its long edge horizontal and its short edge vertical. The
lower long edge of the board and the lowest point of the burner nozzles shall be aligned (see Figure 15). The mid-
point of the burner nozzle is (100 ± 1) mm from the point of support. For 12,5 mm nominal board a load of
(300 ± 10) g is suspended from the specimen at a point (260 ± 1) mm from the point of support. The distance
through which the part of the specimen between the burners and the load may deflect is limited to (10 ± 1) mm (see
Figures 16 and 17). For boards of greater nominal thickness (t) the load is increased proportionately (i.e.
t
to 300 ) and rounded to the nearest 50 g.
12,5
5.10.2.5 Heating system
Two propane Meker burners shall be mounted with their nozzles facing each other and each nozzle (25 ± 1) mm
from the specimen. The axes of the burners shall be aligned to within 1 mm. The thermocouples shall be placed
(10 ± 1) mm from each burner and aligned with the top of the burners (see Figure 17). Commercial propane g
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