kSIST FprEN 14374:2019

SLOVENSKI STANDARD
oSIST prEN 14374:2016
01-julij-2016
Lesene konstrukcije - Slojnat furnirni les (LVL) - Zahteve
Timber structures - Laminated veneer lumber (LVL) - Requirements
Holzbauwerke - Furnierschichtholz (LVL) - Anforderungen
Structures en bois - Lamibois (LVL) - Exigences
Ta slovenski standard je istoveten z: prEN 14374
ICS:
79.080 Polizdelki iz lesa Semi-manufactures of timber
91.080.20 Lesene konstrukcije Timber structures
oSIST prEN 14374:2016 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 14374:2016
oSIST prEN 14374:2016
DRAFT
EUROPEAN STANDARD
prEN 14374
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2016
ICS 79.080; 91.080.20 Will supersede EN 14279:2004+A1:2009,
EN 14374:2004
English Version
Timber structures - Laminated veneer lumber (LVL) -
Requirements
Structures en bois - Lamibois (LVL) - Exigences Holzbauwerke - Furnierschichtholz (LVL) -
Anforderungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 124.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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 NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14374:2016 E
worldwide for CEN national Members.

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Contents Page
European foreword . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Symbols . 10
4.1 Main symbols . 10
4.2 Subscripts . 11
5 Classification. 11
6 Material characteristics and testing, assessment and sampling methods . 12
6.1 Modulus of elasticity, bending, compressive, tensile and shear strength of structural
LVL . 12
6.2 Strength and stiffness under point load of structural LVL (punching shear) . 12
6.3 Racking resistance of structural LVL . 12
6.4 Impact resistance of structural LVL . 13
6.5 Embedment strength of fasteners in structural LVL . 13
6.6 Mechanical durability (i.e. duration of load and creep) of structural LVL . 13
6.7 Bonding strength and durability of bonding strength (also covering moisture
resistance) of structural and non-structural LVL . 13
6.8 Dimensional stability of structural and non-structural LVL (also covering durability-
swelling in thickness) . 14
6.9 Durability of other characteristics against biological attack of structural and non-
structural LVL . 15
6.10 Resistance to fire of structural LVL . 16
6.11 Reaction to fire of structural and non-structural LVL . 16
6.12 Fire protection ability . 19
6.13 Release of formaldehyde of structural and non-structural LVL . 19
6.14 Release/content of other dangerous substances (also covering release/content of
pentachlorphenol (PCP)) of structural and non-structural LVL . 20
6.15 Water vapour permeability of structural and non-structural LVL . 20
6.16 Airborne sound insulation (surface mass) of structural and non-structural LVL . 20
6.17 Sound adsorption of structural and non-structural LVL . 21
6.18 Thermal conductivity of structural and non-structural LVL . 21
6.19 Air permeability of structural and non-structural LVL . 21
6.20 Supplementary properties of structural and non-structural LVL . 21
7 Assessment and Verification of Constancy of Performance (AVCP) . 21
7.1 General. 21
7.2 Type testing . 22
7.3 Factory production control (FPC) . 30
8 Marking and labelling . 42
Annex A (normative) Testing of strength, stiffness and density properties of laminated
veneer lumber . 43
A.1 General. 43
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A.2 Edgewise bending strength and edgewise modulus of elasticity in bending parallel to
the grain of the face veneers . 45
A.3 Edgewise bending strength, edgewise modulus of elasticity and edgewise shear
strength in bending perpendicular to the grain of the face veneers . 45
A.4 Flatwise bending strength and flatwise modulus of elasticity in bending parallel to
the grain of the face veneers . 46
A.5 Flatwise bending strength and flatwise modulus of elasticity in bending
perpendicular to the grain of the face veneers . 46
A.6 Tension strength and modulus of elasticity in tension parallel to the grain of the face
veneers . 46
A.7 Edgewise tension strength in plane of the veneers and perpendicular to the grain of
the face veneers . 46
A.8 Compression strength and modulus of elasticity in compression parallel to the grain
of the face veneers . 47
A.9 Edgewise compression strength and edgewise modulus of elasticity in compression
in plane of the veneers and perpendicular to the grain of the face veneers . 47
A.10 Flatwise compression strength and flatwise modulus of elasticity perpendicular to
the plane of the veneers . 47
A.11 Edgewise shear strength and edgewise shear modulus parallel to the grain of the
face veneers . 47
A.12 Flatwise shear strength and flatwise shear modulus parallel to the grain of the face
veneers . 47
A.13 Flatwise shear strength and flatwise shear modulus perpendicular to the grain of
the face veneers . 48
A.14 Density . 48
A.15 Moisture content . 48
Annex B (normative) Strength classes for structural laminated veneer lumber . 49
B.1 General . 49
B.2 LVL without cross-band veneers . 49
B.3 LVL with crossband veneers . 51
Annex C (normative) Layup factors for laminated veneer lumber with cross-band veneers . 53
C.1 General . 53
C.2 Determination of layup factors for LVL made from one species. 54
C.3 Layup factors for LVL made of different species. 55
Annex D (normative) Testing of bonding quality for structural LVL . 56
D.1 Specimens . 56
D.2 Tests . 56
D.3 Report . 56
Annex E (normative) Testing of bonding strength for non-structural LVL . 57
E.1 General . 57
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E.2 Test pieces . 57
E.3 Apparatus . 64
E.4 Procedure . 64
E.5 Evaluation of test results . 64
Annex F (normative) Release of formaldehyde . 65
F.1 General. 65
F.2 Classification. 65
F.3 Test procedure and test report . 65
Annex G (informative) Supplementary characteristics . 66
G.1 General. 66
Annex H (informative) Supplementary design rules . 67
H.1 General. 67
H.2 Deformation factors k . 67
def
H.3 Provisions for compression perpendicular to the grain . 67
H.4 Charring rate . 68
Annex ZA (informative) Relationship of this European Standard with Regulation (EU) No.
305/2011 . 69
ZA.1 Scope and relevant characteristics . 69
ZA.2 System of Assessment and Verification of Constancy of Performance (AVCP) . 73
ZA.3 Assignment of AVPC tasks . 73
Bibliography . 76

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European foreword
This document (prEN 14374:2016) has been prepared by Technical Committee CEN/TC 124 “Timber
structures”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
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.
This document will supersede EN 14374:2004 and EN 14279:2004+A1:2009.
Compared to EN 14374:2004 and EN 14279: 2004+A1:2009, the following changes have been made:
— both standards have been merged and completely revised;
— the merged standard has been written according to the latest CEN-Template, i.e. each mandated
characteristic is addressed in a separate subclause;
— a universal classification for structural and non-structural LVL has been introduced;
— specific rules for LVL with crossband veneers are given;
— layup factors for LVL with crossband veneers for the determination of properties from tests are
given;
— more strength and stiffness properties are defined and the respective test methods have been
introduced;
— strength classes for structural LVL have been introduced;
— tolerances have been modified;
— provisions regarding resistance to fire and fire protection ability have been introduced.
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1 Scope
This European Standard sets out provisions regarding the performance characteristics of structural
laminated veneer lumber (LVL) for use in buildings and bridges and non-structural laminated veneer
lumber for internal and external applications in construction.
It also lays down procedures for Assessment and Verification of Constancy of Performance of laminated
veneer lumber.
This European Standard covers laminated veneer lumber
— made of at least five veneers having a maximum veneer thickness of 6 mm;
— which may comprise crossband veneers;
— which may comprise veneers made from different species;
— being preservative treated or untreated against biological attack or treated to improve the reaction
to fire.
This European Standard defines provisions for bonding strength and durability of bonding strength in
dry, humid and exterior conditions. It covers structural LVL to be used in all conditions and non-
structural LVL to be used in the respective conditions for which bonding strength tests have been
performed.
This European Standard defines strength classes for structural laminated veneer lumber.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 310, Wood-based panels - Determination of modulus of elasticity in bending and of bending strength
EN 314-1, Plywood - Bonding quality - Part 1: Test methods
EN 314-2, Plywood - Bonding quality - Part 2: Requirements
EN 318, Wood based panels - Determination of dimensional changes associated with changes in relative
humidity
EN 322, Wood-based panels - Determination of moisture content
EN 323, Wood-based panels - Determination of density
EN 324-1, Wood-based panels - Determination of dimensions of boards - Part 1: Determination of
thickness, width and length
EN 326-1, Wood-based panels - Sampling, cutting and inspection - Part 1: Sampling and cutting of test
pieces and expression of test results
EN 335, Durability of wood and wood-based products - Use classes: definitions, application to solid wood
and wood-based products
EN 351-1, Durability of wood and wood-based products - Preservative-treated solid wood - Part 1:
Classification of preservative penetration and retention
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EN 351-2, Durability of wood and wood-based products - Preservative-treated solid wood - Part 2:
Guidance on sampling for the analysis of preservative-treated wood
EN 383, Timber Structures - Test methods - Determination of embedment strength and foundation values
for dowel type fasteners
EN 408, Timber structures — Structural timber and glued laminated timber - Determination of some
physical and mechanical properties
EN 594, Timber structures - Test methods - Racking strength and stiffness of timber frame wall panels
EN 596, Timber structures - Test methods - Soft body impact test of timber framed walls
EN 717-1, Wood-based panels - Determination of formaldehyde release - Part 1: Formaldehyde emission
by the chamber method
EN 789, Timber structures - Test methods - Determination of mechanical properties of wood based panels
EN 1156,Wood-based panels - Determination of duration of load and creep factors
EN 1995-1-1, Eurocode 5: Design of timber structures - Part 1-1: General - Common rules and rules for
buildings
EN 12114, Thermal performance of buildings - Air permeability of building components and building
elements - Laboratory test method
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 12871, Wood-based panels - Determination of performance characteristics for load bearing panels for
use in floors, roofs and walls
EN 13238, Reaction to fire tests for building products - Conditioning procedures and general rules for
selection of substrates
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 Resistance to fire 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 14358, Timber structures - Calculation of characteristic 5-percentile values and acceptance criteria for
a sample
CEN/TS 16516, Construction products - Assessment of release of dangerous substances - Determination of
emissions into indoor air
EN ISO 354, Acoustics - Measurement of sound absorption in a reverberation room (ISO 354)
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EN ISO 717-1, Acoustics - Rating of sound insulation in buildings and of building elements - Part 1:
Airborne sound insulation (ISO 717-1)
EN ISO 9239-1, Reaction to fire tests for floorings - Part 1: Determination of the burning behaviour using a
radiant heat source (ISO 9239-1)
EN ISO 10140-2, Acoustics - Laboratory measurement of sound insulation of building elements - Part 2:
Measurement of airborne sound insulation (ISO 10140-2)
EN ISO 11925-2, Reaction to fire tests - Ignitability of products subjected to direct impingement of flame -
Part 2: Single-flame source test (ISO 11925-2)
EN ISO 12460-3, Wood-based panels - Determination of formaldehyde release - Part 3: Gas analysis
method (ISO 12460-3)
EN ISO 12572, Hygrothermal performance of building materials and products - Determination of water
vapour transmission properties (ISO 12572)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
crossband veneer
veneer whose fibres are oriented perpendicular to the fibres of the face veneers
3.2
dry conditions
conditions corresponding to service class 1 of EN 1995-1-1 which is characterised by a moisture
content in the material corresponding to a temperature of 20 °C and a relative humidity of the
surrounding air only exceeding 65 % for a few weeks per year
3.3
exterior conditions
conditions corresponding to service class 3 of EN 1995-1-1 which is characterised by climatic
conditions leading to higher moisture contents than in service class 2
3.4
humid conditions
conditions corresponding to service class 2 of EN 1995-1-1 which is characterised by a moisture
content in the material corresponding to a temperature of 20°C and a relative humidity of the
surrounding air only exceeding 85 % for a few weeks per year
3.5
laminated veneer lumber
LVL
wood based composite consisting of veneers, glued together predominantly parallel to the direction of
the grain in adjacent layers which may have crossband veneers
Note 1 to entry: See Figure 1.
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a) LVL without crossband veneers b) LVL with crossband veneers
Key
b width
l length
t thickness
Figure 1 — Laminated veneer lumber without and with crossband veneers
3.6
layup
cross sectional arrangement of veneers
3.7
length
the dimension parallel to the plane of the veneers and parallel to the direction of the fibres of the face
veneers
Note 1 to entry: See Figure 1.
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3.8
nominal size
size specified at a reference moisture content to which deviations are to be related
3.9
product type
product defined by layup, thickness range, species or species combination, adhesive, bonding and
strength characteristic
3.10
reference moisture content
equilibrium moisture content at a temperature of 20 °C and a relative humidity of 65 %
3.11
thickness
the cross sectional dimension perpendicular to the plane of the veneers
Note 1 to entry: See Figure 1.
3.12
width
the cross sectional dimension parallel to the plane of the veneers and perpendicular to the direction of
the fibres of the face veneers
Note 1 to entry: See Figure 1.
4 Symbols
4.1 Main symbols
b width, in mm;
f strength, in N/mm ;
E modulus of elasticity, in N/mm ;
G shear modulus, in N/mm ;
k factor;
l length, in mm;
m effective number of veneers;
N number of single layers;
P number of pretreatments;
q number of test pieces;
R airborne sound insulation, in dB;
s size effect parameter;
t thickness, in mm;
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u moisture content, in %;
V coefficient of variation, in %;
X characteristic value for layup i;
i
o
α deviation from the right angle, in ;
α sound absorption factor;
α , γ , δ layup factors for layup i;
i i i
λ thermal conductivity, in W/mK;
d
µ water vapour resistance factor;
ρ density, in kg/m .
4.2 Subscripts
c compression;
cor corrected;
edge loaded parallel to the glue lines between the veneers;
flat loaded perpendicular to the glue lines between the veneers;
k characteristic;
lay layer;
m bending;
mean mean value;
t tension;
v shear;
0 parallel to the grain of the face veneers;
90 perpendicular to the grain of the face veneers.
5 Classification
Laminated veneer lumber shall be classified as follows:
— the abbreviation ”LVL” shall be given;
— the abbreviation “S” for structural LVL and “NS” for non-structural LVL shall be given;
— crossband veneers shall be indicated by “cross";
— for structural LVL assigned to a class according to Annex B the class name shall be given. The class
name comprises the abbreviations “LVL”, “S” and “cross” (if relevant) and also indicates the
characteristic value for flatwise bending parallel to the grain of the face veneer in N/mm shall be
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given. For structural LVL not assigned to a class according to Annex B and for non-structural LVL no
characteristic value shall be given as part of the designation.
NOTE For structural LVL not assigned to a class according to Annex B, all strength, stiffness and density
values are declared within the markings, see Clause 8 and Annex ZA.
The classification mentioned above may be combined with a manufacturer specific brand-name, if, in
the case of structural LVL, that brand-name cannot be mixed up with the denomination of strength
classes according to Annex B.
6 Material characteristics and testing, assessment and sampling methods
6.1 Modulus of elasticity, bending, compressive, tensile and shear strength of structural
LVL
Modulus of elasticity and bending, compressive, tensile and shear strength shall be determined by tests
according to Annex A and declared as strength classes according to Annex B or as individual values.
Results from tests with specimens from laminated veneer lumber without crossband veneers being
representative for the respective thickness range (either t ≤ 75mm or t >75mm)) may be applied for
any thicknesses within that range.
For shear strengths, shear moduli, flatwise compression strength perpendicular to the grain and density
the results from tests with specimens from laminated veneer lumber with crossband veneers being
representative for the respective thickness range (see A.1) may be applied for any thickness within that
range. For all other mechanical properties the test results obtained with the tested layup shall be
adjusted for all other layups by the ratio of the layup factors according to Annex C.
The characteristic edgewise bending strength parallel to the fibres of the face veneers f shall be
m,0,edge,k
valid for laminated veneer lumber with a depth h of 300 mm.
The characteristic tension strength parallel to the fibres of the face veneers f shall be valid for
t,0,k
laminated veneer lumber with a length l of 3 000 mm.
For non-structural laminated veneer lumber, the flatwise bending strength parallel and perpendicular
to the fibres of the face veneers shall be tested according to EN 310 or Annex A. The bending strengths
are determined for purposes of quality control. They are not declared, see Clauses 5 and 8.
6.2 Strength and stiffness under point load of structural LVL (punching shear)
The strength and stiffness under point load for floor or roof deckings on joists of structural LVL shall be
tested according to EN 1195 with a loading pad of 50mm x 50mm, evaluated according to EN 12871 and
expressed as characteristic value of resistance (N) and mean value of stiffness (N/mm).
6.3 Racking resistance of structural LVL
Racking resistance of wall sheatings on studs shall be either:
— expressed as modulus of elasticity, bending, compressive, tensile and shear strength of structural
LVL according to 6.1 and embedment strength according to 6.5; or
NOTE 1 The above information enables the designer to calculate the racking resistance for a specific end-
use situation taking into account additional parameters, e.g. strength, stiffness and density properties of
studs, strength properties of fasteners and geometrical data.
— tested according to EN 594, evaluated according to EN 12871, and expressed as characteristic value
of racking resistance (N) and mean value of racking stiffness (N/mm) under point load.
NOTE 2 The value can only be used for the tested system.
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6.4 Impact resistance of structural LVL
The impact resistance of floor and roof deckings on joists shall be tested according to EN 1195 and
declared as class according to EN 12871.
The impact resistance of wall sheatings on studs shall be tested according to EN 596 and declared as
class according to EN 12871.
6.5 Embedment strength of fasteners in structural LVL
Embedment strength of fastener in structural LVL shall be either
— expressed as characteristic density declared as strength class according to Annex B or as single
value; or
NOTE 1 The above information enables the designer to calculate the embedment strengths for a specific
end-use situation taking into account additional parameters, e.g. diameter of fastener, according to
EN 1995-1-1.
NOTE 2 EN 1995-1-1 only provides embedment strengths for dowel type fasteners having their axis
perpendicular to the plane of the face veneers.
— tested according to EN 383, evaluated according to EN 14358 and expressed as characteristic value
of embedment strength and relevant test parameters (thickness, layup and species of LVL, diameter
of the fastener, yield moment of dowel type fastener and angle between load direction and grain
direction of the face veneers).
NOTE 3 The value can only be used for the tested combination of fastener, LVL and angle between load
direction and grain direction of the face veneers.
6.6 Mechanical durability (i.e. duration of load and creep) of structural LVL
Mechanical durability (i.e. duration of load and creep) of structural LVL shall either:
— be taken from EN 1995-1-1 and expressed as “EN 1995-1-1” or individual values; or
NOTE For structural LVL without crossband veneers and structural LVL with crossband veneers subjected to
edgewise bending, values can be directly taken from EN 1995-1-1. For structural LVL with crossband veneers
subjected to flatwise bending, the values for structural plywood apply. The values can also be taken from
Table H.1.
— be determined and declared as individual values derived from tests according to EN 1156 and
relevant test parameters (thickness, layup and species of LVL, service class duration of load class,
stresses, for which factors apply).
6.7 Bonding strength and durability of bonding strength (also covering moisture
resistance) of structural and non-structural LVL
NOTE The term bonding strength has been taken from the mandate. In some cases, no strengths are to be
determined, so the term bonding quality would be more appropriate.
6.7.1 Bonding strength and durability of bonding strength of structural LVL
Bonding strength and durability of bonding strength of structural LVL shall be determined from a
cleavage test according to Annex D and declared as bonding class exterior. In each tested glue line the
apparent cohesive wood failure percentage estimated according to Annex D shall be at least 70 %.
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6.7.2 Bonding strength and durability of bonding strength of structural and non-structural LVL
Bonding strength shall be determined from shear tests according to Annex E and the test results shall
fulfil the provisions given in EN 314-2.
Bonding strength shall be declared as bonding class dry, humid or exterior.
6.8 Dimensional stability of structural and non-structural LVL (also covering durability-
swelling in thickness)
Consideration of dimensional stability shall be limited to the swelling and shrinkage of laminated
veneer lumber due to changes of its moisture content. Swelling and shrinkage values can be regarded as
constant values for moisture content below fibre saturation. Swelling and shrinkage values shall be
either:
— expressed by the product type;
NOTE The product type allows the distinction between LVL with or without crossband veneers. This
information enables the designer to choose the respective swelling and shrinkage values for a specific end-
use situation from a design code.
— or be tested according to EN 318 and declared as 95 % quantiles and reference to EN 318.
Measurements according to EN 324-1 need only to be done at the actual moisture content.
Corrected sizes at reference moisture content may be calculated from the swelling and shrinkage values
and the measurements at the actual moisture content.
The corrected sizes of LVL which is not pressure treated, shall not deviate from the nominal sizes by
more than the maximum deviations at the reference moisture content given in Table 1 when dispatched
from the producing factory. For pressure treated LVL the maximum deviations from nominal sizes are
subject to individual agreements.

Key
α deviation from the right angle
Figure 2 — Example of the angle α of a cross section of laminated veneer lumber
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Table 1 — Maximum deviations from nominal sizes and nominal angles for laminated veneer
lumber not treated by pressure treatment
Nominal sizes for Maximum deviations
Thickness t t ≤ 27 mm ± 1 mm
27 mm < t ≤ 57 mm ± 2 mm
t > 57 mm ± 3 mm
Width b b ≤ 300 mm ± 2 mm
300 mm < b ≤ 600 mm ± 3 mm
b > 600 mm ± 0,5 %
Length l l ≤ 5 m ± 5 mm
5 m < l ≤ 20 m ± 0,1 %
l > 20 m ± 20 mm
Maximum deviation α of the right angles of the cross section, 1:50
see Figure 2
(approximately 1,1°)
6.9 Durability of other characteristics against biological attack of structural and non-
structural LVL
6.9.1 Laminated veneer lumber without preservative treatment
The durability of laminated veneer lumber shall be declared as use class according to EN 335.
NOTE Guidance for the determination of the use class is given in EN 636:2012+A1:2015, Annex B, and
CEN/TS 1099.
6.9.2 Laminated veneer lumber with preservative treatment against biological attack
Treated panels shall be marked with indication “PT” and the following information shall be given:
— method of treatment with wood preservative;
— target biological agents.
In the case of pressure impregnation the penetration and retention of a preservative treatment shall be
tested and declared according to EN 351-1.
NOTE 1 Guidance on the relationship between these variables and the application of the product for a specific
use is given in national documents.
NOTE 2 Preservative treatments against blue stain and mould do not improve the durability but the
appearance, see 6.20.
NOTE 3 The use of timber preservatives against biological attack or blue stain and mould may be restricted by
provisions valid in the place of use.
If the preservative treatment affects the mechanical properties tests according to 6.1 to 6.6 shall be
done after the treatment.
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6.10 Resistance to fire of structural LVL
Resistance to fire of untreated laminated veneer lumber shall either be given as:
— charring rate, where charring rate is expressed by characteristic density declared as strength class
according to Annex B or as individual value; or
NOTE Resistance to fire of laminated veneer lumber can be calculated later under a fire engineering design
for specific end-use situation taking into account additional parameters, e.g. charring rates, given in
EN 1995-1-2.
— by tests according to the methods specified in the standards referred to in EN 13501-2 and
declared as resistance to fire class(es) according to EN 13501-2 and test parameters for which
class(es) or individual values apply.
For treated laminated veneer lumber tests according to the methods specified in the standards referred
to in EN 13501-2 shall be performed and the results shall be declared as resistance to fire class(es)
according to EN 13501-2 and test parameters for which class(es) or individual values apply.
6.11 Reaction to fire of structural and non-structural LVL
6.11.1 General
The class of reaction to fire performance (including the additional classification on smoke production
and flaming droplets/particles, if any) of laminated veneer lumber shall be determined, classified and
declared:
— either without the need for further testing (CWFT), as given in Table 2, if laminated veneer lumber
meets the material characteristics and the end use conditions given therein;
— or based on testing of laminated veneer lumber according to the relevant test methods, given in
standards referred to in EN 13501-1, when laminated veneer lumber does not meet the
requirements of Table 2 or where a higher classification than the one in Table 2 is sought.
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prEN 14374:2016
1) 2)
Table 2 — Classes of reaction to fire performance for wood-based panels ,
b c
Product EN product End use condition Minimum Minimum Class Class
a
standard mean overall (excluding (floorings)
density thickness floorings)
(kg/m ) (mm)
Plywood EN 636 without an air gap 400 9 D-s2, d0 D -s1
fl
d,e,h
behind the wood-
based panel
Plywood with a closed or an D-s2, d2 -
f,h
open air gap not
more than 22 mm
behind the wood-
based panel
Plywood with a closed air 15 D-s2, d1 D -s1
fl
g,h
gap behind the
wood-based panel
Plywood with an open air 18 D-s2, d0 D -s1
fl
g,h
gap behind the
wood-based panel
a 2
A vapour barrier with a thickness up to 0,4 mm and a mass up to 200 g/m can be mounted in between the wood-based panel
and a substrate if there are no air gaps in between.
b
Class as provided for in Table 1 of the Annex to Decision 2000/147/EC.
c
Class as provided for in Table 2 of the Annex to Decision 2000/147/EC.
d 3
Mounted without an air gap directly against class A1 or A2-s1, d0 products with minimum density 10kg/m or at least class
D-s2, d2 products with minimum density 400 kg/m .
e
A substrate of cellulose insulation material of at least class E may be included if mounted directly against the wood-based
panel, but not for floorings.
f
Mounted with an air gap behind. The reverse face of the cavity shall be at least class A2-s1, d0 products with minimum density
10 kg/m .
g
Mounted with an air gap behind. The reverse face of the cavity shall be at least class D-s2, d2 products with minimum density
400 kg/m .
h
Veneered, phenol- and melamine-faced panels are included for class excl. floorings.
6.11.2 Determination from tests
6.11.2.1 General
When Reaction to Fire is determined by testing, the product shall be tested according to EN 13823 (SBI
test).
Tests may be done without conditioning according to EN 13238 with specimens having a moisture
content of u ≤ 10%. The moisture content shall be reported.
Test results are valid for laminated veneer lumber having at least the density and the minimum overall
thickness of the specimens tested. Test results are valid up to the tested gap width.

1) This table is the same as Table 1 of Commission Decision 2003/43/EC of 17 January 2003 (OJEU L13 of 18.1.2003) corrected by
Corrigendum (OJEU L33 of 8.2.2003) and amended by Commission Decision 2007/348/EC of15 May 2007 (OJEU L131 of
23.05.2007).
2) A Commission´s decision on the applicability of Table 2 for laminated veneers lumber has been requested.
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prEN 14374:2016 (E)
If the laminated veneer lumber is treated with fire-retardants, the fire retardant shall be declared as
"FRT".
If the laminated veneer lumber is preservative treated or treated with fire-retardants, the test results
are valid for
— the product type (veneer thickness, glue type, amount of glue, species) and manufacturer from
which the specimens were taken;
— products for which the same preservative treatment or fire retardant is used;
— with retention values which exceed the value of the
...