Durability of wood and wood-based products - Determination of treatability of timber species to be impregnated with wood preservatives - Laboratory method

This document describes a laboratory method for the determination of the treatability of wood in order to determine the likely reaction of different wood species to impregnation with wood preservatives. It can also be used to investigate variation between samples of the same species but of different origin.

Dauerhaftigkeit von Holz und Holzprodukten - Bestimmung der Tränkbarkeit von Holzarten zur Tränkung mit Holzschutzmitteln - Laborverfahren

Dieses Dokument beschreibt ein Laborverfahren zur Bestimmung der Tränkbarkeit von Holz, um die wahrscheinliche Reaktion unterschiedlicher Holzarten auf die Imprägnierung mit Holzschutzmitteln zu bestimmen. Es kann auch dazu verwendet werden, Abweichungen zwischen Proben derselben Holzart, jedoch unterschiedlicher Herkunft, zu untersuchen.

Durabilité du bois et des matériaux dérivés du bois - Détermination de l'imprégnabilité d'essences de bois par des produits de préservation - Méthode de laboratoire

Le présent document décrit une méthode de laboratoire permettant de déterminer l'imprégnabilité du bois, afin de prévoir la réaction probable de différentes essences de bois à une imprégnation par des produits de préservation. Il peut aussi être utilisé pour vérifier les variations entre les échantillons de la même essence mais d'une origine différente.

Trajnost lesa in lesnih proizvodov - Ugotavljanje možnosti za impregnacijo vzorcev lesa z biocidnimi proizvodi za zaščito lesa - Laboratorijska metoda

General Information

Status
Not Published
Public Enquiry End Date
24-Feb-2021
Current Stage
4020 - Public enquire (PE) (Adopted Project)
Start Date
11-Jan-2021
Due Date
31-May-2021
Completion Date
22-Mar-2021

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SLOVENSKI STANDARD
oSIST prEN 14734:2021
01-februar-2021
Trajnost lesa in lesnih proizvodov - Ugotavljanje možnosti za impregnacijo
vzorcev lesa z biocidnimi proizvodi za les - Laboratorijska metoda

Durability of wood and wood-based products - Determination of treatability of timber

species to be impregnated with wood preservatives - Laboratory method
Dauerhaftigkeit von Holz und Holzprodukten - Bestimmung der Tränkbarkeit von
Holzarten zur Tränkung mit Holzschutzmitteln - Laborverfahren

Durabilité du bois et des matériaux dérivés du bois - Détermination de l'imprégnabilité

d'essences de bois par des produits de préservation - Méthode de laboratoire
Ta slovenski standard je istoveten z: prEN 14734
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
oSIST prEN 14734:2021 en,fr,de

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

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oSIST prEN 14734:2021
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oSIST prEN 14734:2021
DRAFT
EUROPEAN STANDARD
prEN 14734
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2020
ICS 79.040
English Version
Durability of wood and wood-based products -
Determination of treatability of timber species to be
impregnated with wood preservatives - Laboratory
method

Durabilité du bois et des matériaux dérivés du bois - Dauerhaftigkeit von Holz und Holzprodukten -

Détermination de l'imprégnabilité d'essences de bois Bestimmung der Tränkbarkeit von Holzarten zur

par des produits de préservation - Méthode de Tränkung mit Holzschutzmitteln - Laborverfahren

laboratoire

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

CEN/TC 38.

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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14734:2020 E

worldwide for CEN national Members.
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oSIST prEN 14734:2021
prEN 14734:2020 (E)
Contents Page

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

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Principle ............................................................................................................................................................. 5

3 Reagents ............................................................................................................................................................. 5

3.1 Copper sulfate pentahydrate, at least 98 % pure, solution, mass fraction of 5 %. .................. 5

3.2 Indicator solution............................................................................................................................................ 5

3.3 Sealing compound ........................................................................................................................................... 5

4 Apparatus ........................................................................................................................................................... 5

5 Preparation of test specimens .................................................................................................................... 6

6 Procedure........................................................................................................................................................... 7

6.1 Moisture content and density determination ....................................................................................... 7

6.2 Impregnation of test specimens (standard procedure) .................................................................... 7

6.3 Measurement of penetration ...................................................................................................................... 7

7 Data handling.................................................................................................................................................... 9

7.1 Treatability classes for individual test samples .................................................................................. 9

7.2 Differentiation between treatability classes 3 and 4 ......................................................................... 9

7.3 Assignation of a treatability class to a set of specimens ................................................................ 10

8 Report ............................................................................................................................................................... 10

Annex A (informative) Guidance on sampling ................................................................................................ 11

A.1 Origin of the material ................................................................................................................................. 11

A.2 Homogeneity of the sample ...................................................................................................................... 11

A.3 Heartwood ...................................................................................................................................................... 11

A.4 Saw pattern .................................................................................................................................................... 11

A.5 Seasoning ........................................................................................................................................................ 12

A.6 Grading ............................................................................................................................................................. 12

Annex B (informative) Example of a test report ............................................................................................ 13

Bibliography ................................................................................................................................................................. 15

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oSIST prEN 14734:2021
prEN 14734:2020 (E)
European foreword

This document (prEN 14734:2020) has been prepared by Technical Committee CEN/TC 38 “Durability

of wood and wood-based products”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
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oSIST prEN 14734:2021
prEN 14734:2020 (E)
Introduction

The basis for this document was prepared as being part of the work for SMT project MAT-CT 94061

project number 3307: Improvement of CEN standards by short term methods for testing the natural

durability and treatability of solid wood and wood based panel products.

It provides the means whereby the treatability of sapwood or heartwood of different wood species can

be determined in order to determine likely reaction to impregnation with wood preservatives. Such an

assessment provides data for use in EN 351-1 which establishes a system for specifying the treatment of

wood with wood preservatives based upon the penetration and retention of preservatives achieved by

the treatment process. EN 351-1 recognizes that different wood species respond to treatment differently

depending on their ability to absorb preservative, and requires a different level of compliance depending

on the treatability of the wood concerned. While EN 350 includes a subjective classification of the

treatability of different wood species using a four class system, the method described in this document

provides the means to determine the treatability objectively.

Although the method described uses an aqueous solution as the impregnating liquid, the results can be

used to give guidance on the treatability of the samples under test. Alternatively, the method can be

modified using other preservative types, e g organic solvent or emulsion preparations, if the response of

the wood to a specific preservative is required. However, it should be noted that the method does not

take account of preservative formulations where the active ingredients are selectively adsorbed on to the

wood substrate resulting in the solvent penetrating more deeply than the biocides.

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oSIST prEN 14734:2021
prEN 14734:2020 (E)
1 Scope

This document describes a laboratory method for the determination of the treatability of wood in order

to determine the likely reaction of different wood species to impregnation with wood preservatives. It

can also be used to investigate variation between samples of the same species but of different origin.

2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
4 Principle

After moisture and density determination of each of the test specimens, a set of test specimens is

impregnated with copper sulfate solution in accordance with a standard test procedure. After application

of an indicator solution to the exposed cross-section and to one of the exposed longitudinal surfaces of

each of test specimens, the lateral and axial penetration is measured and the treatability class is

evaluated.
5 Reagents

5.1 Copper sulfate pentahydrate, at least 98 % pure, solution, mass fraction of 5 %.

Dissolve 50 g of copper sulfate pentahydrate (CuSO x 5H O) in 950 g water, preferably deionized.

4 2

NOTE The volume of copper sulfate solution required will depend on the capacity of the impregnation

apparatus.
5.2 Indicator solution

For the indication of the penetration an indicator solution, e.g. chrome azurol S, can be used. Dissolve 0,5g

chrome azurol S and 5 g sodium acetate in 100 ml water.

Other indicators can be used but should have at least the same sensitivity to copper as chrome azurol S.

5.3 Sealing compound

A sealing compound which is inert to the copper sulfate solution (5.1) and unaffected by the test

conditions.
6 Apparatus
Ordinary laboratory apparatus and:
6.1 Balance, capable of weighing to an accuracy of 0,01 g.

6.2 Conditioning chamber, well ventilated and controlled at (20 ± 2) °C and (65 ± 5) % relative

humidity.
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prEN 14734:2020 (E)

6.3 Measuring device, capable of measuring the dimensions of test samples of up to 40 mm in size and

to an accuracy of 0,1 mm.
6.4 Drying oven, capable of being controlled at (103 ± 2) °C.
6.5 Desiccator, with efficient desiccant (silica gel for example).

6.6 Impregnation apparatus, consisting of a chamber and header tank with ancillary vacuum

1) 2

andpressure pumps capable of exerting a vacuum of (1 ± 0,5) kPa and a pressure of (10 ± 1) × 10 kPa.

The pipe work between the chamber and the pumps shall be designed so that adding or draining

treatment solutions can be achieved while maintaining the existing pressure in the vessel. A typical

apparatus is shown in Figure 1.
Key
1 storage tank
2 pump
3 vacuum pump
4 chamber
PI pressure gauge
Figure 1 — Typical impregnation apparatus
7 Preparation of test specimens

Prepare a minimum of ten test specimens, each from a different plank of the wood species under test (see

also 8.2). The test specimens of heartwood and sapwood shall be identified and marked appropriately.

The wood shall be sound, straight-grained and without knots and the visible features of the wood shall

be given for example: resin pockets, cross-grain, widths of annual rings and proportion of latewood. At

the time of test, the moisture content of the test specimens shall be between 13 % and 18 %.

NOTE It is important that the timber tested is representative of the population from which it comes. Guidance

on the sampling of timber is provided in Annex A.

It is recommended that 20 test specimens are used to take into account variability between specimens.

From each plank, prepare a strip having a length of at least 800 mm and a cross-section of

(40 ± 0,3) mm × (40 ± 0,3) mm. When the sapwood zone is less than 40 mm wide it might be necessary

to limit the cross-section of each strip. The lateral surfaces shall be planed and shall be true radial and

1 kPa = 10 mbar.
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prEN 14734:2020 (E)

tangential surfaces. Cross cut 15 mm to 20 mm from one end and discard. Cross cut a (10 ± 0,1) mm long

sample from the same end, for moisture content and density determination (see 8.1). Trim the other end

of the remaining length to give a test specimen (750 ± 1) mm long for impregnation. Number both test

specimens so as to retain the identity of the plank. Apply the sealing compound (5.3) to one cross-section

end of each test specimen for impregnation and allow to set. Inspect the end seal to ensure that it

completely covers the end grain and apply a second coat if required.

It is recommended that neither dimension of the cross-section is less than 20 mm.

8 Procedure
8.1 Moisture content and density determination

Weigh each test specimen for moisture content determination to the nearest 0,01 g using the balance

(6.1), to determine the initial mass (m ). Transfer the test specimens to the drying oven (6.4). Dry the test

specimens for 18 h to 24 h, cool to room temperature in a desiccator (6.5), weigh each test specimen to

the nearest 0,01 g and record the final mass (m ). Calculate the moisture content of e

...

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