FprEN 46-1

• Abstract:

  This document specifies a method for the determination of the preventive action of a wood preservative against recently hatched larvae of Hylotrupes bajulus (Linnaeus) when the preservative is applied as a surface treatment to wood.; This method is applicable to:; - water-insoluble chemicals which are being studied as active insecticides,; - organic formulations, as supplied or as prepared in the laboratory by dilution of concentrates,; - organic water-dispersible formulations as supplied or as prepared in the laboratory by dilution of concentrates, or; - water-soluble materials, for example salts.; The method is applicable whether or not the test specimens have been subjected to appropriate ageing procedures.

• Status: Not Published
• Publication Date: 01-Dec-2026
• ICS: 71.100.50 - Wood-protecting chemicals
• Technical Committee: CEN/TC 38 - Durability of wood and derived materials
• Drafting Committee: CEN/TC 38/WG 24 - Insect testing - (beetles - termites)
• Current Stage: 5060 - Closure of Vote - Formal Approval
• Start Date: 24-Sep-2026
• Due Date: 03-Feb-2027
• Completion Date: 24-Sep-2026
• Ref Project: kSIST FprEN 46-1:2026 - Wood preservatives - Determination of the preventive action against recently hatched larvae of Hylotrupes bajulus (Linnaeus) - Part 1: Application by surface treatment (Laboratory method)

• Revises: EN 46-1:2016 - Wood preservatives - Determination of the preventive action against recently hatched larvae of Hylotrupes bajulus (Linnaeus) - Part 1: Application by surface treatment (laboratory method)
• Effective Date: 12-Apr-2023

FprEN 46-1 is the CEN draft European Standard for a laboratory method that measures the preventive action of wood preservatives against recently hatched larvae of Hylotrupes bajulus (Linnaeus) when the preservative is applied as a surface treatment. It tells laboratories how to prepare treated wood specimens, expose them to larvae, judge attack, and report results for wood-protection products and related testing work.

This draft applies to water-insoluble chemicals, organic formulations, organic water-dispersible formulations, and water-soluble materials, and it can be used with specimens that have been aged or not aged.

What does FprEN 46-1 specify?

FprEN 46-1 specifies a laboratory method for determining whether a wood preservative prevents attack by recently hatched Hylotrupes bajulus larvae after surface treatment of wood. The method is built for comparative testing: treated specimens are exposed to larvae and compared with untreated controls, and with solvent or diluent controls where relevant.

The document is organized into scope, normative references, terms and definitions, principle, test materials, sampling, test specimens, procedure, result expression, and test report. It is supported by informative annexes for reporting, culturing the insect, identifying wood tissue, and laboratory safety, plus one normative annex for extended testing.

Annex	What it covers
Annex A	Example of a test report
Annex B	Technique for culturing Hylotrupes bajulus
Annex C	Differentiation of heartwood and sapwood in Pinus species
Annex D	Environmental, health and safety precautions within chemical/biological laboratory
Annex E	Slow acting and deferred effect formulations - extending the test duration

What are the key requirements of FprEN 46-1?

FprEN 46-1 gives a step-by-step test method that controls the wood, the treatment, the larvae, the exposure conditions, and the validity checks. In practice, that means a lab can run comparable tests on different preservatives and report a result that can be interpreted in a consistent way.

Sampling and test specimens

The sample of preservative must be representative, and bulk sampling follows EN 212. The test wood is based on Scots pine (Pinus sylvestris Linnaeus), using sound sapwood with defined quality and growth characteristics. This matters because the wood itself must be susceptible enough for the insect to attack and consistent enough for results to be comparable.

The document requires a defined specimen size, identification marking, and specimen counts for treated sets and control sets. For standard testing, each preservative, concentration, and treatment duration uses six treated specimens, with untreated controls and solvent or diluent controls where applicable. That gives the test enough replication to show whether protection is real or just variation between pieces of wood.

Larvae, reagents, and test environment

The biological material is Hylotrupes bajulus larvae within three days of hatching, with ten larvae per treated or control specimen in the standard method. The larvae should come from different females, which helps reduce bias from one brood. The document also specifies paraffin wax or a suitable sealant, water of grade 3 to EN ISO 3696, and an appropriate solvent or diluent that does not leave a toxic residue.

The method also fixes the laboratory conditions for culturing, conditioning, and testing. These temperature and humidity ranges matter because insect development and preservative performance can shift if the environment is too dry, too warm, or too variable.

Surface treatment and retention

FprEN 46-1 allows brushing, pipette application, and dipping. For brushing or pipette treatment, only the specified lateral face is treated; for dipping, the faces are sealed so only one face remains exposed. The treatment solution must be freshly prepared, and the retained amount is determined from the solution uptake or the applied mass or volume.

For toxic value testing, the document calls for a series of concentrations around the expected toxic level. This is what allows the result to be expressed not just as pass or fail, but as a loading linked to larval death.

Conditioning and ageing

Before treatment, specimens are conditioned for at least two weeks. After treatment, they are conditioned for four weeks in the specified environment, and slow drying products may need longer conditioning, which must be reported. If EN 73 or EN 84 ageing is used, it is carried out after drying.

This sequence matters because the test is meant to show how a treated surface behaves after realistic drying and, if needed, after ageing or leaching. It is not only a fresh-treatment test.

Exposure, examination, and validity

After conditioning, each specimen is fitted with a glass plate and a small gap, and the larvae are introduced into that gap. The standard exposure period is 12 weeks, with an optional 24-week duration for slow acting or deferred effect formulations under Annex E. The specimen is checked after four weeks, and again at the end if the test continues.

The test is valid only if enough larvae survive and tunnel in the control specimens. The document uses this control check to make sure a weak biological challenge or poor larval condition does not invalidate the run. Results are then expressed as counts of dead, live, and unrecovered larvae, with toxic values reported as preservative loading per treated wood surface area.

What terms does FprEN 46-1 define?

FprEN 46-1 defines a small set of core terms that set the basis for sampling and responsibility in the test.

• Representative sample - a sample whose physical and/or chemical characteristics match the volumetric average characteristics of the whole material being sampled.
• Supplier - the sponsor of the test, meaning the person or company that provides the preservative sample.
• Toxic values - the loadings that bracket the point where all larvae die at one concentration and live larvae still occur at the next lower concentration.
• Control test specimen - a specimen used for comparison, either untreated or treated only with solvent or diluent.
• Ageing procedure - a pre-test treatment used to simulate service exposure before biological testing, such as the EN 73 or EN 84 procedures.
• Sapwood - the outer wood used for the test specimens, selected here because it is suitable for this insect test.

Who uses FprEN 46-1?

FprEN 46-1 is used by laboratories that test wood preservatives, by manufacturers developing insecticidal wood treatments, and by quality or regulatory teams that need comparable biological test data. It is also used by technical staff in the wood-protection sector who need to judge preventive performance against Hylotrupes bajulus larvae.

In practice, users apply it to prepare specimens, culture larvae, run exposure tests, determine toxic values, and compile a formal test report. It is especially relevant where a preservative is intended for surface treatment and where ageing or different application methods may influence performance.

What changed in FprEN 46-1 from the previous edition?

FprEN 46-1 will supersede EN 46-1:2016. The draft states these main technical changes compared with that edition:

• sealing specifications for specimens treated with solutions in which an organic solvent is the continuous phase were generalized;
• temperature and humidity requirements were aligned with other insect test standards;
• imaging facilities for non-destructive recording of internal tunnels were generalized;
• storage limitations for wood used to make specimens were deleted;
• a note was added that may reduce the number of concentrations needed to determine toxic value;
• dipping specifications were generalized and aligned with other insect standards.

Which standards are used with FprEN 46-1?

FprEN 46-1 relies on several linked standards and companion parts that support ageing, sampling, water quality, and related biological testing.

• EN 73 - provides the evaporative ageing procedure used when treated wood is aged before biological testing.
• EN 84 - provides the leaching procedure for ageing treated wood before biological testing.
• EN ISO 3696 - defines the water quality used for laboratory work in this method.
• EN 212 - gives general guidance for sampling and preparation of wood preservatives and treated timber.
• EN 46-2 - the companion part for determining the ovicidal effect after egg-laying of young females.
• EN 47 - the related method for determining toxic values against Hylotrupes bajulus larvae in totally impregnated wood.

What does the FprEN 46-1 document contain?

FprEN 46-1 contains a full laboratory workflow, not just a pass-fail criterion. It includes specimen conditioning, face sealing, application by brushing, pipette, or dipping, exposure setup with a glass plate and gap, and the rules for checking tunnelling and mortality.

It also includes an example test report in Annex A, culture guidance for Hylotrupes bajulus in Annex B, a method for distinguishing heartwood and sapwood in Pinus species in Annex C, and laboratory safety precautions in Annex D. Annex E extends the method to 24 weeks for slow acting or deferred effect formulations.

SLOVENSKI STANDARD
oSIST prEN 46-1:2025
01-december-2025
Biocidni proizvodi za zaščito lesa - Ugotavljanje preventivnega delovanja proti
hišnemu kozličku Hylotrupes bajulus (Linnaeus) - 1. del: Ugotavljanje
učinkovitosti proti ličinkam (laboratorijska metoda)
Wood preservatives - Determination of the preventive action against recently hatched
larvae of Hylotrupes bajulus (Linnaeus) - Part 1: Application by surface treatment
(Laboratory method)
Holzschutzmittel - Bestimmung der vorbeugenden Wirkung gegenüber frisch
geschlüpften Larven von Hylotrupes bajulus (Linnaeus) - Teil 1: Anwendung durch
Oberflächenverfahren (Laboratoriumsverfahren)
Produits de préservation du bois - Détermination de l'action préventive contre les larves
récemment écloses d'Hylotrupes bajulus (Linnaeus) - Partie 1 : Application par
traitement de surface (Méthode de laboratoire)
Ta slovenski standard je istoveten z: prEN 46-1
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
oSIST prEN 46-1:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 46-1:2025
oSIST prEN 46-1:2025
DRAFT
EUROPEAN STANDARD
prEN 46-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 71.100.50 Will supersede EN 46-1:2016
English Version
Wood preservatives - Determination of the preventive
action against recently hatched larvae of Hylotrupes
bajulus (Linnaeus) - Part 1: Application by surface
treatment (Laboratory method)
Produits de préservation du bois - Détermination de Holzschutzmittel - Bestimmung der vorbeugenden
l'action préventive contre les larves récemment écloses Wirkung gegenüber frisch geschlüpften Larven von
d'Hylotrupes bajulus (Linnaeus) - Partie 1 : Application Hylotrupes bajulus (Linnaeus) - Teil 1: Anwendung
par traitement de surface (Méthode de laboratoire) durch Oberflächenverfahren
(Laboratoriumsverfahren)
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, Türkiye 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

E U R O P Ä I SC H E S KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 46-1:2025 E
worldwide for CEN national Members.

oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Principle . 6
5 Test materials . 7
5.1 Biological material . 7
5.2 Products and reagents . 7
5.3 Apparatus . 7
6 Sampling . 8
7 Test specimens . 8
7.1 Species of wood . 8
7.2 Wood quality . 9
7.3 Provision of test specimens . 9
7.4 Dimensions of test specimens . 9
7.5 Number of test specimens . 9
8 Procedure. 10
8.1 Preparation of the test specimens . 10
8.1.1 Conditioning of the test specimens prior to sealing . 10
8.1.2 Sealing of the transverse faces . 10
8.1.3 Treatment of the test specimens . 10
8.1.4 Drying and conditioning of the test specimens after treatment . 12
8.2 Exposure of the test specimens to the insects . 12
8.3 Conditions and duration of the test . 13
8.4 Examination of the test specimens . 13
8.4.1 Examination . 13
8.4.2 Validity of the test . 14
9 Expression of results . 14
9.1 Evaluation of attack . 14
9.2 Toxic values . 14
10 Test report . 15
Annex A (informative) Example of a test report . 17
Annex B (informative) Technique for culturing Hylotrupes bajulus (Linnaeus) . 19
B.1 General . 19
B.2 Obtaining parent beetles . 19
B.3 Mating . 19
B.4 Egg-Iaying . 19
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prEN 46-1:2025 (E)
B.5 Hatching of eggs . 20
B.6 Larval development . 20
B.7 Enemies and parasites . 21
Annex C (informative) Differentiation of heartwood and sapwood in Pinus species . 22
C.1 Principle . 22
C.2 Reagents . 22
C.3 Apparatus . 22
C.4 Procedure . 22
Annex D (informative) Environmental, health and safety precautions within
chemical/biological laboratory . 23
Annex E (normative) Slow acting and deferred effect formulations – Extending the test
duration . 24
Bibliography . 26

oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
European foreword
This document (prEN 46-1:2025) has been prepared by Technical Committee CEN/TC 38 “Biological
durability of wood and wood-based products”, the secretariat of which is held by SIS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 46-1:2016.
Significant technical differences between this document and EN 46-1:2016 are as follows:
a) specifications for sealing faces of test specimens to be treated with solutions in which an organic
solvent is the continuous phase were generalized (5.2.2);
b) requirements for temperature and humidity were aligned with other insect test standards (5.3.1;
5.3.4; B5; B6);
c) imaging facilities for non-destructive recordings of insect tunnels inside test specimens were
generalized (5.3.11);
d) storage limitations for wood from which test specimens are to be made from were deleted (7.2);
e) a note was added to 8.1.3.1.3 to optionally reduce the number of concentrations which are
necessary to determine the toxic value;
f) Specifications for dipping (8.1.3.3) were generalized and aligned with other insect standards.
NOTE Test results obtained according to earlier versions of this document or when the tests had started
before this version of EN 46-1 was published are considered as valid.
The standard EN 46 is composed of two parts:
— EN 46-1, Wood preservatives ― Determination of the preventive action against recently hatched
larvae of Hylotrupes bajulus (Linnaeus) ― Part 1: Application by surface treatment (laboratory
method)
— EN 46-2, Wood preservatives ― Determination of the preventive action against recently hatched
larvae of Hylotrupes bajulus (Linnaeus) ― Part 2: Ovicidal effect (laboratory method)
EN 46 consists of two parts to enable preventive action of wood preservatives, against recently hatched
larvae of Hylotrupes bajulus, which are intended to be applied by surface treatment; Part 1 is required to
determine the larvicidial effect of preservatives and Part 2 is required to determine the ovicidal action
of the preservatives after egg-laying of young females.

oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
Introduction
This document describes a laboratory method of testing which gives a basis for the assessment of the
preventive action of a wood preservative, when applied as a surface treatment, against recently hatched
larvae of Hylotrupes bajulus, whereas the method for determining the toxic values against Hylotrupes
bajulus (EN 47) provides a means of checking whether a preservative prevents attack by these larvae
and prevents their survival within totally impregnated wood.
This document provides information for the sealing of all but one lateral face when specimens are to be
treated by dipping.
This method makes it possible to determine whether recently hatched larvae are capable of boring
through the treated surface of a susceptible wood species and of surviving in the untreated part of the
test specimen. For this purpose, the procedure seeks to reproduce normal egg-laying conditions
existing in cracks in wood, which provide the principal egg-laying sites. It takes account of the fact that,
if larvae pass through the treated surface, they will then tunnel in the direction of the least protected
regions of the wood.
This laboratory method provides one criterion by which the value of a preservative can be assessed. In
making this assessment, the methods by which the preservative may be applied should be taken into
account. This test is of particular interest when applied to test specimens which have been subjected to
an ageing procedure. It is further recommended that results from this test should be supplemented by
those from other appropriate tests and, above all, by practical experience.
When products which are very active at low concentrations are used it is very important to take
suitable precautions to isolate and separate, as far as possible, operations involving chemical products,
other products, treated wood, laboratory apparatus and clothing. Suitable precautions should include
the use of separate rooms, areas within rooms, extraction facilities, conditioning chambers and special
training for personnel (see also Annex D for environmental, health and safety precautions).

oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
1 Scope
This document specifies a method for the determination of the preventive action of a wood preservative
against recently hatched larvae of Hylotrupes bajulus (Linnaeus) when the preservative is applied as a
surface treatment to wood.
This method is applicable to:
— water-insoluble chemicals which are being studied as active insecticides;
— organic formulations, as supplied or as prepared in the laboratory by dilution of concentrates;
— organic water-dispersible formulations as supplied or as prepared in the laboratory by dilution of
concentrates;
— water-soluble materials, for example salts.
The method is applicable whether or not the test specimens have been subjected to appropriate ageing
procedures.
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 73, Durability of wood and wood-based products — Accelerated ageing of treated wood prior to
biological testing — Evaporative ageing procedure
EN 84, Durability of wood and wood-based products — Accelerated ageing of treated wood prior to
biological testing — Leaching procedure
EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
representative sample
sample having its physical and/or chemical characteristics identical to the volumetric average
characteristics of the total volume being sampled
3.2
supplier
sponsor of the test (person or company providing the sample of wood preservative to be tested)
4 Principle
Depending on the test being carried out either:
— on a set of test specimens of a susceptible wood species that is surface treated with a solution of the
preservative; or
oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
— if toxic values are to be determined, on several sets of test specimens of a susceptible wood species
that are surface treated with a series of solutions in which the concentration of preservative is
ranged in a given progression.
The treated test specimens are exposed to recently hatched larvae of Hylotrupes bajulus. The resulting
attack is observed and compared with those in untreated control test specimens. If the preservative has
been prepared in the laboratory by dilution of a concentrate or by dissolution of a solid, the resulting
attack is also compared to that in solvent or diluent treated control test specimens.
5 Test materials
5.1 Biological material
5.1.1 Hylotrupes bajulus (Linnaeus) larvae, within three days of hatching.
5.1.2 Source of larvae. Obtain the larvae from cultures reared, e. g. as described in Annex B.
5.1.3 Provision of larvae. Collect larvae from eggs laid by different females.
5.1.4 Choice of larvae. Use a mixed batch of these larvae for the test. Use ten larvae per treated test
specimen or control test specimen.
5.2 Products and reagents
5.2.1 Paraffin wax, for fixing the glass plate and for sealing the end faces as well as all relevant other
faces of test specimens to be treated with solutions in all cases in which water is the continuous phase
(see 8.1.2.1 and 8.1.2.2).
NOTE Paraffin wax with a setting point of approx. 52 °C to 54 °C has been found to be suitable.
5.2.2 Sealant, for sealing the end faces and all relevant other faces of test specimens to be treated with
solutions in all cases in which an organic solvent is the continuous phase (see 8.1.2.1 and 8.1.2.3). The
sealant must be resistant to penetration by the wood preservative under test and the respective solvent.
The sealant must not act repellent or insecticidal in the test specimen.
NOTE Gelatine or two to three coats of a two-component epoxy varnish with a drying step between each coat
has been found to be suitable.
5.2.3 Water, complying with grade 3 of EN ISO 3696 shall be used.
5.2.4 Solvent or diluent, a volatile liquid that will dissolve or dilute the preservative but does not
leave a residue in the wood at the end of the post-treatment conditioning period that has a toxic effect
on the insects.
CAUTION — Do not use benzene or other solvents which pose a health risk.
5.3 Apparatus
5.3.1 Culturing chamber, with air circulation, and controlled at 26± 2 °C and at a relative humidity of
(75 ± 5) %.
5.3.2 Conditioning chamber, well ventilated and controlled at (20 ± 2) °C and at a relative humidity
of (65 ± 5) %.
oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
The conditioning of test specimens may be carried out in the laboratory work area (see 5.3.3) provided
that this has the conditions specified for the conditioning chamber (see 5.3.2).
5.3.3 Laboratory work area, well ventilated, where treatment of the test specimens is carried out.
CAUTION — It is essential to follow safety procedures for handling flammable and toxic
materials. Avoid excessive exposure of operators to solvents or their vapours.
5.3.4 Testing chamber, ventilated and air conditioned, controlled at (22 ± 2) °C and at a relative
humidity of (75 ± 5) %.
5.3.5 Treatment vessels of a material that does not react with the preservative under test, for
example of glass for organic products and of polyethylene for salts containing fluorine.
5.3.6 Weights, to provide ballast for the test specimens.
The weights shall not react with any materials with which they come into contact during the test.
5.3.7 Safety equipment, protective clothing, protective gloves appropriate for the test product
and the test solvent, to ensure the safety of the operator.
5.3.8 Glass plates, (48 ± 1) mm long and (25 ± 1) mm wide, intended to provide a lateral slit on the
test specimens.
5.3.9 Ordinary laboratory equipment, including a balance capable of weighing to an accuracy of
0,01 g.
5.3.10 Pipette, specified in EN ISO 835 shall be used, or brush.
5.3.11 Imaging facilities e. g. X-ray apparatus, or any other device that offers good images (2D), of
internal tunnels caused by small larvae.
6 Sampling
The sample of preservative shall be representative of the product to be tested. Samples shall be stored
and handled in accordance with any written recommendations from the supplier.
For the sampling of preservatives from bulk supplies, the procedure given in EN 212 should be used.
7 Test specimens
7.1 Species of wood
)
The reference species is Scots pine (Pinus sylvestris Linnaeus) .
Additional tests may be carried out using other species but, if so, this should be stated in the test report.

1)
In southern European countries the pine species most frequently infested by Hylotrupes bajulus may be used as an
alternative, provided that the suitability of the species for use in the tests specified in this document has been demonstrated in
all aspects (development of larvae, resistance to impregnation, etc.).
oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
7.2 Wood quality
The wood shall be free from visible cracks, stain, decay, insect damage and other defects. The wood
shall not have been water-stored, floated, chemically treated or steamed. The wood shall originate from
trees preferably felled in winter. The trees shall be cut immediately after felling and the timber rapidly
air-dried or kiln dried at temperatures below 60 °C.
The wood shall be exclusively sapwood containing little resin and having between 2,5 and 8 annual
rings per 10 mm. The proportion of latewood in the annual rings shall not exceed 30 % of the whole.
It is recommended to use test specimens of similar growth rate within a single test.
)
7.3 Provision of test specimens
Prepare planed strips having a cross-section of (25 ± 0,5) mm × (15 ± 0,5) mm removing a minimum of
2 mm from any faces exposed during drying. The longitudinal faces shall be parallel to the direction of
the grain. The annual rings shall have a contact angle of 45° ± 15° to the broad faces. Make transverse
cuts, neatly to give sharp edges and a fine-sawn finish to the end-grain surfaces, to give test specimens
(50 ± 0,5) mm long.
The test specimens shall originate from a minimum of three trees or shall be taken at random from a
stock originally of more than 500 test specimens.
7.4 Dimensions of test specimens
The dimensions of each test specimen after reaching equilibrium in the conditioning chamber (5.3.2)
shall be (50 ± 0,5) mm × (25 ± 0,5) mm × (15 ± 0,5) mm.
Mark each test specimen so that it can be identified throughout the test.
7.5 Number of test specimens
a) Six treated test specimens (no more than two originating from the same tree unless taken at
random from a stock of more than 500) for each preservative, each concentration and each
duration of treatment;
b) Three untreated control test specimens (each originating from a different tree unless taken at
random from a stock of more than 500) for a complete test of any given preservative;
c) Three control test specimens treated with the solvent or diluent (5.2.3 or 5.2.4) (each originating
from a different tree unless taken at random from a stock of more than 500) if a solvent or diluent
(including water) is used.
Control test specimens under c) may be omitted if the solvent or diluents is water of drinking quality.
When dipping is to be used (8.1.3.3) it is advisable to treat more than the specified number of test
specimens so that, after weighing, any test specimens with abnormally high or low retentions can be
rejected from the batch.
To gain further information on a formulation the manufacturer may find it useful to test a version of the
preservative where the active ingredient(s) has been removed.

2)
For special tests, test specimens may be obtained according to a given series. As a result, it may be preferable to take test
specimens from pretreated strips. Where pretreated strips are used details should be included in the test report.
oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
8 Procedure
8.1 Preparation of the test specimens
8.1.1 Conditioning of the test specimens prior to sealing
Allow the test specimens to condition in the conditioning chamber (5.3.2) for a minimum of two weeks.
8.1.2 Sealing of the test specimen faces
8.1.2.1 General
When treatment is to be by brushing or by pipette then only the transverse faces of test specimens shall
be sealed. When treatment is to be by dipping then all faces, except one 25 mm × 50 mm face, shall be
sealed. The material used for sealing shall be resistant to the penetration of wood preservatives under
test. The sealings specified in 8.1.2.2 and 8.1.2.3 have been proven as suitable.
8.1.2.2 For tests with solutions in which water is the continuous phase, apply three coats of the
paraffin wax (5.2.1) at about 90 °C so that the first coat adheres closely to the wood and the successive
coatings bond to one another. Condition the sealed test specimens in the conditioning chamber (5.3.2)
for at least one day.
8.1.2.3 For tests with preservative solutions in which the continuous phase is an organic
solvent that dissolves paraffin wax, use a suitable sealant (5.2.2).
When gelatine is used, apply the first coat as an aqueous solution of 200 g/l at 40 °C, then after a
minimum of 8 h of drying, apply two further coats of an aqueous solution of 300 g/l at 50 °C.
Condition the sealed test specimens in the conditioning chamber (5.3.2) for at least one day.
8.1.3 Treatment of the test specimens
8.1.3.1 Preparation of the treatment solutions
8.1.3.1.1 Solid preservatives
— Water-soluble preservatives:
Dissolve the preservative in the water (5.2.3) to the required concentration, or in a series of
concentrations if toxic values are to be determined.
— Non-water-soluble preservatives:
Dissolve the preservative in an appropriate solvent (5.2.4) to the required concentration, or in a series
of concentrations if toxic values are to be determined.
All treatment solutions shall be freshly prepared.
8.1.3.1.2 Liquid preservatives
If appropriate, use the preservative without further preparation other than any necessary stirring. If it
is a concentrate or if toxic values are to be determined, dilute the preservative with the diluent to the
required working concentration, using the procedure specified by the manufacturer.
If available, a formulation of the preservative to be tested without active substances may also be
included in the test.
All treatment solutions shall be freshly prepared.
oSIST prEN 46-1:2025
prEN 46-1:2025 (E)
8.1.3.1.3 Toxic values
If toxic values are to be determined, prepare a series of at least five concentrations by mass, distributed
evenly about the expected toxic values.
If a toxic value had been determined by other standardised test methods, a series of three
concentrations by mass, distributed evenly about the expected toxic values may be sufficient.
A solvent or diluent control, i. e. treatment at concentration = 0, shall also be used. If the ap
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