Durability of wood and wood-based products - Remedial treatment of wood against insects by injection

This document provides guidance on how to apply curative acting wood preservatives by surface application, by filling pre-drilled holes, and by pressure impregnation through pre-drilled holes. It lists methods in a standardized form followed by additional detailed interpretive information.
This document also includes necessary preparations of structural timber prior to this kind of treatment. It gives guidance on how to calculate necessary retentions for filling pre-drilled holes or for pressure impregnation from test results obtained from surface applications (e.g. EN 1390).

Dauerhaftigkeit von Holz und Holprodukten - Nachbehandlung von Holz gegen Insektenbefall durch Injektion

Durabilité du bois et des matériaux dérivés - Traitement curatif du bois contre les insectes par injection

Trajnost lesa in lesnih izdelkov - Represivna zaščita lesa proti insektom s postopkom injiciranja

General Information

Status
Published
Public Enquiry End Date
13-Jan-2022
Publication Date
15-Jun-2022
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
19-May-2022
Due Date
24-Jul-2022
Completion Date
16-Jun-2022

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SLOVENSKI STANDARD
SIST-TP CEN/TR 17809:2022
01-julij-2022
Trajnost lesa in lesnih izdelkov - Represivna zaščita lesa proti insektom s
postopkom injiciranja
Durability of wood and wood-based products - Remedial treatment of wood against
insects by injection
Dauerhaftigkeit von Holz und Holprodukten - Nachbehandlung von Holz gegen
Insektenbefall durch Injektion

Durabilité du bois et des matériaux dérivés - Traitement curatif du bois contre les

insectes par injection
Ta slovenski standard je istoveten z: CEN/TR 17809:2022
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
SIST-TP CEN/TR 17809:2022 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST-TP CEN/TR 17809:2022
---------------------- Page: 2 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809
TECHNICAL REPORT
RAPPORT TECHNIQUE
March 2022
TECHNISCHER BERICHT
ICS 71.100.50
English Version
Durability of wood and wood-based products - Remedial
treatment of wood against insects by injection

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

Traitement curatif du bois contre les insectes par Nachbehandlung von Holz gegen Insektenbefall durch

injection Injektion

This Technical Report was approved by CEN on 21 February 2022. It has been drawn up by the Technical Committee CEN/TC 38.

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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17809:2022 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
Contents Page

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

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

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

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 General ................................................................................................................................................................ 5

5 Curative control measures........................................................................................................................... 6

5.1 Preparatory work ........................................................................................................................................... 6

5.2 Treatment with wood preservatives ........................................................................................................ 8

5.2.1 Surface treatment ........................................................................................................................................... 8

5.2.2 Pre-drilled hole filling and injection ........................................................................................................ 9

6 Estimation of retention for pre-drilled hole filling .......................................................................... 13

6.1 Assumption of effectively treated wood volume derived from surface application ............ 13

6.2 Assumption of effective diffusion of wood preservative when pre-drilled hole filling

is applied ......................................................................................................................................................... 13

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

---------------------- Page: 4 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
European foreword

This document (CEN/TR 17809:2022) has been prepared by Technical Committee CEN/TC 38

“Durability of wood and wood-based products”, the secretariat of which is held by AFNOR.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national standards body.

A complete listing of these bodies can be found on the CEN website.
---------------------- Page: 5 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
Introduction

Several national guidelines throughout Europe exist, on how to apply curative wood preservatives

especially via drilled holes or through pressure injection into wood. This technical report summarizes the

different national advices on how to properly use this kind of application. It focuses on treatments against

wood boring insects like Hylotrupes bajulus, Anobium punctatum and other anobiids.

---------------------- Page: 6 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
1 Scope

This document provides guidance on how to apply curative acting wood preservatives by surface

application, by filling pre-drilled holes, and by pressure impregnation through pre-drilled holes. It lists

methods in a standardized form followed by additional detailed interpretive information.

This document also includes necessary preparations of structural timber prior to this kind of treatment.

It gives guidance on how to calculate necessary retentions for filling pre-drilled holes or for pressure

impregnation from test results obtained from surface applications (e.g. EN 1390).

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 14128, Durability of wood and wood-based products - Efficacy criteria for curative wood preservatives

as determined by biological tests

EN 1390, Wood preservatives - Determination of the eradicant action against Hylotrupes bajulus (Linnaeus)

larvae - Laboratory method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
filling of drilled holes

application of a wood preservative through a pre-drilled hole without pressure or at low-pressure of less

than 1 bar
3.2
injection

application of a wood preservative through a pre-drilled hole with pressures of 3 to 5 bar (max. 15 bar)

4 General
Curative acting wood preservatives shall only be applied by professional users.

Curative acting wood preservatives are usually applied through surface application by brushing or

spraying all surfaces of the infested wood. If not all surfaces are accessible, an increase in the penetration

depth of a curative acting wood preservative against wood boring insects can be achieved through filling

drilled holes or by pressure treatment through drilled holes. However, it is important to ensure that wood

dimensions are suitable for drilling. The overall structural integrity and the load-bearing capacity shall

not be weakened.
---------------------- Page: 7 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
5 Curative control measures
5.1 Preparatory work

If live infestation by dried wood insects (e.g. house longhorn beetles, anobiid beetles or powder post

beetles) is detected, the spread of the infestation shall be determined based on the spread of their exit

holes.

If damage caused by dry wood insects is present which might lead to a reduction in strength, all accessible

wooden components shall be inspected at an appropriate complexity (e.g. by scratching, axing, drilling)

so that the intensity and extent of the infestation can be adequately determined. Wood-based materials

should only be checked for exit holes.

Additional information: Testing at “appropriate complexity” refers to the distances between the individual

probing spots, which are to be determined by experts in accordance with the overall infestation situation.

For probing, it is recommended that the affected woods in the infested areas be scored with a pinpointed

tool at right angles to the grain direction. In this way, the superficial larval galleries are torn open and the

damage pattern is exposed. The intensity of the infestation can also be determined without major damage

e.g. by test-drilling or random tapping to check the soundness of the wood. Chopping the wood with an axe

can cause severe additional destruction of the wood and should generally be reduced to a necessary

minimum.

In addition, the flooring and, if necessary, cladding shall be taken up to such an extent that the ceiling

beams or bedding timber can be inspected in areas at risk. If infestation is detected, the flooring is to be

taken up further. Areas that are difficult to access (e.g. extensions, sides, roof overhangs) shall also be

included in the inspection. If necessary, openings are to be created for this purpose.

Additional information: Other existing concealed structural timbers shall be included in the investigations

in the same way. To test concealed joists, it is necessary to check whether and, if necessary, to what extent

the infestation reduces the load-bearing capacity of the component. If an infestation is detected, further

excavation work is required to determine the extent of infestation and the load-bearing capacity of

previously concealed timber components. If areas that are difficult to access should or cannot be examined

for cost or usage-related reasons, these shall be listed in detail in the examination report and the client shall

be informed of the risk areas in which further insect damage might be possible.

If insect damage is present, all wooden components shall be carefully examined for live infestation. Curative

control measures may only be carried out if live infestation is verified. The decision as to whether live

infestation is present requires a high degree of specialist knowledge and experience. The following findings

or characteristics allow a reliable proof:

— findings of living insects of wood-destroying insects as well as their antagonists, which presuppose the

presence of pests (e.g. checkered beetles);

— findings of dead insects free of house dust (found especially on windows and other translucent

openings);

— findings of living larvae or pupae of wood-destroying insects or of their antagonists in the wood;

— perception of feeding noises.
---------------------- Page: 8 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
Furthermore, the following indications point to a live infestation:

— detection of light yellow to brown coloured exit holes on surfaces or sides exposed to daylight; darker

coloured exit holes indicate older extinct infestations;

— finding light-coloured piles of frass on horizontal surfaces, or light-coloured drill dust under fresh exit

holes. It should be noted that the ejection of frass and drill dust from old exit holes can also be caused

by secondary colonisation by digger wasps or masonry bees.

If the above-mentioned characteristics for a live infestation are missing at the time of investigation, a live

infestation cannot be automatically excluded in all cases. In cases of doubt, monitoring for beetle presence

should be carried out for some time.

Drilling dust trickling out of cracks or dark-coloured exit holes is usually caused by shocks or vibrations of

the components and is no evidence of a live infestation.

If live infestation can be denied or only a small residual infestation is to be assumed, the necessity of control

measures shall be carefully balanced. In any case, the extent of the damage shall be determined even if the

infestation has deceased in order to determine whether there has been any impairment of the construction.

In the case of infested timber components, the load-bearing residual cross-sections and the load-bearing

capacity shall be determined. If necessary, a structural engineer shall be consulted. The verification of

stability shall be re-established if cross-sections are reduced more than statically permissible. In this case,

parts with reduced cross-sections shall be reinforced or replaced. A visual inspection is usually sufficient

to check the load-bearing capacity of timber with small cross-sections (e.g. roof battens).

Additional information: If there are doubts about the load-bearing capacity of the examined timber

components, they shall be assessed by appropriate experts (structural engineers). As a rule, these refer to

geometric details (residual cross section of the component) determined by the wood preservation expert.

The selection of the location of a cross-section determination is to be carried out in cooperation with a

structural engineer - especially in the case of complicated structural systems.

Before the subsequent treatment with wood preservatives, the structural members shall be cleaned.

Heavily rotten parts shall be removed. The removed material shall be disposed of in an orderly manner.

Additional information: Cleaning and removing rotten parts allow the preservative to take full effect in the

deeper layers of the infested wood. If the mossy edges, e.g. of a beam, are not removed, they absorb most of

the applied wood preservative, so that it cannot penetrate the deeper layers of infestation in sufficient

quantity. In addition, the biocidal active substances contained in the wood preservatives can be released into

the environment in an uncontrolled manner through the detachment of contaminated debris.

At the same time, the removal of the mined wood removes a considerable proportion of larvae by mechanical

means. It is sufficient to simply open the innermost feeding tunnels and brush them out carefully without

removing them completely in order to avoid additional static weakening.

Coatings shall be removed to such an extent as to ensure successful application of wood preservatives.

If paint coats are to be retained (e.g. due to requirements of cultural heritage conservation), alternative

control measures might be more applicable (heat treatment, fumigation).
---------------------- Page: 9 ----------------------
SIST-TP CEN/TR 17809:2022
CEN/TR 17809:2022 (E)
5.2 Treatment with wood preservatives
5.2.1 Surface treatment

Treatment shall be carried out with wood preservatives registered under the European Biocidal Products

Regulation and specified according to EN 14128. According to EN 14128 the following three types of

insecticidal products are considered: fast acting, slow acting and products with deferred effects. The type

of action for a single product might differ for different target species of wood destroying insects.

All surfaces of the infested wood are to be treated evenly with the wood preservative by brushing or

spraying.

Additional information: In the case of treating wooden ceiling structures, the infested timbers shall be

exposed from any cover before the application of the wood preservative.

If the wood has previously been treated with wood preservatives, it shall be ensured that the

effectiveness of the wood preservatives to be used is not impaired.

If there is apparently only a local infestation and the wood components are accessible and controllable

for at least 6 years, only the immediate infested area is to be treated with preservatives:

Additional information: Additional treatment of uninfested timber components with a wood preservative of

preventive efficacy is only required if continuous monitoring of the wood at risk is not possible.

With increasing age of the wooden components, the risk of infestation decreases as the attractiveness of

older wood for the house longhorn beetle decreases. Therefore, it should be checked in each individual

case whether it is necessary to additionally treat the non-infe
...

SLOVENSKI STANDARD
kSIST-TP FprCEN/TR 17809:2022
01-januar-2022
Trajnost lesa in lesnih izdelkov - Represivna zaščita lesa proti insektom s
postopkom injiciranja
Durability of wood and wood-based products - Remedial treatment of wood against
insects by injection
Dauerhaftigkeit von Holz und Holprodukten - Nachbehandlung von Holz gegen
Insektenbefall durch Injektion
Ta slovenski standard je istoveten z: FprCEN/TR 17809
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
kSIST-TP FprCEN/TR 17809:2022 en,fr,de

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

---------------------- Page: 1 ----------------------
kSIST-TP FprCEN/TR 17809:2022
---------------------- Page: 2 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FINAL DRAFT
TECHNICAL REPORT
FprCEN/TR 17809
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
October 2021
ICS 71.100.50
English Version
Durability of wood and wood-based products - Remedial
treatment of wood against insects by injection
Dauerhaftigkeit von Holz und Holprodukten -
Nachbehandlung von Holz gegen Insektenbefall durch
Injektion

This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC 38.

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 Technical Report. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a Technical Report.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 17809:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)
Contents Page

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

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

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 General ................................................................................................................................................................ 5

5 Curative control measures........................................................................................................................... 6

5.1 Preparatory work ........................................................................................................................................... 6

5.2 Treatment with wood preservatives ........................................................................................................ 7

5.2.1 Surface treatment ........................................................................................................................................... 7

5.2.2 Pre-drilled hole filling and injection ........................................................................................................ 9

6 Estimation of retention for pre-drilled hole filling .......................................................................... 12

6.1 Assumption of effectively treated wood volume derived from surface application ............ 12

6.2 Assumption of effective diffusion of wood preservative when pre-drilled hole filling

is applied ......................................................................................................................................................... 13

Bibliography ................................................................................................................................................................. 14

---------------------- Page: 4 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)
European foreword

This document (FprCEN/TR 17809:2021) 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 Vote on TR.
---------------------- Page: 5 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)
Introduction

Several national guidelines throughout Europe exist, on how to apply curative wood preservatives

especially via drilled holes or through pressure injection into wood. This technical report summarizes the

different national advices on how to properly use this kind of application. It focuses on treatments against

wood boring insects like Hylotrupes bajulus, Anobium punctatum and other anobiids.

---------------------- Page: 6 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)
1 Scope

This document provides guidance on how to apply curative acting wood preservatives by surface

application, by filling pre-drilled holes, and by pressure impregnation through pre-drilled holes. It lists

methods in a standardized form followed by additional detailed interpretive information.

This document also includes necessary preparations of structural timber prior to this kind of treatment.

It gives guidance on how to calculate necessary retentions for filling pre-drilled holes or for pressure

impregnation from test results obtained from surface applications (e.g. EN 1390).

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 14128, Durability of wood and wood-based products - Efficacy criteria for curative wood preservatives

as determined by biological tests

EN 1390, Wood preservatives - Determination of the eradicant action against Hylotrupes bajulus (Linnaeus)

larvae - Laboratory method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
filling of drilled holes

application of a wood preservative through a pre-drilled hole without pressure or at low-pressure of less

than 1 bar
3.2
injection

application of a wood preservative through a pre-drilled hole with pressures of 3 to 5 bar (max. 15 bar)

4 General
Curative acting wood preservatives shall only be applied by professional users.

Curative acting wood preservatives are usually applied through surface application by brushing or

spraying all surfaces of the infested wood. If not all surfaces are accessible, an increase in the penetration

depth of a curative acting wood preservative against wood boring insects can be achieved through filling

drilled holes or by pressure treatment through drilled holes. However, it is important to ensure that wood

dimensions are suitable for drilling. The overall structural integrity and the load-bearing capacity shall

not be weakened.
---------------------- Page: 7 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)
5 Curative control measures
5.1 Preparatory work

If live infestation by dried wood insects (e.g. house longhorn beetles, anobiid beetles or powder post

beetles) is detected, the spread of the infestation shall be determined based on the spread of their exit

holes.

If damage caused by dry wood insects is present which might lead to a reduction in strength, all accessible

wooden components shall be inspected at an appropriate complexity (e.g. by scratching, axing, drilling)

so that the intensity and extent of the infestation can be adequately determined. Wood-based materials

should only be checked for exit holes.

Additional information: Testing at “appropriate complexity” refers to the distances between the individual

probing spots, which are to be determined by experts in accordance with the overall infestation situation.

For probing, it is recommended that the affected woods in the infested areas be scored with a pinpointed

tool at right angles to the grain direction. In this way, the superficial larval galleries are torn open and the

damage pattern is exposed. The intensity of the infestation can also be determined without major damage

e.g. by test-drilling or random tapping to check the soundness of the wood. Chopping the wood with an axe

can cause severe additional destruction of the wood and should generally be reduced to a necessary

minimum.

In addition, the flooring and, if necessary, cladding shall be taken up to such an extent that the ceiling

beams or bedding timber can be inspected in areas at risk. If infestation is detected, the flooring is to be

taken up further. Areas that are difficult to access (e.g. extensions, sides, roof overhangs) shall also be

included in the inspection. If necessary, openings are to be created for this purpose.

Additional information: Other existing concealed structural timbers shall be included in the investigations

in the same way. To test concealed joists, it is necessary to check whether and, if necessary, to what extent

the infestation reduces the load-bearing capacity of the component. If an infestation is detected, further

excavation work is required to determine the extent of infestation and the load-bearing capacity of

previously concealed timber components. If areas that are difficult to access should or cannot be examined

for cost or usage-related reasons, these shall be listed in detail in the examination report and the client shall

be informed of the risk areas in which further insect damage might be possible.

If insect damage is present, all wooden components shall be carefully examined for live infestation. Curative

control measures may only be carried out if live infestation is verified. The decision as to whether live

infestation is present requires a high degree of specialist knowledge and experience. The following findings

or characteristics allow a reliable proof:

— findings of living insects of wood-destroying insects as well as their antagonists, which presuppose the

presence of pests (e.g. checkered beetles);

— findings of dead insects free of house dust (found especially on windows and other translucent

openings);

— findings of living larvae or pupae of wood-destroying insects or of their antagonists in the wood;

— perception of feeding noises.
— furthermore, the following indications point to a live infestation:

— detection of light yellow to brown coloured exit holes on surfaces or sides exposed to daylight; darker

coloured exit holes indicate older extinct infestations;
---------------------- Page: 8 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)

— finding light-coloured piles of frass on horizontal surfaces, or light-coloured drill dust under fresh exit

holes. It should be noted that the ejection of frass and drill dust from old exit holes can also be caused

by secondary colonisation by digger wasps or masonry bees.

If the above-mentioned characteristics for a live infestation are missing at the time of investigation, a live

infestation cannot be automatically excluded in all cases. In cases of doubt, monitoring for beetle presence

should be carried out for some time.

Drilling dust trickling out of cracks or dark-coloured exit holes is usually caused by shocks or vibrations of

the components and is no evidence of a live infestation.

If live infestation can be denied or only a small residual infestation is to be assumed, the necessity of control

measures shall be carefully balanced. In any case, the extent of the damage shall be determined even if the

infestation has deceased in order to determine whether there has been any impairment of the construction.

In the case of infested timber components, the load-bearing residual cross-sections and the load-bearing

capacity shall be determined. If necessary, a structural engineer shall be consulted. The verification of

stability shall be re-established if cross-sections are reduced more than statically permissible. In this case,

parts with reduced cross-sections shall be reinforced or replaced. A visual inspection is usually sufficient

to check the load-bearing capacity of timber with small cross-sections (e.g. roof battens).

Additional information: If there are doubts about the load-bearing capacity of the examined timber

components, they shall be assessed by appropriate experts (structural engineers). As a rule, these refer to

geometric details (residual cross section of the component) determined by the wood preservation expert.

The selection of the location of a cross-section determination is to be carried out in cooperation with a

structural engineer - especially in the case of complicated structural systems.

Before the subsequent treatment with wood preservatives, the structural members shall be cleaned.

Heavily rotten parts shall be removed. The removed material shall be disposed of in an orderly manner.

Additional information: Cleaning and removing rotten parts allow the preservative to take full effect in the

deeper layers of the infested wood. If the mossy edges, e.g. of a beam, are not removed, they absorb most of

the applied wood preservative, so that it cannot penetrate the deeper layers of infestation in sufficient

quantity. In addition, the biocidal active substances contained in the wood preservatives can be released into

the environment in an uncontrolled manner through the detachment of contaminated debris.

At the same time, the removal of the mined wood removes a considerable proportion of larvae by mechanical

means. It is sufficient to simply open the innermost feeding tunnels and brush them out carefully without

removing them completely in order to avoid additional static weakening.

Coatings shall be removed to such an extent as to ensure successful application of wood preservatives.

If paint coats are to be retained (e.g. due to requirements of cultural heritage conservation), alternative

control measures might be more applicable (heat treatment, fumigation).
5.2 Treatment with wood preservatives
5.2.1 Surface treatment

Treatment shall be carried out with wood preservatives registered under the European Biocidal Directive

and specified according to EN 14128. According to EN 14128 the following three types of insecticidal

products are considered: fast acting, slow acting and products with deferred effects. The type of action

for a single product might differ for different target species of wood destroying insects.

All surfaces of the infested wood are to be treated evenly with the wood preservative by brushing or

spraying.

Additional information: In the case of treating wooden ceiling structures, the infested timbers shall be

exposed from any cover before the application of the wood preservative.
---------------------- Page: 9 ----------------------
kSIST-TP FprCEN/TR 17809:2022
FprCEN/TR 17809:2021 (E)

If the wood has previously been treated with wood preservatives, it shall be ensured that the

effectiveness of the wood preservatives to be used is not impaired.

If there is apparently only a local infestation and the wood components are accessible and controllable

for at least 6 years, only the immediate infested area is to be treated with preservatives:

Additional information: Additional treatment of uninfested timber components with a wood preservative of

preventive efficacy is only required if continuous monitoring of the wood at risk is not possible.

With increasing age of the wooden components, the risk of infestation decreases as the attractiveness of

older wood for the house longhorn beetle decreases. Therefore, it should be checked in each individual

case whether it is necessary to additionally treat the non-infested
...

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