CEN/TS 15083-2:2005

Durability of wood and wood-based products - Determination of the natural durability of solid wood against wood-destroying fungi, test methods - Part 2: Soft rotting micro-fungi

This CEN Technical Specification specifies a method of test for determining the natural durability of a timber against soft rotting micro-fungi. The method is applicable to all timber species.
NOTE   This method may be used in conjunction with an ageing procedure, for example EN 73 or EN 84.

Dauerhaftigkeit von Holz und Holzprodukten - Bestimmung der natürlichen Dauerhaftigkeit von Vollholz gegen holzzerstörende Pilze, Prüfverfahren - Teil 2: Moderfäulepilze

Diese Technische Spezifikation legt ein Prüfverfahren zur Bestimmung der natürlichen Dauerhaftigkeit einer Holzart gegen Moderfäulepilze fest. Das Verfahren ist auf alle Holzarten anwendbar.
ANMERKUNG   Dieses Verfahren darf in Zusammenhang mit einer Alterungsbeanspruchung angewendet werden, z. B. nach EN 73 oder EN 84.

Durabilité du bois et des matériaux dérivés - Détermination de la durabilité naturelle du bois massif vis-à-vis des champignons lignivores, méthodes d'essai - Partie 2: Micro-organismes de pourriture molle

Le présent document spécifie une méthode d'essai permettant de déterminer la durabilité naturelle du bois vis-à-vis des micro-organismes de pourriture molle. Ladite méthode est applicable à toutes les essences de bois.
NOTE   Cette méthode peut être utilisée conjointement avec une épreuve de vieillissement, par exemple, selon l'EN 73 ou l'EN 84.

Trajnost lesa in lesnih proizvodov - Ugotavljanje naravne trajnosti masivnega lesa za zaščito proti lesnim gobam, preskusne metode - 2. del: Glive razkrojevalke lesa

General Information

• Status: Published
• Publication Date: 26-Jul-2005
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: CEN/TC 38 - Durability of wood and derived materials
• Drafting Committee: CEN/TC 38/WG 23 - Fungal testing (basidiomycetes-microfungi)
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 27-Jul-2005
• Completion Date: 27-Jul-2005
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Ref Project: SIST-TS CEN/TS 15083-2:2006 - Durability of wood and wood-based products - Determination of the natural durability of solid wood against wood-destroying fungi, test methods - Part 2: Soft rotting micro-fungi

Overview

CEN/TS 15083-2:2005 defines a laboratory test method for determining the natural durability of solid wood against soft rotting micro-fungi (soft rot). Published by CEN/TC 38, this Technical Specification applies to all timber species and gives a reproducible procedure to expose wood specimens to soil-borne micro-flora and assess attack by soft rotting fungi. The method can be combined with ageing procedures (for example EN 73 or EN 84) to simulate field-relevant conditions.

Key topics and technical requirements

• Test principle: Expose prepared wood specimens and reference timbers to soil containing natural micro-flora; assess decay by measuring percentage dry mass loss (hardwoods) or loss of modulus of elasticity (softwoods).
• Soil substrate: Use natural topsoil or a loam-based horticultural soil (pH 6–8) with water holding capacity (WHC) between 25% and 60%. Procedures for WHC and rapid soil virulence checks are provided (Annex B, C).
• Reference timbers: Scots pine sapwood (Pinus sylvestris) and beech (Fagus sylvatica) are specified as reference species; wood must be free from prior treatments or defects.
• Specimen dimensions & conditioning: Test specimens are nominally 100 × 10 × 5 mm with target moisture content of 12 ± 2% before exposure. Conditioning and oven-drying regimes (e.g., 103 ± 2 °C for oven drying) and environmental conditions for conditioning and incubation are prescribed.
• Sample sizes: Minimum numbers are specified (e.g., at least 30 test specimens from a minimum of five logs/planks; 10 moisture-content specimens).
• Reporting and evaluation: Calculation of x-values, assessment guidance, diagnostic microscopy and example test reports are included in informative annexes (Annex D–F).

Applications and users

Who uses CEN/TS 15083-2:2005:

• Accredited testing laboratories performing wood durability testing and comparative species assessments
• Wood product manufacturers and timber suppliers validating natural durability of species or batches
• Research institutions studying soft rot mechanisms and soil–wood interactions
• Preservative developers and quality control teams assessing pre-treatment or ageing effects
• Specifiers, architects and regulators seeking laboratory durability data to inform product selection or standards compliance

Practical applications:

• Durability classification of timber samples against soft rot
• Comparative testing of species, provenance or processing effects
• Supporting performance claims and regulatory dossiers
• Integrating with accelerated ageing (EN 73 / EN 84) for lifecycle assessments

Related standards

• EN 84 (accelerated leaching prior to biological testing)
• EN ISO 3696 (laboratory water quality)
• CEN/TS 15083-1 (durability against basidiomycetes - Part 1)

Keywords: CEN/TS 15083-2:2005, natural durability, soft rotting micro-fungi, wood durability testing, timber durability, soft rot, reference timbers, Scots pine, beech.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2006
7UDMQRVWOHVDLQOHVQLKSURL]YRGRY8JRWDYOMDQMHQDUDYQHWUDMQRVWLPDVLYQHJDOHVD
]D]DãþLWRSURWLOHVQLPJREDPSUHVNXVQHPHWRGHGHO*OLYHUD]NURMHYDONHOHVD
Durability of wood and wood-based products - Determination of the natural durability of
solid wood against wood-destroying fungi, test methods - Part 2: Soft rotting micro-fungi
Dauerhaftigkeit von Holz und Holzprodukten - Bestimmung der natürlichen
Dauerhaftigkeit von Vollholz gegen holzzerstörende Pilze, Prüfverfahren - Teil 2:
Moderfäulepilze
Durabilité du bois et des matériaux dérivés - Détermination de la durabilité naturelle du
bois massif vis-a-vis des champignons lignivores, méthodes d'essai - Partie 2: Micro-
organismes de pourriture molle
Ta slovenski standard je istoveten z: CEN/TS 15083-2:2005
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 15083-2
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
July 2005
ICS 79.040
English Version
Durability of wood and wood-based products - Determination of
the natural durability of solid wood against wood-destroying
fungi, test methods - Part 2: Soft rotting micro-fungi
Durabilité du bois et des matériaux dérivés - Détermination Dauerhaftigkeit von Holz und Holzprodukten - Bestimmung
de la durabilité naturelle du bois massif vis-à-vis des der natürlichen Dauerhaftigkeit von Vollholz gegen
champignons lignivores, méthodes d'essai - Partie 2: holzzerstörende Pilze, Prüfverfahren - Teil 2:
Micro-organismes de pourriture molle Moderfäulepilze
This Technical Specification (CEN/TS) was approved by CEN on 1 March 2005 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15083-2:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Introduction.4
1 Scope .5
2 Normative references .5
3 Terms and definitions.5
4 Principle.5
5 Test materials and apparatus.5
6 Test specimens .7
7 Procedure .8
8 Calculation of x-value .11
9 Test report .12
Annex A (informative) Guidance on sampling.14
Annex B (informative) Determination of water holding capacity .15

Annex C (informative) Rapid soil virulence test.17
Annex D (informative) Diagnostic microscopy of exposed samples.18
Annex E (informative) Assessment of results.21
Annex F (informative) Example of a test report for a softwood timber .22
Bibliography.25

Foreword
This document (CEN/TS 15083-2:2005) 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 consists of two parts, Part 1 determines the natural durability of solid wood against wood
destroying basidiomycetes fungi and Part 2 against soft rotting micro-fungi.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and the United Kingdom.
Introduction
This CEN Technical Specification describes a laboratory method of test which gives a basis for the
assessment of the natural durability of a sample of timber against micro-fungi (ascomycetes and fungi
imperfecti) which cause soft rot of wood in service. The infection source is the natural micro-flora of the soil
substrate which can also contain other micro-organisms, such as bacteria, and other fungi such as moulds
and basidiomycetes. These other organisms can influence the development of soft rot attack in the test
specimens. The natural durability of a species of timber can vary depending on the conditions of growth such
as climate and soil type. For this reason, the durability established using the method described in this CEN
Technical Specification will relate only to the sample of timber tested. Guidance on sampling is given in Annex
A.
This laboratory method provides one criterion by which the durability of the timber can be assessed. It is
recommended that this information be supplemented by data from other relevant tests, for example CEN/TS
15083-1, and above all by practical experience.
The procedures described in this CEN Technical Specification are intended to be carried out by suitably
trained and/or supervised specialists.
1 Scope
This CEN Technical Specification specifies a method of test for determining the natural durability of a timber
against soft rotting micro-fungi. The method is applicable to all timber species.
NOTE This method may be used in conjunction with an ageing procedure, for example EN 73 or EN 84.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 84, Wood preservatives − Accelerated ageing tests of treated wood prior to biological testing − Leaching
procedure
EN ISO 3696, Water for analytical laboratory use − Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
supplier
sponsor of the test (person or company providing the sample of timber to be tested)
4 Principle
Test specimens prepared from the timber under test and reference timber test specimens are exposed to
attack by soft rotting micro-fungi. After a prescribed period of incubation under defined conditions, the
percentage loss in dry mass of the test specimens is used to estimate the resistance of hardwood test timbers
to attack by the test fungi and as the basis of a provisional durability rating. For softwood test timbers, the
percentage loss in dry mass is recorded but the provisional durability rating is based on the loss of modulus of
elasticity.
5 Test materials and apparatus
5.1 Biological material
5.1.1 Soil
1)
Natural top soil or a fertile loam-based horticultural soil of pH 6 to pH 8 and not containing added
agrochemical. It shall have a water holding capacity (WHC) of between 25 % and 60 %.
NOTE 1 A suitable method for determining WHC is described in Annex B.

1)
A horticultural soil of the John Innes No. 2 type and with the following composition has been found to be suitable;
seven parts by volume loam, three parts by volume sphagnum peat, two parts by volume sharp sand plus 0,6 g chalk and
6,0 g slow release fertilizer per litre of soil mixture. If the WHC is too high, it can be lowered by modifying the soil with the
addition of sand.
If a natural soil is used, it shall have the turf or top 50 mm removed and shall not be taken from a depth below
200 mm from the original surface. It shall be passed through a sieve of nominal aperture size 12,5 mm. If it is
necessary to store the soil prior to use, it shall be stored in closed moisture proof containers. Before use,
thoroughly mix the sample of soil.
NOTE 2 The soil should only be collected in a moist condition.
If a horticultural soil is used which is sterilised during its preparation, then 20 % of a natural soil, prepared as
above, shall be added and the soils thoroughly mixed prior to the start of the test.
The soil shall be used only once.
NOTE 3 If assurance of the virulence of the soil is required, the test procedure using cotton cloth described in Annex C,
or a similar standardised procedure, may be used.
5.1.2 Reference timbers
5.1.2.1 Species
The following species of wood shall be used for the tests:
 Scots pine sapwood (Pinus sylvestris Linnaeus) for tests with softwoods.
 beech (Fagus sylvatica Linnaeus) for tests with hardwoods and softwoods.
5.1.2.2 Wood quality
The wood shall be free from cracks, stain, decay, insect damage or other defects. The wood shall not have
been water-stored, floated, chemically treated or steamed.
NOTE Wood that has been kiln dried at temperatures below 60 °C may be used.
The Scots pine shall be exclusively sapwood containing little resin and having between 2,5 and 8 annual
growth rings per 10 mm. The proportion of latewood in the annual rings shall not exceed 30 % of the whole.
The beech shall be even-grained, free from tyloses and discoloration. It shall have between 2 and 6 annual
growth rings per 10 mm.
5.1.2.3 Provision of reference timber test specimens
Condition the wood to a mass fraction of (12 ± 2) % moisture content. Prepare planed strips having a cross-
section of (10 ± 0,1) mm × (5 ± 0,1) mm. The longitudinal faces shall be parallel to the direction of the grain.
The annual rings shall have a contact angle of (90 ± 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 reference timber test specimens
(100 ± 1) mm long.
The test specimens shall originate from a minimum of three trees or shall be taken from a stock originally of
more than 500 test specimens.
NOTE 1 A moisture meter of the two-pronged electrical conductivity type is suitable for assessing moisture content.
NOTE 2 A moisture content of mass fraction (12 ± 2) % can be achieved in the conditions provided by the conditioning
chamber (5.2.1).
5.1.2.4 Dimensions and density of reference timber test specimens
The dimensions of each reference timber test specimen at a mass fraction of (12 ± 2) % moisture content
shall be (100 ± 1) mm × (10 ± 0,1) mm × (5 ± 0,1) mm.
In a batch of test specimens, the density of an individual is permitted to differ from the mean value of the batch
by ± 10 %.
5.1.2.5 Number and distribution of reference timber test specimens
For softwoods use at least 30 reference timber test specimens but a minimum of three per test container.
NOTE Both Scots pine sapwood and beech reference timber test specimens should be used in tests with softwoods.
For hardwoods, the test specimens represent three sets of 10 replicates which can be assessed after different
exposure periods (see 7.5.1).
Mark each test specimen so that it can be identified throughout the test.
5.2 Material
Water, complying with grade 3 of EN ISO 3696.
5.3 Apparatus
5.3.1 Conditioning chamber, well ventilated and controlled at (20 ± 2) °C and (65 ± 5) % relative humidity.
5.3.2 Drying oven, capable of being controlled at (103 ± 2) °C.
5.3.3 Desiccators, with efficient desiccant (silica gel for example).
5.3.4 Test containers, made of material which does not have a toxic effect on the soil inhabiting micro-
organisms and provided with a ventilated lid. The depth shall be at least 150 mm, so as to provide at least
30 mm below the test specimens when inserted in the soil to a depth of 80 mm and adequate clearance above
the top of the protruding parts of the test specimens.
5.3.5 Culture chamber, (incubator or room) dark and controlled at (27 ± 2) °C and (70 ± 5) % relative
humidity.
5.3.6 Ordinary laboratory equipment, including a balance accurate to 0,001 g.
6 Test specimens
6.1 Species and source of wood
Ensure that the species of each plank or log to be tested has been identified correctly and record both the
botanical and the trade name. Obtain as much information as possible on the origin and history of the sample
(see Clause 9). The sample of timber shall be free from penetrating wood preservative treatments, for
example boron-based anti-stain products.
NOTE 1 Commercial samples of timber may contain more than one botanical species.
NOTE 2 Guidance on sampling is given in Annex A.
6.2 Wood quality
Record the physical characteristics of the timber sample, for example the sizes of logs/planks, the presence of
resin pockets, cross-grain, knots, sapwood and where possible record the widths of annual rings and the
proportion of latewood. For logs, record the position in the trunk if known.
6.3 Provision of the test specimens
Reject at least the outer 10 mm from lateral faces of planks and 50 mm from the end grain; reject at least
50 mm from the end grain of logs.
Condition the wood to a mass fraction of (12 ± 2) % moisture content. Prepare planed strips having a cross-
section of (10 ± 0,1) mm × (5 ± 0,1) mm which avoid all obvious defects and which are entirely heartwood or
entirely sapwood. The longitudinal faces shall be parallel to the direction of the grain. The annual rings shall
have a contact angle of (90 ± 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 timber test specimens (100 ± 1) mm long.
NOTE 1 A moisture meter of the two-pronged electrical conductivity type is suitable for assessing moisture content.
NOTE 2 A moisture content of a mass fraction of (12 ± 2) % can be achieved in the conditions provided by the
conditioning chamber (5.3.1).
6.4 Dimensions of test specimens
The dimensions of each test timber specimen at a mass fraction of (12 ± 2) % moisture content shall be
(100 ± 1) mm × (10 ± 0,1) mm × (5 ± 0,1) mm.
NOTE The nominal volume of each test specimen is 5,0 cm .
6.5 Number and distribution of test specimens
The timber test specimens are divided into:
e Test specimens:
these are the test specimens of the test timber subjected to attack by the soft rotting micro-fungi. Use at least
30 test specimens obtained from a minimum of five logs or planks (see Annex A).
e Moisture content test specimens:
these are test specimens of the test timber which are used to establish the moisture content of the timber
following conditioning to constant mass, to allow calculation of the initial dry mass of the test specimens. Use
at least 10 moisture content test specimens and a minimum of one from each log or plank.
Mark each test specimen so that it can be identified throughout the test.
7 Procedure
7.1 Preparation of the timber test specimens
7.1.1 Reference timber
Place the numbered reference timber test specimens in the oven (5.3.2) and leave them there for 18 h to 24 h.
Cool to room temperature in a desiccator (5.3.3) and weigh to the nearest 0,001 g to determine the initial dry
mass (m ).
7.1.2 Test timber
NOTE If the test specimens are to be subjected to an ageing procedure, the procedure should be carried out prior to
conditioning to constant mass to avoid the need to establish changes in mass due to the ageing procedure.
Place the numbered timber test specimens (e ) and the moisture content test specimens (e ) in the
1 2
conditioning chamber (5.3.1) until weighing of sample test specimens at 24 h intervals are within ± 0,005 g.
Weigh the timber test specimens and the moisture content test specimens and record the initial conditioned
mass (m ).
Calculate the mean density of the timber test specimens using the mean conditioned mass and the nominal
volume (see 6.4).
Place the moisture content test specimens in the oven (5.3.2) and leave them there for 18 h to 24 h. Cool to
room temperature in a desiccator (5.3.3) and weigh to the nearest 0,001 g to determine the oven dry mass
(m ). Calculate the moisture content of each moisture content test specimen by expressing the mass of water
(m − m ) as a percentage of the oven dry mass (m ). Calculate the mean moisture content (MC) of the
1 0 0
moisture content test specimens. Use the mean moisture content to calculate the initial dry mass (m ) of each
i
test timber specimen using the equation:
mi =m ×
100 +MC
(1)
where
m is the initial dry mass ,in grams, of the timber test specimen;
i
m is the initial conditioned mass, in grams, of the timber test specimen;
MC is the mean moisture content, in percentage, of the timber test specimen.
7.2 Establishment of initial modulus of elasticity (MOE) for soft woods
Impregnate the reference timber test specimens and the timber test specimens (e ) with water using the
method described in EN 84. Leave the test specimens in the vessels for 2 h.
Carry out a static bending test using either a central loading method or a four-point loading method using an
appropriate standard test. Calculate the MOE according to the standard test. The full title and reference to the
method shall be included in the test report.
After testing, condition the test specimens to constant mass in the conditioning chamber (5.3.1).
7.3 Exposure of the test specimens
7.3.1 Preparation of test containers
Determine the mass of soil required to provide at least 120 mm depth of soil in a selected test container
(5.3.4). Calculate the amount of water required the soil in the fully charged container to 95 % of its WHC.
NOTE A suitable procedure for determining WHC and the quantity of water required to wet up the soil is described in
Annex B.
Add the required volume of soil to each test container and add the calculated amount of water slowly whilst
mixing to ensure an even distribution of moisture.
7.3.2 Planting the test specimens
Plant the test specimens vertically with 20 mm of their length protruding above the surface of the soil and with
a minimum of 20 mm between adjacent test specimens and from the sides of the container. Assign the correct
number of reference timber test specimens (5.1.2.5) to each test container and distribute them at random
within each container. Assign the positions of the timber test specimens e at random among all the test
vessels being used. During planting and subsequent handling ensure that the exact location of each test
specimen is recorded to guard against loss of identity if the numbering is obscured. Apply a ventilated lid to
each charged container.
7.4 Culture conditions
Transfer the charged test containers to the culture chamber (5.3.5) and incubate.
7.5 Determining duration of test
7.5.1 Hardwoods
Remove one set of 10 reference timber test specimens after 16 weeks exposure. Cleanse the test specimens
of adhering soil particles. Make good any obscured numbering and weigh each test specimen to the nearest
0,001 g (m ). Transfer the test specimens to the drying oven (5.3.2). Dry the test specimens for 18 h to 24 h,
cool to room temperature in desiccators (5.3.3), weigh each test specimen to the nearest 0,001 g and record
the final dry mass (m ). Calculate the loss in mass of each test specimen by expressing the loss in mass
(m − m ) as a percentage of the initial dry mass (m ). Calculate the mean mass loss of the reference timber
0 3 0
test specimens. If this value exceeds 20 %, terminate the test. If this value is less than 20 %, continue
incubation for a period of 4 weeks and assess a further 10 reference timber samples. If the loss in mass
exceeds 20 %, terminate the test. Repeat this procedure if necessary.
The maximum permitted exposure period is 24 weeks. If 20 % loss in mass of the reference timber test
specimens has not been achieved after 24 weeks exposure, the test is not valid.
7.5.2 Softwoods
Remove all 30 reference timber test specimens after 32 weeks exposure. Cleanse the test specimens of
adhering soil particles and make good any obscured numbering.
Impregnate the test specimens with water and determine the MOE as described in 7.2. Calculate the loss in
MOE for each test specimen and the mean loss. If mean loss exceeds 40 %, terminate the test. If the mean
loss is less than 40 %, condition the test specimens to approximately a mass fraction of 50 % moisture
content, based on their initial dry mass, return to the test containers and continue incubation for a period of
8 weeks. Assess the loss of MOE of the reference timber test specimens again and terminate the test if the
loss in MOE exceeds 40 %. Repeat this procedure if necessary.
The maximum permitted exposure period is 48 weeks. If 40 % loss in MOE of the reference timber test
specimens has not been achieved after 48 weeks exposure, the test is not valid.
7.6 Assessment of test
7.6.1 Hardwoods
At the end of test, withdraw the test specimens from the test containers, including any remaining reference
timber test specimens, and cleanse them of any adhering soil particles. Make good any obscured numbering
and weigh each test specimen to the nearest 0,001 g at the end of the test (m ). Place the test specimens in
the oven (5.3.2) at (103 ± 2) °C until the test specimens have reached constant mass, that is when
consecutive weighings carried out at minimum intervals of 4 h are within ± 0,01 g. Cool the test specimens to
room temperature in desiccators (5.3.3) and weigh each test specimen to the nearest 0,001 g to determine the
final dry mass (m ).
Calculate the moisture content of each test specimen by expressing its water content (m − m ) as a
2 3
percentage of the final dry mass (m ); calculate the mean final moisture content of the timber test specimens.
Calculate the loss in mass of each test specimen by expressing the loss in mass (m − m ) as a percentage of
i 3
the initial dry mass (m ).
i
Calculate the mean loss in mass of all reference timber test specimens assessed after the same incubation
period as the timber test specimens and determine the median value.
Determine the median value for the losses in mass of the timber test specimens taken from each log or plank
sampled and the median value for all the test specimens.
7.6.2 Softwoods
At the end of test, withdraw the timber test specimens from the test containers and cleanse them of any
adhering soil particles. Make good any obscured numbering and weigh each test specimen to the nearest
0,001 g at the end of the test (m ).
Impregnate the test specimens with water and deter
...