ISO 18100:2017

Timber structures — Finger-jointed timber — Manufacturing and production requirements

ISO 18100:2017 specifies the product and performance requirements for finger-jointed structural timber made from sawn timber elements. ISO 18100:2017 does not cover products made using impressed (die-formed) joints or finger-jointed laminations for glued laminated timber, which is covered in ISO 12578.

Structures en bois — Bois assemblé par entures multiples — Exigences de fabrication et de production

General Information

• Status: Published
• Publication Date: 28-Mar-2017
• ICS: 91.080.20 - Timber structures
• Technical Committee: ISO/TC 165 - Timber structures
• Drafting Committee: ISO/TC 165 - Timber structures
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 11-Apr-2023

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18100
First edition
2017-03
Timber structures — Finger-jointed
timber — Manufacturing and
production requirements
Structures en bois — Bois assemblé par entures multiples —
Exigences de fabrication et de production
Reference number
ISO 18100:2017(E)
©
ISO 2017

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ISO 18100:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
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ISO 18100:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Conformance . 3
5.1 Quality systems requirements . 3
5.2 Manufacturing specifications . 3
6 Requirements . 3
6.1 Structural strength . 3
6.1.1 Timber components . 3
6.1.2 Grading methods. 3
6.1.3 Finger-jointed timber . 3
6.2 Adhesive . 4
6.3 Finger joint glue bond integrity . 4
6.4 Utility . 4
6.5 Product identification . 4
7 Verification . 4
7.1 Structural strength . 4
7.1.1 Qualification . 4
7.1.2 Compliance testing . 5
7.2 Adhesive . 5
7.3 Finger-joint glue bond integrity . 6
7.3.1 Verification at qualification . 6
7.3.2 Verification for compliance testing . 6
7.4 Utility requirements . 6
7.5 Product identification requirements . 6
Annex A (normative) Compliance (factory production control) testing — Strength
verification of finger-jointed timber. 7
Annex B (normative) Verification of the strength of finger-jointed timber by double-
bending proof loading . 9
Annex C (normative) Verification of the minimum strength of finger-jointed timber by
tension proof loading.14
Annex D (normative) Verification of finger joint bond quality by assessment of wood
fibre failure .16
Annex E (normative) Verification of finger joint bond quality by cyclic delamination .20
Annex F (normative) Verification of finger joint strength properties using the analytical method 22
Annex G (normative) Product identification .24
Annex H (informative) Basis of factor k .25
fj
Bibliography .26
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ISO 18100:2017(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by ISO/TC 165, Timber structures.
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ISO 18100:2017(E)

Introduction
Finger-jointed timber is viewed as an alternative and substitute for sawn timber. Finger-jointed timber
makes use of timber of various lengths and enables localized defects, particularly knots, to be docked
out of otherwise high-quality sawn timber.
Qualification (initial type testing) and compliance (factory production control) testing are specified
to assess if the components and manufacturing procedures used (finger joint profile, end pressure and
other production variables) are appropriate for the characteristic values being claimed. A representative
sample of the potential production is evaluated for tension and bending strength and finger joints are
assessed for bond quality using delamination or wood fibre failure tests.
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INTERNATIONAL STANDARD ISO 18100:2017(E)
Timber structures — Finger-jointed timber —
Manufacturing and production requirements
1 Scope
This document specifies the product and performance requirements for finger-jointed structural
timber made from sawn timber elements.
The document does not cover products made using impressed (die-formed) joints or finger-jointed
laminations for glued laminated timber, which is covered in ISO 12578.
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.
ISO 9709, Structural timber — Visual strength grading — Basic principles
ISO 10983, Timber — Finger joints — Minimum production requirements and testing methods
ISO 12122-2, Timber structures — Determination of characteristic values — Part 2: Sawn timber
ISO 13910, Timber structures — Strength graded timber — Test methods for structural properties
ISO 13912, Structural timber — Machine strength grading — Basic principles
ISO 20152-1, Timber structures — Bond performance of structural adhesives — Basic requirements
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 http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
finger joint
end joint formed by machining a number of similar, tapered, symmetrical fingers in the ends of timber
pieces that are then bonded together
3.2
finger-jointed timber
timber that contains two or more component pieces end-joined by finger joints (3.1)
Note 1 to entry: All pieces are of a single species or recognized species group, have the same nominal cross-
section and the finger joints are formed using a common adhesive and production method.
3.3
production batch
finger-jointed timber (3.2) made during a continuous run on one production line
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ISO 18100:2017(E)

3.4
strength grade
population of timber having a set of structural properties and utility requirements
Note 1 to entry: Strength grade is defined in accordance with principles detailed with ISO 9709 (visual grading)
or ISO 13912 (machine grading).
3.5
service class
service conditions to which finger-jointed timber (3.2) is subjected
Note 1 to entry: Service classes are defined in ISO 20152-1.
3.6
qualification
initial type testing
testing of finger joints (3.1) or finger-jointed timber (3.2) that is used to establish the statistical variables
that describe the finger joint strength applicable to strength grade (3.4) and the parameters appropriate
to the bond quality of the service class (3.5)
3.7
compliance
factory production control testing
process of demonstrating that finger-jointed timber (3.2) has strength values and bond quality of the
specified strength grade (3.4) and service class (3.5)
3.8
standard length
length used in testing to determine characteristic values
Note 1 to entry: Standard lengths are defined in ISO 13910.
Note 2 to entry: Characteristic values are defined in ISO 12122-2
Note 3 to entry: Finger-jointed timber can be used as a substitute for sawn timber and therefore has its properties
determined over the same test lengths.
4 Symbols
d depth of finger-jointed timber in millimetres
b width of finger-jointed timber in millimetres
f characteristic strength in bending of a strength grade in megapascals
k,m
f characteristic strength in tension of a strength grade in megapascals
k,t
f = k f characteristic finger joint strength in bending of a single finger joint required for
k,m,verif fj k,m
verification in megapascals
f = k f characteristic finger joint strength in tension of a single finger joint required for
k,t,verif fj k,t
verification in megapascals
k factor that allows for the effect of multiple finger joints in a standard length
fj
L standard test length for tension or bending as defined in ISO 13910 in millimetres
M number of finger joints that occur in a standard length
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ISO 18100:2017(E)

NOTE Factor k makes allowance for the negative impact of multiple finger joints on characteristic strengths
fj
and is used with the analytical method of assigning characteristic strengths. With the empirical method, the
allowance is unnecessary.
5 Conformance
5.1 Quality systems requirements
Products conforming to this document shall be manufactured to a formalized manufacturing
specification covering all relevant process variables under a quality system that includes
— in plant process control and internal auditing procedures, and
— auditing of plant process control and end-product quality.
5.2 Manufacturing specifications
The manufacturing specifications shall set the limits on all variables that affect or correlate with final
product quality properties, including
a) materials,
b) glue bond quality,
c) manufacturing process, and
d) secondary processes and treatment, when applicable.
NOTE The above list is not necessarily exhaustive.
6 Requirements
6.1 Structural strength
6.1.1 Timber components
All timber components between finger joints shall have strength and stiffness characteristics of a
declared strength grade. Where preservative or flame retardant treatment is used, the properties shall
be determined after completion of the treatment.
6.1.2 Grading methods
All timber grading methods shall comply with the requirements of either ISO 9709 in the case of visual
grading or ISO 13912 in the case of machine grading.
6.1.3 Finger-jointed timber
Bending and tension strengths are defined by reference to standard lengths defined in ISO 13910. Over
these test lengths, finger-jointed timber shall have characteristic structural strengths in both bending
and tension not less than the bending or tension strengths of the declared strength grade. The bending
and tension strengths of the finger-jointed timber shall be determined during qualification and verified
for each production batch except, if tension tests are omitted, then, in stress terms, the tension strength
shall be deemed equal to 0,55 times the declared bending strength ( f = 0,55 f ).
k,t k,m
NOTE 1 For verification of performance requirements in 6.1, refer to 7.1.
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ISO 18100:2017(E)

NOTE 2 Increasing the number of finger joints in these standard test lengths potentially lowers the overall
tension strength. This is most obvious in tension tests where there is an increased tendency to fail at the weakest
finger joint; see Annexes F and H for details.
6.2 Adhesive
The adhesive shall comply with the Service Class 2 or 3 requirements of ISO 20152-1. For product
intended for use under full weather exposure, the adhesive shall meet the requirements for Service
Class 3 conditions.
NOTE For verification of performance requirements in 6.2, refer to 7.2.
6.3 Finger joint glue bond integrity
When determined in accordance with either Annex D or Annex E, the glue bond quality shall exhibit
characteristics appropriate to the Service Class claimed by a manufacturer. Alternatively, a nationally
accepted test method may be used.
NOTE 1 For verification of performance requirements in 6.3, refer to 7.3.
NOTE 2 Annex D involves wood fibre failure assessment and Annex E involves cyclic delamination testing.
Cyclic delamination testing is unsuitable for testing of finger joint of length less than 12 mm.
6.4 Utility
Finger-jointed structural timber produced to a declared strength grade shall meet the utility
requirements that correspond to those listed for the relevant strength grade.
NOTE For verification of performance requirements in 6.4, refer to 7.4.
6.5 Product identification
Finger-jointed structural timber shall be identified with sufficient information to facilitate its correct
use and to allow for traceability from end user to manufacturer.
NOTE For verification of performance requirements in 6.5, refer to 7.5.
7 Verification
7.1 Structural strength
7.1.1 Qualification
Compliance with the declared strength grade shall be assessed by either analytical or empirical method.
7.1.1.1 Analytical method
Single joint specimens shall be sampled and tested in accordance with ISO 10983 in both bending
and tension (if necessary, see 6.1.3) and the test data evaluated in accordance with ISO 12122-2 to
determine the characteristic finger joint strengths. In addition, the finger joint strengths shall meet the
requirements of Annex F.
ISO 10983 requires at least 30 test specimens for both bending and tension (if necessary) strength tests.
Qualification is required to establish that all the requirements of this document have been met for each
strength grade that is to be produced by the manufacturer. Qualification target test loads are required
to take into account multiple joint effects; see Annex F for magnitude of the effects.
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ISO 18100:2017(E)

7.1.1.2 Empirical method
A representative sample shall be drawn from production, then tested and evaluated in accordance with
ISO 12122-2. The qualification specimens shall have a representative number of joints as anticipated
in typical length put on the market. The characteristic values for bending and tension strengths shall
equal or exceed the declared strength grade values.
If the number of joints between pieces and batches are likely to vary, it is recommended that the
qualification specimens contain the maximum number of joints that is expected to occur in typical
length put on the market. This provides assurance that the qualification testing adequately assesses
the representativeness of the components selected.
ISO 12122-2 requires testing in accordance with ISO 13910 which means that specimens are tested
at the same standardized lengths used to define the characteristic strengths of sawn timber. This
document specifies the requirements for finger-jointed timber that can be used in place of sawn timber
so that testing to the standardized lengths provides the characteristic tension and bending strengths
on the same basis. Other structural properties are ensured by grading the timber components to a
national grading standard.
7.1.2 Compliance testing
7.1.2.1 Analytical method
a) Finger joints shall be sampled in accordance with Annex A and tested in accordance with ISO 10983.
Finger-jointed timber components shall be graded as described in 6.1, sampled in accordance with
Annex A, tested in accordance with ISO 10983 in either bending or tension and shall comply with
the criteria of Annex A.
b) Where finger-jointed timber is proof loaded in reverse bending or in tension as defined in Annex B
or C at a level of 0,5 f or 0,5 f , respectively, or non-destructively assessed by other nationally
k,m k,t
accepted destructive methods of finger joint testing, reduced sampling rates shall apply as detailed
in Annex A.
7.1.2.2 Empirical method
Finger-jointed timber shall be verified by one of the following methods applicable to standard length
finger-jointed timber.
a) Finger-jointed timber shall be sampled in accordance with Annex A, tested in accordance with
ISO 13910 in either bending or tension and shall comply with the criteria of Annex A.
b) Where finger-jointed timber is proof loaded in reverse bending or in tension as defined in Annex B
or C at a level of 0,5 f or 0,5 f , respectively, or non-destructively assessed by other nationally
k,m k,t
accepted destructive methods of finger joint testing, reduced sampling rates shall apply as detailed
in Annex A.
Monitoring the average number of joints per piece may be used to assess if the sample tested at
qualification (i.e. number of joints) continues to be applicable. The information may also be used to initiate
qualification testing involving a greater number of joints per piece by reference to the analytical method.
7.2 Adhesive
Documentary evidence shall be available to verify compliance with the provisions of ISO 20152-1.
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ISO 18100:2017(E)

7.3 Finger-joint glue bond integrity
7.3.1 Verification at qualification
7.3.1.1 Sampling
Five specimens of the same type used for strength testing shall be taken.
7.3.1.2 Testing
Finger joints shall be tested in accordance with either Annex D for assessment of wood fibre failure or
Annex E for cyclic delamination.
7.3.1.3 Acceptance criteria
In the case of assessment of wood fibre failure, the levels given in Table D.1 may be used as a guideline;
otherwise it shall be necessary to establish wood failure levels appropriate for the wood species,
adhesive and Service Class conditions. In the case of cyclic delamination, the criteria given in Annex E
shall be met.
7.3.2 Verification for compliance testing
7.3.2.1 Sampling
The sample shall be
a) one specimen at the commencement of each adhesive batch, and
b) one specimen per machine per day (24 h period) with at least five specimens per week.
7.3.2.2 Testing
Finger joints shall be tested in accordance with either Annex D for assessment of wood fibre failure or
Annex E for cyclic delamination.
7.3.2.3 Acceptance criteria
The criteria specified in 7.3.1.3 shall apply.
7.4 Utility requirements
The utility requirements of this document including dimension, wane, machine skip and distortion shall
be deemed to comply with this document if they meet those of the declared strength grade.
7.5 Product identification requirements
The product shall be deemed to comply with this document if it is identified as described in Annex G.
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ISO 18100:2017(E)

Annex A
(normative)

Compliance (factory production control) testing — Strength
verification of finger-jointed timber
A.1 General
This annex sets out the procedures by which finger joint and finger-jointed timber strengths of a
production batch are verified. It applies to both analytical and empirical methods. With the analytical
method, the finger joint strengths determined at qualification and used as a basis for a strength grade
declaration are based on testing only a single finger joint within a standard test length. To allow for the
presence of multiple joints, an upwards adjustment is made to the target strengths for verification.
NOTE The factor k has the effect of increasing the target values to allow for more than one finger joint in a
fj
standard length.
A.2 Verification criteria
A.2.1 Sampling rate
The minimum sampling rate required depends on the minimum cross-sectional dimension, b.
A.2.1.1 Dimension b ≤50 mm
a) One specimen per hour during a shift (8 h) with no fewer than five specimens collected during any
production shift of less than 5 h.
b) When all finger-jointed timber production is subjected to a proof load of at least 0,5 times the
assigned characteristic strength (0,5 f or 0,5 f ) or non-destructively assessed by other
k,m k,t
nationally accepted methods, the frequency may be reduced to one specimen per 4 h during a shift
(8 h) with no fewer than two specimens collected during any production shift of less than 8 h.
A.2.1.2 Dimension b >50 mm
a) One specimen per 2 h during a shift (8 h) with no fewer than two specimens collected during any
production shift of less than 5 h.
b) When all structural glued timber production is subjected to a proof load of at least 0,5 times
the assigned characteristic strength (0,5 f or 0,5 f ) or non-destructively assessed by other
k,m k,t
nationally accepted methods, the frequency may be reduced to one specimen per 8 h shift with no
fewer than one specimen collected during any production shift of less than 8 h.
A.2.2 Verification criteria
All pieces tested shall equal or exceed the minimum joint strength for the property tested except for the
following.
a) When a batch test value falls below the fifth percentile value for the property tested, but not below
0,9 of the fifth percentile value, the test values of at least 27 of the next 28 pieces shall equal or
exceed the fifth percentile target value.
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ISO 18100:2017(E)

b) Other acceptance criteria shall be permitted, provided it can demonstrate that the procedures
provide an equivalent or better degree of control and ability to detect non-complying product.
c) Failure to meet the above criteria shall indicate an “out-of-control” condition, requiring corrective
action and requalification.
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ISO 18100:2017(E)

Annex B
(normative)

Verification of the strength of finger-jointed timber by double-
bending proof loading
B.1 General
This annex sets out a method based on subjecting both edges to tension stress using double-bending
proof testing for verification of the minimum strength of finger-jointed timber containing fully-cured
finger joints. Finger-jointed timber that survives the proof stress without failure, excessive deformation
or other signs of damage shall be deemed to satisfy the minimum finger-jointed timber strength
requirements of this document.
B.2 Specimens
Test specimens shall be representative of all finger-jointed timber for which verification status is sought.
B.3 Testing
B.3.1 General
The specimens shall be subjected to a double-bending proof test in a machine where the ability of the
specimen to survive without failure or other damage is determined.
B.3.2 Equipment
The proof loading machine shall be capable of maintaining an applied load with a tolerance of ±5 % of
any calibrat
...