MS 758 2001 GLULAM

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MALAYSIAN
STANDARD

MS 758 : 2001

GLUED LAMINATED TIMBER –
PERFORMANCE REQUIREMENTS AND
MINIMUM PRODUCTION REQUIREMENTS
(FIRST REVISION)

ICS : 79.020
Descriptors :

performance requirements, minimum production requirements, adhesive, moisture
content, finger joints, glued-laminated timber, service class, finishing grade,
delamination and block shear

© Copyright
DEPARTMENT OF STANDARDS MALAYSIA

DEVELOPMENT OF MALAYSIAN STANDARDS
The Department of Standards Malaysia (DSM) is the national standardisation and
accreditation body.

The main function of the Department is to foster and promote standards, standardisation and

accreditation as a means of advancing the national economy, promoting industrial efficiency
and development, benefiting the health and safety of the public, protecting the consumers,
facilitating domestic and international trade and furthering international cooperation in relation
to standards and standardisation.

Malaysian Standards are developed through consensus by committees which comprise of
balanced representation of producers, users, consumers and others with relevant interests,
as may be appropriate to the subject in hand.
adoption of international standards.

These standards where appropriate are

Approval of a standard as a Malaysian Standard is

governed by the Standards of Malaysia Act 1996 (Act 549).

Malaysian Standards are

reviewed periodically. The use of Malaysian Standards is voluntary except in so far as they
are made mandatory by regulatory authorities by means of regulations, local by-laws or any
other similar ways.

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Standards. The Department also appoints SIRIM Berhad as the agent for distribution and
sale of Malaysian Standards.

For further information on Malaysian Standards, please contact:

Department of Standards Malaysia
Tingkat 21, Wisma MPSA
Persiaran Perbandaran
40675 Shah Alam
Selangor D.E.

OR

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1, Persiaran Dato' Menteri
P.O. Box 7035, Section 2
40911 Shah Alam
Selangor D.E.

Tel: 60 3 5519 8033
Fax: 60 3 5519 2497

Tel: 60 3 5544 6000
Fax: 60 3 5510 8095

http://www.dsm.gov.my

http://www.sirim.my

Email:central@dsm.gov.my

MS 758 : 2001

CONTENTS


Page

Committee representation……………………………………………………………
Foreword………………………………………………………………………………
1
2
3
4
5
6
7
8

iii
v

Scope………………………………………………………………………………..…..
Referenced documents…………………………………………………………………
Definitions……………………………………………………………………………..…
Symbols……………………………………………………………………………….…
General requirements………………………………………………………………….
Manufacturing requirements……………………………………………………………
Quality control……………………………………………………………………..…….
Marking……………………………………………………………..………………..…..

1
1
1
3
5
9
14
18

Tables
1
2
3
4
5
6
B1
B2
C1

Type of adhesive for given service conditions…………………………………..….
Qualification and routine test procedures……………………………………….……
Maximum values for the total delamination percentages………………………..….
Minimum wood failure percentages, WFP, relating to the shear strength ƒv ……...
Tolerance and overlap limits for appearance grade C glulam…………………..…
Maximum finished thickness t and maximum cross-sectional area A of the
laminations to be used in structures in different service classes …………….……
Climate in the drying duct for the different methods…………………………………
Number of test cycles to be used in the different test methods………………..…..
Number of test bars……………………………………………………………….…….

5
7
7
8
9

Glue lines in cross sections showing the normal position of the glue lines……….
Overlap of laminations………………………………………………………………….
Test specimen cut from a glulam member…………………………………………...
Shearing tool with a test bar inserted…………………………………………….…..
The normal test specimen, a test bar, and the numbering of the individual
glue lines for a test bar cut at the bottom of the cross section…………………….
A drill core with machined parallel plane surfaces
………………………...
Test bars to be cut from a full cross-sectional specimen…………………………..
Suggested identification showing the location of the test bars in the cross
section in a member glued vertically….………………………………………………
Additional identification with numbers showing the location of the glulam
member during the cramping………………………………………………………….

4
9
22
26

11
21
22
29

Figures
1
2
B1
C1
C2
C3
C4
C5
C6

i

27
28
30
30
30

MS 758 : 2001

CONTENTS (continued)


Page
Appendices
A
B
C
D
E

List of some Malaysian timbers with gluing properties…………………………...
Delamination test of glue lines………………………………………………..……..
Shear test of glue lines……………………………………………………………....
Glued laminated timber………………..……………………………………..………
Bibliography..…………………………………………………………………………..

ii

19
21
26
33
36

MS 758 : 2001

Committee representation


The Building and Civil Engineering Industry Standards Committee (ISC D) under whose supervision this Malaysian
Standard was prepared, comprises representatives from the following organisations:
Association of Consulting Engineers Malaysia
Chartered Institute of Building Malaysia
Construction Industry Development Board Malaysia
Department of Standards Malaysia
Pertubuhan Akitek Malaysia
Jabatan Bekalan Elektrik dan Gas
Jabatan Bomba dan Penyelamat Malaysia
Masters Builders Association Malaysia
Ministry of Housing and Local Government (Housing Department)
Ministry of Works (Public Works Department)
The Institution of Engineers, Malaysia
Universiti Teknologi Malaysia
The development of this Malaysian Standard is under the supervision of the following representatives of the CIDB
Standards Committee:
Ir. Mohamed bin Mohd Nuruddin
Megat Kamil Azmi bin Megat Rus Kamarani
Puan Zainora bt. Zainal
Puan Hanishahani bt. Othman

General Manager, Technology Development Division.
Senior Manager, Standard and Quality Unit
Manager, Standard and Quality Unit
The Secretary of CIDB Standards Committee

The Technical Committee on Structural Use of Timber which developed this Malaysian Standard consists of
representatives from the following organisations:
Dr. Abdul Rashid bin Hj. Ab. Malik
(Chairman)

Forest Research Institute Malaysia

(Secretary)

Construction Industry Development Board Malaysia

Tuan Hj. Mohd Shukari bin Midon


Encik Zainudin bin Kader

Public Works Department

Puan Dang Anom bt. Md. Zin

Housing Department

Dr. Badorul Hisham bin Abu Bakar

Universiti Sains Malaysia

Prof. Dr. Zainai bin Mohamed /
Dr. Abd. Latif bin Saleh


Prof. Madya Ir. Dr. Mohd Zamin bin Jumaat

Universiti Malaya

Dr. Mohd Ariff bin Jamaludin

Universiti Putra Malaysia

Encik Nor Zamri bin Mat Amin

Malaysian Timber Industry Board Malaysia

Ir. Yap Chin Tian

Timber Trade Federation Malaysia

iii

MS 758 : 2001

Committee representation (Working Group)


This Malaysian Standard was prepared by the Working Group on Glued Laminated Timber – Performance
Requirements and Minimum Production Requirements consisting of the following representatives:
Prof. Madya Ir. Dr. Mohd Zamin bin Jumaat (Chairman)
Encik Chu Yue Pun (Secretary)

Universiti Malaya
Construction Industry Development Board
Malaysia
Universiti Putra Malaysia
Ministry of Housing and Local
Government(Housing Department)
Universiti Teknologi Mara

Dr. Tan Yu Eng
Encik Suhaimi bin Abu Bakar
Dr. Paridah bt. Md. Tahir
Encik Ahmad Fahmi bin Hj. Abdul Ghaffar
Encik Ahmad Ruslan bin Md. Ridzuan /
Puan Zakiah bt. Ahmad
Encik Haris bin Alpiah
Dr. Razali bin Abdul Kader

Casco Adhesive
Golden Hope Plantations

iv

MS 758 : 2001


FOREWORD

This Malaysian Standard was developed by the Working Group on Glued Laminated Timber –
Performance Requirements and Minimum Production Requirements, established at the
Construction Industry Development Board Malaysia (CIDB) under the authority of the Building
and Civil Engineering Industry Standards Committee.
CIDB is the Standards-Writing Organisation (SWO) appointed by SIRIM Berhad to develop
standards for the construction industry.
This standard is based on BS EN 386 : 1995, “Glued Laminated Timber – Performance
Requirements and Minimum Production Requirements”, and AZ/NZS 1328.1: 1998, “Glued
Laminated Structural Timber – Part 1: Performance Requirements and Minimum Production
Requirements”, as well as BS EN 391: 1995, “Glued Laminated Timber – Delamination Test
of Glue Lines”, and BS EN 392: 1995, “Glued Laminated Timber – Shear Test of Glue Lines”,
which had been amended where necessary to comply with the Malaysian requirements.
Glued laminated timber is obtained by bonding together a number of laminations having their
grain essentially parallel. In this way a member with a rectangular solid cross-section can be
produced.
The purpose of the requirements in this standard is to obtain reliable and durable bonding, so
that the bonds in the glued laminated timber will maintain their integrity throughout the
intended life of the structure. The requirements will need to be supplemented to take into
consideration special production conditions, materials or functional requirements. The
requirements apply to structural members of service classes 1 and 2. For timber structures of
service class 3, special precautions shall be taken, for example weather resistant adhesives
shall be used. The requirements for these are given in BS EN 301 : 1992, “Adhesives,
Phenolic and Aminoplastic, for Load-bearing Timber Structures: Classification and
Performance Requirements”.
This standard supersedes MS 758 : 1981, ‘Specification for glued laminated timber structural
members’.
Compliance with a Malaysian Standard does not of itself confer immunity from legal
obligations.

v

MS 758 : 2001


GLUED LAMINATED TIMBER – PERFORMANCE REQUIREMENTS AND
MINIMUM PRODUCTION REQUIREMENTS
(FIRST REVISION)
1.

Scope

This standard specifies requirements for the components of glued laminated timber members
and minimum requirements for the production of such members for structural use.
The standard is applicable to products with a maximum finished lamination thickness of not
more than 40 mm.

2.

Referenced documents

The following referenced documents contain provisions which, through reference in this text,
constitute provisions of this Malaysian Standard. For dated references, where there are
subsequent amendments to, or revisions of, any of these publications do not apply. However
parties to agreements based on this Malaysian Standard are encouraged to investigate the
possibility of applying the most recent editions of the referenced documents. For undated
references, the latest edition of the publication referred to applies.
BS 5756 : 1997

Specification for tropical hardwoods graded for structural use

BS EN 385 : 1995

Finger jointed structural timber – Performance requirements and
minimum production requirements

MS 544 : Part 1

Code of practice for structural use of timber : Part 1 : General

AS/NZ 4063 : 1992

Timber - Stress-graded - In-grade strength and stiffness evaluation

3.

Definitions

For the purpose of this standard, the following definitions apply :
3.1

Closed assembly

A collection of laminations spread with glue and assembled in a member prior to the
application of pressure.
3.2

Conditioning time

The minimum time which must elapse after the cramping time before heavy machining or
exposure to service conditions. During this time the glue line strength continues to increase.

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MS 758 : 2001

3.3

Cramping time


The time during which the adhesive is required to remain under the action of pressure. During
this time the adhesive reaches a high percentage of its ultimate strength.
3.4

Cramping pressure

The force applied to the contact faces of glued laminations divided by the area of the glued
2
surface over which the force is deemed to act (usually expressed in N/mm ).
3.5

Curing temperature

The temperature needed (at the centre of all the glue lines) to develop the required bond
strength.
3.6

Glue spread
2

The amount of adhesive used (usually measured in g/m ). In single spreading this amount is
applied to one surface; in double spreading it is divided between the two surfaces to be
joined.
3.7

Hardener

A part of some adhesives used to promote setting. It may be supplied in either liquid or
powder form, or may be incorporated in the adhesive by the manufacturer. It is an essential
part of the adhesive, the properties of which depend on using the components as directed.
3.8

Horizontal laminated beam

A beam having the laminations parallel to the neutral plane (see Figure 1a).
3.9

Jigs

Formers to which laminations are cramped at the time of manufacture to give the member its
finished shape.
3.10

Laminating

The process of bonding laminations with an adhesive to form a solid unit.
3.11

Lamination

A layer of wood in a laminated member. The lamination may be formed from several boards,
end or side jointed or both so as to extend to the full width and length of the member.
3.12

Pot life (working life)

The time between the mixing of the constituent parts of an adhesive and it reaching the stage
where it is no longer usable.

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MS 758 : 2001

3.13

Service class 1


Service class 1 is characterised by a condition whereby most timber will attain an average
moisture content of not exceeding 12 %. Typical example is an air-conditioned environment
o
with temperature of 24 C and a relative humidity of not more than 60 % most of the time.
3.14

Service class 2

moisture content higher than that of Service class 1, but not exceeding 20 %. This is
o
achieved in a sheltered environment with temperature of 30 C and a relative humidity of not
more than 90 % most of the time.
3.15

Service class 3

moisture content higher than that of Service class 2. Typical example is an external, fully
exposed condition including marine environment.
3.16

Shelf life (storage life)

The period over which the constituent parts of an adhesive remain usable. This would usually
be specified by the expiry date of adhesive.
3.17

Synthetic resin adhesive

An adhesive substantially composed of a synthetic resin or resins, e.g. phenolic or
aminoplastic resins, including any hardener or modifier which may have been added by the
manufacturer or which may be required to be added before use, according to the
manufacturer’s instructions.
3.18

Vertically laminated beam

A beam having laminations at right angles to the neutral plane (see Figure 1b).

4.

Symbols

A

area, in square millimetres;

a

width of machined flat face of drill core, in millimetres;

b

width of cross section, in millimetres;

d

diameter, in millimetres;

Fu

ultimate load, in newtons;

ƒm

bending strength of a single end joint, in newtons per square millimetre;

ƒm, k

characteristic bending strength of the end joints in the lamination, in newtons per
square millimetre;

3

MS 758 : 2001

required characteristic bending strength of the end joints, in newtons per square
millimetre;

ƒm,15,k

ƒm,r,k

characteristic bending strength of 15 tested end joints, in newtons per square
millimetre;

ƒv

shear strength, in newtons per square millimetre;

h

depth of cross section, in millimetres;

k

modification factor;

Figure 1 a) Horizontal glulam

Figure 1 b) Vertical glulam

Figure 1. Glue lines in cross sections showing the normal position of
the glue lines

l

length of test specimen, in millimetres;

l max, delam

maximum delamination length of one glue line in the test specimen, in
millimetres;

l glue line

length of one glue line, normally the width b shown in Figure B1;

l tot, delam

delamination length of all glue lines in the test specimen, in millimetres;

l tot, glue line

entire length of glue lines on the two end-grain surfaces of each test specimen, in
millimetres;

m

mean value ( the variable is given in parenthesis );

r

radius of curvature, in millimetres; and

t

lamination thickness, in millimetres.
4

MS 758 : 2001

5.

General requirements


The strength grading of the timber and the bonding operations shall result in reliable and
durable bonds.
These general requirements shall be considered satisfied if both the requirements in this
clause and the minimum production requirements in Clause 6 are fulfilled.
5.1

Timber

The timber shall be strength graded in conformity with BS 5756.
5.2

Adhesives

The adhesive shall be capable of producing strong and durable joints so that the integrity of
the bond is maintained throughout the intended lifetime of the structure.
Acceptable strength and durability can be achieved by the use of a polycondensation
adhesive of the phenolic or aminoplastic type as defined in EN 301. The adhesive shall meet
the requirements for adhesive Type I or II as in Table 1.
Table 1. Type of adhesive for given service conditions
Service
Class

Description

Timber e.m.c* Temperature

Adhesive
Type

°

Example

1

Interior

≤ 12 %

< 50 C

II

Melamine-urea
Resorcinol

2

Exterior but
protected

≤ 18 %
untreated
timber
≤ 20 % multisalts treated
timber

< 50 ° C

II

Phenol-resorcinol
Polyphenolic
(tannins)

Any

I

Any

Any

I

Resorcinol
Phenol-resorcinol
Polyphenolic
(tannins)

3

Exterior

*Equilibrium moisture content
NOTE. The adhesive should be chosen considering the climatic conditions in service, the timber species, the
preservative used (if any) and the production methods.

An assurance should be sought from the manufacturer that a particular formulation is suitable
for the service conditions and for the length of life envisaged for the structure.
5.3

Completed glulam

5.3.1

Verification of design properties

The manufacturer shall prove that the finished glulam has the required design properties.
Verification shall be provided through:
a)
b)

(initial) qualification tests; and
quality control tests.
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MS 758 : 2001

5.3.2

Design properties


Members shall have the design properties as claimed by the manufacturer, or as required by
the designer.
The design properties shall be the characteristic values for bending strength, modulus of
elasticity, compression strength, shear strength and tension strength.
5.3.3

(Initial) Qualification test

Qualification tests shall be undertaken whenever a new process or process change involving,
for example, a new adhesive/ species combination, finger joint profile, lamination thickness or
similar. Initial qualification tests shall be carried out by the following method:
Strength determination of completed glulam
The characteristic strength of a glulam member in bending, compression, tension and shear
and characteristic modulus of elasticity in bending, shall be determined by undertaking tests
on completed 300 mm deep glulam members in accordance with AS/NZS 4063 or equivalent.
5.4

End joints in laminations

The characteristic bending strength ƒm, k obtained from flatwise bending tests of the end joints
shall meet the following requirement:
ƒm,k ≥ ƒm,r,k
where,
ƒm,r,k

is the required characteristic bending strengt h.

The flatwise bending tests shall be performed in conformity with EN 385.
The characteristic bending strength shall be determined from the Log - Normal probability
distribution function.
5.5

Glue line integrity

5.5.1

General

The requirements for glue line integrity shall be based on testing of the glue line in a full
cross-sectional specimen, which shall be cut from the manufactured glulam member. The
specimens shall be representative of the production. The test requirements are summarised
in Table 2.

6

MS 758 : 2001
Table 2. Qualification and routine test procedures
Service

Class 1


Qualification Type I
1)
Test
adhesive

Class 2
Type II
adhesive

Type I
adhesive

Class 3
Type II
Adhesive

Type I
adhesive
only

Delamination Delamination Delamination Delamination Delamination
test method A, test method C, test method A, test method C, test method A,
Appendix B
Appendix B
Appendix B
Appendix B
Appendix B
Routine
2)
Test

Type I and Type II
Adhesives

Type I and Type II
adhesives

Type I
Adhesive
only

Delamination test method C,
Appendix B
or
Block shear test, Appendix C

Delamination test method C,
Appendix B
or
Block shear test, Appendix C

Delamination
test method A
or method B,
Appendix B

NOTES :
1.
2.

For each species, adhesive, treatment or process combination, a minimum of 5 full cross-sections shall be
tested and shall meet the requirements of 5.5.2 or 5.5.3.
For each shift in which gluing is carried out, one full cross-sectional specimen shall be tested for each press
load or every 10 m3 of production.

5.5.2

Acceptance criteria for delamination tests

Depending on the method and number of cycles the total delamination percentage of each
cross-sectional specimen shall be less than the values given in Table 3.
Table 3. Maximum values for the total delamination percentages

Method

Applicable to
adhesive type

Maximum total delamination percentage after cycle no. :
1

A

Type I

2

3

-

5

10

B

Type I

4

8

-

C

Type II

10

-

-

For all delamination methods the maximum delamination percentage (for a single glue line)
shall be less than or equal to 40 %.
5.5.3

Acceptance criteria for glue line shear test

Each test result from the block shear tests of each cross-sectional specimen shall comply with
the following requirements with regard to the shear strength and the wood failure percentage.
2

The shear strength of each glue line shall be at least 6.0 N/mm . For lighter density timbers,
2
a shear strength of 4.0 N/mm shall be regarded as acceptable if the wood failure percentage
is 100.
The average wood failure percentage over a cross-sectional specimen and any individual
value shall exceed the minimum wood failure percentages stated in Table 4.
7

MS 758 : 2001

Table 4. Minimum wood failure percentages, WFP, relating to the shear strength ƒ v
(For values in between, linear interpolation shall be used)


Average
Shear strength ƒv in N/mm

2

Minimum wood failure percentage,
%*

Individual values

6

8

≥11

from 4
to < 6

6

≥10

90

72

45

100

74

20

* For average values the minimum wood failure percentage is: 144 - (9ƒ v). For the individual values the minimum
wood failure percentage for the shear strength ƒ v ≥ 6.0N/mm2 is: 153.3 - (13.3ƒ v).

5.6

Finishing

5.6.1

Appearance grades

The appearance grades relate to the aesthetic appearance of the visible surfaces of the glued
laminated members. This classification bears no relationship to structural performance of the
member.
5.6.2

Appearance grade A

This grade is intended for use in applications where appearance of the member is important
and clear or painted finishes are used. All surface voids are filled or repaired. Unless it is
specified otherwise, the surfaces shall be sanded to a minimum of 60 grit finish.
The following voids shall be repaired with inserts and not filled:
a)
b)
c)

holes (circular in general appearance) with a diameter in excess of 30 mm.;
holes (elongated in general appearance) with dimensions exceeding 40 mm x 20 mm;
and
edge checks (elongated) from 40 mm to 100 mm, exceeding 3 mm wide.

NOTE.

Fillers used should be non-shrinking and capable of accepting the finish specified for the members.

5.6.3

Appearance grade B

This grade is intended for use in painted applications where surface appearance is important
but a machine planed finish is acceptable. Each member shall present a machined face on
four sides: there shall be not less than one cutter mark to 5 mm. Occasional skips in the
surface are permissible and minor blemishes, voids and manufacturing want shall be
acceptable. The outer-most laminations shall be free of loose knots and voids.
5.6.4

Appearance grade C

This grade is intended for use in applications where appearance is not important. All
blemishes and voids are acceptable. Where the member is not machined after lay-up, the
allowable tolerances for overlap of laminations shall be as detailed in Figure 2 and Table 5.

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MS 758 : 2001

Figure 2. Overlap of laminations

Table 5. Tolerance and overlap limits for appearance grade C glulam
Dimensions in millimetres

Height or width

Tolerance for
height or width

Maximum overlap for
appearance Grade C
members

(h or b) < 100

±2

4

100 ≤ (h or b) < 300

±3

5

300 ≤ (h or b)

±6

6

6.

Manufacturing requirements

6.1

Production conditions

6.1.1

General

The staff shall have the necessary skill for the production of glulam and the grading of the
timber.
6.1.2

Premises

6.1.2.1 The premises shall be suitable for all phases of the production, taking into
consideration the requirements given in this standard.
Special consideration shall be given to:
a)
b)
c)

size of the members to be produced;
air temperature; and
relative humidity of the air.

9

MS 758 : 2001


6.1.2.2 At the time of assembly and during the cure of the adhesive, the timber shall be at a
temperature not less than that specified by the adhesive manufacturer.
6.1.2.3 Drying and storage facilities of sufficient capacity shall be available to enable the
required moisture content and temperature of the timber to be achieved.
6.1.2.4 Where pre-dried timber is used, storage facilities shall be available to maintain the
required moisture content of the timber.
6.1.2.5 Unless resin and hardener are pumped directly from storage tanks and mixed
automatically during application, there shall be a separate room for the preparation of the
adhesive (mixing of resin and hardener). There shall also be a suitable resin and hardener
storage facilities and an area with access to adhesive cleaning equipment.
The resin and hardener storage shall be arranged so that the “first in first out” principle is
maintained.
6.1.3

Equipment

Equipment shall be available:
a)

j)
k)

to monitor continuously the temperature and relative humidity of the air
(thermohygrograph) in storage, production and curing areas;
to measure the moisture content of the timber and for checking (calibrating) moisture
meters;
for machine and/or visual grading when these operations are carried out by the
producer;
to make end joints in the laminations with sufficient and reliable strength;
to measure lamination thickness;
to provide surfaces fulfilling the requirements of the thickness tolerances and surface
quality (usually a lamination planer; see 6.4.1.5 and 6.4.1.6);
for weighing and mixing resin and hardener in the required proportions;
for the uniform application of the required quantity of adhesive;
to obtain the required glue line pressure, temperature and relative humidity of the air
during curing of the adhesive;
to test the strength of end joints in the laminations; and
to test the integrity of the glue lines.

6.2

Timber

6.2.1

Species

b)
c)
d)
e)
f)
g)
h)
i)

Only species or a mixture of species proven to be suitable by the qualification tests given in
5.3.3 shall be used. Appendix A lists the timbers that have been tested and found to possess
satisfactory gluing properties.
6.2.2

Moisture content

It is preferable that the moisture content of the laminations at the time of gluing for nonpreservative treated timber or preservative treated timber shall be as stated below, unless
experimentation has established adequate bond qualities with moisture contents outside
these limits.
10

MS 758 : 2001


Non treated timber. At assembly, the moisture content in every lamination shall be in the
range of 8 % to 15 %. The range of moisture content of the laminations in a glulam member
shall be not greater than 4 %.
Treated timber. At assembly the moisture content in every lamination shall be in the range of
11 % to 18 %. The range of moisture content of the laminations in a glulam member shall be
not greater than 4 %.
6.2.3

Thickness and cross-sectional area

The finished thickness and cross-sectional area of any lamination shall not exceed the values
given in Table 6.
Table 6.

Maximum finished thickness t and maximum cross-sectional area A of the
laminations to be used in structures in different service classes

Service class 1

Service class 2

Service class 3

t
mm

A
mm2

t
mm

A
mm2

t
mm

A
mm2

40

7 500

40

7 500

35

6000

NOTE.

It is recommended that grooves are cut into the laminations as described in 6.4.1.2 when the crosssectional area exceeds 7500 mm2.

For curved members the maximum thickness is also governed by the radius of curvature r
and the characteristic bending strength of the end joints. The finished thickness t shall
comply with :
t ≤

r
250

(1+

fm,k

)

80

where,
fm,k is expressed in newtons per square millimetre.
6.3

Adhesive

The adhesive shall comply with 5.2.
6.4

Manufacture

6.4.1

Laminations

6.4.1.1 The individual laminations shall be end jointed to the final length before planing.
6.4.1.2 Grooving of laminations to reduce the effect of cupping is permitted. In each
lamination one groove is permitted in the middle part of the cross section, with a maximum
width of 4 mm and a maximum depth of one third of the lamination thickness. Grooves in
adjacent laminations shall be staggered by at least the thickness of the laminations.

11

MS 758 : 2001

6.4.1.3 When laminations are jointed by finger joints these shall be produced in conformity
with BS EN 385 or equivalent Malaysian standard.


The moisture content of the individual boards used in glued laminated timber members shall
comply with 6.2.2 of this standard.
NOTE. The more relaxed requirements in 6.2 in BS EN 385 are valid for finger joints in single laminations.

6.4.1.4 Where a lamination for horizontal glulam consists of two boards side by side and the
edges are not bonded, the edge-joints in adjacent laminations shall be staggered laterally by
at least the lamination thickness. For members used in Service class 1 or 2 the outer
lamination on each face shall be edge-bonded. For members to be used in service class 3
the outer four laminations on each face shall be edge-bonded.
Laminations in vertical glulam to be used in Service classes 1 and 2 are not required to be
edge-bonded, but the edge-joints in adjacent laminations shall be staggered by at least one
third of the board width. In members to be used in Service class 3 the outer laminations shall
be edge-bonded.
6.4.1.5 The laminations shall be planed or similarly finished before bonding. The planing shall
be carried out not more than 24 h before bonding, unless the species and the storage
environment are such that unacceptable surface changes will not take place. With species
that are difficult to bond, e.g. have a high resin content or where the laminations have been
treated with preservative, planing shall be carried out within 6 h of bonding. It is the
responsibility of the glued laminated timber producer to qualify any procedures used and to
determine the permissible delay between machining and gluing.
6.4.1.6 The maximum permitted deviation from the average thickness within a lamination
length of 1 m is 0.2 mm. Where non-gap-filling adhesives are used the limit deviation shall
not exceed 0.1 mm.
The difference in thickness over the cross-sectional width of the lamination shall be less than
0.15 % of the width and in no case exceed 0.3 mm.
6.4.2

Bonding

At the time of bonding the surfaces of laminations shall be clean.
The adhesive spread shall be uniform and in sufficient quantity in accordance with the
recommendations of the adhesive manufacturer.
NOTE. Usually a minimum spread of 350 g/m2 is required, except for high frequency curing, where the minimum is
200 g/m2.

6.4.3

Cramping

The cramping arrangement shall ensure a uniform pressure over the glue line.
The pressure shall be that specified in the adhesive manufacturer’s instructions for the
2
adhesive used but in no case shall it be less than 0.7 N/mm . The application of pressure at
a suitable temperature shall be completed within the closed assembly time, when a
continuous “squeeze out” or “bead” along the edge of each glue line shall be produced. For
curved members higher cramping pressures shall be applied and in such a way that the
laminations can slide over each other in the lengthwise direction to avoid open glue lines.
12

MS 758 : 2001

Sufficient pressure shall be maintained during cramping. Tightening-up shall be carried out as
necessary, and in all cases immediately after initial cramping.


6.4.4

Curing and conditioning

The adhesive manufacturer’s instructions shall be followed.
The temperature during curing shall be less than the maximum temperature prescribed by the
adhesive manufacturer.
Glulam members shall not be loaded until the adhesive has cured completely.
NOTE. It is recommended that this requirement is kept for at least 72 h after the end of cramping for phenolic based
adhesives and 24 h for aminoplastic based adhesives .

13

MS 758 : 2001
Quality Control

7.1

Factory production control (internal control)

7.1.1


7.

General

To ensure that the produced glulam members conform with this standard, the manufacturer
shall establish and maintain documented internal factory production control.
The documented factory production control shall be efficiently implemented in accordance
with procedures and instructions documented in a work’s quality manual.
The adhesive shall be chosen by the manufacturer in consultation with the adhesive supplier
considering the climatic conditions in service, any preservative or fire retardant treatment and
the particular production methods. All conditions which affect the performance of the adhesive
shall be documented in the quality manual.
NOTE. It is recommended that the production control system is audited by a third party. Further information is given
in 7.5.

7.1.2

End joints

From each work shift and each production line a representative sample of end joints shall be
drawn and tested in flatwise bending as described in BS EN 385. Only full size end joints
shall be tested.
For each production line and shift the bending strength is acceptable if one of the following
conditions is met:
The bending strength ƒm of each single end joint tested, is larger than or equal to the required
characteristic bending strength of the end joint ƒm,r,k
ƒm ≥ ƒm,r,k
The characteristic bending strength ƒm,15,k of the last 15 end joints tested from the production
line, is larger than or equal to the required characteristic bending strength of the end joints
ƒm,r,k
ƒm,15,k ≥ ƒm,r,k
The required characteristic bending strength of the end joints is defined in 5.4.
The characteristic bending strength ƒm,15,k shall be determined as described in 7.1.4 of BS EN
385 or equivalent.
7.1.3

Gluing record

7.1.3.1 A gluing record shall be kept containing:
a)
b)
c)
d)
e)

date and number of production;
species;
timber quality;
dimensions of the structure;
moisture content of the timber;

14

MS 758 : 2001


f)
g)
h)
i)
j)
k)

time for start of adhesive application;
time for start and end of the cramping process;
cramping pressure;
resin and hardener;
2
adhesive spread (g/m ); and
calibration of moisture meter.

The gluing record shall be signed by the nominated responsible member of staff.
7.1.3.2 The details of temperature and relative humidity of the air in timber storage, end
jointing room, gluing and cramping area shall be recorded.
7.1.4

Glue line integrity

7.1.4.1 The glue lines shall be tested in a full cross-sectional specimen, which is to be cut
from a cured glulam member produced during each working shift. For each shift in which
gluing is carried out one full cross-sectional specimen shall be taken for every press load or
3
every 10 m of production.
If all tests for a three-month period satisfy the requirements the number of samples may be
reduced to not less than half the number prescribed above.
7.1.4.2 The results of the testing for glue line integrity shall be documented as described in
Appendix B and Appendix C for delamination and block shear respectively.
7.2

Organisation of factory production control

7.2.1

Responsibility and authority

The responsibility, authority and the interrelation of all personnel who manage, perform and
verify work-affecting quality shall be defined, particularly for personnel who need the
organisational freedom and authority to:
a)
b)

initiate action to prevent the occurrence of non-conformity of glulam members; and
identify and record any quality problems with glulam members.

7.2.2

Management representative for factory production control

At every factory unit the manufacturer shall appoint a person who shall have appropriate
authority, knowledge and experience of the production of glulam to be responsible for
conducting and supervising factory production control procedures and ensuring that the
requirements given in this standard are implemented and maintained.
7.2.3

Management review

The production control system adopted to satisfy the requirements of this standard shall be
reviewed at appropriate intervals by the manufacturer’s management to ensure its continuing
suitability and effectiveness. Records of such reviews shall be maintained.

15

MS 758 : 2001

7.3

Documentation of the quality control system


7.3.1 The manufacturer’s documentation, procedures and instructions shall be relevant to
the production and process control of the glulam, and shall be adequately described in a
work’s quality manual, covering:
a)
b)
c)
d)

quality aims and organisational structure, responsibilities and powers of
management with regard to conformity of the glulam;
procedures for specifying and verifying the quality of the timber and the adhesive;
manufacturing, production control and other techniques, processes and systematic
actions to be used; and
inspections and tests that will be carried out before, during and after manufacture,
and the frequency with which they are to be carried out.

NOTE. The documentation of the end joint tests, the gluing record and the glue line tests may be recorded and kept
separately.

7.3.2

Responsibility

The manufacturer shall produce structural timber members in such a way that they are strong,
durable and suitable for use in one of the Service classes 1, 2 or 3 defined in 3.13, 3.14 and
3.15 respectively.
The manufacturer shall identify the Service class that the manufacturer has selected for each
structural member.
Each and every species-adhesive combination and manufacturing process used for each
structural member shall be identified in the work’s quality manual. Each and every adhesive
shall be used in accordance with the supplier’s instructions.
The work’s quality manual shall detail the production controls necessary to ensure that the
required strength and durability characteristics are present in the finished product.
The manufacturer shall maintain records of all relevant production controls which shall be
kept for at least 10 years. All documentation shall be sufficiently detailed that the raw
materials and processing are traceable to the production week and year.
7.3.3

Documentation

The documentation of the end joint tests, the gluing record and the glue line tests may be
recorded and kept separately.
All documentation shall be kept for at least ten years.
All documentation shall be retained so that the raw materials and production conditions for
each glulam member are traceable, at least to the production week and year.
7.4

Inspection and testing

7.4.1

General

All necessary facilities, equipment and personnel shall be available to carry out the necessary
inspections and tests. This requirement may also be fulfilled, if by means of a contract the
manufacturer or his agent involves a subcontractor having the necessary facilities, equipment
16

MS 758 : 2001


and personnel. The manufacturer shall control, calibrate and maintain inspection, measuring
and test equipment, whether owned by the manufacturer, or on hire, to demonstrate the
conformity of the glulam members to the specified requirements of this standard. Equipment
shall be used in a manner which ensures that measurement tolerances are known and are
consistent with the required measurement capability.
7.4.2

Action in case of non-conformity

If there is reason to doubt the quality of any production operation or of the raw materials used,
the internal quality control shall be increased and intensified.
If serious defects are discovered, the inspection body shall be informed immediately.
7.4.3

Control of non-conforming glulam

If the result of the test or inspection of a glulam member is unsatisfactory, the manufacturer
shall at once take the necessary steps to rectify the shortcoming. Glulam members which do
not comply with the requirements shall be set aside and marked accordingly. When the
shortcoming has been rectified, the test or inspection in question shall be repeated without
delay, provided that this is technically possible and is necessary as evidence that the defects
have been overcome.
If glulam members have been dispatched before the test results are available, notification
shall be made to customers, if necessary, for the purpose of avoiding any consequential
damage.
7.5

The inspection body (external control)

NOTE. The purpose of the external control is to supervise the internal control, to check by sampling the quality of the
end joints and the glue lines and to get an insight in the production of glulam so that a certificate can be issued or
maintained.

7.5.1 A minimum of two inspections per year shall be carried out. These shall be
unannounced unless special conditions necessitate an announcement.
7.5.2 The inspection body shall have access to all storage and production rooms, and the
manufacturer shall answer any technical questions. The inspection body shall regard all
technical information as confidential.
NOTE. The manufacturer may be required to forward, at certain intervals some production information and test
results to the inspection body.

7.5.3

During the inspections the following shall be inspected or checked:

a)
b)
c)
d)

raw materials;
production in accordance with the stated requirements of this standard;
components of glulam members (end joints, laminations); and
finished glulam members.

7.5.4 Selection of samples for external testing (end joints and full cross-sectional
specimens for glue line integrity test) shall normally be done by the inspection body.

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MS 758 : 2001

The number of specimens shall be at least 15 for end joints in the laminations and at least six
full cross-sectional specimens for glue line integrity tests. Such samples shall be taken at
each inspection. If superior test values can be documented both from the previous external
test taken at the last inspection and from the internal production control then the sampling can
be omitted.
End joints shall be deemed to have superior strength if the characteristic bending strength is
essentially larger than the required characteristic bending strength. For finger joints see also
7.5.4 of EN 385.
For glue lines a superior block shear test result is equivalent to a shear strength of at least 8.0
2
N/mm .
For glue lines a superior delamination test result is equivalent to a total delamination
percentage less than two thirds of the maximum value given in Table 3.
7.5.5

The inspection body shall prepare a report of each inspection.

8.

Marking

Glulam shall be marked. The durable mark shall contain:
a)
b)
c)
d)
e)
f)

name or identity of the producer;
strength class or other strength identification;
adhesive type;
production week and year;
certificate number; and
standard number.

18

MS 758 : 2001


Appendix A
(informative)
List of some Malaysian timbers with gluing properties
No.

Timbers

Gluing characteristic

1

Bintangor

Satisfactory

2

Damar minyak

Good

3

Durian

Satisfactory

4

Gerutu

Good

5

Jelawai

Satisfactory

6

Jelutong

Satisfactory

7

Kapur

Satisfactory

8

Kedondong

Good

9

Keledang

Satisfactory

10

Kembang semangkok

Satisfactory

11

Kempas

Satisfactory

12

Keranji

Satisfactory

13

Keruing

Satisfactory

14

Machang

Satisfactory

15

Mempisang

Satisfactory

16

Mata-ulat

Good

17

Mengkulang

Good

18

Meranti bakau

Good

19

Meranti (Dark red)

Good

20

Meranti (Light red)

Good

21

Meranti (White)

Good

22

Meranti (Yellow)

Good

19

MS 758 : 2001

Merbau

Satisfactory

24

Merpauh

Good

25

23

Mersawa

Good

26

Minyak berok

Satisfactory

27

Penarahan

Good

28

Ramin

Good

29

Sepetir

Good

30

Sesendok

Good

31

Simpoh

Good

32

Terap

Good

33

Terentang

Good

20

MS 758 : 2001

Appendix B
(normative)


Delamination test of glue lines

B1.

Scope

This Appendix specifies three delamination test methods for continuous quality control of the
glue line integrity of glued laminated timber.

B2.

Principle

A gradient is introduced in the moisture content of the wood to build up internal stresses. This
will result in tensile stresses perpendicular to the glue lines so that inadequate bonding quality
will result in delamination of the glue lines.

B3.

Apparatus

B3.1

Pressure vessel

A pressure vessel designed to withstand safely a pressure of at least 600 kPa (700 kPa
absolute pressure) and a vacuum of at least 85 kPa (15 kPa absolute pressure), and
equipped with pumps or similar device capable of giving a pressure of at least 600 kPa (700
kPa absolute pressure) and of drawing a vacuum of at least 85 kPa (15 kPa absolute
pressure).
B3.2

Drying duct

A drying duct where air is circulating at a velocity of 2 m/s to 3 m/s, and at a temperature and
a relative air humidity as given in Table B1.
Table B1. Climate in the drying duct for the different methods
Method

Relative humidity %

A

60 to 70

< 15

B

65 to 75

8 to 10

C

B3.3

0
Temperature 0 C

25 to 30

25 to 35

Balance

A balance capable of determining mass to an accuracy of 5 g.

21

MS 758 : 2001

B4.

Preparation of test specimens


The test specimens shall be prepared or selected in such a manner that they are
representative of the production run.
Each test specimen shall be taken from a full cross section of the laminated member to be
tested, prepared by cutting perpendicular to the grain of the wood. It shall be (75± 5) mm in
length (along the grain). The end-grain surfaces of the test specimen shall be cut with a
sharp saw or tool that produces a smooth surface.
If the width b of the cross section is greater than 300 mm the test specimen may be split into
two or more test specimens each at least 130 mm wide. If the depth h is greater than 600
mm the test specimen(s) may be cut into two or more pieces each with a depth of at least 300
mm, see Figure B1.

Figure B1. Test specimen cut from a glulam member

B5.

Procedure

B5.1

General

Measure the total length in millimetres of glue lines on the end-grain surfaces of the test
specimens.
Subject the test specimens to the appropriate test cycle described in B5.2, B5.3 or B5.4. The
number of cycles shall be as given in Table B2.
Table B2. Number of test cycles to be used in the different test methods
Method

Number of initial cycles

Number of extra cycles

A

2

1

B

1

1

C

1

0

22

MS 758 : 2001


An extra test cycle needs only be carried out if the total delamination percentage according to
B6.2 is larger than a prescribed maximum value.
At the end of the drying period, measure, in millimetres, the length of open glue lines on endgrain surfaces of the test specimens. Open glue lines at knots shall be ignored and failure in
the wood due to checking or other causes shall not be included as delamination. Isolated
delamination less than 3 mm long and more than 5 mm away from the nearest delamination
shall also be ignored.
NOTES:
1.

2.

When the separation is in the wood, even though very close to the glue line, it is termed wood failure or
checking. Magnification is often necessary to determine whether the failure is in the adhesive or in the wood. A
feeler gauge of 0.08 mm to 0.10 mm in thickness is convenient for probing into the joint to determine if
separation actually exists.
Since glue lines at knots and knotty areas in general are not durable under severe exposure, development of
delamination at knots should be disregarded and not included in the measurements or calculations.

B5.2

Test cycle for method A

Place the test specimens in the pressure vessel and weigh them down. Admit water at a
temperature of 10 ° C to 20 ° C in sufficient quantity so that the pieces are completely
submerged. Separate the test specimens by stickers, wire screens, or other means in such a
manner that all end-grain surfaces are freely exposed to the water. Draw a vacuum of 70 kPa
to 85 kPa (i.e. an absolute pressure of 15 kPa to 30 kPa at sea level) and hold it for 5 min.
Then release the vacuum and apply a pressure of 500 kPa to 600 kPa (600 kPa to 700 kPa
absolute pressure) for 1 h. Whilst the test specimens are still completely immersed, repeat
this vacuum pressure cycle making a two-cycle impregnating period requiring a total of 130
min.
Dry the test specimens for a period of between 21 h and 22 h in air at 60 ° C to 70 ° C and a
relative humidity not greater than 15 %, and circulating at a velocity of 2 m/s to 3 m/s. During
drying, the test specimens shall be placed at least 50 mm apart with the end-grain surfaces
parallel to the stream of air.
B5.3

Test cycle for method B

Weigh and record to the nearest 5 g the weight of each test specimen. Place the test
specimens in the pressure vessel and weigh them down. Admit water, at a temperature of
10 ° C to 20 ° C in such quantity that the specimens are completely submerged. Separate the
test specimens by stickers, wire screens, or other means in such a manner that all end-grain
surfaces are freely exposed to the water. Draw a vacuum of 70 kPa to 85 kPa (i.e. an
absolute pressure of 15 kPa to 30 kPa at sea level) and hold it for 30 min. Release the
vacuum and apply a pressure of 500 kPa to 600 kPa (600 kPa to 700 kPa absolute pressure)
for 2 h.
Dry the test specimens for a period of approximately 10 h to 15 h in air at 65 ° C to 75 ° C and a
relative humidity of 8 % to 10 % and circulating at a velocity of 2 m/s to 3 m/s. During drying,
the test specimens shall be placed at least 50 mm apart with the end-grain surfaces parallel
to the stream of air.

23

MS 758 : 2001

The actual time in the drying duct shall be controlled by the mass of the test specimens.
Delamination shall be observed and recorded when the mass of the test specimens has
returned to within 15 % of the original mass.


B5.4

Test cycle for method C

Place the test specimens in the pressure vessel and weigh them down. Admit water at a
temperature of 10 ° C to 20 ° C in sufficient quantity so that the pieces are completely
submerged. Separate the test specimens by stickers, wire screens, or other means in such a
manner that all end-grain surfaces are freely exposed to the water. Draw a vacuum of 70 kPa
to 85 kPa (i.e. an absolute pressure of 15 kPa to 30 kPa at sea level) and hold it for 30 min.
Then release the vacuum and apply a pressure of 500 kPa to 600 kPa (600 kPa to 700 kPa
absolute pressure) for 2 h. Whilst the test specimens are still completely immersed, repeat
this vacuum pressure cycle giving a two-cycle impregnating period requiring a total of 5 h.
Dry the test specimens for a period of 90 h in air at 25 ° C to 30 ° C and a relative humidity in
the range of 25 % to 35 %, and circulating at a velocity of 2 m/s to 3 m/s. During drying, the
test specimens shall be placed at least 50 mm apart with the end-grain surfaces parallel to
the stream of air.

B6.

Results

B6.1

General

For each test specimen the delamination percentages shall be calculated. If an extra cycle is
performed calculate the results before and after the extra cycle.
B6.2

Total delamination

The total delamination percentage of a test specimen is calculated from the following formula:
100 x

l

tot, glue line

l tot, delam
B6.3

Maximum delamination

The maximum delamination percentage for a single glue line in a test specimen is calculated
from the following formula :
l max, delam
100 x

2 lglue line

24

MS 758 : 2001

B6.4

Test report

The report shall include the following items :


a)

date of the test;

b)

identification of test specimens and members from which they have been cut. Any
other relevant information, e.g. about preconditioning;
species of timber;
type of adhesive;
test method;
delamination percentage and the maximum delamination percentage after the
prescribed number of cycles and any additional cycle that may be necessary;
any relevant observation made during or after testing; and
signature of the person responsible for the testing.

c)
d)
e)
f)
g)
h)

25

MS 758 : 2001
Appendix C
(normative)


Shear test of glue lines

C1.

Scope

This Appendix specifies a method for measuring the shear strength of the glue line parallel to
the direction of the grain.

C2.

Principle

Shear stress is applied to the glue line until failure occurs. The load at failure is recorded and
the wood failure percentage is evaluated.

C3.

Apparatus

C3.1

Testing machine

A calibrated testing machine capable of applying a compressive force to the shearing tool,
referred to in C3.2. The accuracy of measuring the maximum load shall be within ± 3 %.
C3.2

Shearing tool

A shearing tool as illustrated in Figure C1. The cylindrical bearing shall be self-aligning so
that the test specimen is loaded at the end grain with a stress field uniform in the width
direction.

Figure C1. Shearing tool with a test bar inserted

26

MS 758 : 2001

Preparation of test specimens

C4.1


C4.

Test specimens

Special care shall be taken in preparing the test specimens to ensure that the loaded surfaces
are smooth and parallel to each other and perpendicular to the grain direction.
The test specimens shall be of the form shown in either Figure C2 or C3. That depicted in
Figure C2 shows the normal test specimen.

Dimensions :

length,
l;
width,
b : 40 mm – 50 mm;
thickness, t: : 40 mm – 50 mm.

NOTE. If the test bar is cut from a position higher in the cross section the numbers of the lines do not start with 1
(see C4.3).

Figure C2. The normal test specimen, a test bar, and the numbering of the individual
glue lines for a test bar cut at the bottom of the cross section

27


MS 758 : 2001

Dimensions: length,
l
diameter,
d
straight edges, a
thickness,
t

: 70 mm to 80 mm;
: approx. 35 mm;
: approx. 23 mm;
: approx. 26 mm.

Figure C3. A drill core with machined parallel plane surfaces

C4.2

Sampling

Test bars shall be cut from the full cross-sectional specimens as described in this Standard.
At least three glue lines in each of the lower, middle and upper part shall be tested. If there
are less than 10 laminations all glue lines shall be tested.
NOTE. It is recommended that the full cross-sectional specimens are taken within areas of the glulam member
where sufficient cramping pressure has been established. In practice the specimens are frequently cut from the end
of the glulam members where the cramping pressure may be variable and insufficient. If the required shear strength
is obtained from test specimens of this nature, the quality of the glue lines in the member should be deemed
adequate.

The shear testing shall include as far as possible the total cross-sectional width of the glulam
member. The number of test bars to be taken shall be as given in Table C1.

28

MS 758 : 2001

Table C1. Number of test bars


Width of full cross section
(see Figure C4)
mm

Number of test bars

≤ 100

1

> 100 ≤ 160

2

> 160

3

If two or more members are cramped in one operation, see Figure C6, the test bars
necessary according to the testing quantity quoted above, have to be taken from each of the
members.
For testing glue lines within the glulam member, drill cores shall be sampled.
The drill cores shall be cut out perpendicular to the face of the glulam member in such a way
that the glue line to be tested is situated in the middle of the core.
NOTE. For guidance of the drilling tool it is recommended that an appropriate support is used.

The drill cores shall be machined at two faces perpendicular to the glue line as shown in
Figure C3 and divided lengthwise so that the test specimens have a rectangular shearing
area.
C4.3

Marking

Every test bar shall be marked with a durable identification. This shall indicate the location of
the test bar within the cross section of the glulam member.
NOTES:
1.

The relationship between identification and location may be as shown in Figure C5. If the glulam member is
glued vertically the front side of the element should be marked with U and the back side with L. The glue lines of
the glulam member should be numbered beginning with the bottom edge of the member, see Figure C2.

2.

If two glulam members are cramped in one operation, the test bars from the lower member should be marked
additionally with 1 and those from the upper member with 2. An example of this marking is shown in Figure C6.

29


MS 758 : 2001

Figure C4. Test bars to be cut from a full cross-sectional specimen

Figure C5. Suggested identification showing the location of the test bars in the cross
section in a member glued vertically

Figure C6. Additional identification with numbers showing the location of the glulam
member during the cramping
30

MS 758 : 2001


C5.

Procedure

The test specimens shall be conditioned to an equilibrium moisture content in the standard
climate 20/65, i.e. temperature (20 ± 2) ° C and a relative humidity of (65 ± 5) %. For internal
quality control the moisture content of the wood shall be uniform over the test specimen and
within the range of 8 % to 13 %.
Measure the sizes from which the sheared area is determined to the nearest 0.5 mm.
Place the test specimen in the shearing tool so that it is loaded in the direction of the grain.
The glue line shall be positioned so that the distance between this and the sheared plane
does not exceed 1 mm.
The loading shall be undertaken at a constant rate and so that failure occurs after at least 20
s.
Estimate the amount of wood failure percentage rounded off to the nearest 5 %.
From every tested test bar with at least five remaining glue lines a part shall be marked with
the order number, element number, gluing date and position of the test specimen according to
C4.3, and stored for a period as agreed with the certification body.

C6.

Results

C6.1

Calculation of shear stress

Determine the equivalent shear strength ƒv with two significant digits from the following
equation:
ƒv = k

Fu
A

where,
A

is the sheared area (for a test bar A = bt, and for a drill core A = l t);

k

is a modification factor,
k = 0.78 + 0.0044 t; and

t

is the thickness, in millimetres.

NOTE. The factor k modifies the shear strength for test specimens where the thickness in the grain direction of the
sheared area is less than 50 mm.

31

MS 758 : 2001

C6.2

Test report


The test report shall include the following items:
a)
b)
c)
d)
e)
f)
g)
h)
i)

date of the test;
identification of test specimens and members from which they have been cut. Any
other relevant information, e.g. about preconditioning;
species of timber;
moisture content;
type of adhesive;
sizes of the test specimen;
ultimate load and shear strength;
any relevant observation made during or after testing; and
signature of the person responsible for the testing.

NOTE. The information mentioned in items f) to i) is not required to be registered and filed directly, if other data are
filed from which the information may be derived.

32

MS 758 : 2001

Appendix D
(informative)


Glued laminated timber
NOTE. The clauses below list the terms and recommendations for the manufacture, marketing and installation of
glued laminated members.

D1.

Typical stock glulam members

Straight, horizontally laminated, glulam members are available from commercial suppliers in
the country. A typical specification for such stock glulam members is as follows:
-

timber: Mengkulang;
finished lamination thickness: 35 mm or 40 mm;
moisture content at manufacture: 8 % to 15 %;
end joints in laminations: finger joints;
adhesive (including end joints): type I of BS EN 301; and
manufactured surface finish: planed surfaces.

Such components are referred to as stock glulam members. The strength class according to
MS 544: Part 3 will normally be marked on the member. They may, if required by the
specifier, be given a sanded finish or treated with preservatives, or surface coatings.

D2.

Storage and protection of finished members

Finished members should be stored so that they are maintained in an environment not more
severe than that for which they were designed. They should be protected from the effects of
adverse weather and damage or deformation by incorrect methods of handling, stacking,
storage, delivery and erection. Temporary covering during delivery or short term storage to
protect from the effects of adverse weather conditions is recommended.

D3.

Surface fissuring

The natural propensity of timber to shrink when dried can lead to the development of surface
fissures. Glulam will normally be manufactured at around 12 % moisture content and few end
uses result in significantly drier conditions. In practice, however, extremely dry conditions do
occasionally occur. Glulam can also take up moisture during the building process. Both
effects can lead to some degree of fissures developing during the initial period of occupancy.
The following guidelines should be used in the assessment and measuring of fissures:
a)

if the depth of the fissure on the edge of a laminate is less than or equal to 25 % of
the breadth of the member the length of the fissure should not exceed eight times the
breadth of the member; and

b)

if the depth of the defect on the edge of a laminate is greater than 25 % and less than
33 % of the breadth of the member, the fissures should be permitted only if they
occur at the ends of the member and their length should not exceed four times the
breadth of the member.

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MS 758 : 2001

The fissures should be measured in accordance with the following:


a)

if a transverse longitudinal plane cuts through two or more fissures on opposite faces,
then the size of the defect is the sum of the individual sizes; and

b)

the depth of a fissure should be verified by means of a feeler gauge not exceeding
0.3 mm thick.

D4.

Preservative and flame retardant treatment

D4.1

General

Glulam members intended for use in Service class 1, and in the majority of cases Service
class 2, see 3.13 and 3.14, do not normally require treatment to protect them from wood
destroying fungi. Timber is not normally at risk from decay if it is kept dry, that is at a moisture
content below about 20 %. Preservation is a valuable tool, but avoiding risk of high moisture
content is always preferable to dependence on a defensive measure. For Service class 3,
see 3.15, the specifier should consult with the glulam manufacturer and adhesive supplier.
Specifiers may sometimes require members to be treated with insecticides or flame retardant,
irrespective of the service or hazard classes in which they will be used. Both the treatment of
individual laminations before bonding and the treatment of finished members can present
serious practical problems, summarized below. It is essential that these are carefully
considered in cases where preservative and/or flame retardant treatments are applied.
Treatment against decay, or the application of flame retardant and insecticides, either before
or after the individual lamination have been bonded, can affect the performance and
appearance of the finished member and may also interfere with satisfactory application and
durability of surface coatings (such as stains or varnishes).

D4.2 Treatment of laminations before gluing
Treatment of laminations before bonding can result in excessive increases in moisture
content (if water-borne preservatives are used) and high surface concentrations of chemicals
which will impair bond strength and durability. The laminations should be planed not more
than 24 h before bonding and, in some circumstances, a significant proportion of chemicals
will be removed by this planing. When re-drying laminations to the appropriate moisture
content for bonding it is essential that machining is carried out after such re-drying.

D4.3 Treatment of finished members
Treatment of finished members by vacuum/pressure processes may be impracticable due to
their shape and/or size. Members which have been treated with water-borne preservatives
will need to be re-dried to the moisture content appropriate to the service class in which the
finished member is to be used. Re-drying may result in distortion, checking or splitting,
impaired appearance due to colour changes (possibly uneven) and raising of the grain.

D4.4 Hazardous substances
Those responsible for the application of preservatives should ensure that the necessary
training and full hazard assessments required by any relevant existing regulations are
developed and complied with.
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MS 758 : 2001

D5.

Stress grading


Individual laminations will be visually graded in accordance with BS 5756, or machine graded
in accordance with appropriate standards.
Due regard should also be paid to relevant references in MS 544 : Part 1.
Additionally, they should meet the following recommendations:
a)
b)
c)
d)

D6.

Wane. There should be no wane for any grade.
Resin. Pieces containing large resin pockets, which would affect bonding, should not
be permitted for any grade.
Distortion. Any piece which is bowed, sprung, twisted or cupped to an excessive
extent, having regard to the method of laminating, should be rejected.
Wormholes. There should be no wood wasp holes, but pinholes and wormholes may
be permitted in a small number of pieces, provided there is no active infestation of the
wood.

Sapstain

This is not a structural defect and may be acceptable without limitation from a strength
viewpoint.

D7.

Abnormal defects

Any piece which contains defects such as compression wood, insect damage, fungal decay
(but not sapstain), mechanical damage, combinations of knots and/or other characteristics,
which may cause a decrease in strength properties of an amount which threatens the
serviceability of the finished component should be excluded.

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MS 758 : 2001


Appendix E
(Informative)
Bibliography
The following are informative references.
MS 544
Part 3
Part 10

Malaysian Standard Code of Practice for Structural Use of Timber
Glued laminated timber
Preservative treatment

BS EN 355 : 1992

Hazard classes of wood and wood-based products against
biological attack

BS EN 355-1 : 1992

Classification of hazard classes

BS EN 518 : 1995

Structural timber – Grading – Requirements for visual strength
grading standards

BS EN 519 : 1995

Structural timber – Grading – Requirements for machine strength
graded timber and grading machines

DD ENV 1995

Eurocode 5: Design of timber structures

DD ENV 1995-1-1 : 1994 General rules for building (together with United Kingdom National
Application Document)

36

MS 758 2001 GLULAM

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