Timber structures - Strength graded structural timber with rectangular cross section - Part 4: Machine grading - Grading machine settings for machine controlled systems

Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt - Teil 4: Maschinelle Sortierung - Einstellungen von Sortiermaschinen für maschinenkontrollierte Systeme

Structure en bois - Bois de structure de section rectangulaire classé selon la résistance - Partie 4: Classement par machine - Réglages pour les systèmes de contrôle par machine

Lesene konstrukcije - Razvrščanje konstrukcijskega lesa pravokotnega prečnega prereza po trdnosti - 4. del: Strojno razvrščanje - Nastavitve strojev za razvrščanje pri strojno kontroliranih sistemih

General Information

Status
Not Published
Technical Committee
CEN/TC 124 - Timber structures
Current Stage
5060 - Closure of Vote - Formal Approval
Start Date
04-Jan-2008
Due Date
12-Sep-2008
Completion Date
04-Jan-2008

Relations

Effective Date
18-Jan-2023
Effective Date
22-Dec-2008

Overview

EN 14081-4:2005+A2:2007/prA3 is a European standard developed by CEN (European Committee for Standardization) that specifies the machine grading settings for strength graded structural timber with rectangular cross sections. This part of the EN 14081 series focuses on machine-controlled systems used for grading structural timber by strength. Machine grading is a crucial process in timber manufacturing that ensures timber components meet required strength classes for safe and effective use in construction and structural applications.

The standard covers detailed settings for various grading machines, including Cook Bolinder, Computermatic, Micromatic, Euro-GreComat, GoldenEye, Dynagrade, and ViSCAN. It provides parameters such as feed speeds, timber size ranges, and equations to calculate grading machine settings for different species and strength classes.

Key Topics

  • Strength Graded Structural Timber: Timber sorted by mechanical or physical properties to categorize it according to strength classes such as C16, C24, or C30, ensuring structural reliability.
  • Machine Controlled Systems: Automated grading machines applying specific calibration and settings to evaluate and classify timber strength precisely.
  • Grading Machine Settings: Parameters including feed speed, timber size dimensions (thickness and width), temperature requirements, moisture content, and load calculations.
  • Species and Origin: Settings are specific to timber species (e.g., Spruce, Pine, Radiata Pine, Sitka Spruce) and countries of origin, with adaptations to grading parameters.
  • Calibration and Equations: Mathematical formulas and tables for converting stress values to machine pressure or force settings, adapting to timber dimensions and machine model.
  • Operational Conditions: Recommended environmental and timber conditions during grading such as temperature, humidity, moisture content, and surface finish (planed or sawn).

Applications

  • Timber Structures: Ensuring that structural timber used in buildings, bridges, and other constructions meets safety and performance standards through accurate mechanical grading.
  • Manufacturing Quality Control: Machine grading allows timber producers to consistently grade timber in high volume, improving quality assurance and reducing human error.
  • Glued Laminated Timber Production: Specific settings support graded boards used in glue-laminated timber (glulam), widely used in engineered wood products.
  • Export and Compliance: Facilitates meeting EU and national legislative requirements by adhering to standardized machine grading parameters.
  • Species-Specific Grading: Allows grading adjustments tailored for specific local timber species to support regional forestry and timber industries.

Related Standards

  • EN 14081-1: General principles for strength grading of structural timber, including visual and machine grading techniques.
  • EN 338: Strength classes for structural timber, defining characteristic values used in EN 14081 grading.
  • EN 336: Dimensions and permissible deviations for structural timber sizes referenced for machine grading size ranges.
  • CEN/TC 124: Technical committee responsible for standards on timber structures, including grading technologies.
  • National Standards Bodies: Adoption of EN 14081-4 settings in corresponding national standards of CEN member countries for consistent implementation.

Important Keywords

  • Strength graded structural timber
  • Machine grading timber
  • Timber grading machine settings
  • Grading machine calibration
  • Structural timber standards EN 14081
  • Timber species grading parameters
  • C16, C24 timber strength classes
  • Timber dimensional standards EN 336
  • Moisture content in timber grading
  • Timber grading temperature and humidity guidelines

Enforcement of EN 14081-4:2005+A2:2007/prA3 ensures reliable mechanical grading processes for structural timber, offering a benchmark for manufacturers and construction professionals to maintain high quality and safe timber structures across Europe.

Draft

EN 14081-4:2005+A2:2007/oprA3:2007

English language
16 pages
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Frequently Asked Questions

EN 14081-4:2005+A2:2007/prA3 is a draft published by the European Committee for Standardization (CEN). Its full title is "Timber structures - Strength graded structural timber with rectangular cross section - Part 4: Machine grading - Grading machine settings for machine controlled systems". This standard covers: Timber structures - Strength graded structural timber with rectangular cross section - Part 4: Machine grading - Grading machine settings for machine controlled systems

Timber structures - Strength graded structural timber with rectangular cross section - Part 4: Machine grading - Grading machine settings for machine controlled systems

EN 14081-4:2005+A2:2007/prA3 is classified under the following ICS (International Classification for Standards) categories: 79.040 - Wood, sawlogs and sawn timber; 79.120.10 - Woodworking machines. The ICS classification helps identify the subject area and facilitates finding related standards.

EN 14081-4:2005+A2:2007/prA3 has the following relationships with other standards: It is inter standard links to EN 14081-4:2005+A3:2008, EN 14081-4:2005+A2:2007. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

EN 14081-4:2005+A2:2007/prA3 is associated with the following European legislation: EU Directives/Regulations: 305/2011, 89/106/EEC; Standardization Mandates: M/112. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.

EN 14081-4:2005+A2:2007/prA3 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
01-december-2007
/HVHQHNRQVWUXNFLMH5D]YUãþDQMHNRQVWUXNFLMVNHJDOHVDSUDYRNRWQHJDSUHþQHJD
SUHUH]DSRWUGQRVWLGHO6WURMQRUD]YUãþDQMH1DVWDYLWYHVWURMHY]DUD]YUãþDQMH
SULVWURMQRNRQWUROLUDQLKVLVWHPLK
Timber structures - Strength graded structural timber with rectangular cross section -
Part 4: Machine grading - Grading machine settings for machine controlled systems
Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit
rechteckigem Querschnitt - Teil 4: Maschinelle Sortierung - Einstellungen von
Sortiermaschinen für maschinenkontrollierte Systeme
Structure en bois - Bois de structure de section rectangulaire classé selon la résistance -
Partie 4: Classement par machine - Réglages pour les systemes de contrôle par
machine
Ta slovenski standard je istoveten z: EN 14081-4:2005+A2:2007/prA3
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
79.120.10 Lesnoobdelovalni stroji Woodworking machines
SIST EN 14081- en,fr,de
4:2005+A2:2007/oprA3:2007
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
FINAL DRAFT
EN 14081-4:2005+A2:2007
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA3
October 2007
ICS 79.120.10; 79.040
English Version
Timber structures - Strength graded structural timber with
rectangular cross section - Part 4: Machine grading - Grading
machine settings for machine controlled systems
Structure en bois - Bois de structure de section Holzbauwerke - Nach Festigkeit sortiertes Bauholz für
rectangulaire classé selon la résistance - Partie 4: tragende Zwecke mit rechteckigem Querschnitt - Teil 4:
Classement par machine - Réglages pour les systèmes de Maschinelle Sortierung - Einstellungen von
contrôle par machine Sortiermaschinen für maschinenkontrollierte Systeme
This draft amendment is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee
CEN/TC 124.
This draft amendment A3, if approved, will modify the European Standard EN 14081-4:2005+A2:2007. If this draft becomes an
amendment, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion
of this amendment into the relevant national standard without any alteration.
This draft amendment was established by CEN in three official versions (English, French, German). A version in any other language made
by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14081-4:2005+A2:2007/prA3:2007:
worldwide for CEN national Members. E

Foreword
This document (EN 14081-4:2005+A2:2007/prA3:2007) has been prepared by Technical Committee
CEN/TC 124 “Timber structures”, the secretariat of which is held by SFS.
This document is currently submitted to the Unique Acceptance Procedure.
1.1 Modifications to Clause 5
 In first sentence change ‘Tables 1 to 6’ to ‘Tables 1 to 9’.
1.2 Modifications to Table 1
 Replace the first page of Table 1 with the Table 1 included in this amendment.
1.3 Modifications to Table 2
 Replace the first page of Table 2 with the two pages of Table 2 included in this amendment.
1.4 Modifications to Table 4a
 Replace the one page of Table 4a with the Table 4a included in this amendment.
1.5 Modifications to Table 4b
 After the two pages of Table 4b insert the one page of Table 4b included in this amendment.
1.6 Modifications to Table 6
 After the four pages of Table 6 insert the one page of Table 6 included in this amendment.
1.7 Modifications to Table 7
 Replace Table 7 with the two pages of Table 7 included in this amendment.
1.8 Modifications to Table 8
 Replace the three pages of Table 8 with the one page of Table 8a and the three pages of Table 8b
included in this amendment.
1.9 Addition of Table 9
 After Table 8b insert the one page of Table 9 included in this amendment.

Table 1 — Settings for Cook Bolinder (Tecmach) machine types SG-AR, SG-AF and SG-TF
c
Source Source Species Permitted Model value Feed Comments and additional requirements
Grade or
a b
country mark timber sizes speed
grade
or (mm) range
combination
countries (m/min)
UK GB Spruce C24 F = 2,68 150 max Minimum temperature of timber at time of grading
35 ≤ t ≤ 75
n
Ireland IE Picea C16 F = 2,27 shall be -10 °C.
60 ≤ b ≤ 300
n
abies The following equations shall be used to calculate
C16 F = 1,24 150 max
Picea settings for the target size b
× t . (NOTE  For timber
n n
sitchensis with a thickness to tolerance class 1, i.e. sawn, t in the
n
following equations is the target t + 1 mm.)
n
Pine C24 F = 2,79 150 max
35 ≤ t ≤ 75
n
Pinus C16 F = 1,90
60 ≤ b ≤ 300
n
-1,299
a = 830,7 t
nigra n n
C16 F = 1,34 150 max
Pinus
0,61
P = 4,412 F / t (bar)
sylvestris n n n
Chile CL Radiata C27 F = 3,03 150 max
35 ≤ t ≤ 50
n
1.701
pine Pinus C16 F = 1,43
60 ≤ b ≤ 300
Fb t
n
n n
F =
radiata
C24 F = 2,32 150 max
n
()413,9t +57273
n
C16 F = 2,09
C16 F = 0,92 150 max
a
See 7.3 in EN 14081-1:2005.
b
Timber sizes shall be according to EN 336.
c
Grades prefixed by C are strength classes given in EN 338.

Table 2 — Settings for Computermatic and Micromatic machines
Source Source Species Permitted Grade Model Feed speed Comments and additional requirements
a
c
country mark timber value range
b
or
or sizes (m/min)
Deflection
grade
countries (mm) a
combi-
(mm)
nation
UK GB Spruce C24 6,35 105 max Minimum temperature of timber at time of grading shall be
35 ≤ t ≤ 75
n
Ireland IE Picea C16 7,49 -10 °C.
60 ≤ b ≤ 300
n
abies
Picea
C16 13,78 105 max The following equations shall be used to calculate settings for
sitchensis
the target size b × t . (NOTE  For timber with a thickness to
n n
Pine C24 6,10 105 max tolerance class 1, i.e. sawn, t in the following equations is the target
35 ≤ t ≤ 75 n
n
t + 1 mm.)
Pinus C16 8,97 n
60 ≤ b ≤ 300
n
nigra
Actual deflection settings are determined from a /0,19
Pinus
C16 12,74 105 max n
rounded to the nearest whole number. Refer to calibration
sylvestris
tables for machine to convert Force F to pressure setting
Chile CL Radiata C27 5,62 105 max n
35 ≤ t ≤ 50
n
F = 0,010 1 b t
pine C16 11,86 n n n
60 ≤ b ≤ 300
n
Pinus C24 7,35 105 max
radiata
C16 8,13
36,71a()0,00567t +0,7846
n
a =
n
C16 18,52 105 max −5
t()0,9851×10 t b +0,91
n n n
a
See 7.3 in EN 14081-1:2005.
b
Timber sizes shall be according to EN 336.
c
Grades prefixed by C are strength classes given in EN 338

Table 2 — Settings for Computermatic and Micromatic machines (continued)
c
Source Source Species Permitted Grade  Model Feed Comments and additional requirements
a b
country mark timber sizes or grade value speed
or (mm) combination f range
mod
countries (m/min)
Norway NO Sitka spruce 33 < t <53 C18 27,9 105 max Equation (2) shall be used to calculate settings
n
Picea 88 < b < 218 C30 38,8 for the target size t and b where t and b are
n n n n n
Sitchensis target dimensions.
Actual deflection setting an shall be rounded up
to the nearest whole number
If the actual thickness t exceeds the target
a
thickness t more than 1 mm then the pressure
n
shall be increased by
 
t
a
 
 
t
 n
To convert from stress to force F use equation
n
(1). Refer to calibration tables for machine to
convert F to pressure setting.
n
F = 0,0101⋅b ⋅t                   (1)
n n n
−0,814 0,152
8063⋅t ⋅b
n n
a = BIT (2)
n
0,186 0,152
 
2,14 ⋅t ⋅b
n n
 
f ⋅ 1−
mod
 
f
mod
 
Requirements for grading:
- air temperature: 10 °C to 50 °C;
- relative humidity in the air: < 85 %;
- timber temperature: > -10 °C;
- timber mean moisture content: > 10 %.
a
See 7.3 of EN 14081-1:2005.
b
Timber sizes shall be according to EN 336.
c
Grades specified by C are strength classes given in EN 338.

Table 4a — Settings for Euro-GreComat 702
Source Source Species Permitted timber Grade or Settings Comments and additional requirements
a b
country or mark size [mm] grade
countries combination
Spruce
Germany DE 30 ≤ t ≤ 50 L36 IP ≥ 34,5 These grades apply to boards for glued laminated timber.
n
Picea
Austria AT 95 ≤ b ≤ 280 L25 34,5 > IP ≥ 22,3 The characteristic values for the grades are:
abies n
30 ≤ t ≤ 55 L35 IP ≥ 34,0  L36 L35 L25 L24
n
Czech Fir
CZ
Abies alba
Republic
80 ≤ b ≤ 280 L24 34,0 > IP ≥ 21,0 f [N/mm²] 22,0 21,0 14,5 14,0
n t,k
E [N/mm²] 13 000 13 000 11 000 11 000
t,mean
ρρρρ  [kg/m³] 400 400 350 350
k
Requirements for grading:
- timber temperature greater than 0 °C
- timber mean moisture content between 7 % and 15 %;
- feed speed between 80 m/min and 300 m/min;
- timber surface planed or sawn.

a
See 7.3 of EN 14081-1:2005.
b
Timber size shall be according to EN 336.

Table 4b — Settings for GoldenEye 702 (continued)
c
Source Source Species Permitted Grade Settings Comments and additional requirements
a
country mark timber or
b
or size grade
IP = f
mod
countries (mm) combination
Finland FI Spruce Requirements for grading:
35 ≤ t ≤ 55
n
C40 55,6
Norway NO Picea abies - timber mean moisture content between 10 % and 20 %;
90 ≤ b ≤ 220
n C30 40,2
Sweden SE - timber temperature greater than 0 °C;
C18 13,5
Estonia ES - timber surface finish planed or sawn;
C30 36,5
Latvia LV - feed speed not greater than 450 m/min.
d
C18 13,5
Russia RU
Poland PL The settings for C30-C18 can also be used for
C35 52,3
TR26-C18
C27 37,6
C18 13,5
TR26 is a UK grade for trussed rafters. Its primary
C35 52,3
characteristic values are:
C24 22,7
ƒ = 28,3 N/mm²;
m,k
C27 35,9
E = 11 000 N/mm²;
0,mean
C16 13,5
ρ = 370 kg/m³.
k
TR26 29,9
C16 13,5
C24 13,5
a
See 7.3 of EN 14081-1:2005.
b
Timber sizes shall be according to EN 336.
c
Grades prefixed by C are strength classes given in EN 338.
d
Settings apply only to timber grown west of the Ural mountain range in Russia.

Table 6 — Settings for Dynagrade machine (including HC and XHC) (continued)
c
Source Source Species Permitted Grade  Settings Comments and additional requirements
a b
country or mark timber sizes or grade
I
countries (mm) combination (Machine units)
Norway NO Sitka spruce 33 < t <53 C18 4 600 000 Actual setting, I is given in machine units and it is not
n
Picea Sitchensis
88 < b < 218 C24 5 450 000 effected by the timber dimension
n
Requirements for grading:
- air temperature: 10 °C to 50 °C;
- relative humidity in the air: < 85 %;
- timber temperature: > -10 °C;
- timber mean moisture content: 10 % ≤ u < 16 %.
Dynagrade/
− Conveyor speed         ≤ 1 m/s;
− Spacing between pieces  ≥ 200 m
...

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