SIST EN 384:2016/oprA1:2018

Structural timber - Determination of characteristic values of mechanical properties and density

This standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual grades and/or mechanical strength classes of sawn timber. Additionally it covers the stages of sampling, testing, analysis and presentation of the data.
A method is also given for checking the strength of a timber population against its designated value.
The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.
NOTE 1   For assigning grades and species to the strength classes in EN 338 only three characteristic values, i.e. bending or tension strength, mean modulus of elasticity parallel to grain in bending or tension and density need to be determined, other properties can be calculated according to Tab. 6.2.
NOTE 2   EN 1912 gives examples of established visual grades assigned to strength classes.

Bauholz für tragende Zwecke - Bestimmung charakteristischer Werte für mechanische Eigenschaften und Rohdichte

Diese Norm legt fest, wie charakteristische Werte für mechanische Eigenschaften und Rohdichtewerte von definierten Holzgrundgesamtheiten visueller Sortierklassen und/oder mechanischer Festigkeitsklassen von Schnittholz zu bestimmen sind. Zusätzlich umfasst die Norm die Stufen von Probenahme, Prüfung, Analyse und Darstellung der Daten.
Außerdem wird ein Verfahren zur Überprüfung der Festigkeitswerte einer Grundgesamtheit von Bauholz zum Vergleich mit vorgegebenen Festigkeitswerten angegeben.
Die nach dieser Norm bestimmten mechanischen Eigenschaften und Rohdichtewerte sind für die Zuordnung der Holzarten und Sortierklassen in die Festigkeitsklassen nach EN 338 geeignet.
ANMERKUNG 1   Für die Zuordnung der Holzarten und Sortierklassen in die Festigkeitsklassen nach EN 338 ist die Bestimmung von nur drei charakteristischen Werten, d. h. Biege- oder Zugfestigkeit, Mittelwert des Biege- oder Zug-Elastizitätsmoduls in Faserrichtung und die Rohdichte erforderlich; die sonstigen Eigenschaften können nach der Tabelle in 6.2 berechnet werden.
ANMERKUNG 2   EN 1912 gibt Beispiele für die Zuordnung von bestehenden visuellen Sortierklassen zu Festigkeits-klassen.

Bois de structure - Détermination des valeurs caractéristiques des propriétés mécaniques et de la masse volumique

La présente norme fournit une méthode permettant de déterminer des valeurs caractéristiques des propriétés mécaniques et de la masse volumique, pour des populations définies de bois sciés classés en résistance visuellement et/ou mécaniquement. Elle couvre également les étapes relatives à l'échantillonnage, aux essais, à l'analyse et à la présentation des données.
Une méthode permettant de vérifier la résistance d'une population de bois par rapport à une valeur spécifiée est également fournie.
Les valeurs des propriétés mécaniques et de la masse volumique déterminées conformément à la présente norme permettent d'affecter des classes et des essences aux classes de résistance de l'EN 338.
NOTE 1   Pour l'affectation des classes et des essences aux classes de résistance de l'EN 338, il suffit de déterminer trois valeurs caractéristiques, à savoir la résistance à la flexion ou à la traction, le module d'élasticité moyen en flexion ou en traction axiale et la masse volumique ; d'autres propriétés peuvent être calculées conformément au Tableau 6.2.
NOTE 2   L'EN 1912 fournit des exemples d'affectation de classes visuelles établies à des classes de résistance.

Konstrukcijski les - Ugotavljanje karakterističnih vrednosti mehanskih lastnosti in gostote

General Information

• Status: Not Published
• Public Enquiry End Date: 19-Mar-2018
• ICS: 79.040 - Wood, sawlogs and sawn timber
• ICS: 91.080.20 - Timber structures
• Technical Committee: KON.005 - Timber structures
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 06-Dec-2018
• Due Date: 11-Dec-2018
• Completion Date: 06-Dec-2018
• Ref Project: EN 384:2016/prA1 - Structural timber - Determination of characteristic values of mechanical properties and density

Relations

• Consolidated By: SIST EN 384:2016+A1:2019 - Structural timber - Determination of characteristic values of mechanical properties and density
• Effective Date: 18-Jan-2023
• Amends: SIST EN 384:2016 - Structural timber - Determination of characteristic values of mechanical properties and density
• Effective Date: 01-Mar-2018

Overview

EN 384:2016/prA1 - Structural timber: Determination of characteristic values of mechanical properties and density - is a CEN method for deriving the characteristic mechanical values and density of defined populations of sawn timber. The standard covers the full workflow: sampling, testing, data analysis and presentation, and provides a procedure to check a timber population against its designated strength value. Values determined using EN 384 are suitable for assigning visual grades and species to the strength classes specified in EN 338.

Key topics and requirements

• Characteristic values: Methods to determine characteristic values of mechanical properties (e.g., bending/tension strength, modulus of elasticity) and density for defined timber populations.
• Sampling and testing: Procedures and statistical treatment required to obtain representative population values.
• Data analysis and presentation: Statistical methods for calculating characteristic values and documenting results for grade assignment and certification.
• Strength checking: A method to verify that a timber population meets its designated strength value.
• Grade assignment: For mapping grades/species to EN 338 strength classes, only three characteristic values are required: bending or tension strength, mean modulus of elasticity parallel to grain, and density (other properties can be calculated per EN 384 tables).
• Amendment (prA1) updates:
  • Subclause 5.5.1: For non-parametric calculations in type testing of machine-controlled systems, the confidence adjustment factor k (for k0.5,0.75 as defined in EN 14358) may be taken as 0 (No confidence adjustment).
  • Subclause 5.5.2.2.4: Existing visual grade assignments calculated under previous versions do not require recalculation unless evidence shows required grade-determining properties are not met.

Applications and users

Who uses EN 384:

• Timber manufacturers and sawmills conducting type testing and establishing strength classes.
• Product certifiers and laboratories performing mechanical testing and statistical analysis.
• Structural engineers and specifiers who rely on certified characteristic values for design and conformity with EN 338 strength classes.
• National standards bodies and conformity assessment bodies involved in timber grade assignment.

Practical benefits:

• Provides a consistent, traceable method for assigning timber to strength classes.
• Supports certification, regulatory compliance and reliable structural design data.
• Clarifies statistical treatment for machine-controlled production (reduced confidence adjustment option).

Related standards

• EN 338 - Strength classes of structural timber (assignment target).
• EN 1912 - Examples of established visual grades assigned to strength classes.
• EN 14358 - Defines the k factors referenced for statistical confidence adjustments.

Keywords: EN 384, structural timber, characteristic values, mechanical properties, density, visual grading, strength classes, EN 338, sampling, testing, timber standards.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2018
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Structural timber - Determination of characteristic values of mechanical properties and
density
Bauholz für tragende Zwecke - Bestimmung charakteristischer Werte für mechanische
Eigenschaften und Rohdichte
Bois de structure - Détermination des valeurs caractéristiques des propriétés
mécaniques et de la masse volumique
Ta slovenski standard je istoveten z: EN 384:2016/prA1
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
91.080.20 Lesene konstrukcije Timber structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
EN 384:2016
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
February 2018
ICS 79.040
English Version
Structural timber - Determination of characteristic values
of mechanical properties and density
Bois de structure - Détermination des valeurs Bauholz für tragende Zwecke - Bestimmung
caractéristiques des propriétés mécaniques et de la charakteristischer Werte für mechanische
masse volumique Eigenschaften und Rohdichte
This draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 124.

This draft amendment A1, if approved, will modify the European Standard EN 384:2016. 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-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
Recipien
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