ISO 3129:2019 - Wood — Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens

Standard No.: ISO 3129:2019
Release Date: 2019
Published By: International Organization for Standardization (ISO)
Latest: ISO 3129:2019

Introduction

Analysis of the core content of the standard

ISO 3129:2019 standard specifies the complete process system for testing the physical and mechanical properties of wood, which mainly includes three technical modules:

Sampling specifications: Differentiated sampling schemes covering logs (different treatments for diameters ＞180mm and ≤180mm) and sawn timber
Specimen preparation: Clarify the requirements for moisture content control (12% in air-dried state and green state) and grain direction control
Testing system: Establish a complete evaluation framework including 5 types of mechanical property tests and 3 physical index tests

Comparison of key technical requirements

Technical elements	Requirements of the 2012 version	Updates to the 2019 version
Log sampling	Only basic sampling principles are specified	Special treatment plan for logs with a diameter of ≤180mm is added (Figure 2)
Moisture content control	(20±2)℃/(65±5)%RH	The temperature and humidity combination can be adjusted according to climatic conditions (Note 6.1)
Sample quantity calculation	Only basic formulas are provided	Added Table 1 containing reference values of coefficient of variation of 12 performance items

Key points for implementation of sampling plan

Log sampling case

Taking pine wood with a diameter of 200 mm as an example, the following steps need to be performed:

Select the heartwood board (thickness ≥ 60 mm) containing the geometric center
Obtain radial/tangential specimens according to the cutting pattern shown in Figure 1
When comparing green and air-dried properties, use the paired sampling formula in 7.5.2 to calculate the minimum sample size

Standard Evolution Analysis

The main technical improvements of the 2019 version are reflected in the following:

Improved sampling accuracy: The quantitative relationship between sample size and coefficient of variation is established through formulas (1)-(3)
Expanded scope of application: Clearly applicable to wood assessment for non-structural purposes (furniture, doors and windows, etc.)
Enhanced test reliability: New sampling requirements for hardness testing (Note 5.2.2)

Implementation recommendations

Laboratory operation guide

1. Environmental control: It is recommended to configure a dual-temperature zone laboratory to maintain the following conditions:

Green test area: temperature 20±2℃/RH≥95%
Air-dry test area: temperature 20±2℃/RH65±5%

2. Data processing: When using formulas (4)-(8) for statistics, please note:

When CV＞30%, the sample size should be increased (such as the growth ring count in Table 1)
The moisture content correction should use the average value of the paired samples

ISO 3129:2019 Referenced Document

ISO 24294 Timber - Round and sawn timber - Vocabulary*， 2021-08-31 Update

ISO 3129:2019 history

2019 ISO 3129:2019 Wood — Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens
2012 ISO 3129:2012 Wood - Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens
1975 ISO 3129:1975 Wood; Sampling methods and general requirements for physical and mechanical tests

Wood — Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens

ISO 3129:2019Wood — Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens