Standards and Certifications

Standards

In this section we would like to highlight the importance of norms and standards in general, but especially when it comes to timber construction. Timber is an inhomogeneous and anisotropic material. This means that timber shows different mechanical behaviour, depending on the moisture content, inner errors like knots or cracks or the direction in which the timber is stressed. 

Standards give information about the state of knowledge, the different test and experiment setups as well as necessary measurement accuracies. The comparability of results is only possible through identical measurement setups and therefore standards ease the communication between buyers and sellers and allow compliant companies easy access to various markets.

The International Organization for Standardization (ISO)  is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization [1]. 

When it comes to standardization concerning structural applications of timber, wood-based panels, other wood based products and related lignocellulosic fibrous material the ISO/TC 165 committee carries out these processes [2]. 

This working group sets

  • requirements for design;
  • structural properties, performance, and design values of materials, products, components, and assemblies and;
  • test methods and requirements to establish related structural, mechanical and physical properties and performance.

Below you can find only a selection of ISO-Norms that were developed by the ISO/TC 165. 

Here you will be directed to the full list [3]. 

ISO 8375:2017 Timber structures — Glued laminated timber — Test methods for determination of physical and mechanical properties
ISO 9709:2018Structural timber — Visual strength grading — Basic principles
ISO 10983:2014Timber — Finger joints — Minimum production requirements and testing methods
ISO 12122-3:2016Timber structures — Determination of characteristic values — Part 3: Glued laminated timber
ISO 12122-4:2017Timber structures — Determination of characteristic values — Part 4: Engineered wood products
ISO 12580:2007Timber structures — Glued laminated timber — Methods of test for glue-line delamination
ISO 16572:2008Timber structures — Wood-based panels — Test methods for structural properties
ISO 16696-1:2019Timber structures — Cross laminated timber — Part 1: Component performance, production requirements and certification scheme
ISO 19993:2020Timber structures — Glued laminated timber — Face and edge joint cleavage test
ISO/CD TR 21141.3Timber structures – Timber connections and assemblages – Yield and ultimate characteristics and ductility from test data
ISO 22390:2020Timber structures — Laminated veneer lumber — Structural properties

Eurocodes

When we take a look at Europe, where timber construction already has a long history,  the so-called “Eurocodes” apply.
The Eurocodes are standardized design rules for structural design throughout Europe and were officially introduced in the building industry on July 1, 2012 [4]. 

The Eurocodes provide for a number of changes, but the most important is the introduction of the semi-probabilistic safety concept. Until then, the calculation and dimensioning of structures was based on the global safety factor S. 

The following Eurocodes are currently in force:

  • EN 1990 – Eurocode 0: Fundamentals of structural design
  • EN 1991 – Eurocode 1: Actions on structures
  • EN 1992 – Eurocode 2: Design of reinforced and prestressed concrete structures
  • EN 1993 – Eurocode 3: Design of steel structures
  • EN 1994 – Eurocode 4: Design of composite steel and concrete structures
  • EN 1995 – Eurocode 5: Design of timber structures
  • EN 1996 – Eurocode 6: Design of masonry structures
  • EN 1997 – Eurocode 7: Design in geotechnics
  • EN 1998 – Eurocode 8: Design of structures for earthquake resistance
  • EN 1999 – Eurocode 9: Calculation and design of aluminum structures

Each of these standards is subdivided into sub-standards and is adapted to the conditions of the nationally defined parameters of the respective member country with individual National Annexes (NA).

Companies in the field of timber construction should familiarize themselves with all the above standards in order to strengthen their market position in the future and be well prepared for the upswing in the timber construction industry. 


Formaldehyde emission standards

There are many different standards for formaldehyde emissions around the world. The three most common used ones are shown and compared to each other in the table below. The international tendency is in lower the emissions to zero emissions.

NameEuropean formaldehyde emission standard [EN]Japanese Industrial Standard [JAS]California Air Resources Board [CARB]
ValidityEuropean and EU countriesJapan California and other US States
Norms/TestingEN 13986 EN 120 (Perforator) EN 717-1 (Chamber)EN 717-2 (Gas- analysis)EN 717-3 (Flask)JIS A1460 (desiccator)ATCM 93120 (airborne toxic control measure) inASTM E1333 or ASTM D6007 chamber
Classification 0.124mg/m3 = 0.099ppmSE0   0.04ppm
E0     0.07ppm
E1     0.14ppm
E2     0.38ppm
F****0.04ppm             
F***0.07ppm
F**0.14ppm
F*
CARB Phase 2     0.05ppm
CARB Phase 1      0.08ppm


The above section is a compiled of the following sources
[1] https://www.iso.org/obp/ui/#iso:std:iso:16696:-1:ed-1:v1:en
[2] https://www.iso.org/committee/53584.html
[3] https://www.iso.org/committee/53584/x/catalogue/
[4] https://www.baunetzwissen.de/glossar/e/eurocodes-3170527