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 9709:2018 | Structural timber — Visual strength grading — Basic principles |
| ISO 10983:2014 | Timber — Finger joints — Minimum production requirements and testing methods |
| ISO 12122-3:2016 | Timber structures — Determination of characteristic values — Part 3: Glued laminated timber |
| ISO 12122-4:2017 | Timber structures — Determination of characteristic values — Part 4: Engineered wood products |
| ISO 12580:2007 | Timber structures — Glued laminated timber — Methods of test for glue-line delamination |
| ISO 16572:2008 | Timber structures — Wood-based panels — Test methods for structural properties |
| ISO 16696-1:2019 | Timber structures — Cross laminated timber — Part 1: Component performance, production requirements and certification scheme |
| ISO 19993:2020 | Timber structures — Glued laminated timber — Face and edge joint cleavage test |
| ISO/CD TR 21141.3 | Timber structures – Timber connections and assemblages – Yield and ultimate characteristics and ductility from test data |
| ISO 22390:2020 | Timber 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.
| Name | European formaldehyde emission standard [EN] | Japanese Industrial Standard [JAS] | California Air Resources Board [CARB] |
| Validity | European and EU countries | Japan | California and other US States |
| Norms/Testing | EN 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 = 0.099ppm | SE0 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 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