Timber and furniture

DIN EN 16449:2014-06 "Wood and wood-based products - Calculation of the biogenic carbon content of wood and conversion to carbon dioxide" provides a calculation method for the quantitative determination of the amount of atmospheric carbon dioxide based on the content of biogenic carbon. This information can also be used to estimate the potential benefits associated with storing carbon in wood and wood-based products; for example, by architects in the early design phase of buildings. The standard also lays the foundation for the information required by the product category rules and the development of environmental product declarations.

The following standards are examples for the topic of durability and service life of wood and wood-based products: DIN EN 335:2013-06 "Durability of wood and wood-based products - Use classes: definitions, application to solid wood and wood-based products", DIN EN 350:2016-12 "Durability of wood and wood-based products - Testing and classification of the durability to biological agents of wood and wood-based materials", E DIN EN 460:2018-12 "Durability of wood and wood-based products - Natural durability of solid wood - Guide to the durability requirements for wood to be used in hazard classes", DIN 68800-1:12019-06 "Wood preservation — Part 1: General", DIN 68800-2:2012-02 "Wood preservation - Part 2: Preventive constructional measures in buildings".

As a natural material, wood is subject to natural degradation by wood-using organisms (fungi, insects, microorganisms). Over time, wood-based products lose value and function. If the extent of the loss exceeds a specified limit, the service life of the specific wood-based product has ended due to quality loss. The expected service life depends on numerous factors: the place of use (referred to as service class and standardized in DIN EN 335), the natural or induced durability (referred to as durability class and standardized in DIN EN 350), the installation situation (standardized in DIN 68800-1 and -2), the intended function (e.g. load-bearing or non-load-bearing) and the associated consequence of failure, as well as maintenance (not standardized). 

A standard that defines the requirements for durability (DIN EN 350) in the service classes (DIN EN 335) for an expected service life is currently being developed in DIN EN 460. 

As a general rule, the better the durability, the longer the service life. The durability of a wood-based product can be naturally justified, which does not change the actual wood properties and facilitates subsequent recycling, as long as the quality requirements for a subsequent use are not restricted by the primary use. The induced durability changes the natural product wood in different ways (e.g. as a composite with other materials to WPC, through wood preservatives, through wood structure modifications). Recycling or reuse after primary use may be restricted as a result (e.g. due to biocide contamination, plastic components). 

The unrestricted recyclability or further use of a wood-based product could be governed by standards as an additional quality characteristic. It is then to be expected that the service life will be reduced by the factor of the induced durability. This quality trade-off (achieved durability vs. recyclability) would then either have to be favoured in terms of provisions, possibly prescribed by law, or with financial incentives as compensation (e.g. through subsidies). 

Another way to achieve a long service life of naturally durable wood-based products (which also preserves their good recycling properties) is the quality of the installation situation. In Germany this is governed by DIN 68800 Part 1 and especially Part 2. There are no standards on this subject at CEN level so far. There is a need for action here.

DIN ISO 38200:2019-06 "Chain of custody of wood and wood-based products" specifies requirements for a chain of custody (CoC) for wood and wood-based products, cork, lignified material and their products. It applies to material that can be obtained from different categories of input materials and from different manufacturing processes. The standard specifies minimum requirements for the input material. A monitored chain of custody relies on a control system to track and handle material throughout the supply chain or parts of it, including transport, receipt, production, sale, resale and export declaration. The standard is intended to enable the tracking of material from different categories of sources to the final product.

DIN EN 13556:2003-10 "Round and sawn timber - Nomenclature of timbers used in Europe; Trilingual version" contains a list of hardwoods and softwoods traded in Europe. It supports the uniform naming of commercial timbers with their botanical and trade name as well as an assigned four-letter abbreviation. The list of designations comprises two tables. Table 1 contains the hardwoods (dicotyledons); Table 2 contains the softwoods (gymnosperms). Appendix I of the Convention on International Trade in Endangered Species (CITES) contains a list of species that may not be traded. In Table 1 and Table 2, these species are printed in bold and marked as "PROTECTED SPECIES". 
[In NA-042-01-02 AA "Steering Committee Round Wood and Sawn Wood Products" the necessity of a revision of the standard is being discussed, as in particular the important information on the CITES listings is outdated or needs to be extended and the botanical nomenclature of some species has also changed in the meantime].

DIN EN 16485:2014-07 "Round and sawn timber - Environmental Product Declarations - Product category rules for wood and wood-based products for use in construction" provides general product categorization rules (PCR) for Type III environmental declarations for products made of wood and wood-based materials for use in construction works and related construction processes and services. It complements the basic rules for the product category of all construction products as set out in EN 15804 and is intended to be used in conjunction with EN 15804. The assessment of social and economic performance at product level is not the subject of this standard.

The recycling of waste wood, industrial waste wood and used wood, which is regulated in Germany by the End-of-Life Ordinance, is primarily carried out as a raw material for the production of wood-based materials. DIN Technical Report CEN/TR 14823 "Durability of wood and wood-based products - Quantitative determination of pentachlorophenol in wood - Gas chromatographic method" describes a laboratory method for the precise analysis of pentachlorophenol (PCB) and can be applied to treated wood and to wood-based materials. The test method can be used to determine the suitability of waste wood, industrial waste wood and used wood as raw material for wood-based materials.

The standards series DIN EN 15534 "Composites made from cellulose-based materials and thermoplastics (usually called wood-polymer composites (WPC) or natural fibre composites (NFC))" specifies in Parts 2, 4, 5 and 6 properties of WPC materials and products made from them, such as decking boards, façade and fence profiles. WPC are also used for packaging, containers, etc. and can be recycled due to their thermoplastic character. DIN EN 15534-1 specifies test methods for determining the characteristics of WPC.

In the construction industry, sustainability as well as resource and energy efficiency are increasingly coming into focus - and thus also wood, which is used in house construction, for example. In addition to its physical properties, wood offers advantages as a carbon store and as a deconstructible and recyclable building material. DIN EN 13986:2015-06 "Wood-based panels for use in construction - Characteristics, evaluation of conformity and marking" defines wood-based panels for use in construction and specifies their essential characteristics. It can thus promote the use of wood and wood-based products in construction.