The revised din en 12779

14 July 2016


There is a revised EN standard for the safety requirements of woodworking machines, concerning chip and dust extraction systems with fixed installation. In this article, the German machinery makers’ association, the VDMA, explains what is involved.

The standard designated DIN EN 12779:2016 is the German version of the fundamentally revised EN 12779:2004+A1:2009 and replaced it from March 2016. The English version, EN 12779, was published in November 2015.

The standard contains more detailed and supplementary safety-related specifications on the relevant requirements in Annex 1 of the EU Machinery Directive 2006/42/EC for machines placed on the market in the European Economic Area (EEA) for the first time.

The scope of the standard includes fixed plant installations designed to extract, convey, separate and temporarily store dust and chips which are created when solid woods (including hardwood) and wood materials are processed.

Revising the standard became necessary because DIN EN 12779:2005, apart from formal adaptation to the EU Machinery Directive 2006/42/EC in 2009, has been valid since May 2005 and is therefore outdated in technical terms, according to the VDMA, which represents over 3,100, mostly medium-sized, companies in the capital goods industry, making it the largest industry association in Europe.

However, the technical level of the standard was already partially outdated when it was first published in May 2005, due to the extensive discussion and editing period that preceded its publication. As a result, the VDMA Air Handling Technology – Wood Working Group had to convene in July of that year to discuss how to interpret the standard and to come up with initial correction proposals. Furthermore, subsequent practical tests showed that the old version contained various provisions that had not been considered sufficiently.

At the end of 2011, a revision to the standard was discussed in the European Committee for Standardisation (CEN), Working Group 10 of the Technical Committee CEN/ TC 142 Woodworking Machinery – Safety. The negotiations were concluded recently.

The revision took the national interests of the working committee NA 060-09-50 AA Dust Extraction Systems in the Air Handling Technology Association of the DIN Standards Committee Mechanical Engineering (NAM) into account. Representatives from manufacturers and users of woodworking machinery and dust extraction systems, and representatives from the Employers' Liability Insurance Association (Berufsgenossenschaft), were also represented.

All in all, the standard has been significantly optimised with respect to applicability, feasibility and clarity, while the level of safety has been increased substantially. The following examples are intended to demonstrate the positive effect of the revision.

The old version of the standard contained a requirement that the layer thickness of the filter cake must not exceed 15mm (Section 5.4.1.3). This was to ensure the required airflow rate. However, measuring and monitoring the cake thickness is not practicable with the equipment currently available. The new version thus calls for differential pressure measurement/monitoring, which is much easier to implement, with more useful results.

Another negative example from the old version is the demand that the extinguishing piping for the filter unit must be at least 5m away from the filter housing. The assumptions in case of fire on which this provision is based are not very realistic; according to the new version of the standard, the fire extinguishing line may be located directly on the filter wall.

Additional simplifications and exemption provisions were agreed during the revision. For example, individual construction-related explosion protection measures may deviate from EN 1127-1:2011 if a model of the entire plant has been subjected to an explosion test (DIN EN 12779:2016, 5.4.3.3) as an alternative. This can result in enormous savings, while maintaining identical safety levels.

However, stricter provisions have also been added. One example is the introduction of performance levels (PL) for safety controls.

The control must conform with various requirements here (PLs) (Section 5.2, p14 of the standard), depending on how critical to safety the magnitude to be controlled is.

This brief overview of the most important changes to the standard is intended to motivate users to read the final version, published in March 2016. Once DIN EN 12779:2016 is specified as a harmonised standard in the official journal of the European Union, any manufacturer applying it can assume that he has complied with the requirements of the Machinery Directive as specified in the standard.

Below is an annotated comparison of DIN EN 12779:2004+A1:2009 and DIN EN 12779:2016 in table form. The standard is available from Beuth Verlag in Berlin (www.beuth.de).

The NA 060-09-50 -01 AA working committee ‘NWI Dust Extractors’ in the Air Handling Technology Association of the DIN Standards Committee Mechanical Engineering (NAM) is currently reviewing the new draft of the standard E DIN EN 16770:2014 Safety of woodworking machines – chip and dust extraction systems for indoor installation – Safety requirements in preparation for formal consultation.

A woodworking machine with dust extraction