Accidents, in some cases severe, have occurred in the past during work with large forestry machinery. This has prompted KAN to commission a study1 into whether, and if so, to what extent, certain essential requirements of the 2006/42/EC Machinery Directive are supported by the standards governing forestry machinery. The study revealed a need for various aspects of the existing standards to be revised and improved.
The study focused upon the standards governing large forestry equipment. This equipment includes self-propelled forestry machinery (prEN ISO 11850; EN 14861) such as harvesters, skidders and forwarders, with which trees are felled and the trunks cut to size and transported away. Two standards for winches (EN 14492-1 and ISO 19472) and one standard governing wood chippers (EN 13525) were also studied.
Focus on the field of vision, emergency stopping and remote control
The study was performed by the KWF, the German Center for Forest Work and Technology. It revealed the areas in which the standards adequately support the requirements of the Machinery Directive under examination, and those in which, from a prevention perspective, amendments must be made.
A major problem area is that of visibility of the danger zone. For self-propelled forestry machinery in particular, requirements concerning visibility from the driving position must be formulated and introduced into the standardization process. An alternative would be development of a dedicated visibility standard for all forms of forestry machinery.
The topics of emergency stopping and remote control are dealt with inadequately, if at all. Current wood chippers only have a feed control bar, which however does not constitute an emergency-stop device. Whether an emergency- stop device would increase user safety should be examined. Remote controls are being employed increasingly frequently, not least for winches; they present new risks, for example owing to the distance between the machine and its operator. These risks must be addressed in future by the standards.
The standards studied also pay insufficient attention to ergonomics. For example, one winch standard contains no provisions whatsoever governing ergonomics. Other standards make reference regarding this aspect to further standards which in some cases are outdated. Specific provisions in this area should be added to the standards themselves, or the references at least updated.
Structure of the body of standards
At present, all self-propelled forestry machines are governed by a single, generic product group standard: EN ISO 11850, which is due to appear shortly. In order for the particular hazards presented by certain machines to be addressed in detail, supplementary product standards should be developed, for example for harvesters, forwarders and skidders.
An unfortunate situation has arisen through the simultaneous existence of two winch standards presenting differing requirements. In order to assure clarity, they should be merged and amended; all winch groups (traction winches, yarders, winch units) must be treated separately.
Specific requirements governing yarders are absent from standards. KAN will therefore lobby for Germany to support the application submitted to CEN for a standard to be created for this purpose.
A by-product of the study was the observation that choker chains and ropes by which logs are transported on the ground are not currently addressed by standards. KAN recommends that requirements concerning this slinging equipment for cable skidding be governed in standards.
At present, the standard governing wood chippers relates only to machines with manual feed. Since crane-fed machines are also used in commercial wood-chip production, the scope of the standard must be extended to include them.
Mirror committee for forestry equipment should support standardization activity permanently
KAN has requested that DIN create a standing mirror committee for the standardization of forestry equipment, the tasks of which should include implementation of the study results. In the past, agreement has been reached at national level in an ad-hoc group. The new mirror committee should monitor European and international standardization actively, and submit the results of the study to the standardization process in the form of agreed national comments.
Katharina von Rymon Lipinski
1 KAN Report 48, "Safety of forestry machinery"; www.kan.de/en