Inspection and marking

Considerable care is required when making bonded joints, since glue faults are very difficult to detect retrospectively. Manufacturers of Duobalken^® and Triobalken^® beams are therefore required, in accordance with DIN 1052:2008 or DIN 1052: 2004 Annex 1, to have a valid permit for the gluing of load-bearing timber construction components (a so-called “gluing permit”), permit A, B or C. The gluing permit is a form of qualification certificate for the manufacturer, similar to the welding permit for steel construction work. The gluing permit is issued by the Materialprüfanstalt Universität Stuttgart - Otto Graf Institut – acting on behalf of the Deutsche Institut für Bautechnik.

In addition to requiring a gluing permit, manufacturers of Duobalken^® and Triobalken^® beams must also set up a system of internal production controls and have inspections carried out by external agencies. The nature and scope of these are specified in the product approval, with reference to DIN 1052:2008, Annex I. Duobalken^® and Triobalken^® beams have to be labeled with the “Ü” mark (mark of conformity) shown below on the building component itself, on enclosed paperwork, the packaging or the delivery note. In addition, the description of the object of approval, the grading class and the date of production also have to be specified on the building components and/or the delivery notes.

Example: Duobalken^®, S 10-TS-Fi/C24, 01.04.2007

If the product is given preservative treatment in accordance with DIN 68800-3, additional labeling is also required, along with certification in accordance with Section 10.2 of the standard.