The new ETAs come with a number of formal and application-related improve-ments, and overall the structure of the assessment has become easier to understand and more user-friendly. Better resistance parameters and pull-out values enable significant load advantages, a larger range of applications and greater cost-effectiveness. The basis for the use of HECO's universal and wood screws is ETA-11/0284 – it covers all wood screws of the HECO-TOPIX® family and HECO-FIX®-plus universal screws. On the other hand, ETA-11/0452 still regulates the use of HECO-UNIX screws.
What's new in ETA-11/0284: 50% more bearing load
Previously, HECO-TOPIX®-Therm and HECO-TOPIX®-CombiConnect screws were dealt with separately to usual wood screws. Both these designs are now covered by ETA-11/0284, together with the other HECO-TOPIX® versions and HECO-FIX®-plus universal screws. The most significant improvement in this context is the increase in the head pull-through parameter from its previous level of 9.4 N/mm2 to 14 N/mm2 (15 N/mm2 for hard wood), which sums up to a load increase of around 50%. This results in considerable benefits for the user, in particular in on-rafter insulation with part-threaded screws, because far fewer fastening points are required and the project can be implemented more economically with more material savings. Moreover, ETA-11/0284 describes the dimensioning of the screws for use for transverse reinforcement of openings and cross sectional weak points. It also includes screw connections on the end face when using screw-in angles of 0° to the grain with an extension of the screw-in depths. The approval range of full-threaded screws has been extended to include further dimensions, which gives a broader range of applications in timber construction.
What's new in ETA-11/0452: end face work
Screw connections on the end face and parallel to the grain were also included as an important improvement within the scope of the enhanced ETA for HECO-UNIX screws. As a result, there are reduced wood cross sections and a better utilisation of wood material with even more safety for the specific application. Otherwise the content of the ETA which applies to HECO-UNIX-plus and HECO-UNIX-top products has not changed. However, the new approval structure in timber construction comprises a novelty: Both newly issued European Technical Assessments (formerly known as “approvals”) are no longer restricted to a certain period of validity, but are now valid indefinitely.