Stability of METU Profiles (ZI-711)
Deformation Measurements on Rectangular Air-ducts and Parts of the Rectangular Duct Connections: Since their introduction into the market (Patent No. 1 946 547 dated 13.09.1969), the METU-SYSTEM triangular shaped profiles (MM, HM, RM) provide an optimal stability to the rectangular duct connections. The independent MPA tests (only available in German), conducted on October 11th, 1972, proved the superior stability of the METU-SYSTEM profiles when compared to other profiles and rectangular duct connection methods available at that time, including angle iron.
The METU Rectangular duct connection are still considered by many users today to be the strongest on the market, reducing or even eliminating the necessity to use clamps. No Ex or ATEX certifications.