Cause determination for the failure of the bonds
between solar elements and the substructure
Instead of the usual method of installing a solar system on a roof by individually mechanically attaching the elements to the roof in a time-consuming, labor-intensive and costly way…
… 12 elements were each bonded to a substructure in a factory hall, so that they could then be installed on the roof with a minimum of personnel and in a time-saving manner.
However, only 4 months after completion, during a period of strong winds with wind speeds of up to 14 m/sec, the bonding to a first solar element failed.
Further failures occurred as a result of strong wind and storm conditions. Storm “Xaver” then caused serious damage in December 2013.
Several application errors – in the planning, design and execution of the bonding – could be proven to be the cause; here are two examples:
The incompletely filled adhesive flange allows the adhesive to be loaded by water…
…it would have been advisable to fill the adhesive flange completely and thus avoid water enter and at the same time increase the mechanical strength by increasing the bond area.
It was not checked whether the selected adhesive showed sufficient adhesion to the materials involved.
The adhesive failure pattern on the defective parts clearly shows that this was obviously not the case.