Roof Lights with Protective Netting
A recently published patent filing by Evonik Röhm GmbH describes a newly developed process for reinforcing transparent building elements such as domed roof lights made from plastic. The background of the invention: when cleaning snow off roofs or when repairing and servicing air conditioning or satellite equipment on roofs, accidents accompanied by severe injuries occasionally occur, because someone falls through a skylight made from plastic.
To prevent this, a numerous safety measures have been used to date. For instance, wide-mesh metal netting secured between the outer and inner panels of the roof light have been employed to prevent someone falling through. The drawback here, however, is that this limits design freedom, and the metal mesh can cause optical irritation, for instance, when workplaces are located beneath the skylight.
The patent application proposes to increase the shatter resistance of these roof elements by incorporating a net made of threads, wires or tapes. This net could be made from PA, PE or PP and be molded into the matrix material. The benefits of this method are listed as low manufacturing costs, no disruption of transparency, great design freedom, little tendency to splinter and simple cleaning / maintenance.
A roof light made from PMMA with PA netting to provide protection against someone falling through was subjected to a fracture test in accordance with Standard EN 1873. Drop tests from three different heights were performed, and the roof light did not shatter even at -20°C. Although the roof light cracked during the first drop test, the subsequent drop tests did not cause it to shatter.