Aluminium Louvres for Vertical Applications The WPL 100 Vertical Louvre (LouvOsborne-Hume Grilles & Louvres Ltd er) is an all aluminium model for vertical applications. * Free Area % Chart Louvre Widths: 0.138 to 0.687 - 0.748 to 1.297 - 1.358 to 1.907 - 1.968 to 2.517 * Free Area m2 Chart Louvre Widths: 0.138 to 0.687- 0.748 to 1.297 - 1.358 to 1.907 - 1.968 to 2.517