Casement Window
Casement windows are hinged at the sides and can be build for inside or outside opening. The type of opening is up to your choice, for outside opening the security grills have either to be fitted inside, which makes it very difficult to clean the window, or if put outside, designed in such a way that there is sufficient space to open the window.
If the window is made for inside opening, then the security grill can be fitted outside which allows for easy cleaning of both sides of the window.