The purpose of Part Q is to make a window sufficiently robust to resist its ability to be levered open or from the glass pane being removed intact from the window frame. The aim is to make the opportunist burglar give up these means of gaining access and either leave or have to break the glass to gain entry. Breaking glass can draw attention to the burglar and takes time. This will increase the chance of them being discovered. The thief will also need to remove shards of glass to avoid injury or leaving forensic evidence behind.
