>>508822946
Sash windows are low to the ground. A toddler can climb onto the window board and fall right out. It happens. When you release the keep the window lifts up and provides a huge vent, for a lovely breeze.
Windows less than 500cm from the floor must be toughened glass, to stop people falling against them and opening an artery. The anti-pigeon spikes on the sill stop bird shit building up. We do things properly here in Blighty.