Why are sash windows best for safety, well they are incredibly safe, despite acting like a guillotine!
Just think about the way they open, they slide vertically, straight up or down, so unlike other styles, sash windows do not open outwards, therefore there are no sharp corners for little heads to bash into.
Sadly, many companies don’t follow the guidance in the Building Regulations, it says that care must be taken not to install windows that open directly onto pathways or pedestrian areas immediately adjacent to buildings. Side opening windows may cause harm to youngsters in a play ground and top opening fan lights will seriously hurt adults if they walk into them.
Windows that open inwards dont help either. They interfere with curtains and blinds and when opened fully leave a huge void which is easy to fall through at low level (tilt and turn styles when being cleaned).
It is vital however to ensure the sash cords are well maintained or that new windows have the strongest quality balance mechanisms (like Torso balances from Caldwell), then there should never be any concern that a sash will suddenly fail.