Once the staff beads are open, the catches on the top of the sash can be unlocked. There is one at either side of the meeting rail on the bottom sash, and again at either side of the top rail of the top sash. The bottom sash should be opened first.

The catches are on springs and must be held in position as the sash is tilted on it's pivot.

Once the bottom sash is open the top one can then also be opened.