How do you clean windows hundreds of feet above the ground?

For a skyscraper, washing the glass isn't as simple as sending someone up with a bucket and a squeegee.

Buildings need specialized machines, suspended platforms, cables, anchors, motors, safety systems, and carefully engineered access equipment.

In Engineering Insights S2 E86, we explore the engineering behind high-rise window washing systems and how crews safely work on the exterior of some of the world's tallest buildings.

We begin with the building maintenance unit, or BMU — systems often mounted on rooftops that can move platforms across the face of a building.

These machines must support workers and equipment while resisting wind, movement, and changing loads.

We explore how cables and hoists control the platform' ...