Discussion of window washing support and equipment is covered in two separate articles. This article covers the two main platform systems including cages and bosun's (boatswain's) chairs. The first article covers different kinds of primary window washing anchors and suspension systems.
Bosun's / Boatswain's Chair
Bosun's chairs are the most common form of platform used by window washers and facade maintenance crews. However, some companies and jurisdictions do not use them because of safety concerns.
The chairs, shown at left, carry a single person in the seated position. The diagram at left shows the chair suspended from a portable outrigger system, but it can be used with any suspension system. There is always a secondary fall arrest line that is attached to the worker and tied to a different anchor than the platform. Bosun's chairs are decent controlled and cannot be used for ascending.
Cage systems provide more flexibility than Bosun's chairs. Since the cages are powered by on-board motors, the cages can descend and ascend a building. In addition, cages come in various widths (generally up to 10 feet wide) allowing workers to access a wider area of the facade. The first diagram below shows a single-person cage suspended from a davit arm. The second diagram below shows a cage that is 10 feet wide, which can accommodate two workers, suspended by a roof car. There is always a fall-protection line provided for each worker and each of them must be tied to a different anchor.