I often hear people referring to window washing systems as davit systems. While this certainly is true, it is not the only way to complete window washing (see The Roof Anchor Guide and Roof Anchors Design And Installation Guide for more information). So what exactly are davits, davit arms, davit bases, and davit systems then?
Davit Arm Assemblies
Davit arms are used to rig over non-structural parapets, decorative cornices, and glass balcony guardrails. These arms act as the primary suspension points, usually for swing stages, but are also used to support single-man cages and bosun chairs. Comprised of a mast (the vertical piece) and boom (the horizontal piece), davit arms are secured to the structure using bases. These bases vary to suit the roof or wall construction.
The main distinction in Davit systems is whether or not the system is designed to be ground-rigged or roof rigged. In a ground-rigged scenario, each successive “drop” is done by picking up the platform from ground level, raising it to roof level, and then back to the ground level. At ground level, the platform is then moved to the next “drop” location.
In a roof-rigged scenario, the mast on the davit arm is tall enough to lift the platform from ground level and hoist it onto the roof. The stage is then relocated to the roof level to align with each “drop” location.
Quick Facts
- Davit arms are typically portable and are relocated to new bases for every drop.
- They can be broken down into segments for ease of carrying.
- Mast and boom sizes vary depending on building requirements.
- At times, very large arms or arms required in difficult-to-access areas are recommended or necessary to be permanently left in place for facade access. These are also referred to as “dedicated arms.”
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