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 and Roof Anchors Explained for more). So what exactly are davits, davit arms, davit bases, and davit systems then?
Davit Arm Assemblies
Davit arms are commonly used to rig over non-structural parapets, decorative cornices, and glass balcony guardrails. These arms act as the primary suspension points usually for swingstages, but are also used for supporting single man cages and bosun’s 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, 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 allow it to pick the platform up from ground level, and hoist it onto the roof. The stage is then relocated on the roof level to align with each “drop” location.
- 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 size vary depending on building requirements.
- At times, arms that are very large or are required in difficult to access areas, are recommended or necessary to be permanently left in place for facade access. Also referred to as, “dedicated arms”.