Roof davits are essential to the maintenance of high-rise buildings; they ensure workers can conveniently and safely access the façade of the building. They are most often used by window washers, or in the construction or repair of tall buildings.
What is a Davit?
A davit, also referred to as a davit arm, is a part of a rooftop safety system that supports equipment suspended from the roof or over the edge of a building. They are most often used in conjunction with window washing platforms or other motorized façade maintenance equipment. Davits contain a base and an arm, often held together by galvanized steel sockets. The base is an immobile, permanent fixture mounted to the building, while the arm is mobile. It supports the suspended equipment, and it can be removed entirely when not in use.
What’s the Difference Between a Davit and an Anchor?
A davit is mobile, and it normally supports a platform or other suspended equipment when attached to a permanent base. Anchors, however, fundamentally refer to versatile U-bars or similar tie-offs that can come in many different shapes and mounting options: roof or wall. Both options can be secured to structure in multiple ways, but the most common methods are bolting through the structure, embedding into concrete, securing with epoxy bolts, or welding to/wrapping around the structure. Anchors are not mobile and are permanently attached to the building structure.
In general, because of their increased complexity and the rare necessity for mobility, davits are not the initial design concept for a rooftop fall protection system. However, in the specific cases they’re needed, they’re an invaluable safety component.
Options for Roof Davits
Alone or Paired
Davits can be used independently in situations where they’re supporting a single-person rope descent or single-point suspension scaffold. However, when they’re used in pairs they have the ability to suspend a power platform with hoists mounted on either end.
Ground or Roof Rigged
Ground-rigged davits offer an anchor point for suspending a platform set on a lower level, such as the sidewalk or street. Roof-rigged davits are set up to initially rig and board a platform on the roof, which will then be launched over the edge and suspended against the building façade.
Davit System Considerations
Roof davits are not ideal for every situation. Here are just a few of the guidelines you should follow when considering if a roof davit is right for your maintenance and fall protection system.
- The building should be less than 490’ tall. Davit systems are most often used on buildings between 300′ and 490′ tall but can also be used on buildings shorter than 300′.
- Platform lengths, and therefore davit base spacing, can exceed 20’ without minimizing effectiveness.
- The construction includes a base attached to the structure, plus a mobile davit which connects to the base sometimes with the use of a socket.
Wikstrom Engineering Consulting, P.C. has over 14 years of experience and clients across the country—we perform over 375 inspections annually to ensure the safety and compliance of rooftop fall protection systems. Put your employees in the hands of experts you can trust.
