Bordering Chinatown on the east side of downtown Washington, D.C., Verizon Center, comprising 1,020,000 square feet (94,760 m²), is both a retail and multi-purpose entertainment complex hosting two major sports teams (NBA and NHL).
The original design drawings and construction documents were reviewed to provide a practical window cleaning/exterior building maintenance and fall arrest system. In this project, many window areas were located below large roof overhangs occasionally obstructed by signage and a decorative steel superstructure. Also the arched roof with low parapets required special consideration since these types of roofs can be difficult to service for roof inspection and maintenance, and annual inspection of the roof anchorages as required by law.
Pro-Bel Technical Approach
For this project, ground rigged davits were employed on the roof and davit arms are moved from base to base around the perimeter of the roof. Ground rigged davit masts are typically short and easy to handle, and is a popular method of rigging with window cleaners i.e. the platform is set up and moved from drop location to drop location at ground level. Hoist motors lift and lower the platform and workers independent lifelines are secured to roof mounted safety anchors.
Rigging sleeves were installed on the roof at overhang locations since the only option for suspending lines was, in many instances, through the roof. Pro-Bel rigging sleeves provide pathways through roofs, floors and walls or other inaccessible elements for suspension lines or lifelines where access would otherwise be difficult, unsafe or impossible. For this facility, to show how versatile sleeves are, one rigging sleeve was engineered to fit beneath a spectator seat.
To access all roof mounted Pro-Bel equipment or anchors located close to the precipice-like roof edges, workers safety harness lanyards are secured to a Pro-Bel horizontal cable lifeline system to provide safe, continuous horizontal mobility.