Correct Installation for Maximum Safety
An anchor point consists of a bar that is fixed to a roof and has an eye to which lifelines and lanyards can be attached. These can be permanent anchor points for regular window washing and maintenance or can be temporary for one-off or infrequent jobs.
Anchor points are typically installed in pairs, with window washing tie-back anchors for the suspension line and the second anchors for the fitting of lifelines (or safety lines). These anchors are generally installed in line with the point of suspension, with an offset degree to the lifeline. Anchors are typically placed six feet apart for a narrow roof area and up to twenty feet apart where space permits.
The building parapet has to be able to withstand the applied loads (310 pounds working load, 900 pounds fall arrest load, and 1,800 pounds factored fall arrest load). Non-structural parapets will generally not withstand such loads so a davit arm will normally be used.
Window washing on relatively low buildings can generally be accomplished using ladders, lifts, or water-fed poles. However, window washing anchors are necessary for any building that is higher than three storeys.
According to OSHA regulations, rope descent systems fixed to anchor points can be used on buildings with a drop height no greater than 300 feet. These are also known as direct rigging systems and enable operatives to work from a cradle supported by ropes. For buildings of a greater height, a suspended platform hung from davit arms is the recommended method of working. This is a more costly method to install but is extremely effective and efficient in use, with davits usually placed twenty feet apart and roof safety anchors fixed between or behind the davits to attach vertical lifelines.
