Hazard Description
The roof of one Downtown Seattle highrise is made up of three semi domes. The top semi dome is the complete length of the building. The second semi dome is a quarter dome for much of its length. The third semi dome protrudes 20 to 30 feet from the face of the building at a much lower floor.
Window washers accessed the dome windows of the building using a series of ropes tied off to anything that might be found on the building. As a result, workers were exposed to fall hazards in excess of 300 feet during window washing activities.
They were exposed to these fall hazards for weeks at a time during the quarterly window washing requirement. Even worse, they didn't use any fall protection when accessing the gutters of the building. And, when climbing the arched ladders (located on the ends of the semi domes) workers used a vertical lifeline and a crude rope grab made from a prussic knot. Then, once on top of the domes, workers rigged up a makeshift horizontal lifeline and rappelled off of the rope horizontal lifeline to reach the windows along the dome. They connected their fall protection system to the same synthetic rope from which they were rappelling.
Problems
The management company that operates the building's maintenance department was aware of the problems with the existing window washing practices, however, they were not aware of the legislation and regulations that applied to the resulting fall hazards. They were also unaware of the alternatives to the existing procedures and equipment, and they had little luck finding an engineering firm that had the knowledge to provide safe, effective fall arrest systems that were user-friendly.
The building managers had previously contracted an engineering and architecture firm to address the fall hazards encountered by the window washers. The firm provided solutions, drawings and engineering that were not acceptable alternatives and in some cases did not solve the fall hazards to which the workers were exposed. The building managers then contacted Gravitec.
The window washers who accessed the building did not see the inherent danger in the systems that they were using and because they wanted to provide the lowest price, they were not receptive to new access ideas.
Although there were drawings for the building, many of the outside areas had no detailed drawings of the building structure. Many of the areas where fall arrest anchor systems were required had no details about strength and structure.
Existing procedures and systems did not allow for 100% fall protection in all areas. In many cases, workers were not connected to a fall protection system when moving from one system to another.
None of the previously-contacted engineers could provide a fall protection system that would function on the arched ladders because the ladders stretched vertically, then reached angles between 0 and 90 degrees before finally reaching a horizontal orientation. There are very few fall arrest systems that can lock on an incline over 15 degrees and still function in a vertical and horizontal application.
Solutions
Gravitec took the time to educate the building maintenance department about the problems with the existing systems. Gravitec provided a report and an oral presentation that detailed all of the issues with the existing systems, provided as many solutions to the issues as possible and explained the pros and cons of each solution so that the customer could make a logical and educated decision.
Gravitec reviewed the proposed systems and provided the building management team with the reasons why the proposed systems would not work. Gravitec then provided alternatives to the proposed systems and ensured compliance with existing legislation and regulations.
Gravitec met with the users of the systems prior to installation and fabrication. The meeting was intended to get valuable input from the existing users of the system to ensure the systems, as designed, would meet all of their requirements and make any changes that would enhance the systems. The meeting also allowed Gravitec to present new equipment to the end users, educate them about the benefits of the new equipment, and involve them with the end product.
Gravitec had to perform non-destructive testing on many parts of the building to ensure adequate strength for the systems. In some cases, Gravitec removed the exterior façade to ensure that the underlying structure existed. Testing was performed by Gravitec technicians who employ a wide range of experience when testing fall protection systems.
Gravitec designed all of the systems and equipment so that there was seamless movement from one system to the next, ensuring that workers had 100% fall protection.
Gravitec used a combination of an off-the-shelf system along with specially-designed anchors that would function seamlessly on the arched ladder. A turntable was installed at the top of the ladder so the worker could climb one side of the system, spin around and descend the other side. None of the other companies that had proposed designs to address the fall hazards had offered this type of system for the arched ladders or matched Gravitec's attention to detail.
Conclusion
The end result was an integration of a number of fall arrest systems that provides compliance as well as 100% fall protection while workers are on the domed roofs and other areas of the building. Other engineering and fall protection companies were given the opportunity to provide solutions for the hazards that were presented, however, only Gravitec provided a compliant, cost-effective, safe and user-friendly system that directly addressed the user's needs and common sense.