By: Edward Pon permanent scaffolding
April 28, 2021
Local Law 10 and Local Law 11, or most recently FISP (Façade Inspection Safety Program), regulations have been with us since 1980. Since then, New York buildings seem to be constantly adorned with sidewalk sheds, suspended platforms, or pipe scaffolding. There is an entire sub-industry of permanent scaffolding and sidewalk shed installers that is closely tied to the exterior façade restoration construction sector.
We are now in the midst of the 9th FISP cycle. There are still some buildings that are very poorly maintained, but these seem to be very few and far between, at least for those that are over 6 stories tall and require FISP inspections and filing. There are very few buildings that have gone 40 years without having underwent a major façade restoration. Most conscientious building Owners have gone through many cycles where the worst and most hazardous conditions have been addressed and repaired. It has gotten to the point where it is not uncommon to find that the cost to rig the buildings exceeds the cost of repairs.
Since FISP regulations are here to stay, this is why it is important to look at ways to reduce the cost to rig our buildings. Designers of many new, tall buildings have taken these considerations into account and equipped their buildings with their own façade maintenance systems, “house rigs,” or derricks. At the other end of the spectrum, some buildings have completely ignored the issue of maintenance altogether and are notoriously difficult to rig. These may have very narrow setback terraces, facades with reverse setbacks, overhangs at upper floors, or recesses at lower floors.
Typically, permanent scaffolding or suspended platforms that are used to perform repair work on the exterior of most buildings are either “hooked” or “suspended” with outriggers. Hooked platforms are platforms that are supported from steel “C” hooks that are simply hooked over parapet walls. Outriggers are comprised of swing stage platforms that are supported from cables on the front end of cantilevered beams that rest on roof decks or terrace setback roofs counterbalanced with thousands of pounds of counterweights attached to the back end of the beams.
All suspended platforms, whether on hooks or outriggers, require 2 tiebacks (one for each hook or outrigger beam), and at least 2 (sometimes 3) tiebacks for worker safety lines. The third safety line is reserved for a third man or architect/Engineer inspector. In total, each typical suspended platform will require up to 5 tiebacks. Tiebacks are a second safety attachment point that will secure the scaffold supporting equipment or personnel in the event of a failure or an overloading event and prevents the equipment or workers from falling to the street below. These tiebacks must be secured to the building structure, such as another parapet wall, steel dunnage, or a roof bulkhead. Mechanical ducts, plumbing vent pipes are not sufficiently strong and are unacceptable tieback attachment points. Tiebacks for platforms must withstand a 5,000 pound lateral load and safety lines for workers must withstand a 1,000 pound lateral load.
By code, tieback lines must extend perpendicular to the building face horizontally and cannot be run upwards at a steep angle. The problem is that sometimes many tall buildings that are terraced “wedding cake” style often have very narrow terraces that are not wide enough to accommodate the outriggers beams, supports, and counterweights and often, there is no convenient structure for a proper tieback. Sometimes tiebacks wrap around the masonry or pier between two open windows. And sometimes contractors go to great lengths by removing face brick, through bolting to back up masonry, etc., to secure tiebacks to the structure of the building only to remove everything when they are done. However, in another 5 years to 10 years, this same work will have to be repeated. We recommend taking a longer view by considering an option to spend a bit more at the very beginning of a project and designing a permanent anchor point that can be reused in the future.
The designers of the older terraced building never anticipated the need to accommodate suspended scaffolding equipment and tiebacks. The frequency to rig a building to perform FISP inspections and repairs make the case for designing and installing permanent supports or tieback anchors that are anchored back to the structural steel or concrete frame of the building. These anchor points make setting up outrigger beams and safety lines more convenient, expedient, and less expensive.
These requires both a licensed structural engineer and architect to provide a design that can complement or blend in and almost disappear against the façade material. The steel anchor must be designed to withstand corrosion not only on the face, but behind the masonry face brick, and can be fitted with removable threaded eyebolts and nylon plugs that maintain water tightness when eyebolts are removed.
The initial installation will require a building permit, and each subsequent installation of the scaffolding will still require a licensed rigger to file the CD-5 permit with the Department of Buildings, Cranes and Derricks Division. A copy of the initial signed and sealed set of the structural design drawings must be kept on hand by the Building Manager. Also, if the building can accommodate the storage, purchasing and storing the outrigger beams can lower the subsequent installation costs of the rigging.
Below are examples of permanent anchors that we have designed and installed on difficult-to-rig buildings to accommodate supported (pipe) scaffolding or suspended scaffolding:
- Safety line eyebolts permanently anchored into an embedded concrete pad on the centerline of roof slabs because parapet walls were too fragile to install parapet clamp anchored safety lines
- Tube steel welded to structural steel columns with end caps set flush to the face brick. End caps are drilled and tapped to accommodate ¾” eyebolts for tie backs on a steeply terraced “wedding cake” building with no safe options to secure the safety lines and outrigger beam tie backs
- Wide flange sections welded to structural steel columns that protruded 6” from brick face and end plated, which bolted to removable end plated cantilevered wide flange sections providing a steel frame platform for support of pipe scaffolding on a building with inaccessible terraces as they were fully enclosed with glass sunrooms
- Outrigger beam end anchors (no need for separate tiebacks) and safety line tieback anchors anchored to reinforced concrete beams with mounting plates flush with face brick
Although there is a significant upfront cost to design and install these anchorage point systems, we estimate that depending on the complexity of the design, the payback period can be returned after 3 to 6 uses of the system.