Engineer's Corner: FISP Inspections of Curtain Wall Buildings



By Grace Gallagher, Sullivan Engineering

Curtain wall façades have become increasingly popular in New York City over the past several decades, and it is common to see newly constructed buildings boasting glass curtain wall systems. Curtain wall manufacturers are required to rigorously test their systems to ensure they can handle wind loads; however, exterior inspections of curtain wall façades should still be periodically performed to ensure their performance and safeguard pedestrians. Under the New York City Department of Buildings (DOB) Façade Inspection Safety Program (FISP), formerly Local Law 11/98, the façades of all buildings over 6 stories must be cyclically inspected for any conditions that could threaten the public’s safety. Since most buildings constructed with a curtain wall façade are at least 6 stories high, they are almost always in the FISP universe, and mandated for inspection by a Qualified Exterior Wall Inspector (QEWI) every FISP cycle.

Glass curtain wall can be difficult to inspect for a host of reasons. Access to perform physical inspections via a boom lift or suspended scaffolding must be arranged. Also, coordinating access to courtyards, balconies, fire escapes, the roofs of neighboring buildings, etc. to perform both visual and physical inspections can involve lengthy and sometimes frustrating negotiations. The building envelope professional should understand what constitutes an “unsafe” vs. a “SWARMP” (Safe with A Repair and Maintenance Program) condition. Common “unsafe” conditions include loose trim pieces and broken glass. Typical examples of SWARMP conditions deteriorated sealant at metal-to-metal joints, missing or damaged glazing gaskets, and rusted or deteriorated metal. When façades are not entirely constructed of curtain wall, it is important to check the joints between the curtain wall panels and the adjacent material to ensure that the sealant at these joints is not failing.

Most repairs for unsafe and SWARMP conditions are fairly straightforward: broken glass can be removed and replaced, loose trim pieces can be secured to the window frame with a bead of sealant, and deteriorated sealant can be removed and replaced. Replacement of deteriorated glazing gaskets can be more challenging as preset gaskets are not easily removed and replacing preset gaskets can require removing and resetting the glass.

Curtain wall buildings should be regularly inspected by a Qualified Exterior Wall Inspector (QEWI) to ensure that no unsafe conditions develop over time. QEWIs should also inform building owners and property managers of any identified unsafe or SWARMP issues so that the proper façade maintenance and repair work can be performed and no incidents resulting from unaddressed unsafe or SWARMP conditions occur.

Photo: Since most buildings constructed with a curtain wall façade are at least 6 stories high, they are almost always in the FISP universe, and mandated for inspection by a Qualified Exterior Wall Inspector (QEWI) every FISP cycle. (Source: Sullivan Engineering).


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