Investigation and Repair of a Curtain Wall Damaged by a Blast

The explosion of an oxygen tank within a patient room of a recently constructed hospital caused damage to the building’s facade, which consists of a stick-built aluminum-framed curtain wall with insulating glass unit (IGU) infill. Damage included permanent deformation and fracture of the curtain wall mullions. To minimize the scope of repair work that would disrupt the operations of a working hospital, a two-stage field investigation was performed by architectural and structural engineers working in collaboration with the original construction contractor’s personnel. First, to identify the minimum extent of framing replacement required to address structural damage, visual surveys and measurements of the interior and exterior surfaces of the curtain wall system were performed. Second, to test the hypothesis that the extent of glazing damage might exceed the extent of structural damage, in-situ frost point testing of IGUs was performed in accordance with ASTM E576, Standard Test Method for Frost/Dew Point of Sealed Insulating Glass Units in the Vertical Position, to determine whether the perimeter edge seals of IGUs were damaged in surrounding areas where curtain wall framing repairs were not required. The repair program included temporary shoring to maintain the structural stability of the partially disassembled curtain wall during replacement of damaged structural and glazing components, followed by water penetration testing on the repaired portion and surrounding areas, to verify the repaired system’s ability to resist water penetration. This paper will demonstrate how multiple engineering disciplines, with contractor support, can develop cost-effective and quickly implemented curtain wall repairs that avoid unnecessary replacement of undamaged components.