ALCOSAN Expansion Uses Intumescent Fire Block for Deep Cladding Cavity

The Allegheny County Sanitary Authority (ALCOSAN) is expanding its East Headworks facility in Pittsburgh, Pennsylvania, to increase treatment capacity from 250 million to 600 million gallons per day. The project serves over 83 municipalities. An engineered stone cladding system was selected for the facade, triggering fireblocking requirements under IBC Section 718.2.6 for exterior wall coverings. The cladding's unusually wide ventilated air cavity posed a compliance challenge. To meet code, the project team chose Tenmat's FF102/50Plus Intumescent Fire Block, which expands across the large gap while maintaining airflow and moisture management. The solution allowed ALCOSAN to proceed with its preferred cladding design.