How does a curtain wall system handle water infiltration, air leakage, and pressure equalization?

Water infiltration and air leakage are managed in a metal curtain wall system through a combination of gasket design, pressure-equalized cavities, drainage paths, and tested sealing systems. A pressure-equalized curtain wall system segregates the external face from the inner cavity, allowing the cavity to be vented so that the pressure inside the cavity approximates external ambient pressure; this minimizes the net driving force for water penetration at seals and joints. Primary weather seals (EPDM gaskets, silicone sealants) prevent direct water passage, while secondary internal seals protect against incidental moisture. Open drainage systems within mullions and transoms direct any infiltrated water down to weep holes and out of the building; properly graded internal channels and redundant drainage paths reduce clogging risk from dust and sand prevalent in Middle Eastern climates. Air-tightness is achieved with continuous compression gaskets, precision extrusions, and strict installation tolerances; air leakage testing (per AAMA or EN standards) validates performance. Movement joints and thermal breaks maintain seal integrity despite expansion and contraction. For coastal or heavily polluted Central Asian sites, specifying larger weep sizes, corrosion-resistant drain components and routine maintenance of drainage routes ensures long-term functionality. Successful water and air control relies on an engineered façade system, validated by mock-up testing and careful on-site installation supervised by the curtain wall manufacturer.