04/12/2018_Window walls are a type of metal curtain wall installed between floors or between floor and roof and typically composed of vertical and horizontal framing members, containing operable sash or ventilators, fixed lights or opaque panels or any combination thereof.
Advantages over stick or window wall systems:
1. System partially built under factory conditions leading in higher quality. There is some field work required to install sill and head tracks and make seals which are prone to workmanship errors in the field.
2. Performance achievable for thermal, structural and water infiltration resistance is middle of the line.
3. Fabrication of panels is done during the erection of the building frame and can be concurrent for faster installation.
4. Logistics and staging can be done from each floor and multiple panels can be hoisted to floors for local installation and staging at the floor level.
5. Opaque portions of the façade can be incorporated within a façade unit.
Disadvantages compared to other system types:
1. Window walls are usually mounted on top of the slab, and as such, allows for less tolerance in the concrete.
2. Exterior access is required for installation of slab edge insulation and metal covers increasing the amount of field labor required and logistics of the installation.
3. Head and sill tracks are the most critical components that are prone to leaks. These components are installed and sealed in the field that can lead to workmanship errors.
4. Very few systems that can meet the stringent air infiltration requirements of the code which affects competitive procurement.
5. Difficult to achieve thermal and condensation performance of the project using off-the-shelf systems window wall systems.
6. Customizing and using a new extruded system increases cost reducing the cost-benefit of these systems.
Durability and Life expectancy:
Window walls can be expected to achieve 20-25 year life with proper maintenance.