Storefront Systems
Summary
Storefront systems are shallow aluminum frames glazed on site with glass or panels to form entrances, retail fronts, and low-rise glazed walls. They are designed to the project's opening, span, and glass, and they carry lower wind and water performance than curtain wall, so test data and glass design must be checked against project criteria.
Cols
Terminology
- Storefront: framing for low-rise glazing, usually one story, glazed from outside or inside
- Curtain wall: deeper, higher-performance framing spanning several stories
- Window wall: wall built from window products
- Thermal break: insulating strip between inner and outer metal
- Mullion: vertical or horizontal frame member between lites
- Entrance: storefront door and frame set into the system
- Sealant joint: wet or dry seal that keeps water out of the frame
Standards
Storefront and curtain wall differences
- Storefront framing is about 2 in. deep; curtain wall is typically 6 to 7 in.
- Storefront relies on sealant joints for water management; curtain wall uses a pressure-equalized system with internal gutters and weeps
- Basic storefront frames often have no thermal break; thermally broken types cost more and still do not match curtain wall
- One source puts storefront design pressures at about 30 to 50 psf versus 60 psf and above for curtain wall; sources conflict
Test standards
- ASTM E283: air leakage
- ASTM E330: structural performance under uniform static pressure
- ASTM E331: static water penetration
- AAMA 501.1: dynamic water penetration
- AAMA 503: field testing of newly installed storefronts, curtain walls, and sloped glazing
- AAMA 501.4: interstory drift for window walls
Materials
- Aluminum extrusions: framing members
- Glazing: insulating glass, laminated glass, and tempered glass
- Gaskets and sealants: water and air seals
- Entrance doors: aluminum or all-glass doors set in the system
Detailing
- Verify the project wind load against the manufacturer's tested pressure for the span and lite
- Design anchors, slab edge, and head and sill flashing with the wall system
- Specify glazing type with the framing maker: glass thickness, safety glazing, and coatings
- Decide whether a thermal break is needed from the energy requirements
- Coordinate entrance hardware, power, and accessibility
- Set field testing under AAMA 503 where the project needs proof
Uses
Specific uses
- Retail fronts and lobbies
- Ground-floor entrances
- Interior partitions and vestibules
- Low-rise glazed walls
- Window openings in commercial buildings
Pros and cons
Pros
- Lower cost than curtain wall
- Quick site assembly
- Many glass and finish options
Cons
- Lower design pressure and thermal performance than curtain wall
- Depends on sealants for water control
- Limited span and height
Manufacturing and cost
Construction
- Extruded aluminum members are cut, fabricated, and shipped as sticks or kits, then assembled and glazed on site
Main manufacturers and suppliers
Trade association: Fenestration and Glazing Industry Alliance.
Sources
- Construction Specifier: window walls, blurring the line between glazing products, https://www.constructionspecifier.com/window-walls-blurring-line-glazing-products/2/
- Projul: curtain wall vs storefront glazing guide, https://projul.com/blog/construction-curtain-wall-vs-storefront-glazing-guide/
- BNP Media: design considerations for commercial fenestration systems, https://continuingeducation.bnpmedia.com/courses/national-glass-association/design-considerations-for-commercial-fenestration-systems
- Construction Specifier: vertical visions, selecting and specifying curtain wall systems, https://www.constructionspecifier.com/vertical-visions-selecting-and-specifying-curtain-wall-systems/