A storefront is usually the first glass a guest or customer touches: the hotel lobby entrance, the restaurant frontage, the ground floor of a mixed-use building. In much of Florida it’s also the glass most exposed to wind-borne debris, because it sits closest to grade.
That combination puts storefront under more scrutiny than almost any other part of the envelope. The system has to look right, open and close thousands of times, keep water out, and in many locations hold its glass after a missile impact and hours of cycling wind pressure. It also needs an approval that matches the exact configuration on the drawings, or the permit stalls.
This guide explains what an impact storefront system is, how it differs from non-impact storefront, what drives its performance, how Florida approvals work, what architects should specify, and what to check before replacing an existing storefront. It’s written from the perspective of a Florida manufacturer that fabricates its storefront systems in-house.
What is an impact storefront system?
Short answer: An impact storefront system is an aluminum-framed, glazed wall and entrance assembly, typically at ground level, tested to resist wind-borne debris impact and cyclic wind pressure. It combines laminated glass, frames and anchorage that work together. Its approval covers specific sizes, glass make-ups and design pressures, not every possible configuration.
The key word is system. Impact performance comes from the glass, the glazing method, the frame, the anchorage and the substrate together. Upgrading any one piece doesn’t make the opening impact rated.
Impact vs. non-impact storefront
| Factor | Non-impact storefront | Impact storefront |
|---|---|---|
| Glass | Typically monolithic or insulating tempered glass | Laminated glass, often within an insulating unit |
| Frame | Standard storefront profiles | Deeper or reinforced profiles to retain laminated glass |
| Glazing retention | Standard gaskets and stops | Structural glazing or engineered retention to hold glass after breakage |
| Testing | Wind load, air and water | Adds missile impact and cyclic pressure testing |
| Where used | Areas without wind-borne debris requirements, or where openings are protected | Wind-borne debris regions where openings are not otherwise protected |
| Weight and anchorage | Lighter | Heavier glass; anchorage is engineered to the approval |
Where impact is required depends on the project location and the adopted code. Under the 2021 International Building Code Section 1609.2, glazed openings in wind-borne debris regions must be impact resistant or protected. Openings within 30 feet of grade, where storefront usually sits, are generally subject to the large-missile test. Florida has its own adopted code and requirements, so confirm with the Authority Having Jurisdiction (AHJ).
What determines storefront performance
1. Design pressure
Design pressure is the positive and negative wind load the storefront is rated to resist. It’s set by the building’s location, height, exposure and the opening’s position on the facade. Corners and edges usually see higher pressures than the middle of a wall. Specify design pressure from the engineer of record’s wind-load calculations, then confirm the approved system meets it at the actual opening size.
2. Glass make-up
The glass make-up sets impact resistance, thermal performance, solar control, acoustics and weight. Impact storefront typically uses laminated glass with a bonded interlayer that holds fragments in place. Laminated glass is often combined with an insulating unit for energy performance. The approval lists the specific make-ups tested, so a different interlayer, thickness or coating can fall outside it.
3. Frame and mullion depth
Deeper mullions span farther and carry higher loads. Storefront width, height and mullion spacing are all limited by the approval tables. A wider bay than the approval allows may need a deeper profile, steel reinforcement or a different system.
4. Anchorage and substrate
Anchors carry wind and impact loads into the building. Approvals usually specify anchor type, edge distance, spacing and the substrate they were tested in, such as concrete, masonry or steel. A substrate that differs from the approval may require site-specific engineering.
5. Doors and hardware
Entrances are often the most-used and most-stressed part of the storefront. Impact doors need hardware tested with the door assembly. Thresholds are a common water-entry point and need careful detailing.
Approvals: Florida Product Approval, Miami-Dade NOA and HVHZ
In Florida, storefront used in permitted construction generally needs a product approval. There are two main paths.
| Florida Product Approval | Miami-Dade NOA | |
|---|---|---|
| Issued by | Florida Building Commission | Miami-Dade County Product Control |
| Where accepted | Statewide, within the approval's limits | Miami-Dade County, and elsewhere at the AHJ's discretion |
| HVHZ use | Only if the listing is approved for HVHZ | Designed for HVHZ requirements |
| Lookup | floridabuilding.org | Miami-Dade Product Control search |
Florida’s High-Velocity Hurricane Zone (HVHZ) covers Broward and Miami-Dade counties. Products there are tested to Florida’s Testing Application Standards, including TAS 201 (large-missile impact), TAS 202 (uniform static air pressure) and TAS 203 (cyclic wind pressure). Outside the HVHZ, impact testing typically follows ASTM E1886 and ASTM E1996.
Three checks before you specify:
1. The approval is current, not expired or pending.
2. It covers the exact configuration: series, glass make-up, size, design pressure, anchorage and doors.
3. It’s valid for the project location, including HVHZ if the project is in Broward or Miami-Dade.
What architects should specify
Architects should verify:
● Section 08 41 13 (Aluminum-Framed Entrances and Storefronts) written to the actual design pressures, impact requirements and glass make-ups for the project.
● Design pressures by zone, from the engineer of record’s calculations, including corners.
● Approval scope that covers each elevation’s bay sizes, mullion spacing and door configuration.
● Glass make-up with interlayer type and thickness, coatings and insulating unit construction that match the approval.
● Thermal performance, if required by the energy code, using the manufacturer’s tested or simulated values.
● Entrances and hardware tested with the storefront assembly.
● Anchorage and substrate that match the approval or are covered by site-specific engineering.
● Water management at the sill: subsill, receptor or sill flashing with end dams, and clear weep paths.
Submittals should include: shop drawings with elevations, sections and anchorage; the current approval document; design-pressure and glass make-up confirmation; hardware schedules; finish data; installation instructions; and warranty terms.
Installation and water management
Most storefront leaks come from the sill and perimeter, not the glass. Storefront typically drains water that gets into the frame through weeps at the sill. That only works if the sill can drain to the outside.
● Subsill or receptor. Many storefront systems sit on a subsill or receptor that collects water and directs it out. End dams keep water from running off the ends into the wall. Champion Glass uses a patented receptor system (company-stated as US 11,414,914 B2) designed to give the frame a consistent seat and simplify installation. [CLIENT VERIFY: patent number]
● Perimeter sealant. Use a properly sized joint with backer rod, and don’t seal over weeps.
● Thresholds. Detail door thresholds for drainage and slope away from the building.
● Fasteners. Don’t fasten through the subsill’s water path unless the approval detail shows how it’s sealed.
● Field testing. Specify field water testing on sample bays, typically ASTM E1105 applied through AAMA 502 or 503, so problems surface before finishes go in.
Pre-glazed delivery. Some manufacturers glaze storefront in the shop rather than on site. Shop glazing can improve consistency and shorten field time. It also requires careful handling and lifting plans for heavy laminated units.
Replacing existing storefront
Check the approval era. Storefront installed before current requirements may not meet today’s impact or design-pressure requirements. Replacement usually has to meet the current code.
● Inspect the substrate. Corroded anchors, spalled concrete or deteriorated framing changes the scope.
● Plan for occupancy. Hotel lobbies and retail can’t close for long. Sequence bays to keep entrances open, and consider pre-glazed units to shorten field time.
● Match finishes to adjacent windows if only part of the facade is being replaced.
● Confirm the approval covers the replacement sizes and doors before ordering.
Conclusion
Impact storefront performs as a system: glass make-up, frame, anchorage, doors and sill drainage tested and installed together. Specify from real design pressures, check that the approval covers the exact configuration and location, and detail the sill and perimeter so water that enters the frame can get back out.
Next step: Architects can request 450 Series storefront details, glass make-up options and current product approvals for a project. Contractors can request a project-specific quote and talk through pre-glazed delivery and installation sequencing.