A Frequent question is what are the span, height, pressure, and installation limitations for large & small missile impact products.
The following takes into consideration the Florida Building Code 8th Edition (2023) limitations for designing & installing operable and non-operable windows/glass doors & impact protection devices.
For Operable Windows & Glass Doors
Inside the HVHZ (Broward & Dade Counties)
For the 8th Edition of the Florida Building Code (previous codes are similar), Chapter 2411.3.2.4.i is summarized as:
- For Windows and Doors other than bifold or sliding glass doors, the tested frame area (Frame width x Frame Height) shall not be exceeded the frame area of the tested approved unit.
- For sliding or bifold glass doors, the tested panel area (Panel width x Panel height) shall not exceed the panel area of the tested approved unit. If the door stiles or interlocks do not meet FBC 1616.3.1(6), the maximum allowed unit’s frame area shall be limited to 1.5X the tested frame area.
- Frame sizes shall vary from the tested approved unit only in width, height, or load requirements and shall not exceed 100% deflection, stress, concentrated load, water infiltration, or cyclic pressure of the tested approved unit per TAS 201, 202, 203 (see them here or see all TAS Protocols here – click left side, no sign-in required).
TAS 203 section 5.1 specifically states: “All Parts of the specimen shall be full size”.
TAS 202 Section 5.4 states “Specimens sucessfully tested shall qualify assemblies of a smaller size & of the same type and construction, provided the anchorage of the product remains unchanged”.
- Takeaway: In all cases, the tested frame height (structurally loaded direction) & pressure shall not be exceeded.
Please refer to the full code text of 2411.3 for more information as the above is a summary.
Outside the HVHZ ( Other than Broward & Dade Counties)
The code is written essentially the same for non HVHZ areas of Florida.
See section 1709.5.1(3) for the 2023 FBC text.
For Non-Operable Windows
Inside the HVHZ (Dade & Broward Counties)
For the 8th Edition of the Florida Building Code (and numerous previous codes), Chapter 2411.3.2.4.ii is summarized as:
- The frame area of the alternate size unit shall not exceed the frame area of the tested approved unit.
- Shall vary from the tested approved unit only in width, height or load requirements.
- The maximum uniform load distribution (ULD) of any side shall be equal to the uniform load carried by the side divided by the length of the side.
- The ULD of any member shall not exceed the ULD of the corresponding member of the tested approved unit & shall be calculated in accordance with standard engineering analysis.
- Shall not exceed the air and water infiltration resistance of the tested approved unit, or cyclic pressure of the tested approved unit when tested per TAS 201 and 203
- (see them here or see all TAS Protocols here – click left side, no sign-in required).
Please refer to the full code text of 2411.3 for more information as this is a summary.
Outside the HVHZ (Other Than Dade & Broward Counties)
The code is written essentially the same for non HVHZ areas of Florida.
See section 1709.5.1(3) for the 2023 FBC text.
For Large Missile Impact Protection & Similar Standards
Large missile impact protection systems, such as storm panels, accordion, roll-up, and fabric systems, all follow the same guiding principles.
Each have to pass a battery of impact & cyclical tests to ensure they remain intact after a category 5 storm.
Watch the engaging video of how storm panels go from coil to store shelves. The photo above is a large missile impact test hit (9lb 2 X 4 at 50ft/second).
Inside the HVHZ (Dade & Broward Counties)
Florida Building Code Section 1626 covers HVHZ Impact Tests For Wind-Borne Debris.
Miami Dade publishes guidelines that relate to the limitations of use for impact-protection products, windows, and doors. You can find those specifications here. Miami-Dade relies on numerous standards including the Florida Building Code & related referenced standards to adopt these criteria.
The Florida Storm Shelter Code ICC-500 is another referenced standard governing the limitation of use. Section 802.1 Test Assembly lists the following limitations.
Outside the HVHZ (Other Than Dade & Broward Counties)
Outside the HVHZ, ASTM E-1886 and E-1996 govern. Those codes frequently reference maximum frame sizes and spans for testing, water, and air infiltration.
For example, from ASTM E-1996 as referenced in the 2023FBC as a required standard for impact protection, Section A2.11 states:
ASTM E-1996 Panel Systems Section A2.11.1
Any modification to mounting hole size, shape, or location shall require the testing of one additional specimen, provided the diameter of the shape or both, of the hole are not increased or altered.
A2.11.2 Any substitution of a larger diameter or increased area mounting holes shall not be allowed.
ICC 500 is also a non-HVHZ criterion, as outlined above.
In Summary
Designing for large missile impact protection is unlike typical static load designs.
The main difference with designing for impact is how the product behaves after it gets struck by missiles – making the calculation nearly impossible to perform without testing.
After a tested product is impacted several times, it is then cycled thousands of times to levels above the design limits. The behaviour of the product cannot be estimated, rationally analyzed, or compared to other spans or pressures due to this degree of unknown.
This is why the test results are so important in developing impact-resistant systems. They simulate storms lasting hours, with multiple missile hits, and heavy rain infiltration.
Engineering Express would be glad to discuss your product or site-specific need. Start a quote request or chat with us to explore more.
Last Update: November 20, 2024
