In the state of Florida’s product approval website, there’s a setting called ‘impact’. This setting relates to the large missile impact rating given to opening protection devices per ASTM E1886/1996 & TAS protocols in the HVHZ zones. This is also known as Missile Level ‘D’ as defined below.
Refer to the product’s testing or evaluation documents for limitations of the product’s use in other missile level zones.
A frequently asked question is whether a large missile impact-approved product is also approved for small missile impact. The answer isn’t always yes. Refer to this article by Engineering Express for more.
See below to better understand the Florida Building Code sections on limitations of use of Large Missile Impact Protection Devices.
*** Always refer to a Design Professional licensed & experienced in this field for certified engineering prior to permitting & installing any impact protection devices. ***
More technical information – ASTM Missile Levels
ASTM E-1996 breaks down impact resistance into (5) levels, A through E.
Missile Level A is better known as ‘small missile impact’ – a 2g steel ball shot at 130 ft/second in a prescribed array.
Missile Level B isn’t used in wall wind zones but appears for skylights listed below. It represents a 2.0lb 2 X 4 at 50 ft/second shot at a prescribed pattern to glazing.
Missile Level C is known as ‘medium missile impact’ – a 4.0lb 2 X 4 shot at 40 ft/second in a prescribed pattern. It’s used in wind zones 1 & 2 & is not all that common in Florida.
Missile Level D is the most common & represents ‘large missile impact’ known to protect against the strongest of hurricanes. It represents a 9lb 2 X 4 shot at 50 ft/second. Most storm protection systems for residential & commercial structures meet this standard & is applied to a certain portion of the building (typically below 30′ but with exceptions) in wind zones 1, 2, or 3.
Missile Level E is enhanced impact protection & represents a 9lb 2 X 4 shot at a prescribed pattern at 80 ft/second at glazed surfaces.
ASTM E-1996 focuses on the testing protocol of these missile levels.
More technical information – Large & Small Missile Impact Levels per the Florida Building Code
Referencing Florida Building Code Seventh Edition, (2020) Chapter 2411.3.2.4.i & 1709.5.1.3.i for Operable Windows and Glass doors:
- For Windows and Doors other than Bifold or sliding glass doors, the Tested area (Frame width x Frame Height) shall not be exceeded in alternate frame sizes mentioned in the design charts.
- For Bifold or sliding glass doors, the Tested panel area (Panel width x Panel height) shall not be exceeded in alternate frame sizes mentioned in the Design charts. However, the alternate overall frame area shall exceed the tested area by a maximum of 1.5 x tested overall frame area.
In all cases, the Tested Frame height shall not be exceeded.
- Frame Tributaries may vary, considering Horizontal member length limitations, load, and deflection calculated from the new tributary width.
- All other Factors such as deflection, distributed or concentrated load applied on members, cyclic wind pressure, design wind, and unbraced member length shall not be exceeded and/or studied while preparing the design charts.
Referencing Florida Building Code seventh Edition (2020) Chapter 2411.3.2.4.ii & 1709.5.1.3.ii for Non-Operable Windows and Glass doors:
- For Windows and Doors other than Bifold or sliding glass doors, the Tested area (Frame width x Frame Height) shall not be exceeded in alternate frame sizes mentioned in the design charts.
- In all cases, the Tested Frame height shall not be exceeded.
- Frame Tributaries may vary, considering Horizontal member length limitations, load, and deflection calculated from the new tributary width.
- All other Factors such as deflection, distributed or concentrated load applied on members, cyclic wind pressure, design wind, and unbraced member length shall not be exceeded and/or studied while preparing the design charts.
