 |
InspectAPedia® |
InspectAPedia
|
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair | Ask a Question or Search InspectAPedia |
Hurricane-resistant skylights, windows & doors: choices, protection methods, construction, standards & codes. Here we provide a guide to hurricane, storm, and wind resistant windows and skylights, including citing storm resistance standards, building codes, and products. Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman. Guide to Hurricane, Wind, & Storm-Resistant Windows
We review the proper installation details for windows and doors, and we compare the durability of different window and door materials and types. This article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons. See WINDOWS & DOORS our home page for window and door information, and also see POLYCARBONATE GLAZING for impact resistant window glazing, and see WINDOW TYPES - Photo Guide for a photographic guide to window and door types and architectural styles. Ourlinks listed at Related Topics provide in-depth articles on window and door selection, inspection, installation, problem diagnosis, and repair. In response to the devastating impact of Hurricane Andrew in 1992, Florida enacted stringent codes to protect homes from severe storms. Other coastal states have followed suit in recent years, and now similar provisions in the International Residential Code (IRC) apply to coastal areas from Texas to Maine. Protect the Window OpeningsResearchers attributed much of Andrew’s destruction to wind penetration into homes through broken doors and windows, leading to extensive water damage and, in many cases, roofs blown off and houses destroyed. Our photo (left) shows storm-exposed beach-front hotel windows at Boca Raton, FL. The keys to preventing these problems were strengthening roofs and protecting windows and doors from wind and wind-borne debris. To protect windows, the new code allows three options:
The trend in new home construction is toward impact-resistant windows, sometimes marketed as “storm resistant” or “hurricane-rated.” Miami-Dade County Standards for Storm-Resistant WindowsMiami-Dade County enacted the most stringent standard and test protocols, subjecting windows (and storm shutters) to a test in which a 9-pound 2x4 is hurled into the glass at 50 feet per second, followed by 4,500 cycles of positive and negative wind loads equivalent to a 146-mph wind. Miami-Dade also conducts AAMA/NWWDA testing for design pressure and water intrusion, but it conducts the water intrusion test after the structural test is completed rather than on a new window. Windows and doors that pass the Miami-Dade Product Control Standards are required throughout Miami-Dade County and most other coastal areas in Florida. International Residential Code for Impact-Resistant WindowsThe International Residential Code (IRC) requires impact-resistant windows in all hurricane-prone regions along the Gulf and Atlantic coasts from Texas to Maine. Depending on the wind-speed zones established in the IRC, windows need to meet design pressures ranging from 30 to 80 psf, and they must meet impact-resistance standards under ASTM E1886 or E1996. The design pressure required depends on both an area’s design wind speed, found on IRC maps, and the building’s exposure rating from A to D. Most buildings are rated Exposure B for “urban and suburban areas or wooded areas” or Exposure C for flat, open terrain with scattered obstructions of less than 30 feet. Waterfront buildings exposed to winds flowing over open water for at least a mile are rated Exposure D, the most severe. Storm-Resistant Window ConstructionUnder pressure from both the building codes and insurance industry, most major window manufacturers have developed impact-resistant windows for residential applications that feature laminated glass along with heavier frames and hardware. The glass is similar to auto windshields with a plastic interlayer, but it is significantly heavier. Double-glazed units get a second layer of tempered glass either on the interior or exterior. Vinyl-framed windows are heavily reinforced with aluminum, and all windows use metal mullion bars anchored to the framing between mulled units. Window-to framing attachment methods are also beefed up to comply with the new codes, and in some cases, metal clips are used to anchor the window to the frame. Storm-resistant windows cost from two to four times as much as standard windows; but under pressure from code agencies and insurance companies, these windows will soon become standard fare in coastal construction and other storm-prone areas. Performance Grade and Design Pressure for WindowsHow well a window performs when subjected to heavy rains and high winds is indicated by its performance grade and design pressure. The design pressure is a structural rating only, while the performance grade also indicates that a window has met the water resistance and air infiltration standards for that grade (see Table 3-2 below).
The minimum recommended design pressure for residential doors and windows is 15 psf. A design pressure of 15 means a window has been tested to withstand sustained wind pressures of 22.5 psf, roughly equivalent to a 95-mph wind, applied to either side of the window, simulating both positive and negative wind pressures. The test pressure is always 150% of the rated design pressure to provide a safety factor. To earn a performance grade of 15, a window must also pass a water pressure test of 2.86 psf, which simulates rainfall of 8 inches per hour with a wind speed of 34 mph. In coastal areas or other areas prone to heavy winds or hurricanes, higher grade windows are recommended and may be required by code. Also see WINDOW TYPES - Photo Guide. Industry Associations for Windows & DoorsAmerican Architectural Manufacturers Association (AAMA) www.aamanet.org Efficient Windows Collaborative www.efficientwindows.org National Fenestration Rating Council (NFRC) www.nfrc.org Sustainable by Design www.susdesign.com Shareware calculators for sun angles, solar heat gain, and shading Window and Door Manufacturers Association (WDMA) www.wdma.com -- Adapted and paraphrased, edited, and supplemented, with permission from Best Practices Guide to Residential Construction. Frequently Asked Questions (FAQs)... Ask a Question or Search InspectApediaQuestions & answers or comments about building storm & hurricane protection: how to choose, install, use hurricane-damage-resistant windows. Ask a Question or Enter Search Terms in the InspectApedia search box just below. Technical Reviewers & ReferencesRelated Topics, found near the top of this page suggest articles closely related to this one.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
| |||||||||
Carson, Dunlop & Associates Ltd.,
The Home Reference Book - the Encyclopedia of Homes
