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WELCOME!
CES Course 000104Designing for Impact
104 Designing for Impact
Weather Shield’s Continuing Education Program for Architects
AIA Course Reference: WS101
This course qualifies for 1.0 LU AIA/CES credits
“Designing for Impact”
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Weather Shield was founded in 1955 and is family owned.Weather Shield Windows and Doors is one of the nation’s
leading window and door manufacturers.
LifeGuard® is a complete line of code-approved impact-resistant windows and doors providing lasting beauty,superior energy performance and sound control while
reducing the likelihood of wind-borne damage
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Weather Shield Mfg., Inc. is a Registered Provider withThe American Institute of Architects Continuing EducationSystems. Credit earned on completion of this program willbe reported to CES Records for AIA members. Certificatesof Completion for non-AIA members available on request.
This program is registered with the AIA/CES forcontinuing professional education. As such, it does
not include content that may be deemed orconstrued to be an approval or endorsement by theAIA of any material of construction or any method ormanner of handling, using, distributing, or dealing inany material or product. Questions related to specificmaterials, methods, and services will be addressed at
the conclusion of this presentation.Thank you!
104 Designing for Impact
Our Learning Objectives Today
1. You will have a basic understanding of windload requirements and Design Pressure (DP)ratings for windows and doors
2. You will understand the basic wind-borne debriscode requirements for impact-resistant windowsand doors
3. You will learn about the various applicationsand specifications for impact-resistant windowsand doors
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Top Ten Most Destructive Hurricanes (Atlantic)
Note: damages are listed in U.S. Dollars and are not adjusted for inflation
Source: www.mthhurricane.com
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The Dynamics of a Hurricane• High velocity winds create flying debris acting as
shooting missiles
• Flying debris breaks through windows or doors allowingpressure to build up inside the structure
• Rapid changes in both negative and positive wind pressurescan cause severe structural damage
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The Ongoing Threat of Destructive HurricanesCauses Code Change
• High Design Pressure (DP Rating) required for windowsand doors
• Wind-borne debris protection becomes mandated in specificregions for all openings (windows and doors)
• Cyclical pressure test to simulate the negative and positivepressures of a hurricane
• Energy efficiencyrequirements aswind-borne debriscodes move north
104 Designing for Impact
SECTION ONE
Understanding wind load requirementsand Design Pressure ratings for
windows and doors
This section will review the basic wind loadrequirements and Design Pressure (DP) ratings for
windows and doors in hurricane-prone regions
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Wind Loads• The first item that must be established is the wind load rating
of the building or structure
• The basic wind speed maps from ASCE-7 can help determinethe proper wind speed delineation zones for a specific area
• There are special requirements for buildings sited in areascalled “wind-borne debris regions,” defined as areas alongthe Atlantic and Gulf coasts where the design wind speed is120 mph or above
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U.S. Wind Speed Map
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Florida Wind Speed Map
www.floridabuilding.org
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Design Loads• Represents wind load pressure
for which the product is designed
• Incorporates a safety factor;testing 150% of design pressure(DP50 is tested at 75 PSF)
• Positive and negative designpressure requirements forwind-borne debris regions
• Water performance must meetthe positive pressure required forstructural design
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Determining Design Loads
2. Exposure Classification 3. Building Importance
4. Mean Roof Height 5. Unit Size 6. Wall Location
1. Wind Speed Zone
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Wind-Borne Debris Requirements• After determining the design load, the next requirement for
the coastal area is to determine the proper wind-bornedebris protection
• Windows and doors designed forwind-borne debris regions will havethe following characteristics– High design loads– Missile impact approval– Cyclical pressure test for
specific design pressures
104 Designing for Impact
SECTION TWO
Understanding the different wind-bornedebris code requirements for impact-
resistant windows and doors
This section will review the basic wind-borne debriscodes and performance requirements for windows
and doors in wind-borne debris regions
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Key Building Codes• International Building Code (IBC)
for commercial construction
• International Residential Code (IRC)for residential construction
• Florida Building Code (FBC)for all construction in the state of Florida
www.iccsafe.com www.floridabuilding.org
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Wind-Borne Debris Standards• The IRC and IBC have provisions for wind-borne
debris standards
• The standard test method and specifications referenceASTM E 1886 and ASTM E 1996 for large missile impactand cyclic pressure loading
• Various approval and state agencies have adopted thewind-borne debris standards such as Texas Departmentof Insurance, Miami-Dade, State of Florida, WDMAand AAMA
TDI
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Wind-Borne Debris Standards• Wind-borne debris requirements are defined by missile level
and wind zone (building height and location)
• Wind-borne debris requirements are only applicable wheremandated by local or regional building codes
• It is up to the architect to determine the right productperformance and code approval for the project
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Wind-Borne Debris OptionsGlazed openings must be protected
1. Impact-resistant panels
2. Impact-resistant shutters
3. Impact-resistant glazing system
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Wind Zones and Missile Types
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Impact Missile Requirements
80 (55)
50 (34)
40 (27)
50 (34)
130 (89)
Impact Speedfeet/sec (mph)
Less than 30 ft.Wind Zone 3 and 4 (Enhanced)
Less than 30 ft.Wind Zone 3 and 4 (Basic)
Wind Zone 1 and 2 (Enhanced)
Less than 30 ft.Wind Zone 1 and 2 (Basic)
Skylights < 30 ft.Wind Zone 2 (Basic)
Above 30 ft.Wind Zone 1 through 4
Typical Use
2 gram steel ballA
2 lb. LumberB
4.5 lb. LumberC
9 lb. LumberE
9 lb. LumberD
MissileMissileLevel
Wind Zone 1 – 110mphWind Zone 2 – 120mphWind Zone 3 – 130mphWind Zone 4 – 140mph
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Wind Zones
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Cyclical Pressure Testing• Designed to simulate the positive
and negative pressures causedby a hurricane
• Determines the maximum positiveand negative design pressures ofeach approved window anddoor system
• 9,000 total cycles with 3 secondsper cycle of design pressure
• Cycling occurs after impact
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Cyclic Static Air Pressure Loading
9,000 total
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Product ApprovalsAPPROVAL CHECKLIST
• Request a copy of the approval
• Make sure the product is approvedfor impact
• Check size and design pressures
• Make sure it meets the properimpact requirement(large versus small)
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Example Design Pressure Calculation1. Unit installed in Zone 5 of structure
2. Mean roof height of 30’
3. Window product is 3’ x 4’ = 12 square feet
4. Home located in wind zone of 140 mphPositive and negative design pressures of +33.7/–36.7 basedon Table R301.2(2) calculated for Exposure B
5. Home located in exposure “C” requires adjustmentcoefficient of 1.40 in accordance with Table R301.2(2)+33.7 x 1.40 = +47.18 (positive design pressure)-36.7 x 1.40 = -51.38 (negative design pressure)
Design Pressure required is +47.2/-51.4
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SECTION THREE
Understanding the various applicationsand specifications for impact-resistant
windows and doors
This section will review the design options andspecifications for impact windows and doors based
on building codes, applications and installation
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Product OptionsActive Glazing Options
• Plywood that meets code specifications• Code-approved screens• Code-approved storm panels• Code-approved shutters
Passive Glazing Options• Code-approved impact-resistant
windows and doors– Wood– Aluminum Clad– Aluminum– Vinyl– Fiberglass
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Product LimitationsAluminum and aluminum clad (wood) impact-resistant windowstypically give designers the greatest selection in size, options anddesign pressures offering the largest glazed openings and thehighest design pressures
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Window and Door Sizing
Example: Manufacturer’s Sizing Charts
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Product Selection
Example: Manufacturer’s Specification Sheet
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Critical Design Elements• Physical location of structure
• Type of windows/doors (wood, aluminum, vinyl)
• Overall window/door size
• Missile approval (large or small)
• Design pressures (to meet local requirements)
• Product code approvalmeets project specifications
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Proper Installation is CriticalHigh DP ratings and impact-resistant products may require specificinstallation (often more in-depth than standard product installation)
• 1/4” maximum shim space
• Additional anchoring through nailing fins
• Different anchoring method (i.e., screws instead of nails)
• Longer anchors
• Use of installation brackets
• Installing anchors throughsash/frame into the openings
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Certified Installation MethodsProducts tested in accordance with American ArchitecturalManufacturers Association (AAMA) have certified methods ofinstallation noted in body of test reports
Installation which differs from the certified details will not assuresimilar product performance and will not be accepted in areasrequiring specific design pressure ratings
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Example of Installation forHigh Performance Product
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Installation for Impact-Resistant Window
Example: Manufacturer’s Installation Specifications
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Energy Efficiency• As mandated codes for wind-borne debris requirements
moves north, the demand for energy-efficient impact-resistantwindows and doors will increase
• Most impact-resistant windows and doors use monolithiclaminated glass offering great impact-resistance but poorinsulation or energy efficiency
• There are code-approved products that use insulated Low Eglass offering energy efficiency – look for impact-resistantwindows and doors with the Energy Star seal
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Energy-Efficient Windows
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SUMMARY – SECTION ONE
Understanding the wind loadrequirements and DP ratings for
windows and doors
• Wind loads are critical and are determined from wind speedmaps (ASCE-7)
• Design loads represent wind load pressures for window anddoor products
• Design loads take in consideration six critical elementsWind speed, exposure classification, building importance, roof height,window/door unit size and location on the building
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SUMMARY – SECTION TWO
Understanding the different coderequirements for impact-resistant
windows and doors
• The IBC and IRC are national building codes that providestandards for wind-borne debris regions
• Various governing bodies and agencies adopt the recognizedstandards and enforce the approval process
• There are various impact requirements depending ongeography, window/door placement and building type
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SUMMARY – SECTION THREE
Understanding the various applicationsand specifications for impact-resistant
windows and doors
• There are two general categories of glazing protection:Active systems and Passive systems
• It is critical to make sure the code-approved productsspecified meet the required wind-borne debris specifications
• Proper installation of code-approved windows and doors is amust to provide the level of performance the systems havebeen tested to
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Review of Learning Objectives
1. You will have a basic understanding of windload requirements and Design Pressure (DP)ratings for windows and doors
2. You will understand the basic wind-borne debriscode requirements for impact-resistant windowsand doors
3. You will learn about the various applicationsand specifications for impact-resistant windowsand doors
104 Designing for Impact
Copyright Materials
This presentation is protected by U.S. and Internationalcopyright laws. Reproduction, distribution, display and
use of the presentation without written permissionof the speaker is prohibited.
© Weather Shield Mfg., Inc. 2007
THANK YOU!
This concludes the American Instituteof Architects Continuing Education
System Program
www.weathershield.com
Please contact your Weather Shieldrepresentative for additional information