Wind load

Wind Load Technical Information(A Dis-Gust-Ing Subject?)

Joe HetzelTechnical Director

Door & Access Systems Manufacturers Association

DASMA’s Mission:

• “DASMA, acting through the united efforts of its members, is the industry’s voice for regulatory, technical and product issues affecting market growth, safety and acceptance of the product categories manufactured by member companies.”

Overview Of Our Seminar

• What?

• Who cares?

• Where do we even need it?

• Why should we even bother with this?

• “Tech” Time!

• Photos – What the wind left behind….

• Resources for you

People Are Saying….

• “…garage doors performed relatively well in the 2004 Florida hurricanes…”

• “…garage door performance has improved in the last ten years…”

• Current lists of building products of high concern have NOT included garage doors

• DASMA Wind Load Technical Information Is Helping Make A Difference!

What?

• TDS-152, Garage Doors And Hurricanes

• TDS-153, Vertically Reinforced Garage Doors

• TDS-155, DASMA Wind Load Guides

• TDS-161, Connecting Garage Door Jambs to Building Framing

• TDS-168, Frequently Asked Questions

Who Cares?

• Building owners and homeowners do!

• Insurers do!

• Essential services personnel do!

• Code officials do!

• Design professionals do!

• We as an industry do, too!

Where do we even need it?

• Everybody knows about Florida…but how about

• The Gulf Coast

• The Atlantic seaboard

• North Carolina

• Kansas City (huh?)

• Be on the lookout for your area

Why should we even bother with this?

To strengthen the chain links!

1. Code content

2. Code adoption

3. Code enforcement

4. Product specification

5. Product integrity

6. Product installation

Link #1 – Code Content

• “Model” Building Codes

• Technical Research

• DASMA Influence

Link #2 – Code Adoption

• State And Local Levels

• More Politics!

• Which Code?

• Which Amendments?

Link #3 – Code Enforcement

• Local level

• Blend of technical and political

• Plan reviews; site inspections• Common problem: Technical misunderstandings

• Appeals process

Link #4 – Product Specification

• Knowing the applicable job conditions, along with the correct code interpretation

• Knowing the available product selection and selecting the right product

• Recent examples– Essential facilities– Metal buildings

Link #5 – Product Integrity

• Suitability (Material Choices)

• Quality (Control; Assurance)

• Strength (Testing)

• DASMA standards– ANSI/DASMA 108; ANSI/DASMA 115

• Other standards– ASTM E 330; Miami-Dade TAS 201/202/203

Link #6 – Product Installation

• Installation instructions

• Installation quality

“Tech” Time !!!!!

TDS-152, Garage Doors And Hurricanes

• Don’t back car against door

• Close the door before a hurricane

• Homeowner should not add weight to the door

• Know if “breakaway” construction supersedes wind load requirement

• Have a professional evaluate the door

TDS-153, Vertically Reinforced Garage Doors

• General– Comply with industry standards– Test to wind standards

• Types– Integrated into door design– Supplied with door by manufacturer– Aftermarket product

TDS-161, Connecting Garage Door Jambs to Building Framing

• 8 different fastener types

• Charts show maximum spacing

• Variables:– Door Width– Design Load– Jamb Materials

TDS-168, Frequently Asked Questions

• Does orientation of the door on the building affect load?

• Does direction the door faces affect load?• Does house layout configuration affect load?• Why can’t the industry just supply a “100 MPH

door”?• Why do people ask questions? (Not included)

TDS-155, Wind Load Guides

• Cover sheet

• Codes old and new (current codes are 2003 IBC and 2003 IRC)

• Standards old and new (current standard is ASCE 7-02)

Wind Fundamentals

• Inward and Outward Loads• Normal to Surface• Loads Influenced By:

– Geographic Location– Exposure Condition– Building Importance– Opening Size– Opening Protection– Building Configuration– Door Location

Wind Load Variables

• Building height above finished grade• Design wind speed• Exposure category• Garage door horizontal location• Product designation• Use factor• Building Type, with respect to openings• Roof Pitch• Door Area

DASMA “Wind Load Guides”

• Based on ASCE 7 and the IBC

• In process of referencing ASCE 7-02 (equivalent to ASCE 7-98)

• In process of reference the 2003 IBC (equivalent to the 2000 IBC)

• Commercial and Residential Guides

• Guides based on Exposures B, C and D

Building Height Above Finished Grade

• ASCE 7-98 Section 6.5.12.4.1

• IBC Section 1609.6 (“Simplified Wind Load Method”)

• Buildings less than 60 feet in height (“Low-Rise Buildings)

• Guides use building heights of 15’ and 25’

Design Wind Speed

• ASCE 7-98 Figure 6-1

• IBC Figure 1609

• Guides based on 90-150 MPH

• Three Second Gust values

Exposure Categories

• ASCE 7-98 Section 6.5.6.1• IBC Section 1609.4• Exposure B: Typical Residential

Subdivision; Wooded Areas• Exposure C: Open Terrain; Hurricane-

Prone Shorelines• Exposure D: Within 1/4 Mile of an Inland

Lake at least One Mile Across

Garage Door Horizontal Location

• ASCE 7-98 Figure 6-5A• IBC Section 1609.6.3• Smaller of 10% of least horiz. dim. (use

40’) or 40% of eave height (use >10’): 4 ft.• Not less than the larger of 4% of the least

horiz. dim. (use 40’) or 3’; 3 ft.• Guides use 4 ft.; 2 ft. of which extend onto

the garage door surface

Product Design Designation

• ASCE 7-98 Section 6.2• IBC Section 1609.2• Main Wind-Force Resisting System: An

assemblage of structural elements assigned to provide support and stability for the overall structure.

• Components and Cladding: Elements that do not qualify as part of the MWFRS.

• Guides based on garage doors as Components and Cladding

Importance Factor

• ASCE 7-98 Table 6-1

• IBC Table 1604.5

• Guides based on Category II factor

• Applies to non-essential structures, and structures with no substantial hazard to human life in the event of failure

Building Type

• ASCE 7-98 Section 6.2• IBC Section 1609.2• Partially Enclosed Building:

– Openings in a wall > Openings in the balance of the building envelope by more than 10%

– Openings in this wall > 4 SF or > 1% of wall area– Openings in the balance of the building <20%

• ASCE 7-98 Figure 6-5A• Guides apply to Enclosed Buildings

What’s An Opening?

• ASCE 7-98 Section 6.2

• Not in the IBC

• Apertures or holes in the building envelope

• Which allow air to flow through the building envelope

• And which are designed as “open” during design winds

Roof Pitch

• ASCE 7-98 Figure 6-5A

• IBC Figure 1609.6(2)

• 10% coefficient reduction if roof pitch is less than 10 degrees (“low-slope”)

• Guides: “Low-slope” roof systems are treated as commercial structures

• IBC “Simplified” Table 1609.6.2.1(2) does not include reduction option

• Guides include both residential and commercial structures

Wind Load Equation

• ASCE 7-98 Section 6.5.10

• IBC Section 1609.6.2.1

• Velocity Pressure at height H

• Pressure Coefficients

• Basic Wind Speed

• Importance Factor

The Guides - Explained

• Geographic Location

• Design Wind Speed

• Exposure Category

• Structure Use

• Structure Height

• Garage Door Width

The Guides - Example

• Charleston, SC• IBC (based on ASCE 7-98)• 130 MPH design wind speed, Exposure B• Residential structure• Double story house (25’ mean roof ht.)• Double garage door (16’ x 7’)Calculated Wind Load:• 25.9 PSF (positive wind load)• -28.8 PSF (negative wind load)

Garage Door Wind Load Comparisons130 MPH Design Wind Speed

Exposure/Size 9’ x 7’ 16’ x 7’

B +26.9 -30.8 +25.9 -28.8

C +36.3 -41.6 +35.0 -38.9

D +43.3 -49.6 +41.7 -46.4

Exposure/Size 9’ x 7’ 16’ x 7’

B +26.9 -30.8 +25.9 -28.8

C +32.5 -37.3 +31.3 -34.8

D +39.5 -45.3 +38.1 -42.3

One-Story House:

Two-Story House:

The Guides - Exceptions

• Another code or standard used

• Garage doors with > 2 ft. in end zone(s)

• Local enforcement requires higher loads

• Special retrofit situations

• Partially enclosed and open structures

• Essential facilities/hazardous buildings.

Photos – What The Wind Left Behind

Possible Coming Attractions!

• Post-high wind event door inspection guidelines for dealers!

• Post-high wind event door operation guidelines for building occupants!

• New and improved technical coordination with doors on metal buildings!

• DASMA web site wind calculator!

When You Need Technical Information, …

• DO go to the web www.dasma.com• DO E-mail us [email protected]• DO fax us 216-241-0105• DO call us 216-241-7333• DO get our magazine (Door & Access

Systems)• DO talk to your product supplier• DON’T…hesitate!