Wind Calculator

The ANSI/SPRI ES-1 Standard is now required by the International Building Code (IBC). The ES-1 Standard is a performance based standard for low slope roof edge systems. The importance of this standard and the role of the roof edge as the first line of defense against wind is highlighted in RICOWI's recent report on Hurricane Ike.

Use the calculator below to determine what design pressure your project requires.

Instructions

Enter some basic building characteristics about your project and we will calculate the design pressure your roof edge will need to meet or exceed. We will also provide the wind speed for your region and a list of recommended Metal-Era products that will suit the needs of your projects. To have a product quoted, please e-mail our technical sales department or call them at 800-373-9156.

Building Characteristics

Height*	feet
Category*
Exposure*
State*
County*
Roof Edge Type: Fascia Coping
Building is downwind or a hill, ridge or escarpment

Disclaimer

Project Information (Optional)

Project Name
Building Type
City
Zip Code

Disclaimer

All basic wind speed velocities and velocity pressure calculations are based on the maps and formulas provided in the document ANSI/SPRI ES-1 2003 "Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems" and the SEI/ACSE 7-02 standard.

Although every care has been taken to ensure that the information based on state and county is accurate according to the standards, official wind speed requirements can vary based on local and county jurisdiction. It is highly recommended that any information regarding wind speed velocity provided be verified with local and county officials before any action is taken. No liability is accepted or implied by the provider for such information and advice.

The provider reserves the right to change any part of the wind calculator without notification.

Comparing Wind Calculator Results with ANSI/SPRI ES-1 2003

Differences between values for the Design Pressure (P) listed on this site and those computed using the ANSI/SPRI ES-1 documentation are the result of generalizations of structure heights in producing the ANSI/SPRI ES-1 velocity pressure charts.

Both the ANSI/SPRI ES-1 charts and the Wind Calculator use the same formulas in the SEI/ACSE 7-02 standard to produce velocity pressure values (qz). However, the ANSI/SPRI ES-1 charts show velocity pressure values for a single, generalized height within a range of heights supplied. This method is less exact than by using the true height with the formulas in the SEI/ACSE 7-02 standard for calculating velocity pressure, as the Wind Calculator does.

The most dramatic difference in these two approaches is in exposures B and C since the ANSI/SPRI ES-1 charts use a broad range of 0-60 ft. for the lowest values while using 10 to 20 ft. jumps for the rest of the charts. Less dramatic are the generalities in the charts for exposure D since it uses 0-15 initially then ranges 5 to 20 ft. there after. The smaller the range used, the more similar the Wind Calculator and ANSI/SPRI ES-1 final Design Pressure values will be.

Since ANSI/SPRI ES-1 is a guide to the SEI/ACSE 7-02 standard, and as such does not reflect the standard in whole, every effort was made to be more exact to the SEI/ACSE 7-02 standard in calculating out values using the Wind Calculator. For this reason, the results provided by the Wind Calculator should, with all supplied values being the same, supersede those provided by the ANSI/SPRI ES-1 documentation in accuracy to the SEI/ACSE 7-02 standard.

Building Exposure

Type	Exposure Description
B	Area with numerous closely-spaced obstructions having the size of single-family dwellings or larger. For all structions shown, terrain representative or surface roughness Category B extends more than ten times the height of the structure or 800 meters, whichever is greater, in the upwind direction.
C	Open terrain with scattered obstructions having heights generally less than 30 feet for most wind directions. All one-story structures with a mean roof height less than 30 feet in the photograph are less than 1500 feet or ten times the height of the structure, whichever is greater, from an open field which prevents the use of Exposure B. Also includes shoreline in hurricane-prone regions.
D	A building at the shoreline (excluding shorelines in hurricane-prone regions) with wind flowing over open water for a distance of at least one mile. Shorelines in Exposure D include inland waterways, the Great Lakes, and coastal areas of California, Oregon, Washington and Alaska.

Building Category

Category	Nature of Occupancy
1	Buildings and other structures that represent a low hazard to human life in the event of failure including, but not limited to: Agricultural facilities Certain temporary facilities Minor storage facilities
2	All buildings and other structures except those listed in Categories 1, 3, and 4.
3	Buildings and other structures that represent a substantial hazard to human life in the event of failure including, but not limited to: Buildings and other structures where more than 300 people congregate in one area Buildings and other structures with day care facilities with capacity greater than 150 Buildings and other structures with elementary school or secondary school facilities with capacity greater than 250 Buildings and other structures with a capacity greater than 500 for colleges or adult education facilities Health care facilities with a capacity of 50 or more resident patients but not having surgery or emergency treatment facilities Jails and detention facilities Power generating stations and other public utility facilities not included in Category 4 Buildings and other structures not included in Category 4 (including, but not limited to, facilities that manufacture, process, handle, store, use, or dispose of such substances as hazardous fuels, hazardous chemicals, hazardous waste, or explosives) containing sufficient quantities of hazardous materials to be dangerous to the public if released. Buildings and other structures containing hazardous materials shall be eligible for classification as Category 2 structures if it can be demonstrated to the satisfaction of the authority having jurisdiction by a hazard assessment as described in Section 1.5.2 that a release of the hazardous material does not pose a threat to the public.
4	Buildings and other structures designated as essential facilities including, but not limited to: Hospitals and other health care facilities having surgery or emergency treatment facilities Fire, rescue, ambulance, and police stations and emergency vehicle garages Designated earthquake, hurricane, or other emergency shelters Designated emergency preparedness, communication, and operation centers and other facilities required for emergency response Power generating stations and other public utility facilities required in an emergency Ancillary structures (including, but not limited to, communication towers, fuel storage tanks, cooling towers, electrical substation structures, fire water storage tanks or other structures housing or supporting water, or other fire-suppression material or equipment) required for operation of Category 4 structures during an emergency Aviation control towers, air traffic control centers, and emergency aircraft hangars Water storage facilities and pump structures required to maintain water pressure for fire suppression Buildings and other structures having critical national defense functions Buildings and other structures (including, but not limited to, facilities that manufacture, process, handle, store, use, or dispose of such substances as hazardous fuels, hazardous chemicals, hazardous waste, or explosives) containing extremely hazardous materials where the quantity of the material exceeds a threshold quantity established by the authority having jurisdiction. Buildings and other structures containing extremely hazardous materials shall be eligible for classification as Category 2 structures if it can be demonstrated to the satisfaction of the authority having jurisdiction by a hazard assessment as described in Section 1.5.2 that a release of the extremely hazardous material does not pose a threat to the public. This reduced classification shall not be permitted if the buildings or other structures also function as essential facilities.

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Wind Calculator

Instructions

Building Characteristics

Project Information (Optional)

Disclaimer

Comparing Wind Calculator Results with ANSI/SPRI ES-1 2003

Building Exposure

Building Category