** helps you with your entries. This information is provided on each program for quick and**

**easy reference, but can also be found in the ASCE 7 book; in Chapter 6).**

**1. **__Wind Velocity__: The number entered in this cell is to have the units

** in miles per hour (mph). This is the velocity zone**

** location that your building is located, according to**

** the ASCE 7 Basic Wind Speed Map. The map is**

** provided with the purchase of your programs.**

**2. **__Building Category__: Make your selection from the pull-down list. The

** options are provided in the description given on the**

** program (place cursor over the top of the**

** description.) If you need more information on**

** Building Categories, please reference Table 1-1 in**

** the ASCE 7 book.**

**3. **__Importance Factor__: The value is automatically calculated for you, based

** on your “Building Category” entry. You can view**

** the values of the Importance Factor from the**

** “Building Category” description; when placing your**

** cursor over the top of the description.**

**4. **__Exposure__: From the pull-down list you have three (3) choices.

** Exposures B, C, & D. (Exposure A was eliminated**

** after ASCE 7-98). Make your selections based on**

** the information that is provided is the description.**

** (The description provided is the same description**

** you will find in ASCE 7).**

**5. **__Internal Pressure__: Make your selection from the pull-down list

** provided. You have three (3) choices. 1) Partially**

** Enclosed, 2) Enclosed Building, 3) Open Building.**

** a. Partially Enclosed: This type of building has**

** walls under the roof, but also has at least one**

** side that is exposed or open to the outside.**

** b. Enclosed: This is the most common. This type**

** of building has no openings exposed to the**

** outside. The walls enclose the entire building**

** under the roof.**

** c. Open Building: This type of structure has no**

** walls under the roof, and is completely exposed**

** to the outside. This would basically be a roof**

** that is only supported by post, pillars or similar**

** supports.**

**6. **__Height Above Ground__: This is also know as the value “z”. This value is for

** elevated buildings, for the simple fact that the value**

** of “z” is the dimension from the ground to the**

** bottom of your building. So if your building is at**

** ground level, this value would be zero (0).**

**7. **__Standard Wall Height__: This value is the dimension measured from the

** ground to the eave height (or where the lower**

** portion of your roof meets the side-wall) of your**

** building.**

**8. **__Mean Roof Height__: This also known as the value “h”. This value is the

** dimension measured from grade to the average of**

** the roof eave height and the highest point on the**

** roof surface, except that eave height shall be used**

** for the roof angle if it is less than or equal to 10**

** degrees.**

** Remember: When h > 60 ft., your roof angle must**

** be less than or equal to 10 degrees; according to the**

** ASCE 7.**

** Flat Roofs: This will be the actual building height**

** value.**

**9. **__Building Width__: This value is the width dimension of your building;

** in feet.**

**10. **__Building Length__: This value is the length dimension of your building;

** in feet.**

**11. **__Roof Slope__: This is the value of “x” over twelve; or x/12. You

** need to enter a value from 0-12 (Zero (0) is flat, and**

** twelve (12) is 45 degrees).**

**12. **__Roof Angle__: This value is automatically calculated and entered

** for you. It displays the angle of your roof based on**

** the value of “x” entered for your roof’s slope.**

**13. **__Edge Strip__: This value is also known as the value of “a”. This

** value is automatically calculated based off of the**

** building information you entered. The Edge Strip**

** value (“a”), is used to determine the dimensions of**

** zone five (5) for your wall sections, and zone (3) for**

** your roof sections.**

**14.**__ End Zone__: This value is the total Edge Strip value along one

** side of your wall. This value is also automatically**

** calculated for you, based off of the building**

** information you entered in. It is basically the value**

** of “a” multiplied by two (2).**

**All the “Building Information” is entered, next is to find the wind loads for the roof,**

**door(s), and window(s).**

**Below is a diagram that shows the garage that we are finding wind loads for. As you can**

**see the numbers below show the zones for the garage.**

** **

**Note:**

**1. Zones 1, 2, & 3 are always applied to the roof.**

** a. Zone 3: are the edge or corner sections; always equal to the value of “a”.**

** b. Zone 2: are the perimeter sections; minus the Zone 3 (edge/corner) areas.**

** c. Zone 1: are the interior sections. Basically the interior area left over after**

** subtracting the areas of the Zone 3, and Zone 2.**

**2. Zones 4 & 5 are always applied to the walls.**

** a. Zone 5: are the corner sections; always equal to the value of “a”.**

** b. Zone 4: are the interior sections; or the area remaining after subtracting the**

** Zone 5 sections.**

**3. Remember: The Value of “a” is always applied to the roof and wall corners.**

**4. Remember: Any door or window dimension that falls within the area of “a”**

** (edge/corner = Zone 5) section must have the Zone 5 applied to it.**

**5. Remember: Any opening dimension that falls with the area of “a” (edge/corner =**

** Zone 3) on the roof (such as a sky-light) must have the Zone 3 applied to it.**

__Finding Roof Wind Loads:__

**First find the dimension (from center-to-center) of your roof’s truss frames. For this example our truss frames are dimensioned 3 feet from center-to-center (Reference the diagram below). Building Length is 30ft, and the value of “a” (Edge Strip) is 3 feet.**

**From this we can determine the areas with our Zones 1, 2, & 3.**

**Zone 3**

= (**Value of “a”**) x (**Value of “a”**)

= (**3 feet**) x (**3 feet**)

= 9 square feet.

**Zone 2 (Perimeter: Width Side)**

= (**Truss Frame: center-to-center**) x (**Value of “a”**)

= (**3 feet**) x (**3 feet**)

= 9 square feet.

**Zone 2 (Perimeter: Length Side)**

= (**Value of “a”)** x (**Dimension between Zone 3**)

= (**3 feet**) x (**8.14 feet**)

= 24.42 square feet

**Note: Program calculates the precise number, but shows the effective area on the program rounded up.**

** **

**Zone 1 (Interior Section)**

= (**Truss Frame: center-to-center**) x (**Dimension between Zone 3)**

= (**3 feet**) x (**8.14 feet**)

= 24.42 square feet.

**It is not necessary to calculate for each individual area for the zones on the roof since they are equally distributed, meaning the following applies:**

** **

**Ø All of the areas for Zone 3 = 9 sqft.**

**Ø All of the (Perimeter: Width Side) Zone 2 = 9 sqft.**

**Ø All of the (Perimeter: Length Side) Zone 2 = 24.42 sqft.**

**Ø All of the areas for Zone 1 = 24.42 sqft.**

__Finding Wall Wind Loads for Window & Doors__:

** For this example we have:**

** Door A: Garage Door = W x H = (16 feet x 8 feet) = 128 square feet**

**Window B: Side Window = W x H = (4 feet x 4 feet) = 16 square feet**

**Window C: Side Window = W x H = (6 feet x 4 feet) = 24 square feet **

** Note: The “Opening Elevation” is the dimension measured from the ground to the center point of the opening. The following diagrams show how to determine the “Opening Elevation” for the garage door and the windows.**

**We are now able to enter in all the information into the Windloadcalc.com Program. The following is the computed spreadsheet.**