All light fixtures or pole assemblies require proper evaluation to ensure that the structural integrity of the assembly is not compromised when applied in specific wind conditions. Therefore, the basis for pole selection in this catalog is total weight and effective projected area, EPA (ft sq), shown on the individual pole catalog pages. Determination of maximum EPA (ft sq) and weight loading must include all light fixtures, bracketry, signs, decoration, overhead wire or other equipment that will be mounted to the subject pole. Light fixture EPA (ft sq) and weight data are found on their respective product pages.
The total effective projected area of the light fixtures and brackets shall not exceed the EPA (ft sq) listed for the pole selected at a given wind velocity. Poles that are to be located in areas of known abnormal conditions will require special consideration. Please consult factory if poles are required for Florida Building Code or other special wind load requirements. The wind map page gives the wind velocities to be used in determining light fixture pole capability.
Note: If during the pole warranty period of one year, the product proves defective in material or workmanship, the company shall correct, at its option, by repairing or replacing at no charge to the purchaser, if the purchaser promptly notifies the company. This warranty specifically excludes fatigue failure or similar phenomena resulting from induced vibration harmonic oscillation or resonance associated with the movement of air currents around the product.
Pole Selection Procedure:
Step 1. Select the light fixture and decide how many will be mounted per pole. Determine the effective projected area, EPA (ft sq), which is given on the dimensional information table.
Step 2. Determine the appropriate mounting method for the fixture. Options include arm, bracket or wall mounting.
Step 3. Add together the EPAs (ft sq) of the light fixture and arm/bracket. Multiply by number of fixtures to be mounted on one pole.
Step 4. Consult the wind map below to determine the basic wind velocity for your area.
Step 5. Select the material (steel or aluminum) and shape (square or round) of the pole (refer to Ordering Tree).
a. Find the desired nominal mounting height in the second column.
b. Verify that the fixture weight does not exceed the maximum weight listed for the desired pole.
c. Compare your total EPA (ft sq) loading with the maximum EPA (ft sq) value found in the wind speed column for your area. Check that the equipment you are using will not exceed this value.
d. If both the weight and EPA (ft sq) valued does not exceed the value for which the pole is rated, you have selected the correct pole. If, however, either one of those numbers exceeds the maximum rated values, compare the EPA (ft sq) and fixture weight loads to the next larger pole of the same mounting height.
Note: “Call Before Number” and complete pole description MUST be included before order can be processed. Bolt templates will be shipped with anchor bolts. To pre-ship templates, place an order for the appropriate template number.
Caution: This pole selection process is a guideline only. Acuity Brands assumes no responsibility for selection and recommends consultation with qualified individuals for verification of light fixture or pole assembly selection.
The proper selection of a light standard (pole) for a particular application always requires careful consideration to ensure that the pole will not be over stressed from loading forces that are applied to the pole structure potentially creating a safety hazard should the pole ultimately fail. To this end, all lighting fixtures or pole assemblies require a careful evaluation to ensure that the structural integrity of the assembly is not compromised when subjected to various load forces.
The loads that are placed upon a pole are called static (dead weight) loads and dynamic loads. The weight of the light fixtures and any other attachments affixed to the pole are considered dead weight loads and generally do not vary (an exception of an intermittent increase would be due to icing in cold climates). Dynamic loads are variable and are created by the pressure of the wind based on its velocity against the surface area of the pole and light fixture assembly. The surface area in square feet of the light fixtures and all attachments are expressed as Effective Projected Area (EPA) and are calculated as a product of the actual exposed surface area multiplied by a drag coefficient.
When selecting a pole and light fixture assembly, the stresses put upon the pole from both the dead weight load in pounds and the total EPA in square feet of the light fixture and any additional attachments to the pole must be assessed.
First select the light fixture to be used and decide how many will be mounted to the pole.
Determine the EPA of the light fixture which is given in the dimensional information table located on the product page or specification sheet for the lighting product (link to EPA CHART). Next establish the appropriate mounting method of the light fixture; options include mast arms, cross arms, bullhorns or other bracket types.
Additional attachments may include signs, banners, decorations, antennas, solar panels, overhead wiring, et cetera. These additional attachments require special consideration on a case by case basis and you should always consult the pole supplier for assistance prior to final pole selection. Add together the EPAs of the light fixtures and brackets (and any additional attachments) that will mount to the pole. Add together the weights of all light fixtures and attachments as well.
Next, utilize a mean recurrence isotach 50 year wind map to verify the fastest mile per hour velocity of the wind for the installation site; when in doubt contact your local building department or your pole supplier.
Please note that there are areas of special concern regarding wind velocities. These include areas subject to high wind velocities due to hurricanes or special wind zones such as the Chinook winds of the eastern Colorado Rockies or Santa Ana winds in California to name a few. Additionally, open areas such as airports and the Plains regions of the United States can have low velocity (10 to 25 mph), steady wind conditions that may cause a pole assembly to vibrate; this is known as induced harmonic vibration or resonance and is a local, site specific condition. This condition is associated with the movement of air currents around the product and is unpredictable. If left unchecked, harmonic vibration can cause severe damage to the pole assembly and its ultimate failure. This type of vibration is not an indication of substandard material, workmanship, or pole design. Heavier poles and/or the addition of special devices called vibration dampers installed at the factory during the pole manufacturing process, or field installed at a later date, can help reduce or eliminate harmonic vibration in many instances.
Once you have determined the total EPA and weight of all attachments to the pole and verified the fastest wind velocity for the location of the pole installation, you can then establish which pole type may be suitable for the application. Select the material (steel, aluminum, concrete, fiberglass or wood) and shape (square or round, straight or tapered) of the pole. Refer to the “Technical Information” chart on the appropriate pole page. Find the desired nominal mounting height for the selected pole and verify that the total EPA and weight do not exceed the maximum values listed for the wind speed in your area. If both the EPA and weight are less than the maximum values for which the pole is rated, you have selected an appropriate pole. If any value is exceeded, compare the values to the next larger pole of the same mounting height or consider a pole of a different material and/or shape.
Let’s walk through an example of how this works. You want a 30 foot tall pole to mount two Lithonia Lighting KAD series light fixtures at 180 degrees from each other to illuminate a small parking lot located in a 90 MPH wind region. The total loading for the pole will be 2 times 1.2 EPA for the KADs which will give you a total EPA of 1.4. The weight of each fixture is 36 lbs. or a total of 72 lbs. Using the chart above the SSS 30 4G pole will work as it will handle 4.4 EPA and 110 lbs.. The SSS 30 5C pole will not work as it will only handle 2.0 EPA and 50 lbs. The SSS 30 5G will work as it will handle a 6.7 EPA and 167 lbs. So you would order either the SSS 30 4G DM28 DDB pole or the SSS 30 5G DM28 DDB pole from your local ABL distributor or agent.
Let’s walk through a more complicated example of how this works. You want a 30 foot tall pole to mount two Lithonia Lighting KAD series light fixtures at 180 degrees from each other to illuminate a small parking lot. Additionally, you would like to mount a TFA series floodlight with a horizontal arm bracket at 25 feet between the two KAD series light fixtures to illuminate the storefront. You’ve determined that the wind zone for your area is 90 mph with 1.3 gusts.
First determine the total EPA and weight that will load the pole. Per the Product Selection Guide or the KAD specification sheet, you will find that the KAD has an EPA of 1.2 square feet and weighs 35.9 Lbs. The guide or specification sheet for the TFA flood lists 2.6 EPA and 65 Lbs. Finally, we have to consider the bracket arm that will support the flood. The H1-18S horizontal arm bracket has and EPA of 0.50 EPA and weighs 11 Lbs. The total loading for the pole will be 2 times 1.2 EPA for the KADs plus 2.6 EPA for the single flood plus 0.50 EPA for the bracket arm for a total EPA of 5.5 EPA. By following the same formula for the weight values, we can calculate that the total weight for the light fixtures and bracket arm is 147.8 Lbs.
You have decided you would like a square straight steel (SSS) pole for the application and by consulting the Technical Information Table for the SSS pole you will find that the SSS 30 4G is rated for a maximum of 4.0 EPA and 100 Lbs at 90 mph and the SSS 30 5C pole is rated for 2.0 EPA and 50 Lbs at 90 mph. In these cases, the poles will fail in the application as the intended loading for the pole exceeds the pole’s rated maximum load limits. Continuing down the column, however, reveals that the SSS 30 5G pole is rated for 6.7 EPA and 167 Lbs at 90 mph with 1.3 gusts. This pole is suitable for the application and will withstand the dynamic load created by the wind because both the total 5.5 EPA and 147.8 Lbs is less than the maximum load ratings for EPA and weight for this pole. Though this pole will handle the loading at 90 mph, it will fail at 100 mph as its rating drops to 3.9 EPA and 100 Lbs. If you determine you really need the pole to handle the loading at 100 mph then you will need to go to a heavier duty pole such as the next larger size in the table and use the SSS 30 6G pole with a 9.0 EPA and 225 Lbs rating for 100 mph zones.