What is EPA for light fixture?
Definition: EPA is a coefficient used by the lighting industry to determine how much force a luminaire will apply to the mounting brackets or pole at a given wind velocity.
How do you calculate the EPA of a light pole?
EPA = (Frontal Projected Area) x (Drag Coefficient) This is measured in square feet (ft2). mounted luminaire, however, is taken as the fixture’s side cross sectional area.
What is EPA for wind?
It is important to remember that EPA is a coefficient reflecting wind drag on a fixture, during a specific mounting scenario, and not a safety or design limit. EPA is used to determine the amount of stress on a fixture and/or the structure supporting the fixture and is highly dependent on local wind loads.
What is EPA rating for light poles?
For convenience, poles are rated in terms of their EPA capacity at several wind speeds. (80, 90, 100 and 110 mph) EPA = Actual Wind Silhouette of an Object x Cd. The height at which a fixture is mounted measured from the pole base, not the length of the pole.
What is EPA sqft?
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.
How do you calculate the area of a projection?
The projected area calculation therefore uses the area formula for a circle: area equals pi times radius times radius, or A=πr2. If the diameter of the sphere is 20 feet, then the radius will be 20÷2=10 and the projected area will be A=π × 102≈3.14 × 100=314 square feet.
What is projected area of a cylinder?
projected area of the cylinder is the area formed by the points of tangency l 0 on the z 0 plane. This area is enclosed inside 1 and 2 2 1 when Eqs.
What is 1.3 gust factor?
Most manufacturers’ calculations include a 1.3 gust factor over a steady wind velocity. This means that a pole designed to withstand winds of 70 mph will withstand gusts to 91 mph.
How do you calculate area?
Area is calculated by multiplying the length of a shape by its width. In this case, we could work out the area of this rectangle even if it wasn’t on squared paper, just by working out 5cm x 5cm = 25cm² (the shape is not drawn to scale).
How do you calculate projected diameter?
The circle’s projected diameter equals the diameter of the sphere. The projected area calculation therefore uses the area formula for a circle: area equals pi times radius times radius, or A=πr2.
How do you calculate gust factor?
For example, if the winds are reported at 18 knots, gusting 30 knots, it means you have a gust factor of 12 knots (30-18 = 12). So if you take half the gust factor, you get 6 knots (12/2 = 6). Yes, it’s math, but it’s really simple math you can do in the airplane.
What is difference between wind speed and wind gust?
The fundamental difference between the two is duration. A sustained wind is defined as the average wind speed over two minutes. A sudden burst in wind speed is called the wind gusts and typically lasts under 20 seconds.
What does EPA stand for in lighting category?
Effective Projected Area (EPA) Calculation. Definition: EPA is a coefficient used by the lighting industry to determine how much force a luminaire will apply to the mounting brackets or pole at a given wind velocity. This value is used in combination with a luminaire’s weight to determine the mounting requirements for a particular application.
What does a wind rating on a light fixture mean?
This is, of course, prohibitive for a fixture manufacturer, hence the subbed in values. Okay, so what does all of that mean? It all adds up to an EPA wind rating, which is the wind velocity at which a fixture may suddenly fail when installed at a given height (usually 30 feet for standard lighting poles).
How is the EPA of a luminaire determined?
Equation: To determine the EPA of a luminaire, the frontal projected area is multiplied by the drag coefficient of the luminaire. Frontal Project Area (FPA) is the maximum, achievable cross sectional area of the luminaire and it’s mounting as installed.
Where can I find Energy Star light fixtures?
Visit the Light Fixtures page for usage tips and buying guidelines. Visit ENERGY STAR Rebate Finder to search for rebates and special offers on other products in your area. 0 heat pump water heater installers in your area. .. ..