OVERAGE AREA OF A PARKING LOT LIGHT?

Parking lot lighting refers to outdoor lighting that provides illumination for parking lots, pathways, roadways and pedestrian walkaway. Most of the parking lot fixtures are mounted on poles to cover large area lighting. Requirements for various lighting areas vary from each other. Parking lot light is supposed to be comfortable without causing eye strain. Knowing What is the Coverage Area of a Parking Lot Light is important for a safe working environment for customers or employees. When working within the parking lot, there are risks of hazards or safety issues within the parking lot. Therefore, it is very important to have adequate lighting in this area.

A Type Lens is a Transmissive Optical Device that affects the focus of a light beam through refraction. A simple lens consist of a single piece of material, while a compound lens consist of several simple lenses usually a long a common axis. Optics lens are key in every parking lot light design. LED lenses come in various shapes and sizes, such as round, square and hexagonal. Common lens materials include plastic and silicone. Therefore some are rigid and some are flexible. Type 3 LED lenses are designed for use with single or multiple LEDS for parking lot lighting. They sit over the LEDs to create the desired lighting effect. The various properties of type 3 lenses enable precise control over the beams of light. LED type 3 lens can offer a nice aesthetic appearance by masking the LED components within. It is important to note that optics with identical viewing angle can differ a lot in intensity and quality of the beam depending on the emitters of the optical design.

Mounting heights for parking lots lights can range from 12feet to 20 feet, but in some cases, the poles can go as high as 35 feet. The size of the parking lot determines the recommended height of your light poles. 

 It is recommended to have 2 LED Parking Lot lighting heads of 20, 000 lumens each at about 15-20 feet high on each pole. Space the poles about 20 feet apart. This is the average lighting. However, with different parking lots, you can determine the number of lights you need for your parking lot, by focusing on footcandles on the ground and uniformity. Footcandle measures the amount of light that reaches a surface area. Light uniformity is expressed as the ratio of maximum- to minimum illumination levels. Currently, the most recommended ration for most outdoor parking lot application is 3:1.  Basically, when lighting lacks uniformity, it is because of space between the fixtures. Often, other features, like trees complicate the uniformity.

The type of poles you use on your parking lot will also determine the number of lights you use on your parking lot. Mounting heights for parking lots can range from 12feet to 20 feet, but in some cases, the poles can go as high as 35 feet. The size of the parking lot determines the recommended height of your poles. For larger area, tall poles are preferred, and vice-versa. Once you determine the height of pole to use, then you can decide on the spacing of your fixtures. The rule of thumb as far as this is concerned is: the higher the mounting height, the fewer the poles you need.

  i. No, designed to have similar patterns.  They might be brighter but not always more area

Using LED light fixtures does not cover more area rather; LED fixtures help you design a layout for your parking lot that provides optimum light coverage. LED lighting have patterns which when projected onto an object or surface define how light is dispersed from an illumination fixture. It is determined by the point at which 50% of the fixture’s luminous intensity is met. These distributions are an optimal choice for parking lot lighting. The 5 distinct distribution types are- Type I, Type II, Type III, Type IV and Type V light distribution. 

Light Pattern Distributions

Type I pattern provides a wide, symmetrical light for fixtures located in the middle of the walkway. 

Type II light fixtures have a slightly lower distribution and are intended for installations where the fixture is placed at the side of roadway or street lighting.  Also see Street Lighting mount and wiring info here

Type III light distribution cats lights about 2.75 times wider than the mounting height of the fixture. 

Type IV light distribution fixtures are also called asymmetrical fixtures. Like type III, these light fixtures cast light 2.75 wider than their heights but produce a more rounded distribution pattern that pushes the light outward, with little light falling behind the fixture. 

Type V light distribution fixtures are omnidirectional fixtures. They distribute light in a uniform or circle around the fixture.

The commonest parking lot light is a T3, short form for Type III is the defacto standard which had been around for many years. In the light type chart below, 140 degrees wide and 90 degrees forward, at 20 feet high that is about 46 feet wide and 28 feet forward.

A 300 watt light, which happens to be NextGen II 300 watt, at 30 feet high looks like what we have below. The numbers in circles are the footcandles. Remember that a 150 watt of the same efficiency would be exactly half this number. This light at half height, 15 feet, would be half this coverage area.

 

You can see where the footcandles drop off. This helps us to determine where the next light is needed. In the example above, 30 foot high, you can see you would probably need the next light about 30 feet away to maintain an even 8feet candle along the stretch. If you don’t mind a darker spot in the middle, you could go 40-50 feet away but it means you will be going from 7fc down to 2fc and then back to 7. That is fine for back lots, thou not very uniform to suit parking lot lighting.

A parking lot coverage area is calculated by multiplying the parking lot’s square footage by the footcandle requirement. For instance, a parking lot of 100 square foot, which needs 20 footcandles, will need 2, 000 lumens.

You must always pay attention to wattage lumens and footcandles. LED lights provide more lumen output per watt. For efficient lighting, this is what matters. If you want the light to cover 15 to 20 feet it is best to look for 16000-20000 lumens. On the other hand, if you want cover 20 to 30 feet, 40000 lumen light is an ideal choice. Therefore, when looking for LED parking lot lights, your focus must be on lumens.  The brightness of LEDs is determined by lumens. Lumen is a unit of measurement of brightness provided by the light while a watt is a measurement of how much energy the light draw. 

Footcandles are the most common unit of measurement used to calculate light levels in outdoor spaces. A foot-candle can be defined as the luminance of a one square foot surface from a uniform source of light. Thus, it is a measure of the amount of light that reaches a surface area. From a candle lit source, light falling on one square foot of area equals one lumen per square foot. The activeness of an area is the main determinant for the adequate light level. Lighting experts recommend a minimum light level of 1 fc throughout the desired area and 2 to 4 fc being more desirable for appeal and optimal visibility.

References:

www.actiongroupservice.com 

www.energy.gov

https://www.ledopticslenses.com/sale-10103794-type-3-high-power-led-street-light-lens-multi-led-lens-with-pcb-board.html

https://www.ledlightexpert.com/How-Many-Lights-Do-I-Need-For-My-Parking-Lot-_b_137.html