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Application Based Solutions


The following pages are dedicated to comparing HID and LED in a small and large parking area. Our examples show three photometric layouts designed to the Commercial Building Energy Alliances (CBEA) Lighting Zone 4 minimum horizontal luminance of 1 foot candle utilizing hydroformed reflectors with HID, segmented reflectors with HID and LED lighting technology. A summary sheet highlights the advantages and payback with LED.

IESNA RP 20 recommended maintained illuminance values for parking lots
BasicEnhanced
Minimum horizontal illuminance0.2 fc0.5 fc
Uniformity ratio, (max/min)20:115:1

It is also important to consider current IESNA recommended RP20 guidelines for designing fixed lighting for parking facilities. IESNA recommendations only apply to the design of new lighting systems for parking facilities. The lighting recommendations given here are for the reasonably safe movement of vehicular and pedestrian traffic in parking facilities. These values should be considered a minimum guideline, which are subject to changes based on sound engineering judgment. Considerations on illuminance requirements of a parking facility are affected by layout, operation, and vehicular traffic safety issues, plus the visibility and security needs of pedestrians walking to or from their vehicles. More commonly, parking lots are illuminated to higher levels for safety and security reasons.

  Minimum Horizontal Uniformity
Illuminance Maximum: Minimum
Lighting Zone 0 Wilderness areas, parks and preserves, and undeveloped rural areasN/AN/A
Lighting Zone 1 Rural and low density residential areasN/AN/A
Lighting Zone 2 Light commercial business districts and high density or mixed use residential districts0.50 fc10:1
Lighting Zone 3 Large cities' business districts0.75 fc10:1
Lighting Zone 4 High intensity business or industrial zone districts1.00 fc10:1

Technology Comparison

FIGURE 1


HYDROFORMED

Traditional HID

The large area of excessive lumens in the center of the diagram above provides a visual representation of wasted energy.

HID shoeboxes typically use a lamp in the horizontal position, emitting most of the light straight down at 0 degrees. The excessive lumens gather directly underneath the fixture resulting in:

  • Bright, hot spot
  • Increase in overall average footcandle levels for poor uniformity

FIGURE 2


HYDROFORMED


SEGMENTED

HID Segmented Reflectors

The diagram above illustrates how segmented reflectors redirect light where it is needed in comparison to hydroformed optics.

The use of segmented reflectors:

  • Reduces the hot spot
  • Enhances overall visual acuity
  • Improves lumen distribution and uniformity

Depending on certain criteria, it is even possible to:

  • Reduce the overall fixture count
  • Save money during initial installation
  • Consume less energy throughout the year

FIGURE 3


HYDROFORMED


CIMARRON LED

LED – Cimarron

The diagram above illustrates the performance of the Type IV Cimarron LED, Note the absence of excessive lumens directly under the fixture.

Each LED optical configuration is designed for maximum performance. The advantages of Cimarron LED include:

  • Energy-efficiency
  • Better uniformity
  • Reduced pole and fixture count in certain configurations
  • Long life
  • Money savings during installation
  • Virtually maintenance free (no relamping)