What is BUG (BUG Rating) for an Area Light?
You may not have heard for "BUG" or a "BUG Rating" for area lights, do not worry or despair as most people have not heard of it either. Fortunately we have some great technical people here at ACE Lighting direct who have been working with BUG rating for area lights for years.

So, what is BUG? 
It's an acronym for Backlight, Uplight, and Glare.

So, every area light has a bug rating, but the numbers will be different for different types of fixture but its not always shown. it may not be shown as it either hasn't been tested or the rating will not be designed for use in area where BUG rating is important. 


Who came up with BUG?
It was a system developed by the IES (Illuminating Engineering Society) and was then reinforced by the IDA (Dark-sky Alliance) to give a standardized way of rating the B-U-G parameters of a exterior light fixture.

BUG Overview 

  B U G
Designation Backlight Uplight  Glare
Information This is the amount of light emitted behind the light fixture This is the amount of light emitted upwards (above the horizontl plane) from the light fixture into the night sky This is the amount of light emitted from the fixture at high angles that can cause visual discomfort or even tomporary blindness to observers (usually pedestrians or drivers)
Details High Backlight can lead to Light Trespass (this is whereunwanted light spills onto the adjacent properties or land - such as shining into a neighbours window) High uplight contributes to Sky Glow (Light Pollution) which reduces view of the star, disrupts wildlife and wastes energy. High Glare is can reduce visibility and create safety hazards
Ratings Typicall range from B0 (least backlight) - B5 (most backlight)

 Typically ranges from U0 (least uplight) to U5 (Most uplight) - U0 is an ideal factor for "Dark Sky" compliance, meaning no light is emitted above 0 degrees from the fixture Typically ranges from G0 (least glare) to G5 (most glare) - Lower number indicates better glare control and visual comfort


How it works is that each of the categories is then assigned a number between 0-5/6 with 0 being the best in each category. the amount of light (which is measured on Lumens) emitted from the fixture in specific zones/angles around the fixture is measured (the zones are defined by IES standards e.g. TM-15-11).

e.g. B1 U0 G2 
B1 - Minimal Backlight
U0 - No Uplight ( excellent for Dark Sky Compliance)
G2 - Low to Moderate Glare

Importance of BUG
- Light pollution reduction - minimizes Light Trespass & Sky Glow
- Energy Efficiency - Paying for light where it's needed
- safety & Comfort - minimizes glare
- Code Compliance - local and state area codes (such as California Title 24) and lighting ordinances have BUG requirements
- Informed Decision Making - Providing our customer with information to make an informed decision

See the diagram below:



BUG Rating Testing
Testing for the BUG rating is based on the light distribution (the way the light output comes out of the fittings) and measured between specific angles with a focus on specific directions, the image below is a great representation of the testing:


 



Please feel welcome to get in touch if you have any questions or need further information.


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