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What is BUG Rating

Horace He

Last Updated: December 26, 2023

What is BUG Rating

Bug rating is a measurement system used to evaluate the performance of nighttime luminaires. It is a lingo specifically used in the lighting industry and is part of the BUG lighting classification system, which was developed by the Illuminating Engineering Society (IES) and the International Dark Sky Association.

The BUG lighting classification system was created to assess outdoor light fixtures and their performance in terms of three types of stray light: Backlight, Uplight, and Glare. The term “BUG” is an acronym for these three types of stray light.

Backlight refers to the light emitted behind the fixture, causing a glow or halo effect. Uplight refers to the light emitted upward from the fixture, contributing to light pollution and skyglow. Glare refers to the excessive brightness or discomfort caused by the light fixture, affecting visibility and creating visual discomfort.

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The Bug Rating system helps quantify and classify the performance of a luminaire in terms of these three types of stray light. It is typically expressed as a combination of three letters, each representing the level of stray light in a specific category. The letters are assigned a value ranging from 0 to 5, with 0 indicating no stray light and 5 indicating the highest level of stray light. A lower Bug Rating indicates better control over light distribution and reduced light pollution.

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By using the Bug Rating system, lighting professionals and designers can make informed decisions about the selection and placement of outdoor light fixtures. They can choose luminaires with lower Bug Ratings to minimize the negative impact of stray light and reduce light pollution while still meeting the specific lighting requirements of the application.

Frequently Asked Questions

What Is an Example of a BUG Rating

For instance, a light with 136 lumens in zone BH would be classified as a B1 rating for that specific sub-zone. In the case where it had an output of 930 lumens in zone BM and 985 lumens in zone BL, the overall backlight rating would be categorized as B2, as it represents the highest backlight value among the sub-zones.

How Is BUG Rating Determined

Simply put, a BUG rating is a measurement that determines the direction of light emitted from a fixture, particularly during nighttime in outdoor areas such as parking lots. The definition of BUG ratings is provided by the Illuminating Engineering Society (IES), and their enforcement is carried out by the International Dark-Sky Association (IDA).

What Is the Acronym for BUG Light

In relation to these ratings, the term “BUG” stands for Backlight, Uplight, and Glare.

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