Due to the increased awareness of both the general public and the design community regarding light trespass and Dark Sky issues, coupled with lighting code requirements, which prescribe the quantity and directionality of light emitted by outdoor luminaries, there has been the need for a system to aid lighting designers, architects, and manufacturers in the creation and selection of appropriate "Dark Sky compliant" light fixtures according to a standard set of protocols. Developed by the International Dark Sky Association (IDA), the Fixture Seal of Approval Program is one such available tool.

According to the IDA's Fixture Seal of Approval Program White Paper, "The Fixture Seal of Approval Program aims to address the demand for a third-party 'certification' of luminaries which do not pollute at night." Any manufacturer may submit a luminaire for review. The IDA evaluates fixtures based on the Upward Light Output Ratio (ULOR), meaning the "amount of upward flux a fixture produces." Currently, the IDA only approves fixtures deemed "full cutoff" and "fully shielded," although with the development of the first draft of the Model Lighting Ordinance (MLO), to be released in 2007, these categories will change to meet the new Luminaire Classification System (LCS) terminology--upward light, forward light, backward light, and glare zone.

Submission Process

The submission process is fairly straightforward and according to the IDA website, takes approximately four weeks. Manufacturers must submit an application form along with the relevant IES photometry files, photographs of the product, and the required fees--$20 per each photometric file submitted and a one-time $500 registration. Once a fixture is "approved" the manufacturer may use the "IDA-Approved Dark Sky Friendly Fixture" logo on the marketing, sales, and technical brochures and even on the actual luminaire "for a period of three years from the date of approval, or until the luminaire is modified, whichever comes first."

For complete information visit: www.darksky.org

Glossary

  • Cutoff angle
    The angle of light distribution from a luminaire, measured upward from nadir, between the vertical axis and the first line at which the bare source (lamp) is not visible.

  • Cutoff classification
    The classification system of the Illuminating Engineering Society of North America (IESNA) that describes the light distribution of an outdoor luminiare. Cutoff classifications define the luminous intensity limits in two illumination zones that occur within the range of 80° to 180° above nadir.

  • Cutoff luminaire
    IESNA classification that describes a luminaire having a light distribution in which the candela per 1000 lamp lumens does not numerically exceed 25 (2.5%) at or above an angle of 90 above nadir, and 100 (10%) at or above a vertical angle of 80 above nadir. This applies to all lateral angles around the luminaire.

  • Full cutoff
    The luminous intensity (in candelas) at or above an angle of 90 above nadir is zero, and the luminous intensity (in candelas) at or above a vertical angle of 80 above nadir does not numerically exceed 10% of the luminous flux (in lumens) of the lamp or lamps in the luminaire.

  • Cutoff
    The luminous intensity (in candelas) at or above an angle of 90 above nadir does not numerically exceed 2.5% of the luminous flux (in lumens) of the lamp or lamps in the luminaire, and the luminous intensity (in candelas) at or above a vertical angle of 80 above nadir does not numerically exceed 10% of the luminous flux (in lumens) of the lamp or lamps in the luminaire.

  • Semicutoff
    The luminous intensity (in candelas) at or above an angle of 90 above nadir does not numerically exceed 5% of the luminous flux (in lumens) of the lamp or lamps in the luminaire, and the luminous intensity (in candelas) at or above a vertical angle of 80 above nadir does not numerically exceed 20% of the luminous flux (in lumens) of the lamp or lamps in the luminaire.

  • Noncutoff
    There is no candela limitation in the zone above maximum candela. Glossary Source: Lighting Research Center; IDA-Approved Manufacturer List: International Dark Sky Association.