Dark Sky Friendly Outdoor Lighting: Choosing Dark Sky Compliant Light Fixtures

Many US outdoor-lighting codes build on the Model Lighting Ordinance from DarkSky International and the Illuminating Engineering Society. Wording varies, but five requirements recur.

1. Full cutoff or fully shielded fixtures

No light may be emitted above a horizontal plane through the lowest part of the fixture. In practice that means an opaque shade with the light source recessed inside it, mounted level, with no drop lens or glowing side panels. The IES files we publish for LED Standard Dome, Step Neck Dome and Deep Bowl shades, open bottom and hung level, record no light above 90 degrees. Tilt the shade and that changes.

2. Warm color temperature

A common limit is 3000K. Dark-sky communities and parks often go to 2700K, and some ask for amber. The adjustable LED module is set to 3000K on the fixture; its 90 CRI versions also offer 2700K.

3. Lumen caps

Many codes cap lumens per fixture or total lumens per site area, by lighting zone. Trim output rather than oversizing: the 23W module offers 1,500, 1,850 or 2,400 lumens, and every version dims 0-10V down to 10%.

4. BUG ratings

Area, wall and pole fixtures are often limited by their Backlight, Uplight and Glare rating (IES TM-15). U0 is the lowest uplight rating. BUG is calculated from the IES file for each exact configuration; ask us for the file and we'll help confirm it.

5. Curfews and controls

Many ordinances require lights off or dimmed after a set hour. Plan timers, photocells or motion sensors from the start.

DarkSky Approved is a certification program run by DarkSky International (formerly the International Dark-Sky Association). A manufacturer submits a specific luminaire; if it passes third-party review of shielding, distribution and color, it may carry the seal. Some specifications, DarkSky Places and DarkSky Approved lodgings require certified products by name.

Ordinance compliant means a fixture, as configured and installed, meets the rules of your city or county. Most codes judge that from cut sheets and photometric data, not from a seal. Bock has no products in the DarkSky Approved program. If your spec names the seal, tell us early. If it names shielding, CCT, lumens and BUG, we can help you show compliance.

Configuration choices that matter

• Skip the globe. Glass jelly jars and cast guards are useful for impact and wet-location protection, but our own IES files show the globe-and-guard versions put noticeably more light near the horizontal. Where a code is strict, specify the open-bottom version.
• Hang it level. A gooseneck or pole bracket that holds the shade horizontal keeps the rim below the LED. Angle shades belong on signs, aimed down.
• Go bigger and deeper, not brighter. A 16 in dome at 1,850 lumens hides the source better than a 12 in dome at 2,400.
• Put it on the order. Write the CCT and lumen setting into the part number so the fixtures arrive already set, and there is no field adjustment for an inspector to question.

What to submit for plan review

A cut sheet for each fixture type, the IES file for the exact shade, lamp and lumen setting, the CCT, a site photometric plan if required, and a controls note covering the curfew. Send us your ordinance and fixture schedule and we'll pull the matching files. The IES file viewer shows each file's candela distribution before you submit.