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Q. Where can I find industry-accepted standards for lighting?

Q. Is it possible to retrofit a ‘cobra-style’ sag lens roadway luminaire?

Q. What is the difference in cost between full cutoff and the ‘standard’ sag-lens cobra-style luminaires?

Q. What lamp shields are available to retrofit (add to) PAR-style flood or spot lights, or NEMA-style yard lights?

Q. What kinds of motion detectors are available? The excuse I hear most for not having them, is that they turn the lights on for raccoons and for pets passing by.

Q. When are dusk-to-dawn meters appropriate?

Q. Are dark-sky-friendly sports lights available? What about the availability of other kinds of other fixtures such as wall-packs, canopy, residential, etc.?

Q. Are LED outdoor lights always more “dark-sky friendly” than traditional incandescent light systems?

Q. Where can I find industry-accepted standards for lighting?

A:

1.   Study IDA’s Model Outdoor Lighting Ordinance (MLO) at http://www.darksky.org/index.php?option=com_content&view=article&id=622

2.  See IESNA Lighting Handbook, 9th Edition or later. Many lighting designers have this reference. http://www.iesna.org/handbook/

3.        Purchase IES Recommended Practices RP-8-00 (Roadway Lighting) and RP-33-99 (Lighting for exterior environments) or other pertinent practices, through an IES Member (See Useful links to IES-NA)

4. IDA maintains a database of Approved Dark-Sky Friendly Fixtures that go through a rigorous certification process by IDA. A list of them by category can be found here.

Q. Is it possible to retrofit a ‘cobra-style’ sag lens roadway luminaire?

A: ‘Cobra-style’ luminaire or ‘cobra-head’ is a slang term describing the rounded housing that is mounted on an extended arm, which resembles a cobra. Other fixture types include ‘shoeboxes’, discs and cylinders. If a ‘sag-lens cobra-style’ luminaire is made by GE, a ‘hula skirt’ shield can be used. The North Texas Toll way Authority (NTTA) installed some of these Dallas North Toll way north and south of Beverly Drive.

They can be ordered for about $30 from GE; however if the luminaire is 8 to 10 years old, it would be cheaper to install a full cut-off street light, since the average life of the ballast transformer inside the fixture is 8 to 10 years, and you have to figure in the cost of labor. A new cobra-style luminaire may cost about $195. You might ask your city to specify full cutoff street lights to use for replacements.

There are two hula skirt shields sold by GE:

ELS-M250-360 fits the M-250A and M-250R2 luminaires

ELS-M400-360 fits the M400 and M400A luminaires

They can be found at:

https://secure.ge-lightingsystems.com/gels01/r2/productcentral/data/roadway/catalog/r48_roadway_accessories_2008.pdf

Q.  What is the difference in cost between full cutoff and the ‘standard’ sag-lens cobra-style luminaires?

A: The difference in cost between full cutoff (FCO) and sag-lens cobras can be just a few dollars each, if bids are requested from a number of manufacturers and they offer a good deal.

An IDA member in Connecticut, where state law requires FCO lighting for ALL municipal and state roads, sent me the following information. For cobra-style luminaires, I believe CT uses a 70-watt HPS M250R2 (the true Full Cutoff version as indicated in the GE7304.IES photometric data report). When purchased in bulk, it has been bid for as little as [email protected] up to $495 each.

The Lithonia flat lens full-cutoff costs $157.75 including the lamp, if purchased from W.W.Grainger. Also, the Lithonia CHE full-cutoff roadway series cobrahead is available from the manufacturer in 35, 50, 70 and 00 watt luminaires for varying needs. [Thanks to Cliff Haas]

Mercury Vapor lamps are much less efficient than other HID (High Intensity Discharge) lamps such as compact fluorescent (CF), Metal Halide (MH), High Sodium Pressure (HSP) or Light Emitting Diodes (LED). Your community could save energy costs by choosing a more efficient (lumens per watt) lamp. It’s best if the city decides on either yellow light or the white light in order to have a uniform ambiance to the City.[Thanks to Cliff Haas]

Q.    What lamp shields are available to retrofit (add to) PAR-style flood or spot lights, or NEMA-style yard lights?

A:   1.      The GE SkyGard for NEMA-style “barn lamps” luminaires: Old and New Security Lights Compared … The GE SkyGard is the fixture that Northern Virginia Electric Cooperative (NOVEC) has chosen to replace the old-style ‘glare bomb’ that is so intrusive.   http://www.mediasoft.net/macdowell/oldandnew.htm

2.      The ParShield, at http://www.Parshield.com, patented by Susan Harder, fits any PAR 38 parabolic floodlamp, as does a sheet metal (roof flashing) do-it-yourself cut-out with a 5-inch hose clamp–@$1.30 designed by Cliff Haas. http://members.aol.com/ctcadman/shielding.htm

3.      The improved Hubbell Sky Cap—resists wind better than the original. See http://www.hubbell-canada.com/lighting/download/DarkSkies.pdf

4.    The Glarebuster full cut-off yard light is a new fixture, not a retrofit, but can be mounted on a post, flat wall, shingles, brick or under an eave. It accepts most common sensors and can use compact florescent (CF) lamps. See http://www.theglarebuster.com/index.html?body=page3.html

5. RAB lighting has ‘Shades’ that can be affixed to the wall around various sizes of glaring ‘wall-pack’ lights, to convert to full cutoff shielding.

See: http://www.rabweb.com/product_line_detail.php?prodline=ACCWP

Q.    What kinds of motion detectors are available? The excuse I hear most for not having them, is that they turn the lights on for raccoons and for pets passing by.

A. Passive Infrared (PIR) motion detectors can be designed to minimize false alarms caused by pets (sometimes called ‘Pet Immune’). By modifying a Fresnel lens to have more lenslets and by separating the pyroelectric elements into a dual element configuration, the device becomes more sensitive to vertical shapes (humans). Check to make sure the product you buy has been modified in these ways. [From WHITE PAPER Pet Immune PIR Motion Detection Keith Kuhnly, co-author of two patents in PIR technology:

Q.  When are dusk-to-dawn meters appropriate?

A: The first question to ask is, “What is the purpose of the lights and are they really necessary?” If not, turn them off or remove them. Then ask, “Would motion detectors serve the purpose?” If the answer is no, then there are several choices. The lights could be turned off manually, by a computer system or timer; or the lights could be put on a dusk-to-dawn meter. The dusk-to-dawn type of meters sometimes burn out and the lights end up being on all day, until the meter can be replaced. Whatever the choice, the light should be fully-shielded and aimed downward with as low wattage as possible to accomplish the purpose.

Q. Are dark-sky friendly sports lights available? What about the availability of other kinds of other fixtures such as wall-packs, canopy, residential, etc.?

A:  Yes, dark-sky friendly outdoor luminaires come in many shapes, sizes, colors, and serve a variety of applications. Even traditional “period-style” or “park lamp style” outdoor fixtures can be rendered full cutoff while still yielding aesthetic value. For a complete list of all IDA dark-sky friendly fixtures see http://www.darksky.org/index.php?option=com_content&view=article&id=452

Q. Are LED outdoor lights always more “dark-sky friendly” than traditional incandescent light systems?

A: No, not always. While LED outdoor luminaires use a fraction of the energy that incandescent systems use (e.g. high pressure sodium, metal halide, mercury vapor, etc.), the intensity of the LED light and its coloring can still be a problem. Typically, LED luminaires that emit light in the blue/white spectrum (5500 degrees Kelvin) are replacing low-pressure sodium streetlamps whose emissions are amber colored (3500K or less). As many will note from personal experience, the amber coloring of light at night is softer on the eyes, reduces glare, and fits better into the natural environment compared with blue-rich white light. This is why amateur astronomers use red lights at night; it is less disruptive to our dark-adapted eyes. LED luminaires DO exist that emit light in the 3500K or lower range, but are being passed-by infavor of the blue-rich white light emitting ones. We must be careful to make sure that the proper coloring of LED luminaires is adhered to or we risk dramatically increasing the brightness of our cityscapes. For more information on blue-rich white light emitted from LED outdoor luminaires, please read the IDA’s Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting

Graphic from the aforementioned IDA paper:

For more information:

Contact Texas IDA

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