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[DSLF] Digest Number 1464
There are 2 messages in this issue.
Topics in this digest:
1. remedial measures
From: "Mark Kinsler" <kinsler33@hotmail...>
2. Re: remedial measures
From: ctstarwchr@aol...
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Message: 1
Date: Sat, 02 Oct 2004 13:08:56 -0400
From: "Mark Kinsler" <kinsler33@hotmail...>
Subject: remedial measures
I am new to this group. My question has probably been addressed a thousand
times here, but there seems to be nothing on it at the International Dark
Sky Association's website.
I am trying to find out means of reducing skyward radiation from existing
outdoor light fixtures, primarily street lighting luminaires and parking lot
lighting. The IDA website has a description of a cap that can be applied to
the backyard lights of cooperative neighbors, but it doesn't look like the
sort of thing that would work on streetlights or the lights at a Walmart
parking lot.
My guess is that there is existing research on the subject and perhaps
commercially-available devices to accomplish the task.
M Kinsler
512 E Mulberry St. Lancaster, Ohio USA 43130 740-687-6368
http://home.earthlink.net/~mkinsler1
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Message: 2
Date: Sun, 3 Oct 2004 07:32:16 EDT
From: ctstarwchr@aol...
Subject: Re: remedial measures
In a message dated 10/3/2004 6:17:50 AM Eastern Daylight Time,
kinsler33@hotmail... writes:
> I am trying to find out means of reducing skyward radiation from
> existing outdoor light fixtures, primarily street lighting luminaires
> and parking lot lighting.
Hi Mark:
Welcome to the DarkSky List Forum! In Connecticut we passed a
state law in 2001 (Public Act 01-134) requiring the use of full
cutoff lighting on all roadways throughout the state.
http://www.cga.state.ct.us/2001/act/Pa/2001PA-00134-R00HB-05449-PA.htm
In simple terms, full cutoff lighting permits no light to emit above
the horizontal plane and it reduces intensity to 10% (for each angle)
at and above 80° (above nadir) measured in the vertical plane. See
the images in the Photos > Photometry folder of the DSLF to see what
this means.
Today we now have thousands of excellent examples in place on CT
roads and this law is working very well to help improve nighttime
driver safety while reducing visible skyglow and it also allows
dramatic wattage reductions for some of the existing applications
receiving new fully shielded fixture retrofits.
In some cases we retrofitted 400 watt high pressure sodium semi-cutoff
sag lens fixtures with 150 watt full cutoffs with no loss in visual
perception and roads still exceed the minimum recommendations of the
American National Standard for Roadway Lighting ANSI/IESNA RP-8-00.
Light trespassing into bedroom windows and yards has been dramatically
reduced and people are speaking highly in favor after they experience
these results on their properties. Some have never had dark bedrooms
before the new lighting was installed.
Fully shielded fixtures with flat lenses installed level will help to
reduce a lot of skyglow, but some of that light will still reflect upward
from the illuminated surfaces, so it is vital to also reduce brightness
to minimum levels recommended in lighting standards to assure adequate
safety will be provided. In many cases extreme overlighting has exceeded
minimum levels and each one allows an outstanding opportunity to save tons
of money and energy reducing wattage when applying fully shielded lighting.
In many cases the cost to replace lighting fixtures can be returned through
savings in a few years.
I have designed retrofit lighting systems that reduced wattage by so
much the new system paid for itself within 5 years simply by the savings
achieved on the annual electricity bill. Visual quality and aesthetics
were improved as well. For some excellent examples of good lighting
products visit the Manufacturers section of my LiteLynx List at the Light
Pollution Awareness Website at:
http://members.aol.com/ctcadman/LiteLynx.htm#mfrs
Also see "Good Fixtures and Where to Get Them" on the IDA web site.
An excellent IDA information sheet titled, "The Environmental Aspects
of Roadway Lighting" is available that provides good information on
applying fully shielded lighting.
The Tech Talk section of the LiteLynx List offers outstanding information
on good lighting practice.
http://members.aol.com/ctcadman/LiteLynx.htm#tech
The Citizens for Responsible Lighting web site offers good information
in the Engineering section. http://www.crlaction.org
Also be sure to visit the Links, Files, and Photos sections of the Dark
Sky List Forum for some excellent educational information. The following
axioms are overly simplistic but they apply for reducing light pollution
effectively...
1. Apply fully shielded lighting aimed properly to keep direct light below
the horizontal plane to reduce visible glare as much as possible.
2. Mount, aim, and shield fixtures carefully to assure direct light stays
within the property boundaries and illuminate only the task areas.
3. Never apply more light than minimally needed for the tasks.
4. Use sensor driven lighting whenever possible and turn the lights
off when nobody is present to benefit from them.
Other references at the LiteLynx List will lead you to an intriguing
adventure exploring the wild and woolly world of low impact outdoor
lighting. Also try some experimenting with your lighting at home.
For some ideas check out the shielding section of the LiPAW at:
http://members.aol.com/ctcadman/shielding.htm
The best example of industrial applications where incredible savings
were achieved is the Premcor Refinery Group in Port Arthur, Texas.
They reduced wattage in half after applying full shielding on outdoor
fixtures and save nearly $500,000 on the annual electricity bill while
exceeding minimum OSHA lighting standards for petrochemical plants.
The most outstanding savings achievement full cutoff lighting has
achieved in municipal lighting savings is the City of Calgary, Alberta
in Canada. They are saving $2,000,000 annually on roadway lighting
costs and have also reduced wattage in half while still meeting the
minimum standards in ANSI/IESNA RP-8-00.
http://members.aol.com/copernicanview/calgary1.pdf
http://www.calgary.ca/docgallery/BU/roads/streetlights/envirosmart_logbook.pdf
Hope this helps provide a robust foundation on the basic concepts.
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Author Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctcadman
http://www.crlaction.org
Member: IESNA, CRL, NELPAG, AARP
[Non-text portions of this message have been removed]
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