[Darksky]Shielding nonsense

Jan Hollan
Wed, 15 Dec 2004 10:26:26 +0100 (CET)

In my view, the most disastrous feature in MLO is the fact, that it
demands almost no full shielding: a lot, if not most of the existing
lighting would be OK according to it. This is completly against the
interests of IDA. Our goal is not just slow down a bit the growth of
pollution, but to stop and reverse it.

I thought I wrote it earlier already to this group, but it seems I didn't.

In my first reaction sent to the IDA, I just mentioned that the watt
limits for the non-FS luminaires *should be divided by five*, for
discharge sources, and that it would do. But it would not do, sometimes
*they have to be divided by as much as 15*!

To clarify the situation, I wrote some sentences to Tim, and he put the
idea in a short form to his draft http://www.fixthemlo.org/whyisitsobad.php.
I wrote the numbers as crude guesses.

After that I googled to get lumen outputs of the most efficient lamps, and
the numbers changed a bit (down for the 150W limit, up for the 30W limit),
in the adapted copy of the text from Dec 2 the numbers are corrected and
lamp names added:

 ``permits too strong lights without full shielding''

 The usual maximum limit for lamps without full shielding is either
 1 800 lumens (Connecticut) or 1 500 lm (Italian provinces). These are
 laws which work with no problems.

 However, MLO allows 150 W for any purposes in Zone 4, what translates to
 up to 15 000 lm or even 26 000 lm for some discharge lamps!
  [135W SOX-E, or Osram SXE131 having just 127 lamp watts,
 Even for Zone 1, it permits 30 W, what translates to 4 000 lm
  [Osram SXE26, with merely 27 W lamp power!],
 more than twice the usual maximum limit (instead of halving it, as do
 some municipalities and as would be proper for Zone 1, allowing no more
 than 800 lm)!

 The maximum limits in a good legislation are made in such a way,
 that they exempt those lamps, which are most often used by ordinary
 citizens at home, at yards and gardens (like incandescent bulbs or common
 compact fluorescents). And they ensure, that all strong professional
 lighting by high intensity discharge (HID) sources is made fully
 shielded. This is a necessary condition to stop the growth of sky
 luminance, as shown years ago already by scientific papers.

 There is no reason at all, why professional lighting systems should be
 further made without using full shielding. All claims that full shielding
 is not possible in some cases have been disproved already.

As Italian experts say, having a bad law is much worse than having none at
all. They know it from years of experience with different provinces.

Such a major mistake in MLO seems to be a strong evidence, if not a
proof, that it is written either by incompetent people, or still worse,
drafted by people whose interests are quite contrary to those of the
International Dark Sky Association.

I'm sorry to say it, but it's really so.