Rules for Protecting
the Night Environment
- a necessary and sufficient set
(The numbering is the
same as in the Proposal for Changes of the Czech Clean Air Act from Sep 13,
2003, see www.astro.cz/darksky/cz_law
for its plain basic text and other info regarding it. This version of the rules
contains very short comments meant for getting a better overview. The rules are
meant as a template for legal protection of the night anywhere, esp. in the the
European Union, including it into the standard protection of the atmosphere)
PROTECTION
OF THE NIGHT ATMOSPHEREENVIRONMENT
§ 35a
Artificial sources of light (as sources of air pollution)
Artificial sources of light
and luminaires containing them with, exception of light equipment of vehicles,
are considered to be small stationary sources of pollution of the air.
§ 35b
Measures to lower light pollution
(1)
(enabling lumens instead of kilograms per second for expressing this kind of
pollution)
Because of the nature of light as a
polluting substance, instead or in addition to the quantities given in
§ 2, analogous photometric quantities are used: pollution, emission limits
and ceilings are expressed rather in units of luminous flux instead of units of
mass flux (units of mass per unit of time), as it is in § 2 art. 1 lett.
c), e) and f), level of the pollution, imissions and imission limits in units
of luminous flux density instead of mass concentration (units of mass per unit
of volume), as it is in § 2 art. 1 lett. g), i) and j).
(2)
(setting the demands for all future changes of lighting)
All luminaires and systems of them,
which are from January 1, 2005 being installed in the territory of the Czech
Republic, have to obey the rules according to articles 3 to 6 of this §
(3)
Luminaires and outdoor lighting systems shall:
a)
(shine
down! - defined by a standard technical definition demanding 0 cd/klm upwards)
shine exclusively down,
with exception of the case given in article 6; as a luminaire, which does not shines just down even horizontally and upwards each such is
considered, whose specific luminous intensity horizontally and upwards in such directions, after being rounded to
a whole number, is zero candela per thousand lumens of the
luminous flux produced inside it;
b)
(limit
on amount of light)
be used in such
a way that the illuminance of the target surfaces does not exceed the
value demanded by safety standards, if they exist, or in the absence of such
standards, the illuminance of the target surface does not exceed 10 lux or at least the luminance of the target
surface does not exceed 1 cd/m2, with exception of the surfaces
given in article 5;
c)
(dimming
or switching-off late at night)
be equipped with
devices capable of reducing the amount of emitted light by at least thirty per
cent compared to the full output; such reduction of the amount of light is
applied when the conditions of the use of the illuminated surface are such that
safety is not endangered.
(4)
(general exceptions)
The properties given in article 3 are not
obligatory for luminaires which fulfil at least one of the following three
conditions:
a)
(faint
sources)
contain just light
sources whose luminous flux does not exceed 1500 lumens, if the cumulative
luminous upward flux from the luminaires placed in any region with
a radius of two metres does not exceed 2250 lumens;
b)
(temporary
sources)
are in use at most for
three weeks in a single year and are not used in the period from 23:00 to
5:00;
c)
(traffic
lights)
are used as light
signals for the purposes of ensuring transport safety, defence and security of
the Republic.
(5)
(higher limits for shop signs etc.)
Illuminated surfaces of the size below 500 square
metres in area, if they To illuminate surfaces which convey
text information or image instructions, more light than given in art. 3 lett. b) can be
used, are allowed to reach a luminance over
1 cd/m2, provided the luminous intensity of such surfaces does not exceed two hundred candelas, or three hundred candelas for
surfaces sized 5 m2 and more, or five hundred candelas for surfaces sized 30 m2 and more. following limits are obeyed: mean luminance
(divided by 1 cd/m2, L) of the illuminated surface of the size
1 m2 and larger (divided by 1 m2, S) does not exceed a value
L = 150 / S0.8 and the luminous intensity of the surface of the
area of 1 m2 and smaller does not exceed a value of
150 cd.
(6)
(architectural lighting additional rules and an exception not easy to
misuse)
Illumination of bBuildings and pieces of art are not to be lit in such a way, that their
luminance exceeds the luminance of the surrounding illuminated surfaces, in any
case their luminance must not be over 1 cd/m2 or at least their illuminance over 10 lux. The
illumination is to be, for the whole period from 23:00 to 5:00,
switched off or reduced by at least one half. Even luminaires shining upwards
can be exceptionally used for this purposeillumination of these structures,
provided that the municipal corporation decides that such a way of
lighting a specified surface is needed; in case of such illumination there
is an obligation that the margin of the beam does not exceed the outline of the
illuminated object.
(7)
(labeling the luminaires)
Manufacturers and importers are
obliged since January 1, 2005 to declare the coherence of the luminaires with
the demands of this law in such a way, that the product will carry a label
“optics shining only downwards”, and in the enclosed service manual they have
to include instructions on how to use the luminaires in accordance with the
law.
(8)
(banning skybeamers)
Using upward, only into the air
aimed movable or fixed beams of any type from a light source producing more
than 1500 lumens is considered as an especially serious light pollution. Such
beams are prohibited, if a special law does not say otherwise.
§ 35c
Protection of particularly sensitive sites
(1)
(nature reserves and observatories)
Light pollution is lowered by this
law in the small-sized particularly protected areas defined in a special
law (namely national nature reserves, nature
reserves, national nature monuments and nature monuments) and further around
buildings, which are approved as astronomical observatories.
(2)
(reducing direct light to them soon)
The luminaires which are located
within the areas given in article 1 or in their surroundings or in surroundings
of buildings given in article 1, if they are nearer than 1 km from such
sites, shall be shielded before July 1, 2005 in such a way, that they will
not be visible at night from there, or at least so that the luminous flux
density from any of them does not exceed one millilumen per square metre when
viewed from the given site. Luminaires more distant than 1 km but nearer
than 5 km have to obey this condition before January 1, 2008.
(3)
(switching-off unessential lights late at night)
Luminaires placed nearer than
1 km to a given site shall be extinguished during the period from
23:00 to 5:00, if their use is not necessary because of safety reasons.
(4)
(empowering communes to demand sooner and larger improvements)
The local governmentcommune may issue a generally
obligatory edict, in which it sets further measures to lower light pollution,
in addition to those which are given in § 35b. The reason for accepting
such measures may be protection of pedestrians and drivers against glare,
protection of citizens in their homes against light trespass, nature
protection. The commune may declare some localities in the edict, where the
direct glare and the night hours for using the luminaires are restricted.
Additional rules for a localcommune level (not to be a part of the national law)
On the national level,
the rules should be simple and stable. On a localcommune level, some additional ones
are recommended:
·
limiting
the proportion of light flux missing the terrain to be illuminated (for the
beginning, say to 15 % for broad roads and 35 % for narrow paths),
·
prohibiting
light sources which emit light with a non-negligible blue component after
curfew,
·
controlling
the yearly change of installed light flux on a commune territory or its
specified parts – allowing a positive number like 2 % for the
beginning but demanding a negative number some years later,
·
demanding
barriers for light escaping from windows of houses to be build.