Obtrusive Light – The Step ForwardEYE Lighting
Outdoor lighting is provided for a variety of purposes, for work or recreation, for safety or security, for advertising or display or for the beautification of the night time environment. The obtrusive effects of outdoor lighting can be described in these terms:
Spill Light: The spilling of artificial light beyond the area (useful light) being lit or boundary of a property, are all forms of obtrusive light which may cause nuisance to others.
Glare: Luminaire intensities in some directions can cause nuisance outside of the area being lit, towards owners/users of adjacent properties, road users and transport systems.
Sky glow: Brightening of the night sky is a major pollution issue for astronomers.
Biota: The effects of outdoor lighting can be detrimental to people but can also affect the night time living of insects, birds, mammals and sea turtles.
Outdoor lighting, no matter how well designed, will generally have some effect on the environment in which it is installed.
AS/NZS 4282: Control of the obtrusive effects of outdoor lighting.
The standard specifically refers to the potentially adverse effects of outdoor lighting:
- on nearby residents,
- users of adjacent roads,
- transport signalling systems,
- astronomical observations.
The standard does not apply to:
- Public lighting, unless specified by the relevant authority
- Environmental impacts associated with the daytime appearance of outdoor lighting systems, including their support structure.
- Biota due to its diversity and minimal information on threshold and behavioural response of species due to artificial light, however some information is provided.
AS/NZS 4282 is broadly adopted by most regional Councils and States as a regulatory standard for outdoor lighting installations.
The differentiation for limits and light technical parameters applied in the standard takes account of land use zoning which is mostly based on level of night time activity to be expected in the area.
Maximum limits specified applying to each zone are quantified for the following light technical parameters:
- Vertical levels of illuminance in lux during non-curfew and curfew hours,
- Threshold increment (TI) as a percentage with a default adaptation level,
- Skyglow as an Upward light ratio,
- Luminous intensities in cd,
- Luminance in cd/m2.
At EYE lighting we are often involved in the lighting of exterior environments whether it is for a parking area, a sports ground, the outdoor premises of an industrial estate, walkways, mining infrastructure, etc… it is always challenging and as a designer you always keep in mind to minimise any form of obtrusive effect.
Luminaires that we use are now ‘nearly’ exclusively based on LED technology. We have acknowledged that LED luminaires are a great saviour of energy but are generally glarier, simply because in comparison HID lamps are a bigger light source and were usually enclosed inside the reflector.
In regards to obtrusive lighting our main concern is in regards to the use of floodlights, in most cases we intend to use asymmetric type of floodlights because they offer an immediate better control to minimise obtrusive effects.
New installations are always easier because we can look at the best options. Older installations are far more challenging because we often have to use existing electrical reticulations, infrastructure and pole heights.
There is an increased pressure for lighting designers, and manufacturers of lighting equipment to minimise obtrusive effects from lighting installations. Scientists are observing the negative effects that artificial light is having on wildlife and our environment and lighting designers are increasingly confronted with the issue as well, and in recent years, what is known as light pollution, has become an issue of growing concern and global discussion.