What is Fully Shielded Fixture
A fully shielded fixture is a type of light fixture or luminous tube that is designed and installed in a manner that directs all emitted light below the horizontal plane. This means that no light is projected above the horizontal direction, whether it originates directly from the lamp, tube, or diffusing element, or indirectly through reflection or refraction from any part of the fixture.
To determine if a fixture is fully shielded, it should not have any visible lamps, reflective surfaces, or lens covers (clear or prismatic) when viewed from above or directly from the side, from any angle around the fixture or tube. In essence, the fixture should be enclosed at the top and mounted in a way that the bottom opening is horizontal.
The primary purpose of a fully shielded fixture is to minimize light pollution and reduce glare. By directing all light output below the horizontal plane, it helps prevent light from spilling into the sky or causing discomfort to nearby residents or drivers. This is particularly crucial in areas where preserving dark skies is desired, such as observatories or residential neighborhoods.
Frequently Asked Questions
Why Are Fully Shielded Fixtures Recommended
A fully shielded fixture is designed in such a way that the light source is not visible to people or wildlife in close proximity. By using fully shielded lighting, you can effectively avoid light trespass onto your neighbors’ property and minimize both glare and skyglow.
What Is the Difference Between Shielded and Unshielded Lights
Unshielded lights, in contrast to shielded lights, do not only direct light towards the ground for safety and security purposes. Instead, they allow light to stray in various directions. On the other hand, fully shielded lights, also referred to as “full-cutoff lights” or “FCO lights,” are considered the optimal choice for light fixtures that are friendly to the night sky.