 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Recessed light" – news ·newspapers ·books ·scholar ·JSTOR(May 2016) (Learn how and when to remove this message) |
Arecessed light ordownlight (alsopot light inCanadian English, sometimescan light (for canister light) inAmerican English) is alight fixture that is installed into a hollow opening in aceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction as a broadfloodlight or narrowspotlight. Most recessed fixtures are cylindrical and fit into a circular hole in the ceiling.
There are three parts to a traditional recessed lighting fixture: housing, trim and bulb. The trim is the visible portion of the light. It is the insert that is seen when looking up into the fixture, and also includes the thin lining around the edge of the light.[1] The housing is the fixture itself that is installed inside the ceiling and contains the lamp holder. There are many different types of bulbs that can be inserted into recessed lighting fixtures, with the amount of heat generated by the bulb being an important consideration.
Canless recessed lights, also known as "wafer lights" are thin one-piece assemblies with a built-in LED light source. These are inserted into a hole in the ceiling like traditional recessed lighting, but do not require as much space above the ceiling.[2]
The earliest recessed lights were developed in the 1940s by Ivan Kirlin of the Kirlin Company,Detroit, Michigan.[3]
Recessed lighting offers the advantages of being a hidden light source andenergy efficiency[citation needed]. However, the tradeoff is that they are relatively permanent and may be unflattering.
InNorth America,UL 1598 recessed housings generally fall into one of four categories.
The main feature of the housing is designed to ensure that no flammable materials come into contact with the hot lighting fixture. Badly-housed downlights can be a fire hazard, though all newer ones contain aself-resetting thermal switch for safety.
The housings come in various sizes based on the diameter of the circular opening where the lamp is installed. The most commonly used sizes are 4, 5 and 6 inches in diameter, with 4 inch IC New Construction units less readily available at present. Smaller housings (2 and 3 inch) are also available for specialized uses.
The housing can also be "Air Tight", which means it will not allow air to escape into the ceiling or attic, thus reducing both heating and cooling costs.
The City of Chicago has an additional requirement, "Chicago Plenum", which requires the housing to be airtight in addition to requiring all wiring and to be sealed off and gasketed from the plenum air space. This housing rating must be used on all recessed luminaires installed in air plenums in the City of Chicago as well as nearby municipalities which have adopted the Chicago amendments to theNEC. The intent of this rating is to prevent potential sparks from escaping the luminaire into the air plenum and getting recirculated in the HVAC system.[4]
IEC 60598 has two classifications.
Recessed lighting styles have evolved with more manufacturers creating quality trims for a variety of applications. Recessed lighting trim usually comes in the standard baffle in black or white, which is the most popular.[citation needed] They are made to absorb extra light and create a crisp architectural appearance.
There are cone trims which produce a low-brightnessaperture. Multipliers are offered which are designed to control the omnidirectional light from "A" styleincandescent light bulbs andcompact fluorescents.
Lens trim is designed to provide a diffused light and protect the lamp. Lensed trims are normally found in wet locations.
The luminous trims combine the diffused quality of lensed trim but with an open downlight component.
Adjustable trim allows for the adjustment of the light whether it iseyeball style, which protrudes from the trim orgimbal ring style, which adjusts inside the recess. These lights allow for full versatility.[5]
Lastly, there are the wall-washer trims, which are designed to eliminate the often seen "scalloped light effect".
There are two types of bulbs for recessed lighting: directional and diffuse. Directional lamps (R, BR,PAR,MR) containreflectors that direct and control the light. Diffuse lamps (A, S, PS, G) provide omnidirectional light, which is directed by trim in the light fixture.