Unit 8 Plant Auxiliary Systems Flashcards
Luminaire
A complete lighting unit, including the lamp, a voltage controlling device or ballast and is the means of light control (reflector or refractor)
Luminaires provide
Direct or indirect lighting or a combination of the two
Four types of Luminaires
Recessed troffer, surface mounted wrap arounds, open reflectors, structural lighting
Recessed troffer
Rectangular light fixtures that fit in grids or recessed ceilings. They have Prismatic panels that distribute light. Commonly used for General lighting in offices and Commercial Interiors.
Ceiling mount wraparound
Fluorescent fixtures that are mounted directly on the ceiling or wall surface. Clear Prismatic plastic covers that surround the lamp. Give broad light distribution, inexpensive and efficient. May appear too bright in many installations
Open reflectors
Serve as Shields to partially screen the lamps from View. Used in industrial installations or in storage areas of commercial buildings
Structural Lighting
Fitted into Architectural Components of a room
Three main types of Illumination
General (uniform)
Local (supplementary)
Combined general/local
General illumination (uniform)
Designed to provide uniform illumination throughout an area. Used in most offices since it is difficult to predict the location of workstations, which require more lighting. Luminaires are spaced at regular intervals
Local or supplementary illumination
Used to illuminate work areas or displays regardless of the overall uniform ambient light.
Ex; track lighting that illuminates wall displays
Combined general/local (non-uniform or task lighting)
Provides reasonable lighting level. In addition an effort is made to identify specific work areas to increase their illumination levels. Requires more design work, but will be more energy efficient than a uniform system. More difficult to alter the lighting system if the room is rearranged
Direct lighting
All or most of the Luminous intensity is directed down, toward the work area
Indirect lighting
All or most of the Luminous intensity is directed up, at the ceiling. Light reflected off the ceiling, arrives at the work area indirectly
Direct lighting advantages and disadvantages
Advantages; more energy efficient, low initial cost, lower floor to ceiling height possible, easier to control and direct
Disadvantages; harsh Shadows, potential for direct glare, greater potential for ceiling Reflections and reflected glare, excessive luminance and glare
Indirect lighting advantages and disadvantages;
Advantages; potential for maximum Visual Comfort, greater glare control, Blends in with environment, produces uniform shadow free light
Disadvantages; less energy efficient, requires a uniform unobstructed reflecting sealing surface, increase in building cost, electrical installation may be more expensive
Incandescent light
One of the oldest developed light sources. Electrical current passes through a wire filament inside a glass bulb or globe. Filament glows and emits visible light
Main reason for coated glass
To distribute light evenly. Coding can also be colored
Halogen lamp
Type of incandescent light. Bulb is filled with halogen gas to prolong life of filament. Halogen provides a brighter light emission than typical incandescent lights. Operates at higher temperature then regular incandescent light.
Incandescent light luminous efficacy
Low ratio of energy to light emission efficiency. Most energy supplied to produce light is converted to heat.
Fluorescent lights
Type of gas discharge light source. Filled with mercury vapour. Electrical current is applied to the gas, producing ultraviolet light. The UV light then causes the phosphor coating inside the tube to Glow White. Consumes less energy than incandescent light.
Straight tube fluorescent light
All require external ballasts to work
Two types of compact fluorescent
Screw in and plug in. Both operate the same way as straight tube fluorescent lights
Screw in compact fluorescent light
Has an integrated ballast. Simply screws into existing electrical sockets
Plug-in compact fluorescent light
Requires a ballast and a socket that corresponds to a specific base configuration