06 Flashcards
Lightness
In color theory, lightness is how bright or dark a color is. It is the amount of black or white in color. It is independent of hue and saturation. Also called value.
Hue
Defined by wavelength and what most of us mean when we say “color.”
UV Rays
UV rays, or ultraviolet light, are located between visible light and x-rays on the electromagnetic spectrum. Invisible to the naked eye, UV rays can damage surfaces and cause colors to fade.
Rods and Cones
Photoreceptor cells in the retina of the eye named for their shapes. Rods are very abundant in the human eye, work in low light, and do not see color very well, making everything at night appear grayish. Rods are good at detecting motion. Cones are less abundant, require higher lighting levels to activate, and are closely packed in the fovea, where they are used to perceive color and details.
Layers of light
- General Lighting: fundamental and required by code
- Accent Lighting: creates mood or ambiance
- Task Lighting: localized lighting for any particular task like cooking or reading, for example.
A common error in kitchen and bath lighting design
Placing downlight fixtures in the ceiling behind a person, where their head casts a shadow over what the person is doing.
Dry, Damp, or Wet-Listed
Wet-listed fixtures are for use in areas with direct exposure to water, such as showers or outside in the rain. Damp-listed fixtures are located in areas subject to condensation, like a pool area or bathroom. Listings are provided by the UL. Dry location lights are designated simply as UL-listed.
Estimate the diameter of a pendant for a dining room.
Add the width of the room plus length and make it equal to x. Turn the value of x feet into x inches and that is the diameter of the pendant. For example, imagine a room that is 16’ x 14’. Because 16 + 14 = 30, the pendant should be around 30” in diameter.
Give an example of how the thermal and luminous environments of a building cannot be separated.
- Lighting in commercial buildings is a primary source of heat gain, directly effecting the HVAC system.
- Shading devices designed to limit solar heat gain affect the quality of daylighting.
- When designing for passive solar, one must also consider glare, contrast, and privacy.
Luminance Exitance
The luminous flux density leaving a surface, irrespective of direction viewer position. It is a product of illuminance and reflectance. Unit is lumens per unit of area.
Why are clear skies blue?
As white light from the sun is scattered by oxygen and nitrogen in the atmosphere, the blue wavelength scatters more and this is what makes the sky appear blue.
Why is the sunset shades of red, orange, and yellow?
When the sun is lower in the sky, it travels through more particles that scatter all the shorter blue, green, and violet light; this leaves only the longer wavelength red, orange, yellow light to reach our eyes.
Doppler Effect
The change in a sound frequency due to an observer’s movement.
More than one candlepower distribution curve is needed for __________ (symmetrical/nonsymmetrical) light sources.
Nonsymmetrical.
Fenestration
The entire aperture assembly, including the opening, glazing, and surrounding overhang, and any screens, mullions, louvers, blinds, draperies, etc.
Calculating illuminance
If the number of lumens striking a surface and the area of the surface are known, then the illuminance can be calculated. For example, if 5,500 lumens are striking an area that is 10’ by 10’, then the illumination is 55 foot-candles (fc). This is done by taking the lumens and dividing by the area. 5,500/100 = 55. This does not account for light loss factors.
Visual Field
The visual field is 180º wide, minus obstructions from facial features such as nose and cheeks.
Binocular Vision
Both eyes focus on the same center of vision. The slight difference in the information each eye receives is what provides us with 3-D depth.
The part of the eye that controls how much light enters is called the ______.
Iris.
Adaptation
The physiological process where the eye changes to adapt to different levels of illumination. Includes changes in the pupil diameter and retinal cell sensitivity.
Transmittance
The quality of a material to transmit light either specularly or diffusely. It is the ratio of transmitted light to incident light and is less than 1.0.
Transmitted Luminance
A product of the transmittance and the illuminance on the reverse side. The unit of transmitted illuminance is either candelas per square foot or footlamberts.
When light hits a surface, it can be ______, ______, or ________.
Transmitted, reflected, absorbed.
Absorption
The ratio of absorbed flux to incident flux.
Do we see with our eyes or our brain?
Our brain. The eye contains the photoreceptors that receive the light but they cannot see. Sight is done with the occipital lobe, a large area of the brain at the back of one’s head. The brain sees in 2D but uses learned cues to perceive a 3D space.
Optics
In luminaire design, optics is the science of getting a light to do what one wants by interacting the light with lenses and reflectors of the luminaire.
Fiber Optics
Fiber optics are very thin fibers of glass that can be used to transmit light over long distances.
True or false? Emergency egress lighting is not required in older buildings that are grandfathered in.
False
Water Curtain
A sheet of water from fire sprinklers that forms a temporary fire separation.
Self-Luminous
Illuminated by a self-contained power source other than batteries and operated independently of external power sources.
Photoluminescent
Having the property of emitting light that continues for a length of time after exposure from visible light has been removed.
Opening Protection
Openings such as doors and windows allow fire to come through a rated assembly. In fire-resistance-rated construction, opening protection refers to the ability of an opening to limit the transmission of fire and smoke.
Smokeproof Enclosure
A type of exit stairway that is designed to keep out smoke in the event of a fire so that occupants can escape.
NFPA 13, NFPA 13D, NFPA 13R
NFPA 13 is the standard for design and installation of sprinkler systems. NFPA 13D (one- and two-family dwellings) and NFPA 13R (up to and including 4 stories residential) are subsets of NFPA 13.
Fire extinguisher classes
A (for ordinary combustibles like wood and paper)
B (for flammable liquids such as grease, gas, or oil
C (for electrical fires)
D (flammable metals) K (kitchens)
Fire extinguisher class mnemonic
Class A is for any ordinary fire.
Class B is for flammables such as gasoline.
Class C is for electrical conductance fires.
Class D is for metals.
Class K is for kitchens.
Fire extinguisher types
Dry, inert gas (halon); CO2 (carbon dioxide).
Smoke alarm requirements for dwellings
Inside every sleeping room, outside every sleeping room in the immediate vicinity, and on each story of the home; must be hardwired and interconnected.
Calculation of horizontal illuminance by the lumen (flux) method (definition)
A method of calculating the average maintained illuminance in food candles on the work plane within a space. The method assumes that luminaries are spaced to provide a uniform illumination level within the space.
Calculation of horizontal illuminance by the lumen (flux) method (formula)
Illuminance E = (lamp lumens x CU x LLF)/area
E: expressed in foot-candlesLamp Lumens: number of fixtures x lamps per fixture x initial lumens per lamp
CU: the ratio between the lumens reaching the working plane in the specific space and the lumen generated
LLF: Loss light factor
Loss Light Factor
Loss light factor (LLF) is a calculation of the effect of light output in a room due to temperature and voltage variations, dirt accumulation on luminaries and room surfaces, lamp output depreciation, and maintenance conditions. LLF is a product of recoverable and non-recoverable factors. Recoverable factors can be fixed by maintenance, and include room surface dirt, lamp lumen depreciation, burnouts, and luminaire dirt depreciation. Non recoverable factors cannot be fixed by maintenance, and include luminaire ambient temperature, voltage, luminaire surface depreciation, and components.
Zonal Cavity Method
The zonal cavity method takes into account three cavities: a ceiling cavity above the fixture, a floor cavity below the working plane, and a room cavity between the two; this is to account for the luminaire’s mounting height and its relationship with the working plane. The coefficient of utilization (CU) connects the utilized fixture to the zone it is lighting by relating the luminaries’ light distribution to the room’s size and its surface reflectance.
Isofootcandle Chart
A type of chart that is based on the output from a luminaire; typically is provided by the manufacturer of the luminaire.
Sound Intensity
The minimum sound intensity for the human ear to detect noise is 0dB, and maximum sound intensity for an ear to hear without damage is 130 dB. 130 dB would be painful to hear; 110dB is an equivalent of a 75-piece orchestra; 90 dB is listening to shouting 5’ away; 70 dB is speech at 3’ away; 50 dB is ambient noise in an occupied office; and 30 dB is equivalent to ambient noise in an unoccupied office setting. Sound intensity lessens as the distance from the source increases. Sound intensity from the source is defined as: I = P/A, where I is sound (power) intensity, P is acoustic power, and A is area.
Echo
An echo is caused when sound is reflected at a sufficient intensity (defined as being heard between 50 ms to 80 ms after a person heard the initial sound). Echoes make speech less intelligible and make music sound muddy.
Transmission Loss
Transmission loss is an acoustics term for the barrier ratio, in dB, of the acoustic energy that escapes from one space into another, at the barrier.
Building Management System
BMS
Controls systems in a building such as temperature, lighting, HVAC, water heaters, appliances, door and window locks, and security cameras.
Compare and contrast expansion, control, and construction joints.
Expansion joints are continuous breaks in a material to accommodate movement due to thermal expansion. Expansion joints can also be called isolation joints. Control joints are breaks in a material that are designed to create a weak spot so when a material, such as a concrete slab, inevitably cracks, the cracking occurs within the control joint. A construction joint describes the joint created when construction stops and starts again at a later date.
Through-Wall Flashing
Continuous flashing used in water sensitive areas such as windowsills. It extends through the entire wall section to prevent water from entering the main portion of the wall and causing damage.
Termination Bar
A preformed detailing element that is placed at the vertical end points of various waterproofing, flashing, and barrier systems to provide a watertight connection at the system’s termination.
Vapor Barrier
Application Methods: mechanically fastened, peel and stick, or fluid applied
Water Vapor Permeance: “vapor permeable” types allow water vapor to pass through them, and “vapor impermeable” ones do not; different levels of permeance are determined by standardized testing
Continuity: Wrap behind door and window frames and overlap with roofing and waterproofing membrane
Compare and contrast grout and mortar.
Mortar is for bonding; it holds things together, such as the joints between bricks or a bed for tile. Grout is a filler; it is of a thinner consistency that can be poured, for example, into the cavities of masonry walls. Both come in multiple variations for differing purposes.
Construction Joints
Horizontal or vertical joints between successive concrete pours.
Expansion Joints
Joints that allow free movement of adjacent parts due to expansion or contraction of concrete; typically waterproof, watertight, filled with an elastic filler; required at buildings over 200’ long, at joints of building wings, and at additions.
Control Joints
Joints that allow for shrinkage of large areas, as well as control and induce cracking to occur along the joint.
Isolation Joints
Joints located at slab on grade, columns, or walls to allow for independent movement.
Acid Etching
Process of cutting into a surface (concrete, glass, etc.) by applying acidic, caustic, or abrasive substances.
Honing
Process of sanding/polishing for a matte or slightly reflective surface.
Lamella
A thin finished top layer of an engineered wooden floor.
Anodizing
Process of coating aluminum with a protective oxide layer by an electrolytic process.
Galvanic Corrosion
An electrochemical process where one metal corrodes preferentially to another when they both are in electrical contact and immersed in an electrolyte (which is a liquid or gel that contains ions and can be decomposed by electrolysis).
Monel
Metal used for roofing, flashing, countertops, and sinks.
Bessemer Process
Steelmaking procedure where carbon, silicon, and other impurities are removed from iron to make steel.
Ferrous Alloy
Alloys that contain a lot of iron (e.g., stainless steel, galvanized iron).
Nonferrous Alloys
Nonferrous alloys that do not contain much iron (e.g., aluminum, copper, zinc).
Efflorescence
Efflorescence consists of one or more water-soluble salts that were originally present in the masonry unit or in the mortar. Efflorescence is brought to the surface and deposited there by water that seeped into the masonry, dissolved the salts, then migrated to the surface and evaporated.
Allowable Stress Design
A method of proportioning structural members, such that elastically computed stresses produced in the members by nominal loads do not exceed specified allowable stresses (also called “working stress design”).
Audible Alarm Notification Appliance
A notification appliance that alerts by the sense of hearing.
