Week 9

 Electrical Systems & Lighting 

Gina Christopher 

ELECTRICITY 

Electrical current can be either in the form of alternating current (AC) or direct current (DC). Electricity travels from the utility company to the user through a combination of overhead and underground electrical lines. Transformers are used to step down the electrical current to specific locations and for specific uses. Electrical power travels across electrical lines to a point of entry at each building it services. Electrical power is typically connected to a building used a drop head. The power line is then run through an exterior meter that is grounded and then into the interior electrical panel. Several types of cable are available depending on the use. Commercial electrical power requires hard conduit, whereas flexible cable (Romex) can be used residentially as long as it is enclosed. Designers use common electrical symbols on electrical plans and need to understand them to read plans for subcontractors. One of the areas where an interior designer needs to work directly with electrical supply is when integrating systems furniture solutions.  

ENERGY-MANAGEMENT DEVICES 

The use of energy can be managed in several ways including keeping the building well-insulated and lowering the thermostat temperature, using lighting control devices, using motion and daylight sensors, and using dual switch options. All of these devices will help conserve energy in a building. 

INTERIOR DESIGN IMPLICATIONS 

Interior designers must have a working knowledge of electricity and how it gets distributed in a building in order to properly integrate their designs safely and correctly. The single most potent impact an interior designers can have on the energy efficiency, and the ultimate sustainability of a building is through good lighting design. It is important to not over-light a space. The less lighting used means the less air conditioning needed, because lighting creates one of the biggest heat loads within a space. 

LIGHTING 

Light is defined as the visible part of the electromagnetic spectrum. It is a form of energy that is visible to the human eye. As electromagnetic waves, lighting reacts in various ways when it meets a solid surface. Depending on the material of the surface, the light may be reflected, refracted, transmitted, diffused, or some combination of these outcomes. People perceive different levels and types of lighting differently. How lighting is distributed within a space affects how people view that space. The color temperature of light and the colors used within a space affect whether the space feels cool or warm. Incandescent lighting is perceived as warmer, while fluorescent lighting is perceived as cooler. Good lighting has been associated with improved worker performance. Control over light levels correlated with higher employee satisfaction. Glare is created by an excessive amount of light coming into people's eyes from the wrong direction. Light bulbs are actually referred to as lamps, lamps are a fixture, and together the lamp and the fixture (plus a ballast any other items require to make a functioning light source) form a luminaire. 

LAMPS & THEIR APPROPRIATE APPLICATIONS/ENERGY IMPLICATIONS  

The incandescent light source provided lighting for more homes in the U.S. Incandescent lighting is warm in appearance and is perceived by most as a flattering source of artificial lighting. The goal of circadian lighting is to stimulate the daylight provided by the sun throughout the day with the blest light being in the middle of the day with the lower color temperatures in the late afternoon and early evening hours. Germicidal lighting is becoming more popular in light of the need to prohibit the spread of germs in interior environments. The halogen lamp is a form of incandescent. It has a warm-white appearance and a strong focused beam of light; these are often used to illuminate display items and artwork. Fluorescent lighting is mainly used in commercial spaces. Fluorescent lamps provide an energy-efficient, long-lasting, and economical choice for this type of application. High-intensity discharge (HID) lamps have been used in outdoor applications such as street lighting, roadway lighting, and landscape lighting. Parking garages and factories exemplify the only interior applications of these sources, with the exception of metal halide. Light emitting diodes (LEDs) were introduced recently as an energy efficient solution to interior lighting. Research is still being done of LED lighting due to the concern of over color consistency, but LEDs are long lasting light sources. There are several types of light fixtures for a variety of uses. Some of the most common light fixtures include wall sconces, pendants, wall washers, recessed fixtures, and surface-mounted fixtures. Fixture manufacturers produce cut sheets for their light fixtures. These include information about the construction of the fixture, the electrical requirements, available finishes, lamp requirements, size, and operation. 

COLOR   

Each lamp has a correlated color temperature (CCT) that is provided in degrees Kelvin. The CCT describes how white the light emitted appears as compared to sunlight. The higher CCT makes for a cooler (bluer) appearance, whereas a lower CCT looks warmer. All lamps have a color-rendering index (CRI). The CRI of a lamp measures its ability to render colors. The ability to render color is rated on a 100-point scale. 100 is the best and 0 is the worst. A chromaticity chart shows the range most people feel comfortable seeing.  

SUSTAINABILTIY & LIGHTING DESIGN 

Energy efficiency of a light source can be determined based on the amount of energy needed to produce the light output in lumens and is expressed as lumens per watt (LPW).  Correctly controlling the distribution of light can reduce or eliminate glare, light trespass, and light pollution, Light trespass occurs when light from one building spreads to an adjacent building Light pollution occurs when light is directed into the night sky or other areas, disrupting wildlife. The International Dark Sky Association (IDA) seeks to halt environmental light pollution. The 1995 US Environmental Protection Agency Universal Waste Rule requires companies handling and consuming fluorescent and HID lamps to recycle them. The Green Seal's lighting recommendations include compact fluorescent, high-intensity discharge, and linear fluorescent. Sensors automatically control flow of electrical current to light fixtures. One of the best ways to reduce energy is to harvest the available daylight. These include open-loop and closed-loop systems. Open-loop systems use solar sensors to measure the daylight and control the electric lighting to maintain a uniform lighting level. Closed-loop systems measure the illuminance on the work surfaces and are quick to set up. On the other hand, vacancy sensors automatically turn off the lights when a space is not occupied.   

LIGHTING METRICS 

Five lighting metrics are used to quantify lighting. The science of light is called photometry. Luminous flux is the time rate flow of light. Luminous intensity is the directional force casing luminous flux to be emitted. Illuminances are defined of luminous flux incident at a point on a surface. Luminance refers to the luminous intensity of a source in a particular direction. Luminous exitance describes the density of luminous flux leaving a surface in all directions at a point.   

CALCULATIONS 

The simple lumen method is a quick rule-oh-thumb method for calculating the number of fixtures you might need in a space. The watts per square foot method is another rule of thumb, quick method for calculating the number of fixtures you might need in a space. The most accurate method for calculating lighting levels and the number of fixtures required to achieve a specific level of light is the lumen method. Several lighting manufactures provide free online software programs for doing photometric calculations; however, it is critical that you understand how these programs work to know whether the data you enter is correct. 

DESIGNING WITH LIGHT (DESIGN PROCESS)

There are several steps to take in the design of a lighting system. First you need to identify the spaces and the tasks. Then verify the number of foot candles and select the best lamp type. Then select luminaire consistent with the design and do the lumen calculations. Then analyze daylighting in the space and need for artificial lighting. Next, create solutions for handling and managing daylighting. Then, do a lighting layout and create a 3-D model of the lighting to study distribution. Lastly, design special lighting effects. The light design packet for each phase includes programming, schematic design, design development, construction documents and post-occupancy evaluation. 

LIGHTING PLANS 

The critical pieces of documentation used to convey lighting design intent to a contractor are the lighting plan, specifications, and any design details for specialty lighting installations. these documents must be clear and complete and must include all information needed to create a finished solution while leaving no design decisions to chance. For easy understanding by electricians, contractors, and other tradespeople in the field, it is customary to use a reflected ceiling plan, which is a layer added to the floor plan. 

LIGHTING RENDERING ASSIGNMNET 

For this assignment I choose an image than showcased multiple lighting fixtures within a space. This specific image has cove lighting in the ceiling, inset lighting in the back walls, recessed lighting in the ceiling, a pendant lighting fixture, and a lamp. I did the best I could at articulating that with one pencil and not outlining shapes. This rendering assignment was challenging but overall, I think you can articulate the lighting fixtures well.