Architectural Science-I (Lighting) Lecture Note 1 PDF

 The form of energy that makes it possible to see things.  A narrow wavelength-band of electromagnetic radiation (from about 380 nm to 780 nm is perceived by our eyes as light.  Electromagnetic radiation of any wave length that travels in a vacuum with a speed of about 300,000 km/s.  Su...

 The form of energy that makes it possible to see things.  A narrow wavelength-band of electromagnetic radiation (from about 380 nm to 780 nm is perceived by our eyes as light.  Electromagnetic radiation of any wave length that travels in a vacuum with a speed of about 300,000 km/s.  Such radiation is visible to the human eye.  The brightness produced by the sun, by fire, a lamp.. etc. Based on the source, it is divided in to two  Natural light (day light)  Artificial light (man-made) The color of light is Wave determined by its spectrum Color length or spectral composition. band Light of a particular (nm) wavelength, or a narrow band Red 780–660 of wavelengths is referred to Orange 660–610 as monochromatic. The color Yellow 610–570 of broad-band light depends Green/ 570–550 on the relative magnitude of yellow its components. Green 550–510 Blue/green 510–480 Based on the source, it is divided in to two  Natural Sources of Light (day light)  Artificial Sources of Light (man-made) Light from natural sources such as the sun is known as white light. Artificial light from sources such as candles, tungsten filaments and gas discharge lamps, etc., has a different mix of frequency components which produce a different color light. The combination of all direct and indirect sunlight outdoors during the daytime. It has two main components:  That arriving directly from the sun is referred to as sunlight (or ‘beam sunlight ’).  Varying fractions of this are diffused by the atmosphere or indirect from the sun, e.g. by clouds, which is referred to as daylight. Daylighting The controlled admission of natural light-direct sunlight and diffuse skylight-into a building to reduce electric lighting and saving energy The practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting. 1.1. Passive daylighting A system of both: collecting sunlight using static, non moving, and non-tracking systems such as Windows, Sliding glass doors, most skylights, light tubes, and reflecting the collected daylight deeper inside with elements such as light shelves. 1.1. Active daylighting A system of collecting sunlight using a mechanical device to increase the efficiency of light collection for a given lighting purpose. Passive daylighting systems are different from active Daylighting systems in that active systems track and/or follow the sun, and rely on mechanical mechanisms to do so.  Orientation  Sunlight Effect  Color  Importance of View  Health  Glare  Brightness  Aesthetical: the play of light from windows on surfaces and texture casting interesting shadows, the endless variety of mood and appearances due toe the movement of the sun  Psychological Response: the sense of well-being associated with daylight and the sense of orientation that comes with being ‘‘connected’’ with the exterior.  Health: improved resistance to infection, skin disorders, and cardiovascular impairment.  Energy/cost: Reduction in electric use and related air conditioning load from electric lighting.  Light reacts differently whenever it strikes a surface. It behaves according to the following principles: 2.1. Diffusion 2.2 Polarization 2.3 Transmission 2.4. Reflection 2.5. Refraction 2.1. Diffusion - when light rays leaving the source strike a rough or opaque surface which spreads the light in various directions. Light is broken up while in reflection, the light bounces back at a different direction. 2.2 Polarization - when light ray striking a polarized glass causes the illumination of the horizontal light rays and allows the vertical rays to penetrate the glass (resulting in soft lighting) Un polarized Light Polarized Vertical Polarizer Light 2.3 Transmission- when light rays strike a plain (surface) transparent glass which allows the rays to proceed farther 2.4. Reflection - when light striking a silvered surface is reflected back with no diffusion and the angle of incidence is equal to the angle of deflection. 2.5. Refraction - when light rays striking a clear glass placed at an angle with respect to the rays are reflected at an angle within the glass and continues at another angle on the far side of the glass Solar control and shading can be provided by a wide range of building components such as: Fenestration/opening type and size landscape features such as mature trees or hedge rows; exterior elements such as overhangs or vertical fins; horizontal reflecting surfaces called light shelves; low shading coefficient (SC-shading coefficient) glass; and, interior glare control devices such as venetian blinds or adjustable louvers. To properly design shading devices it is necessary to understand the position of the sun in the sky during the cooling season. The position of the sun is expressed in terms of altitude and azimuth angles. Altitude angle is the angle of the sun above the horizon, achieving its maximum on a given day or solar noon. (0) Azimuth angle also known as the bearing angle, is the angle of the sun's projection onto the ground plane relative to south.(d) Orientation is the positioning of a building in relation to seasonal variation in the suns path 1.Sun angles 2.Days of sunlight solstice 3.Cloud cover 4.Shading of (or from) adjacent structures, natural features, and vegetation  A transparent or translucent opening in a wall or door that allows the passage of light and, if not closed or sealed, air and sound. Windows are held in place by frames, which prevent from collapsing.  light entering a window  direct light  shade/diffuse  reflection 1. fixed - generally offer better air infiltration and water penetration resistance, and require less maintenance; consist of frame with an infill that are sealed together 2. operable- allow natural ventilation; consist of a frame and sash that are weather sealed by weather- strips in addition to the infill being sealed to the sash. Two (2) configurations of operable window A. sliding seal windows B. compression seal windows A. sliding seal windows Sliding seal window types include the  Hung windows  Horizontal sliding B. compression seal windows Compression seal windows include the following:  Awning (Top hinged, project out bottom)  Hopper (Bottom hinged, project in top)  Casement (Side hinged, project in or out)  Vertically or horizontally pivoted windows Or a combination of the two Pivot windows, jal-awning, and jalousie (louver) windows generally offer the poorest resistance Transom Window- is a window above the door; in an exterior door the transom window is often fixed, in an interior door it can open either by hinges at the top or bottom OTH ER WIN DOW TYPES.... BAY CLEARSTORY FIXED WINDOW WINDOW WINDOW ETC… TYPES OF GLASS 1.Architectural glass 2.Laminated glass 3.Coated glass 4.Tinted glass 1. Architectural glass comes in three different strength categories. A. Annealed glass B. Heat-strengthened glass C. Fully-tempered glass A. Annealed glass: is the most commonly used architectural glass. Because it is not heat-treated and therefore not subject to distortion typically produced during glass tempering, it has good surface flatness. On the downside, annealed glass breaks into sharp, dangerous shards B. Heat-strengthened glass has at least twice the strength and resistance to breakage from wind loads or thermal stresses as annealed glass. C. Fully-tempered glass provides at least four times the strength of annealed glass, which gives it superior resistance to glass breakage. 2. Laminated glass consists of two or more layers of glass adhered together with a plastic interlayer. Because it can prevent the fall-out of dangerous glass shards following fracture, it is often used as safety glazing and as overhead glazing in sky Lights.  3. Coated glass is covered with reflective or low-emissivity (low-E) coatings. In addition to providing aesthetic appeal, the coatings improve the thermal performance of the glass by reflecting visible light and infrared radiation 4. Tinted glass contains minerals that color the glass uniformly through its thickness and promote absorption of visible light and infrared radiation Patterned Glass ETFE Wired Fibber Glass Glass THREE CLASSIFICATION OF SKYLIGHTS A. Ventilating Skylight B. Fixed Skylight C. Tubular Skylight A. Ventilating Skylight may be opened to allow air to pass through. B. Fixed Skylight any type of skylight which doesn't open. This type of skylight is intended solely to allow light to pass into the house. C. Tubular Skylight essentially a very small skylight, intended mainly for hallways and small rooms where a traditional skylight wouldn't easily fit. Types of Skylights: Circular Domes Hipped Vault Ridge  In modern architecture, an atrium is a large open space, often several stories high and having a glazed roof or large windows.  In most cases situated within a larger multistory building and often located immediately beyond the main entrance doors. Burj Al Arab, Dubai tallest atrium(180m high) Luxor Hotel, Las Vegas largest atrium(820,000m3