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85-420: Borgund Stave Church was built sometime between 1180 and 1250 AD with later additions and restorations. Its walls are formed by vertical wooden boards, or staves, hence the name "stave church." The four corner posts are connected to one another by ground sills , resting on a stone foundation . The intervening staves rise from the ground sills; each is tongued and grooved , to interlock with its neighbours and form

170-529: A "second storey". While not a functional gallery , this is reminiscent of contemporary second story galleries of large stone churches elsewhere in Europe. Smaller beams running between these upper supporting columns help clamp everything firmly together. The weight of the roof is thus supported by buttresses and columns, preventing downward and outward movement of the stave walls. The roof beams are supported by steeply angled scissor trusses that form an "X" shape with

255-616: A 16th-century lectern , and a 16th-century cupboard for storing altar vessels. After the Reformation , when the church was converted for Protestant worship , pews , a pulpit and other standard church furnishings were included, however these have been removed since the building has come under the protection of the Fortidsminneforeningen (The Society for the Preservation of Norwegian Ancient Monuments). The interior structure of

340-412: A Mass. A travelogue from 1668 claims that a reindeer was shot during a sermon "when it marched like a wizard in front of the other animal carcasses". To the south of the church is a free-standing stave-work bell tower that covers remnants of the mediaeval foundry used to cast the church bell. It was probably built in the mid-13th century. It is Norway's only remaining free-standing stave-work bell tower.It

425-441: A broader area of a room makes the room appear brighter, and makes more of it usefully lit. Remote daylight distribution systems have losses, and the further they have to transmit the daylight and the more convoluted the path, the greater the inefficiency. The efficiency of many remote distribution systems can also vary dramatically from clear to overcast skies. Nonetheless, where there is no other possibility of providing daylight to

510-404: A building envelope which also includes windows, doors, etc. ) forming all, or a portion of, the roof of a building space. Skylights are widely used in daylighting design in residential and commercial buildings, mainly because they are the most effective source of daylight on a unit area basis. An alternative to a skylight is a roof lantern . A roof lantern is a daylighting cupola that sits above

595-467: A cause of glare. On the other hand, you should also take into account the undesirable effects of large windows. Windows grade into translucent walls (below). Another important element in creating daylighting is the use of clerestory windows. These are high, vertically placed windows. They can be used to increase direct solar gain when oriented towards the equator. When facing toward the sun, clerestories and other windows may admit unacceptable glare . In

680-427: A ceiling over the chancel, and various windows including two large windows on the north and south sides. As the goal was to return the church to pre-Reformation condition, all post-Reformation interior paintwork was also removed. Images from the 1990s show deer antlers hung on the lower, east-facing pillars. A local story claims that this is all that remains of a whole stuffed reindeer, shot when it tried to enter during

765-408: A cube", each independent of the other. The inner "cube" is formed by continuous columns that rise from ground level to support the roof. The top of the arcade is formed by arched buttresses , knee jointed to the columns. Above the arcade, the columns are linked by cross-shaped, diagonal trusses, commonly dubbed " Saint Andrew's crosses "; these carry arched supports that offer the visual equivalent of

850-503: A design element. Good daylighting requires attention to both qualitative and quantitative aspects of design. Utilizing natural light is one of the design aspects in architecture; In 1929, the French architect, Le Corbusier said that "The history of architectural material... has been the endless struggle for light... in other words, the history of windows." As he emphasized in his architecture (such as Notre Dame du Haut ), daylighting has been

935-511: A direct effect on human health because of the way it influences the circadian rhythms . A well daylit space needs both adequate lighting levels and light that is well distributed. In the current building industry, daylighting is considered a building performance measure in green building certification programs such as LEED . Illuminating Engineering Society (IES) and the society of Light and Lighting (SLL) provide illuminance recommendation for each space type. How much daylighting contributes to

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1020-505: A few percent of the light is transmitted (the percent transmittance is about half the percent of the surface that is fibers, and usually only ~5% fibers are used). Both glass and concrete conduct heat fairly well, when solid, so none of these walls insulate well . They are therefore often used outdoors, as a divider between two heated spaces (see images), or in very temperate climates . Greenhouse walls (and roofs) are made to transmit as much light and as little heat as possible. They use

1105-442: A grid is a basic level to derive an average illuminance of a space. The spacing of the measurement points vary with project purposes. The height of these points depends on where the primary task is performed. In most office spaces, desk level (0.762m above the floor) will be measured. Based on measurements, average illuminance, maximum-to-minimum uniformity ratio, and average-to-minimum uniformity ratio will be calculated and compared to

1190-512: A hall is necessary for privacy or room isolation, inexpensive patio door safety glass can be placed on both sides of the hall. Drapes over the interior glass can be used to control lighting. Drapes can optionally be automated with sensor-based electric motor controls that are aware of room occupancy, daylight, interior temperature, and time of day. Passive solar buildings with no central air conditioning system need control mechanisms for hourly, daily, and seasonal, temperature-and-daylight variations. If

1275-407: A light conducting fiber optic bundle. It is frequently capped with a transparent, roof-mounted dome "light collector" and terminated with a diffuser assembly that admits the daylight into interior spaces and distributes the available light energy evenly (or else efficiently if the use of the lit space is reasonably fixed, and the user desired one or more "bright-spots"). The tubular daylighting device

1360-579: A major architectural design element (See MIT Chapel and Church of the Light for examples). Not only the aesthetic aspects, the impact of daylighting on human health and work performance is also considered as qualitative daylighting. The current studies show that lighting conditions in workplaces contribute to a variety of factors related to work satisfaction, productivity and well-being and significantly higher visual acceptance scores under daylighting than electrical lighting. Studies have also shown that light has

1445-495: A more even distribution of the same amount of light makes a room appear brighter. The source of all daylight is the Sun. The proportion of direct to diffuse light impacts the amount and quality of daylight. "Direct sunlight" reaches a site without being scattered within Earth's atmosphere . Sunlight that is scattered in the atmosphere is " diffused daylight ". Sunlight reflected off walls and

1530-470: A narrow top span and a broader bottom span, tied by a bottom truss to prevent collapse. Additional support is given by a truss that cuts across the "X", below the crossing point but above the bottom truss. The roof is steeply pitched, boarded horizontally and clad with shingles. The original outer roof would have been weatherproofed with boards laid lengthwise, rather than shingles. In later years wooden shingles became more common. Scissor beam roof construction

1615-423: A new alternative to skylights called hybrid solar lighting. This design uses a roof-mounted light collector, large-diameter optical fiber , and modified efficient fluorescent lighting fixtures that have transparent rods connected to the optical fiber cables. Essentially no electricity is needed for daytime natural interior lighting. Field tests conducted in 2006 and 2007 of the new HSL technology were promising, but

1700-413: A plank sill or timber sill sit on top of the joists. Another rare, historic building technique is for the posts of a timber-frame building to land directly on a foundation or in the ground and the sills fit between the posts and are called interrupted sills . In modern wood construction, sills usually come in sizes of 2×4, 2×6, 2×8, and 2×10. In stick framing , the sill is made of treated lumber , and

1785-555: A roof, as opposed to a skylight which is fitted into a roof's construction. Roof lanterns serve as both an architectural feature and a method of introducing natural light into a space, and are typically wooden or metal structures with a number of glazed glass panels. As an element of architecture , a laylight is a glazed panel usually set flush with the ceiling for the purpose of admitting natural or artificial light. Laylights typically utilize stained glass or lenses in their glazing, but can also use alternative materials. For example,

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1870-444: A space, remote distribution systems can be appreciated. Once used extensively in office buildings, the manually adjustable light reflector is seldom in use today having been supplanted by a combination of other methods in concert with artificial illumination. The reflector had found favor where the choices of artificial light provided poor illumination compared to modern electric lighting. Light shelves are an effective way to enhance

1955-425: A sturdy wall. The exterior timber surfaces are darkened by protective layers of tar, distilled from pine. Borgund Stave Church is built on a basilica plan, with reduced side aisles, and an added chancel and apse . It has a raised central nave demarcated on four sides by an arcade . An ambulatory runs around this platform and into the chancel and apse, both added in the 14th century. An additional ambulatory, in

2040-407: A variety of materials, and may be transparent or translucent. It is possible to provide some daylight into spaces that have low possibility of windows or skylights through remote distribution devices such as mirrors, prisms , or light tubes . This is called anidolic lighting , from anidolic (non-image-forming) optics . The non-linear response of the human eye to light means that spreading light to

2125-401: A west-facing window, designers use an R-13 foam-filled solid energy-efficient exterior door. It may have a glass storm door on the outside so that light can pass through when the inner door is opened. East/west glass doors and windows should be fully shaded top-to-bottom or a spectrally selective coating can be used to reduce solar gain. Architects and interior designers often use daylighting as

2210-406: Is anchored to the foundation wall, often with J-bolts , to keep the building from coming off the foundation during a severe storm or earthquake. Building codes require that the bottom of the sill plate be kept 6 to 8 inches above the finished grade, to hinder termites, and to prevent the sill plate from rotting. In automobiles , the sill plate is located underneath the door and sometimes displays

2295-514: Is beneficial when determining how daylight enters and illuminates a space. The drawback, however, is that there is no upper limit on luminance levels. Therefore, a space with a high internal heat gain deemed uncomfortable by occupants, would still perform well in the analysis. Achieving daylight autonomy requires an integrated design approach that guides the building form, siting, climate considerations, building components, lighting controls, and lighting design criteria. Continuous daylight autonomy,

2380-430: Is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming or switching off electric lights in response to

2465-406: Is needed. This method has the advantage of reducing the directionality of light to make it softer and more diffuse, reducing shadows. Another roof-angled glass alternative is a sawtooth roof (found on older factories). Sawtooth roofs have vertical roof glass facing away from the equator side of the building to capture diffused light (not harsh direct equator-side solar gain). The angled portion of

2550-524: Is one of the only stave churches to have preserved its crested ridge caps. They are carved with openwork vine and entangled plant designs. The four outer dragon heads are perhaps the most distinctive of all non-Christian symbols adorning Borgund Stave Church. Their function is uncertain, and disputed; if pagan, they are recruited to the Christian cause in the battle between Good and Evil. They may have been intended to keep away evil spirits thought to threaten

2635-407: Is placed into a roof and admits light to a focused area of the interior. These somewhat resemble recessed ceiling light fixtures. They do not allow as much heat transfer as skylights because they have less surface area. TDDs use modern technology to transmit visible light through opaque walls and roofs. The tube itself is a passive component consisting of either a simple reflective interior coating or

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2720-400: Is similar to daylight autonomy but partial credit is attributed to time steps when the daylight illuminance lies below the minimum illuminance level. For example, if the target illuminance is 400 lux and the calculated value is 200 lux, daylight autonomy would give zero credit, while continuous daylight autonomy would give 0.5 credit (200/400 = 0.5). The benefit of continuous daylight autonomy

2805-411: Is the percentage of time that daylight levels are above a specified target illuminance within a physical space or building. The calculation is based on annual data and the predetermined lighting levels. The goal of the calculation is to determine how long an individual can work in a space without requiring electrical lighting, while also providing optimal visual and physical comfort. Daylight autonomy

2890-458: Is to provide a visual experience and a degree of contact with the outside for people in the working areas. The daylighting of successive storeys of rooms adjoining an atrium is interdependent and requires a balanced approach. Light from the sky can easily penetrate the upper storeys but not the lower, which rely primarily on light reflected from internal surfaces of the atrium such as floor-reflected light. The upper stories need less window area than

2975-731: Is typical of most stave churches. Borgund has tiered, overhanging roofs, topped at their intersection by a shingle-roofed tower or steeple that straddles the ridge. On each of its four gables is a stylised " dragon " head, swooping from the carved roof ridge crests, Hohler remarks their similarity to the carved dragon heads found on the prows of Norse ships . Similar gable heads appear on small bronze church-shaped reliquaries common in Norway and Europe in this period. Borgund's current dragon heads are possible 18th century replacements; similar, original dragon heads remain on older structures, such as Lom Stave Church and nearby Urnes Stave Church . Borgund

3060-449: Is typically omitted in America and carpenters speak simply of the "sill". Other names are rat sill , ground plate , ground sill , groundsel , night plate , and midnight sill . Sill plates are usually composed of lumber but can be any material. The timber at the top of a wall is often called a top plate, pole plate, mudsill, wall plate or simply "the plate". In historic buildings

3145-456: Is usually significant glass on the equator side. A large area of glass can also be added between the sun room and the interior living quarters. Low-cost, high-volume-produced patio door safety glass is an inexpensive way to accomplish this goal. The doors used to enter a room should be opposite the sun room interior glass, so that a user can see outside immediately when entering most rooms. Halls should be minimized with open spaces used instead. If

3230-480: The Lyme Art Association Gallery utilizes translucent white muslin laylights below its skylights. A laylight differs from a glazed (or closed) skylight in that a skylight functions as a roof window or aperture, while a laylight is flush with the ceiling of an interior space. When paired with a roof lantern or skylight on a sloped roof, a laylight functions as an interior light diffuser. Before

3315-844: The September equinox to the March equinox in the Northern Hemisphere, and from the March equinox to the September equinox in the Southern Hemisphere .) In the Northern Hemisphere , the north-facing wall is the "polar-side" and in the Southern Hemisphere, it is the south-facing wall. Traditionally, houses were designed with minimal windows on the polar side, but more and larger windows on

3400-682: The Norwegian Directorate for Cultural Heritage has funded a program to research, restore, conserve and maintain stave churches. The church served as an example for the reconstruction of the Fantoft Stave Church in Fana , Bergen , in 1883 and for its rebuilding in 1997. The Gustav Adolf Stave Church in Hahnenklee , Germany , built in 1908, is modeled on the Borgund church. Four replicas exist in

3485-744: The United States, one at Chapel in the Hills , Rapid City, South Dakota , another owned by Timothy Mellon in Lyme, Connecticut , the third on Washington Island, Wisconsin , and the fourth in Minot, North Dakota at the Scandinavian Heritage Park. Sill plate#Timber sills A sill plate or sole plate in construction and architecture is the bottom horizontal member of a wall or building to which vertical members are attached. The word "plate"

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3570-404: The advantage of savings on trenching, landscaping, and maintenance costs, as well as on the electric bills, despite their higher initial cost compared to conventional street lighting. They are designed with sufficiently large batteries to ensure operation for at least a week and even in the worst situation, they are expected to dim only slightly. Oak Ridge National Laboratory (ORNL) has developed

3655-478: The advent of electric lighting, laylights allowed transmission of light between floors in larger buildings, and were not always paired with skylights. An atrium is a large open space located within a building. It is often used to light a central circulation or public area by daylight admitted through a glass roof or wall. Atria provide some daylight to adjacent working areas, but the amount is often small and does not penetrate very far. The main function of an atrium

3740-414: The amount of light available from a window: (a) placing the window close to a light colored wall, (b) slanting the sides of window openings so the inner opening is larger than the outer opening, or (c) using a large light colored window-sill to project light into the room. Besides permitting daylighting into the building, windows serve another function in daylighting practice, providing views out. To enhance

3825-514: The benches that run along the walls of the nave are largely intact, together with a medieval stone altar and a box-shaped baptismal font in soapstone. The pulpit is from the period 1550–1570 and the altarpiece dates from 1654, while the frame around the tablet is dated to 1620. The painting on the altarpiece shows the crucifixion in the centre, flanked by the Virgin Mary on the left and John the Baptist on

3910-447: The brightness of the light outdoors and of the required brightness indoors. The use of heliostats , mirrors which are moved automatically to reflect sunlight in a constant direction as the sun moves across the sky, is gaining popularity as an energy-efficient method of lighting. A heliostat can be used to shine sunlight directly through a window or skylight, or into any arrangement of optical elements, such as light tubes, that distribute

3995-571: The case of a passive solar house, clerestories may provide a direct light path to polar-side (north in the northern hemisphere; south in the southern hemisphere) rooms that otherwise would not be illuminated. Alternatively, clerestories can be used to admit diffuse daylight (from the north in the northern hemisphere) that evenly illuminates a space such as a classroom or office. Often, clerestory windows also shine onto interior wall surfaces painted white or another light color. These walls are placed so as to reflect indirect light to interior areas where it

4080-433: The church building; to ward off evil, rather than represent it. On the lower side panel of the steeple are four carved circular cutouts. The carvings are weather-beaten, tarred and difficult to decipher, and there is disagreement about what they symbolize. Some believe they represent the four evangelists, symbolised by an eagle, an ox, a lion and a man. Hauglid describes the carvings as "dragons that extend their heads over to

4165-444: The church is characterized by the twelve free-standing columns that support the nave's elevated central space. On the long side of the church there is a double interval between the second and third pillars, but with a half pillar resting on the lower bracing beam (the pier) which runs in between. The double interval provides free access from the south portal to the church's central compartment, which would otherwise have been obstructed by

4250-522: The commonplace demolition of stave churches in that period. A new Borgund Church was built in 1868 a short distance south of the old church. The old church has not been formally used for religious purposes since that year. Borgund Stave Church was bought by the Society for the Preservation of Ancient Norwegian Monuments in 1877. The first guidebook in English for the stave church was published in 1898. From 2001,

4335-411: The decks of ships to transmit light below. Later, pavement lights or vault lights were used to light basement areas under sidewalks. Prisms that used total internal reflection to throw light sideways, lighting the deeper portions of a room, later became popular. Early thick, slow-cooling cast glass prism tiles were often known as "luxfer tiles" after a major manufacturer. They were and are used in

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4420-555: The dragon was often used as a symbol of the devil himself but Bugge believes that the carvings were protective, like the dragon heads on the church roof. The church interior is dark, as not much daylight enters the building. Some of the few sources of natural light are narrow circular windows along the roof, examples of daylighting . It was supposed that the narrow apertures would prevent the entry of evil spirits. Three entrances are heavily adorned with foliage and snakes, and are only wide enough for one person to enter, supposedly preventing

4505-408: The entry of evil spirits alongside the churchgoers. The portals were originally painted green, red, black, and white. Most of the internal fittings have been removed. There is little in the building, apart from the row of benches that are installed along the wall inside the church in the ambulatory outside of the arcade and raised platform, a soapstone font, an altar (with 17th-century altarpiece ),

4590-736: The equatorial side (south-facing wall in the Northern Hemisphere and north-facing wall in the Southern Hemisphere). Equatorial-side windows receive at least some direct sunlight on any sunny day of the year (except in the tropics in summer ), so they are effective at daylighting areas of the house adjacent to the windows. At higher latitudes during midwinter , light incidence is highly directional and casts long shadows. This may be partially ameliorated through light diffusion , light pipes or tubes , and through somewhat reflective internal surfaces. At fairly low latitudes in summertime, windows that face east and west and sometimes those that face toward

4675-587: The evening at St. Olav 's Mass" blames the pagan Norns for his problems; perhaps a residue of ancient beliefs, as these female beings were thought to rule the personal destinies of all in Norse mythology and the Poetic Edda . The medieval interior of the stave church is almost untouched, save for its restorations and repairs, though the medieval crucifix was removed after the Reformation. The original wooden floor and

4760-401: The form of a porch, runs around the exterior of the building, sheltered under the overhanging shingled roof . The floor plan of this church resembles that of a central plan, double-shelled Greek cross with an apse attached to one end in place of the fourth arm. The entries to the church are in the three shorter arms of the cross. Structurally, the building has been described as a "cube within

4845-416: The glass-support structure is opaque and well insulated with a cool roof and radiant barrier . The sawtooth roof's lighting concept partially reduces the summer "solar furnace" skylight problem, but still allows warm interior air to rise and touch the exterior roof glass in the cold winter, with significant undesirable heat transfer. Skylights are light transmitting fenestration (products filling openings in

4930-463: The ground also contributes to daylighting. Each climate has different composition of these daylights and different cloud coverage , so daylighting strategies vary with site locations and climates. At latitudes north of the Tropic of Cancer and south of the Tropic of Capricorn , there is no direct sunlight on the polar-side wall of a building between the autumnal equinox and the vernal equinox (that is, from

5015-457: The light where it is needed. The image shows a mirror that rotates on a computer-controlled, motor-driven altazimuth mount . Solar street lights raised light sources which are powered by photovoltaic panels generally mounted on the lighting structure. The solar array of such off-grid PV system charges a rechargeable battery , which powers a fluorescent or LED lamp during the night. Solar street lights are stand-alone power systems , and have

5100-432: The lighting from windows on the equator-facing side of a structure, this effect being obtained by placing a white or reflective metal light shelf outside the window. Usually the window will be protected from direct summer season sun by a projecting eave. The light shelf projects beyond the shadow created by the eave and reflects sunlight upward to illuminate the ceiling. This reflected light can contain little heat content and

5185-547: The low-volume equipment production is still expensive. HSL should become more cost effective in the near future. A version that can withstand windstorms could begin to replace conventional commercial fluorescent lighting systems with improved implementations in 2008 and beyond. The U.S. 2007 Energy Bill provides funding for HSL R&D, and multiple large commercial buildings are ready to fund further HSL application development and deployment. At night, ORNL HSL uses variable-intensity fluorescent lighting electronic control ballasts. As

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5270-402: The lower ones, and if the atrium walls are light in color the upper walls will reflect light toward the lower stories. Walls made of glass brick are translucent-to-transparent. Traditionally they are hollow and grouted with a fine concrete grout, but some modern glass brick walls are solid cast glass grouted with a transparent glue. If the glue matches the refractive index of the glass,

5355-416: The make or model of the vehicle. In naval architecture , sill also refers to the lower horizontal plate (frame) height, above which doors and access opening are fixed. Daylighting (architecture) Daylighting is the practice of placing windows , skylights , other openings, and reflective surfaces so that direct or indirect sunlight can provide effective internal lighting. Particular attention

5440-416: The middle bar. The tops of the poles are finished with grotesque, carved human and animal masks. The tie-bars are secured with braces in the form of St. Andrew's crosses with a sun - shaped center and carved leaf shapes along the arms. The crosses reappear in less ornate form as braces along the church walls. On the north and south sides of the nave, a total of eight windows let in small amounts of light, and at

5525-481: The nearer pole receive more sunlight than windows facing toward the equator. Passive daylighting is 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 . Passive daylighting systems are different from active daylighting systems in that active systems track and/or follow

5610-451: The neighboring field's dragon and bite into it", and points out their similarity to carvings at Høre Stave Church . The church's west portal (the nave's main entrance), is surrounded by a larger carving of dragons biting each other in the neck and tail. At the bottom of the half-columns that flank the front entrance, two dragon heads spew vine stalks that wind upwards and are braided into the dragons above. The carving shares similarities with

5695-400: The presence of daylight – a process known as daylight harvesting . The amount of daylight received in an internal space can be analyzed by measuring illuminance on a grid or undertaking a daylight factor calculation. Computer programs such as Radiance allow an architect or engineer to quickly calculate benefits of a particular design. The human eye's response to light is non-linear , so

5780-480: The quality of the view seen from a window, three primary variables need to be ensure: view content (what can be seen in the view), view access (how of the window view can be seen), and view clarity (how clearly the view can be seen). View clarity is often influenced by the amount of shading provided by blinds or devices used to protect occupants from harsh daylight (e.g. glare ) or for reasons of visual privacy . Environmental criteria serve as important criteria to gauge

5865-429: The quality of window view content. These criteria can be distilled into five important factors, namely: Location, time, weather, people, and nature. Notably, views that are able to provide building inhabitants with content of nature far outweigh the other four Environmental Information Criteria. Different types and grades of glass and different window treatments can also affect the amount of light transmission through

5950-530: The recommended lighting level determines daylighting performance of a building. There are two metrics that IES has approved to evaluate daylighting performance: Spatial Daylight Autonomy(sDA) and Annual Sunlight Exposure (ASE). sDA is a metric describing annual sufficiency of ambient daylight levels in interior environments. See Daylight autonomy and LEED documentation sections for more details. In existing buildings, field measurements can be undertaken to evaluate daylighting performance. Illuminance measurements on

6035-828: The recommended lighting level. A diagnostic survey specific to lighting can be conducted to analyse the satisfaction of building occupants. Computational simulations can predict daylighting condition of a space much faster and more detailed than hand calculations or scale model testing. The simulations allow for the effects of climate with hourly weather data from typical meteorological year . Computer models are available which can predict variations in internally reflected light. Radiosity and ray-tracing are methods can deal with complex geometry, allow complex sky distributions and potentially produce photorealistic images. Radiosity methods assume all surfaces are perfectly diffusing to reduce computational times. Ray-tracing techniques have accuracy and image rendering capacity. Daylight autonomy

6120-541: The reflective illumination from the ceiling will typically reduce deep shadows, reducing the need for general illumination. In the cold winter, a natural light shelf is created when there is snow on the ground which makes it reflective. Low winter sun (see Sun path ) reflects off the snow and increases solar gain through equator-facing glass by one- to two-thirds which brightly lights the ceiling of these rooms. Glare control (drapes) may be required. The oldest use of prisms for daylighting may well be deck prisms , let into

6205-409: The right. In the tympanum field, a white dove hovers on a blue background. Below the painting is an inscription with golden letters on a black background. A sacrament from the period 1550–1570 in the same style as the pulpit is also preserved. A restoration of the building was carried out in the early 1870s, led by the architect Christian Christie, who removed benches, a second-floor gallery with seating,

6290-406: The sills were almost always large, solid timbers framed together at the corners, carry the bents , and are set on the stone or brick foundation walls, piers , or piles (wood posts driven or set into the ground). The sill typically carries the wall framing (posts and studs) and floor joists . There are rare examples of historic buildings in the U.S. where the floor joists land on the foundation and

6375-441: The sun, and rely on mechanical mechanisms to do so. Windows are the most common way to admit daylight into a space. Their vertical orientation means that they selectively admit sunlight and diffuse daylight at different times of the day and year. Therefore, windows on multiple orientations must usually be combined to produce the right mix of light for the building, depending on the climate and latitude. There are three ways to improve

6460-567: The sun. There are two types of active daylighting control systems: closed loop solar tracking , and open loop solar tracking systems. Smart glass is the name given to a class of materials and devices that can be switched between a transparent state and a state which is opaque, translucent, reflective, or retro-reflective. The switching is done by applying a voltage to the material, or by performing some simple mechanical operation. Windows, skylights, etc., that are made of smart glass can be used to adjust indoor lighting, compensating for changes of

6545-422: The sunlight gradually decreases at sunset, the fluorescent fixture is gradually turned up to give a near-constant level of interior lighting from daylight until after it becomes dark outside. HSL may soon become an option for commercial interior lighting. It can transmit about half of the direct sunlight it receives. In a well-designed isolated solar gain building with a solarium, sunroom, greenhouse, etc., there

6630-501: The temperature is correct, and a room is unoccupied, the drapes can automatically close to reduce heat transfer in either direction. To help distribute sun room daylight to the sides of rooms that are farthest from the equator, inexpensive ceiling-to-floor mirrors can be used. Building codes require a second means of egress, in case of fire. Most designers use a door on one side of bedrooms, and an outside window, but west-side windows provide very-poor summer thermal performance. Instead of

6715-474: The top of the nave's west gable is a window of more recent date - probably from pre-Reformation times. On the south wall of the nave, the inauguration crosses are still on the inside of the wall. The interior choir walls and west portal have engraved figures and runes , some of which date to the Middle Ages. One, among the commonest of runic graffiti, reads " Ave Maria ". An inscription by Þórir (Thor), written "in

6800-413: The upper portions of windows, and some believe that they contributed to the trend from dark, subdivided Victorian interiors to open-plan, light-coloured ones. Daylight redirecting window film (DRF) is a thin plastic version of the old glass prism tiles. It can be used as a substitute for opaque blinds. Another type of device used is the light tube, also called a tubular daylighting device (TDD), which

6885-494: The wall can be fairly transparent. Increasing the amount of concrete, bottle walls embed bottles that run right through the wall, transmitting light. Concrete walls with glass prisms running through them have also been made. With the advent of cheaper optical fibers and fiber-optic concrete walls, daylight (and shadow images) can then pass directly through a solid concrete wall, making it translucent; fiber optics will lead light around bends and over tens of meters. Typically only

6970-478: The west portal of Ål Stave Church, which also has kites in a band braiding pattern, and follows the usual composition in the Sogn-Valdres portals, a larger group of portals with very clear similarities. Bugge writes that Christian authority may have come to terms with such pagan and "wild scenes" in the church building because the rift could be interpreted as a struggle between good and evil; in Christian medieval art,

7055-415: The windows. The type of glazing is an important issue, expressed by its VT coefficient (Visual Transmittance), also known as visual light transmittance (VLT). As the name suggests, this coefficient measures how much visible light is admitted by the window. A low VT (below 0.4) can reduce by half or more the light coming into a room. But be also aware of high VT glass: high VT numbers (say, above 0.60) can be

7140-426: Was given a new door around the year 1700 but this was removed and not replaced at some time between the 1920s and 1940s, leaving the foundry pit exposed. To preserve the interior, new walls were built as cladding on the outside of the stave walls in the 1990s. One of the medieval bells is on display in the new Borgund church. In 1868 the building was abandoned as a church but was turned into a museum; this saved it from

7225-461: Was invented by Solatube International in 1986 and brought to market first in Australia in 1991. Active daylighting is a system of collecting sunlight using a mechanical device to increase the efficiency of light collection for a given lighting purpose. Active daylighting systems are different from passive daylighting systems in that passive systems are stationary and do not actively follow or track

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