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INTRODUCTION-1The sun is the main source of light for the earth, and it is about 150million Km away from the earth.The natural light better than the artificial that it has variableillumination according to the path of the clouds and this changes inthe degree and the color of the light is efficient for the protecting ofthe human intelligence and the human health in the contrary of theconstant artificial light which is boring the design of day lightinginside the building is trying to enter the most quantity of lightwithout glare.To avoid glare we must avoid the direct sunrays.conclude:From this we1-The general goal for day lighting is the same as that for electriclighting to supply sufficient quality light while minimizing directglare veiling reflections and excessive brightness ratios.2-the second goal is to reduce or prevent the severe direct glareof unprotected windows and skylight.3-the third goal is to prevent excessive brightness ratio especiallythose caused by direct sunlight.4-the fourth goal is to prevent or minimize veiling reflectionespecially from skylight and clerestory windows, lighting should notbe too directional because of the dark shadows that result.5-the fifth goal is to diffuse the light by means of multiplereflections of the ceiling and walls.To satisfy the goals some strategies must be addressed at theearliest moments in the schematic design process, for exampleboth of the orientation and form of the building are critical to asuccessful day lighting scheme.Basically light finishes are required to increase the distribution.It is also difficult to shade horizontal glazing. For these reasons it isoften appropriate to use vertical glazing on the roof in the form ofclerestory windows, monitors. or saw tooth arrangements.
There are four ways to measuring of daylight in building:1_coefficent of daylight method.2_lumen method.3_artificialdoom method.4_computer programs method.
2-General data of natural lighting.Position MaterialsSky light Window wall Clerestorya-positionRecommended spacing for skylights without windows.Classification ofopenings
Recommended spacing for skylights with windows.Place skylight in front of a north wall for more uniform lighting andless glare.Steeply sloped sky lights will perform better by collecting morewinterLight and less summer light.The ideal Plan for day lighting as well as general solar controlHas all windows facing north and south
While day lighting from windows is limited to the area about 15 feetFrom the outside walls, roof openings can yield fairly uniformlightingOver unlimited areasThese are the various possibilities for overhead openings for daylighting.
This diagram shows the effect of painting some of the room walls withthe black color on the quantity of light at the point x.
3-Day-lighting Design FactorsPrimary ObjectivesThe report to be published on completion of thisresearch in August 2001 should assist the reader to:• Understand the benefits of utilising natural lighting in sportshalls; Appreciate that daylighting can contribute significantlyto the energy efficiency of a sports hall; Appreciate thatdaylighting can contribute significantly to the architecturalopportunities of a sports hall; Communicate to clients theimportance of daylighting to running costs savings;• Appreciate good practice in natural lighting design in generaland in sports halls in particular, and its integration withartificial lighting and other building services;• Understand the requirements and constraints of individualactivities and standards of play, in relation to patterns of use,lighting levels, variations in light quantity, subjectiveresponses and spatial needs;• Understand and be able to access the guidance, tools andtechniques available for daylighting design;• Be capable of making informed decisions to assist indesigning a sports hall that uses daylighting withoutdetriment to the activities;• Understand the requirements and constraints of differentdesign and control strategies, in relation to building operationand maintenance;• Work creatively with others disciplines [architect, engineer,qs and client] in the design process.Natural daylight can effectively be used to displace theillumination and energy demands of a conventionalmechanical lighting system during suitable periods of daylight.The BRE derived simplified DF formula is given asfollows:
DF = CG AG θ τAIS (1 -ρ ρ 2 )Where:DF =Daylight FactorCG =Glazing obstruction coefficient (dirt or barriers to lighttransmission)AG =Area of glazingθ =Angle of visible skyτ =Glazing transmission factorAIS =Area of internal surfacesρ =Area weighted average reflectance of room surfacesWhen average daylight factors greater than 5%areachieved,this indicates effective use of daylight.As a result ofthese “high”daylight factors,artificial lighting is mainly usedduring periods of night-time/ darkness and for specific tasksrequiring high illuminance.As daylight would be the majorlighting component for this environment,this does not justifythe installation of expensive,complex artificial lighting controlcircuitry as financial savings would be considerably smallerthan the capital outlay and installation costs associated withthis type of control.When average daylight factors between 2%and 5%areachieved careful consideration should be given to the plannedlighting installation and control strategy to take full advantageof the daylight when available.The lighting strategies for these environments requireomprehensive control and can justify the installation of acomplex system.When average daylight factors are less than 2%,this indicatesthat natural day-lighting would not be effective in illuminatingthe environment and artificial lighting would be operational forthe majority of the day, therefore care should be taken toensure an energy efficient lighting design is developed.
Lighting Control:When incorporating natural daylight within buildings,it isimportant that a complimentary active control system isinstalled.To maximise energy savings,the control systemshould be a proportional system directly linked to the artificiallighting system so that the lighting output will vary inverselywith daylight availability.Over illumination should be minimisedto reduce excessive energy loss,therefore,placingconsiderable importance on lamp choice and installationlayout.Mounting of daylight sensors for the control system should besuch that they are installed in locations representative of thetask area and the set-points should reference the daylightincidental on the working plane.
4-GUIDELINES TO SPORTS LIGHTINGIncreased leisure time,along with advancements in illuminatingengineering design and technology,have brought about anincrease in sporting events played and watched at night.Lightsource efficacies have more than doubled;drastically reducing theenergy requirements of sports facilities in spite of increased illumi-nances to satisfy the elevated skill level of modern athletes.Associated with the improved illuminance levels are increasedproblems of glare and color rendering for better visual performanceand quality television broadcasting.Sports lighting has outgrownthe design by approximation,it requires sophisticated computerprograms for application.This requires a thor-ough understandingof illuminating engineering principles and associated computerprograms by the lighting designer.Class of PlayAs the skill level of play is elevated,players and spectators requirea more criti-cally illuminated environment.There is a correlationbetween the size of a facility and the skill level of play,i.e.,thenumber of spectators is directly related to the skill level of play.Todetermine illumination criteria,facilities are grouped intofourclasses to satisfy the skill levels.Class I -for competition play before a large group of spectators.Due to the complexity of design for major stadiums requiringspecial design consideration, the criteria presented for this classwill be for spectator capacity of 10,000 or less.Class II -for competition play with approximate spectator capacityof 4,000 to 6,000.Class III -for competition play without specific provisions forspectators.for social and recreational play only.-Class IV
Natural light in swimming poolsis an increasingly attractive option for indoor aquatic facilkites.large windowsor open fenestration can be energy-efficient ways to supplement artificial heatand lighting.However, natural light can be accompained by an undesirable partner_glare.glare rom poorly positioned window openings can turn competitiveswimmers into unidentifiable anonymous silhouettes in front ofcoaches,spectors and television cameras.Reflections occur when light rays hit a surface and bounce off.the angle atwhich the ray hits the surface is equal to the angle at which it bounces off. Weperceive the glare beacause of the highly reflective nature of water and thesharp contrast between the light from the windows or artificial light source andthe relative darkness of the surrounding walls,celling and floor .The worst-case glare problem occur when viewers spectators,lifeguards_arepositioned oppisite windows.wall openings or artificial lighting with the pool inbetween.Contrasting elements of light and dark can shed unwanted reflections onwater’s surface any time the light source is within the field of vision of theviewer.Solving glare problems is frequantly simple .if light can be provided withoutthe river experiencing light and dark contrasts in his or her field of vision, themost objectionable glare will be eliminated.the most commen architecturalsolution in constucting new competitive venus is to place the windows or otherfenestration behind the spectator sands so light washes over the ceiling to thefar wall and down to the pool dack.as shown in the figure below:by positioning the light source dehind the viewers,out of their line ofvission,intense of reflections and glare problems are avodid.Windows and open fenestration on oppisite walls can be controlled bycosucting opaque wall,partitions(as in the figure below):
or facades,soffits or baffles(as in the figure below)to block the directlight,allowing indirect,deflected light to bounce off the structure and spell intothe nataorium space.In designing these features,careful considration should be given to wallcoloring,using combinations of light and dark surfaces areas to maximize theeffectiveness ot the indirect natural light.Glare caused by end-wall lighting is not as serve as that created by oppisite-wall lighting,but it can be a problem,particularly for compotitive swimmersperforming the breaststoke,backstroke or butterfly.An attractive solution to end-wall lighting problems is a wall design using saw-tooth panels to direct light away from the water.(as shown in the figure below):
Sky light are usually not problematic, since the angle of reflection from anover head source is normally not great enough to be an issue (as in the figurebelow):If glare compromises the view from high spectator seating, however, arecessed clerstory can be installed to achieve top-lighting with the sameindirect benefits as achieved with baffles(asshown in the figure below):
the preferred positioning, then,for overhead lighting in a competitive poolenviroment is directly above the water surface.this is particulary important forpools wihout underwater lighting.Casting light straight down penetrates the deep water most efficiently andcreates aminimum of shadows.at greater angles, more of light is reflected offthe water surfae, casting bigger shadows from the pool edge and causing thebottom of the pool to appear darker.The relation between the pool and the building surrounding it and we take incare not to construct buildings which could make shadows so as not to affectthe vision of the attendance and the players.The relationship between the sun and the jumping pannel (اﻟﻘﻔز .)ﻣﻧﺻﺔ
1- Oita Main Stadium:location: Kyoto,TokyoUsage of natural light: Skylight and Materials.• To give the field adequatesunlight exposure, theelliptical roof opening runsalong the north-south axis.• The stationary portion of theroof is clad in titanium, givingit a futuristic appearance. Thenoticeable interior lightness isthanks to the Teflon panels ofthe movable roof structure.• The use of ultra-modern Teflonmembrane panels with 25%light-permeability removes theneed for artificial lightingduring daylight hours.