Modul Kuliah Sains Bang.pdf

MODUL SAINS BANGUNAN Ernaning Setiyowati

1. CLIMATE Weather is the set of the atmosphere conditions prevailing at a given place and time. Climate can be defined as the integration in time of weather conditions, characteristic of a certain geographical location. The climate of earth is driven by the energy input from the sun. For designer there are 2 essential aspects to understand: 1. The apparent movement of the sun (the solar geometry) 2. The energy flows from the sun and how to handle it (exclude it or make use of it) The earth moves around the sun on a slightly elliptical orbit. At its maximum (aphelion) the earth-sun distance is 152 million km and at its minimum (perihelion) 147 million km. The earth axis is not normal to the plane of its orbit, but tilted by 23,5o. on june 22 (northern solstice) +23,45o 0 on march 21 and Sept 22 (equinox dates) o on December 22 (southern solstice) -23,45 ELEMENTS OF CLIMATES: 1. Temperature (DBT) Measured in the shade, usually in a ventilated box, 1,2-1,8 m above ground level. 2. Humidity Which can be expressed as RH or AH, or the WBT or dew-point temperature (DPT) can be stated. 3. Air movement i.e. wind, normally measured at 10 m above ground in open country, but higher in built up areas, to avoid obstruction; both velocity and direction are recorded. 4. Precipitation The total amount of the rain, hail, snow, or dew, measured in rain gauges and expressed in mm per unit time (day, month, year). 5. Cloud cover Based on visual observation, expressed as a fraction of the sky hemisphere covered by clouds. 6. Sunshine duration i.e. the period of clear sunshine, measured by a sunshine recorder, shown as hours per day or month.

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7. Solar radiation Measured by pyranometer (solarimeter). The quatity can be measured in two ways: a. Irradiance, in W/m2: the instantaneous flux/energy flow density/power density b. Irradiation, in J/m2 or Wh/m2, an energy quantity integrated over a specified period of time (hour, day, month, or year) There are large variations in irradiance amongst different locations on the earth, for three reason: a. Angle of incidence: according to the cosine law the irradiance received by a surface is the normal irradiance times the cosine of the angle of incidence (INC) b. Atmospheric depletion, a factor varying between 0,2 and 0,7, mainly because at lower altitude angles the radiation has to travel along a much longer path through the atmosphere, but also because of variations in cloud cover and atmospheric pollution. c. Duration of sunshine, i.e. the length of daylight period (sunrise to sunset) and to a lesser extent also on local topography The maximum irradiance at the earth’s surface is around 1000 W/m2 and the annual total horizontal irradiation varies from about 400 kWh/m2y near the poles to a value in exess of 2500 kWh/m2y in the sahara desert or northwestern inland Australia. CLASSIFICATION OF CLIMATE: 1. Cold climates, where the main problem is the lack of heat (underheating), or excessive heat dissipation for all or most of the year. 2. Temperate (moderate) climates, where there is a seasonal variation between underheating and overheating but neither is very severe. 3. Hot-dry climates, where the main problem is overheating, but the air is dry, so the evaporative cooling mechanism of the body is not restricted. There is usually a large diurnal (day-night) temperature variation. 4. Warm-humid climates, where the overheating is not as great as in hot dry areas, but is aggravated by high humidites, restricting the evaporation potential. The diurnal temperature variation is small. CLIMATIC DESIGN 1. Cold Climates Characteristic -

Underheating Recorded temperature range from -34o to 108o F Too much sun in summer and not enough in the winter Cold winds during a long winter Persistent NW-SE wind

Design Objectives

Architectural Guidelines To minimise any heat - The surface to volume loss ratio is important. To reduce cold wind eskimo igloos have the effect best surface-to-volume ratio - Insulation of the envelope - Air infiltration is not greater than about 0,5 air changes per hour

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pattern throughout the year Short heavy rain in the summer Long, fine misty rains or snow in the winter Average rainfall is about 27” Average snowfall is about 40,5”

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a compact building form is desirable U-value is less than 0,5W/m2K Except on the south Windows should be small, at least double glass/tripple glass/double glass with & low-e-treatment partially evacuated with inert gas fill Capacitive insulation (massive construction) Entrances should be fitted with an air-lock and should be protected externally from cold winds Blocking the winds without blocking the sun The buildings in urban neighborhood should be of about the same height Open angle to the south-southwest, with steep southern-sloped roof, to allow glazing to maximize the use of sun radiation Terrace in the sheltered zone, raised above ground to avoid snow accumulation Structures shall be compact with minimum exterior surface Optimum sun orientation lies 12o E of south. The prevailing wind pattern (NW-SE) may influence the orientation of free standing buildings Sun exposed surfaces in medium colors; recessed surface can be of dark absorbent colors if shade in summer can be

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2. Temperate Climates Characteristic -

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Underheating Overheating The nighttime temperatures are too high even in the summer Recorded temperature is -14o – 102o F The distribution of clear and cloudy days is fairly uniform throughout the year Wind velocities are generally stable throughout the year, with 10 mph summer

Design Objectives To minimise heat loss and maximise heat gain (winter) To maximise heat loss and minimise heat gain (summer)

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provided Exterior surfaces of smooth non-absorbent materials are preferable A sloping roof is desirable to prevent moisture penetration and ice-filled gutters West wall material with 6 hours time lag balance internal heat distribution Vapor seal on warm (interior) side of outer walls is important Avoid exterior materials that are absorptive Basement should receive sunlight in summer or have artificial dehumidification to prevent condensation resulting from earth temperatures Water and sewer pipes should be kept out of exterior walls, particularly NW and SE walls

Architectural Guidelines U-value is 0,3-0,7 W/m2K Any large (equatorfacing) windows used for winter solar heating may cause summer overheating Overhanging eaves or other horizontal shading devices may ensure summer shading but allow winter entry of solar radiation If overheating occurs in the summer, ventilation

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and 12 mph winter average speeds Monthly average precipitation are fairly uniform throughout the years; varying from 3,0” in November to 4,3” in August Design for snowfall up to 3’ Yearly average of relative humidity lies between 56-76%. It is lower in winter than in summer

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could be relied on to dissipate the unwanted heat, as air temperatures are unlikely to be too high Heavy construction (capacitive insulation) The time lag of a solar heated massive wall can be set to equal the time difference between the maximum of solar input and the time when heating would be welcome Wind breaks are desirable against winter NW wind direction Tree layouts should not block prevailing S-SW summer breezes. Evergreen trees are best for wind protection, deciduous for shading purposes Lawns near structure are useful for radiation absorption Shade trees are preferred on E and W sides of residences Buildings should open to S-SE and be closed on westerly sides. Bedrooms should be located on easterly sides, open porch on SSE side Cross-shaped of free building formations are possible, elongation in E-W axis is preferable Sol-air orientation of 17½o E to S secures balanced heat distribution The orientation of high buildings should be correlated with wind exposure Provision for adequate

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cross ventilation is necessary. Humidityproducing areas should be separated from rest of building Sun penetration is desirable Medium colors are advantageous, dark colors only in recessed places protected from summer sun, light colors on roof surfaces South exposed glass areas work well on seasonal bases Protection is needed for summer radiation Opening should be screened Location of openings should allow cross ventilation Reduced openings on westerly side is desirable Avoid absoprtive materials Rains and moisture penetration is mostly on NW exposures Eave and gable ventilation is needed Attic fan is also effective Gutters should be able to carry 1” of rain off total roof area in 15 minutes Snow and rain pockets must be avoided West wall material with 6 hour time lag balances internala heat distribution Vapor barrier on warm side prevents condensation Deciduous trees on east and west sides, 68o overhang on south exposure, protects low

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3. Hot-Dry Climates Characteristic -

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The daytime temperature can be very high but the diurnal range is large, often more than 20 K Night temperature may be too cold The outdoor environment is often hostile, hot and dusty Low humidity High summer daytime temperature Direct solar radiation is as intense as the radiation reflected from the light-coloured and bare land The sky is clear most of the year, promoting solar heating during the days and long-wave radiant loss during the night Horizontal global radiation can approach 1000 W/m2 Air temperatures can reach in extreme cases up to 50oC, although in many hot arid regions the typical maximum air temperature is about 35-40oC. Winds are usually strong Dust storm Sunlight reflection for the bare, often light coloured ground, may produce intense glare Prevailing wind axis

Design Objectives -

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Large thermal mass To maximize shade and minimize wind Slow rate of indoor heating during summer daytime Fast rate of indoor cooling in summer evenings Minimizing dust penetratioin Good ventilation in the summer evening Higher indoor temperatures relative to the outdoors in winter Heat loss High solar reflectivity

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structures Eggcrate type of sunshade on E and W, vertical fins on N side protects higher buildings

Architectural Guidelines Massive walls but also a roof with high thermal capacity Building surfaces should be white. White paint has a high emittance Roofs exposed to the night sky. The radiant cooling effect can help to dissipate the heat stored during the day An inward looking, courtyard type building The air mass enclosed by the building, by solid walls or fences is likely to be cooler than the environment, heavier, thus it would settle as if in a basin This air can be evaporatively cooled by a pond or a water spray The reservoir of cool air thus created can then be used for fresh air supply to habitable spaces With adequate vegetation such a courtyard can become quite a pleasant outdoor living space The traditional courtyard with shading, trees, and some water element can be substantially cooler than the ambient at the height of summer Ventilation, beyond the

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lies in E-W direction Average yearly rainfall to about 8” Air is dry during all periods of the year -

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small fresh air supply from the courtyard is undesirable as the outdoor air is hot and dusty The surface area of its external envelope should be as small as possible, to minimize the heat flow into the building Vegetation is desirable both as a radiation absorbent surface and for its evaporative and shade giving properties Compact ‘patio’ house type is prefered Closed building arrangements around green areas are preferable High ceilings are not necessary Outdoor or roof sleeping possibilities should be considered Windows should be shielded from direct radiation, and set high to protect from ground radiation Openings should be tight-closing as protection against high diurnal heat Openings should be located on S, N, and to a lesser degree on E sides Walls of daytime living areas should be of heat-storing materials, walls of night use rooms of materials with light heat capacity E and W walls should preferably be shaded High reflective qualities are desirable for both thermal and solar radiation

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4. Warm-Humid Climates Characteristic -

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The temperature maxima may not be as high as in the hot dry climates But the diurnal variation is very small (often less than 5 K) The humidty and rainfall are high most of the year The roof receives very strong radiation The average temperature is about 27-30oC, and the range of average monthly temperature is about 1-3oC. The wind condition depend on the distance from the sea and may vary during the year Average wind velocity of 10 mph comes from easterly direction both in morning and afternoon The average rainfall of about 60”

Design Objectives -

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To ensure that the interior does not become much warmer that the outside (it cannot be any cooler) Undue increase of ceiling temperature Avoid heat input from a low-angle sun, and should be reflected and insulated Providing effective natural ventilation, even during rain To ensure maximum cross ventilation Minimizing solar heating of the building Maximizing the rate of cooling in the evening Preventing rain penetration, even during rainstorm Preventing entry of insect while the windows are open for ventilation Providing spaces for semioutdoor activities as integral part of the living space

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Shaded, ventilated roof is applicable, primarily over night use rooms Water spray or pool on roof is effective

Architectural Guidelines Evaporation from the skin is restricted and evaporative cooling will be neither effective , nor desirable, as it would increase the humidity Indirect evaporative cooling may be used, as it does not add moisture to the supply air and produces some sensible cooling The elevated house (to catch the breeze above local obstruction) of lightweight construction Adequate ventilation removing any excess heat input The ceiling temperature may be elevated due to solar heat input on the roof Using elevated roof surface Having a seperate ceiling, forming an attic space Ensuring adequate ventilation of the attic space Using a reflective surface for the underside of the roof skin Using some resistive insulation on the ceiling Walls facing the east and west should have no windows The physiological

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cooling effect of air movement The major openings should face within 45o of the prevailing wind direction North and south walls could have large openings The rooms could be arranged in one row, to allow both inlet and outlet openings for each room Shade trees should be high branching so that they do not interfere with breezes Low vegetation must be kept away from houses so as not to block air movement Air coming into a structure from across a shaded lawn is desirable House types: individual Buildings should be shaded structures which encourage cooling air movements Shade protection should be on all sunexposed sides, mainly on roof and E and W exposures Screened areas are necessary to keep out insect Interior spaces must be shaded and well ventilated Floor material must be impervious to moisture Daytime living areas should allow the flow of E to W winds Reflective light colors in the pastel range are best, in order to avoid glare both inside and outside

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Ventilation is needed 85% of the year E-W cross ventilation is essential Elements such as screening, louvres, jalousies, and grills are useful to admit air flow and to protect from sun Structure must be sheltered from sun and rain, it must be shielded from sky radiation and glare A ventilated double roof is desirable. The upper roof functioning as sun protection. It must be watertight, insulated, and reflect solar rays A wide overhang is necessary for rain protection and for reduction of sky glare Sunbreakers are important because of powerful radiation mainly on E and W sides Basement is impractical because of constant high humidity Foundation must be protected from moisture, mold, fungus, termites, and other gnawing insect and animals

MICROCLIMATIC CONTROL Local factor that will influence the site climate may be the following: 1. Topography, slope, orientation, exposure, elevation, hills or valleys at or near the site 2. Ground surface, natural or man-made, its reflectance, permeability, soil temperature, paved areas or vegetation 3. 3D objects, such as trees, tree-belt, fences, walls and buildings as these may influence the wind, cast shadows and may subdivide the area into smaller distinguishable climate zones Solar radiation is affected by the clarity of the atmosphere: it will be reduced by pollution, smog, and dust. Slope and orientation of such slope has an effetct on irradiation. Hills, trees and

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buildings around the site also affect the apparent sunrise/sunset times, therefore the length of day, thus the daily irradiation. Microclimatic controls can serve two purposes: 1. Control the conditions (sun, wind) in outdoor spaces 2. Assist building performance by ameliorating outdoor conditions adjacent to the building Such controls may be of two kinds; 1. Vegetation, trees, shrubs, vines, and ground covers 2. Built objects, fences, walls, screens, pergolas, shade structures pavements ASSIGNMENT 1. Jelaskan bagaimana pergerakan matahari dapat mempengaruhi terjadinya iklim! 2. Jelaskan mengapa iklim panas kering memiliki temperature diurnal yang besar sedangkan di tropis lembab memiliki temperature diurnal yang kecil? 3. Jelaskan dengan sketsa, desain arsitektur yang sesuai pada setiap kondisi iklim (dingin, sedang, panas kering, tropis lembab)!

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2. NATURAL VENTILATION WIND Windward: arah anging datang (+) Leeward : arah angin pergi (-) Wind calculation: Table 2.1. values of gradient height, zG, power law exponents α, β, and the roughness length z0 Terrain category

Terrain description

Gradient height, ZG (m)

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Open sea, ice, tundra, desert Open country with low scrub or scattered trees Suburban areas, small town, well wooded areas Numerous tall building, city centres, well developed industrial areas

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Roughness Mean Gust length, z0 speed speed (m) exponent exponent α β 0,001 0,11 0,07

300

0,03

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𝑧𝑧 𝑉𝑉𝑧𝑧 = 𝑉𝑉𝑔𝑔 ( )𝛼𝛼 𝑧𝑧𝑔𝑔

Vz : kecepatan angin pada lokasi z Vg : kecepatan angin pada lokasi g (yang diketahui berdasarkan data iklim) Z : ketinggian lokasi z Zg : ketinggian di lokasi g tempat data iklim diukur α: mean speed exponent

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Figure 1. Profil vertikal rata-rata kecepatan angin dari beberapa terrain Contoh soal: Data iklim yang diukur pada kawasan laut menunjukkan angka 5 m/s, di mana pengukuran dilakukan pada ketinggian 10 m. Berapa kecepatan angin di tengah kota pada ketinggian 10 m? Jawaban: Langkah 1. Dicari dahulu kecepatan angin di lokasi open sea pada ketinggian 100% (gradient height) di mana angka ini nantinya akan sama dengan kecepatan angin di lokasi yang diukur pada ketinggian 100%. 𝑧𝑧 𝑉𝑉𝑧𝑧 = 𝑉𝑉𝑔𝑔 ( )𝛼𝛼 𝑧𝑧𝑔𝑔 5 m/s = Vg (10/250)0,11 Vg = 7,14 m/s Langkah 2. Menghitung kecepatan angin di lokasi yang ditanyakan dengan yang diketahui adalah kecepatan angin di kondisi tertinggi open sea sama dengan di kondisi tertinggi lokasi yang ditanya

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𝑧𝑧 𝑉𝑉𝑧𝑧 = 𝑉𝑉𝑔𝑔 ( )𝛼𝛼 𝑧𝑧𝑔𝑔 Vz = 7,14 m/s (10/500)0,36 Vz = 1,75 m/s Jadi kecepatan angin pada ketinggian 10 m di tengah kota adalah 1,75 m/s. Table 2.2. Summary of wind effects on people based on the Beaufort scale

Calm, light air Light breeze Gentle breeze

Beaufort number 0,1 2 3

Speed (m/s) 0-1,5 1,6-3,3 3,4-5,4

Moderate breeze

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Strong breeze

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Near gale gale Strong gale

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13,9-17,1 17,2-20,7 20,8-24,4

Effects Calm; no noticable wind Wind felt on face Wind extends light flag Hair is disturbed Clothing flaps Raises dust, dry soil, and loose paper Hair disarranged Force of wind felt on body Drifting snow becomes airborne Limit of agreeable wind on land Umbrellas used with difficulty Hair blown straight Difficult to walk steadily Wind noise on ears unpleasant Windborne snow above head height Inconvenience felt when walking Great difficulty with balance in gusts People blown over vy gusts

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NATURAL VENTILATION What is ventilation? Ventilation is the process by which ‘clean’ air (normally outdoor air) is intentionally provided to a space and stale air is removed. Why is ventilation needed? Ventilation is needed to provide oxygen for metabolism and to dilute metabolic pollutans (carbon dioxide and odour). It is also used to assist in maintaining good indoor air quality by deluting and removing other pollutants emitted within a space but should not be used as a substitute for proper source control of pollutants. Ventilation is additionally used for cooling and to provide oxygen to combustion appliances. Good ventilation is a major contributor to the health and comfort of building occupants. How does ventilation work? Ventilation is accomplished by introducing ‘clean’ air into a space. - Mixing ventilation Mixing is stimulated by natural turbulance in the air and by the design of the air supply diffusers. - Displacement ventilation - Interzonal ventilation Extract air from ‘wet’ rooms. Fresh ‘make up’ air is then drawn through air inlets or mechanically supplied to anothe rooms. This induces a flow pattern that inhibits the cross-contamination of air from ‘polluted’ spaces to ‘clean’ spaces. - Short circuiting If a ventilation system is poorly designed, ‘short circuiting’ may occur in which fresh ventilation air is extracted from the building before it has mixed with or displaced stale air. This can occur if air diffusers and outlets are positioned too close to each other, or, in the case of displacement systems, the supply air temperature is higher than the room air temperature. How much ventilation is needed? The quantity of ventilation needed depends on the amount and nature of pollutant present in a space. The minimum acceptable ventilation rate is that which is required to dilute the dominant pollutant to an acceptable concentration.

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Table 2.3. Typical ventilation rates for carbon dioxide and obdour control Function of space Residences Living room Kitchen Bedroom Bathroom School classroom Factories (no smoking) Community halls (heavy smoking)

Ventilation Rate (m3/h fresh air) 45 60-90 25 25 40 per person 30 per person 50 per person

Good ventilation design is essential to ensure the reliable provision of fresh air to building occupants. In particular, ventilation design should satisfy the following basic requirements: - Comply with relevant building regulations and associated standards and codes of practice - Satisfy minimum ventilation rates for optimum health and comfort - Be capable of removing pollutants at source before they disperse into occupied areas - Be compatible with the building in which the system is installed - Provide high rates of ventilation for cooling purposes or for rapidly purging polluted air from a building - Incorporate occupant or automatic controls to ensure that the ventilation rate can be adjusted to meet changing demand - Be reliable - Be capable of being cleaned and maintaned - Comply with smoke and fire control requirements - Be cost and energy efficient There are two energy sources that create air pressure differences used to promote natural ventilation: 1. Pressure differences due to variations in air density with height, created by differences in air temperature, referred to as the ‘stack effect’ 2. Pressure differences due to distribution of wind pressures on buildings Udara bergerak biasanya mengikuti kontur permukaan lengkung dengan pola yang dapat diperkirakan. Sudut-sudut tajam (dan/atau permukaan kasar) akan menyebabkan pemisahan dan pusaran.

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Tata letak yang ditunjukkan dalam denah di kiri dan tengah sangat berguna untuk membelokkan angin musim dingin dari arah bangunan. Tata letak yang bersilangan di kanan cocok untuk penyebaran angin musim panas untuk struktur-struktur yang berdekatan.

Bangunan tinggi dapat membelokkan angin ke arah tanah yang menyebabkan kecepatan angin yang tinggi di daerah pejalan kaki. Dasar podium yang besar, kanopi yang lebar, dll dapat digunakan untuk melindungi area pejalan kaki.

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DESIGN GUIDELINES FOR NATURAL VENTILATION Design Programme The information needed during the design programme phase in order to define proper requirements for natural ventilation: 1. The type of building 2. The type of space 3. The schedule of use for each space 4. The climate of the location 5. The quantity of heat to be removed Site Design Main Objectives when selecting and designing the site for a building project suitable for natural ventilation:

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The best exploitation of the airflow pattern due to topography and surrounding buildings, in order to increase the potential ventilation rate within the interior spaces The best compromise between summer and winter comfort condition The avoidance of permanent unwanted wind sheltering situations The avoidance of disomfort due to outdoor conditions or caused by high wind velocities The avoidance of airflow paths transporting dust and pollutants

If the site is not in urban area, a building should be located in a way that takes advantage of local gradient winds. In mountain and hill sites, the best location is generally at the middle of a slope along the contour lines. Similarly, by the sea, a lake or a large river, a building shoud be positioned fairly close to the shore and with the longitudinal axis parallel to the line of the coast or the bank in order to make use of day water and night land breezes. If a building is designed for an urban site, its location should be at a distance from other buildings that is greater than the depth of their wake so that they will not shelter it from summer winds. If this is not possible, the building should be positioned randomly with regard to the upwind buildings and with its longitudinal axis perpendicular to the prevalent summer wind direction in order to catch the streamline flow. In a very dense urban areas, spaces most needing ventilation should be put on the highest floors where wind flow is stronger and less turbulent than near the ground.

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Landscape the main functions of vegetation as far as air movement is concerned are: wind sheltering, wind deflection, funnelling and acceleration of air, air conditioning. It is recommended that the landscaping be designed to allow for reduced air velocities without large scale turbulence. When the placement of trees on a site is being designed, their distance from buildings should be determined in relation to the area of the wake as well as to the cross-sectional airflow pattern, which is characterized by the proportion between canopy and stem. Rows of trees and hedges can be placed to direct air towards or away from a building. Vegetation can create areas of higher wind velocities by deflecting winds or funnelling air through a narrow passage. Reducing the spacing of the trees used to funnel air can increase the airflow up to 25% above that of the upwind velocity.

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Building Design The aspect of building design related to air movement can be grouped according to their relation to: 1. The form of the building envelope 2. The internal distribution of spaces and functions 3. The dimensions and location of openings 4. The characteristics and dimensions of the exposed thermal mass 5. The interactions with the HVAC system The wind velocity and pressure fields around a building are greatly affected by the form of the building envelope and in particular by: 1. The height of the building 2. The roof form

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3. The aspect ratios (the ratios of the height of the building to its length and width) 4. The corrugation of the building envelope (overhangs, wingwalls, and recessed spaces)

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Opening design Position and size openings of a building: • Outlet openings should be equal to or greater in size than inlet openings in order to avoid excessive air velocities with a limited airflow rate • For occupant cooling purposes, openings should be placed at occupant height • For structural cooling requirements, the position of openings should be closer to the thermal exchange surfaces (wall, ceiling, or floor) • The vertical position of inlet openings in two-storey dwellings or high spaces should be lower than the position of outlet openings in order to avoid a conflict between cross ventilation and the stack effect • In single-sided ventilation, more than one opening should be provided to a room; these openings should be placed far apart so that a better use of skewed winds can be made; wind deflectors can be used to enhance ventilation within the room • When stack ventilation is used in multistorey buildings, outlet openings should be located in the leeward side of the building; the height of their position and the size of the overall opening area should be chosen as a means of controlling the neutral pressure level and thereby enhancing the ventilation of the spaces.

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Openings can be grouped in the following categories: • Windows, which have multiple integrated functions such as viewing, daylighting, solar gain control and ventilation; windows are divided into various categories in relation to: - The plane of placement - The position on the building envelope - The opening system (simple opening, vertical vane opening, horizontal vane opening) Simple opening

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Vertical-Vane Openings

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Screens, which function basically as shading devices, but can also be designed for ventilation purposes, as in traditional Arabic architecture; however, even if used as shading devices only, screens alter the opening size and the aerodynamic performance of the windows on which they are installed - Fixed screen - Operable screen The most common types of operable screens are: Exterior screen: - Rolling blinds - Sliding-sash shutter, single or double, with or without slats - Side-hinged casement shutter, with or without slats Interior screen: - Venetian blind - Vertically operating curtains - Horizontally operating curtains - Louvres

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Doors, with the basic function of interconnection between spaces and maintaining the privacy of a room, and with additional functions depending on the material and location

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Vents and ventilators, functioning only as means to enhance and direct the air movement Vents can be divided into various types in relation to their function and position in a building: - Attic vents, such as gable louvres, soffit vents, and ridge vents

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Wall-to-floor vents, for night structural cooling of commercial and office buildings Door vents, for interzonal air change

Vegetation

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Space Dimension

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Space Division

AIR FLOW CHARACTERISTIC IN HOUSING TYPES Single family detached house

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Town house (Row house)

Multistorey Apartment Building

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ASSIGNMENT: 1. Data iklim di daerah laut menunjukkan kecepatan angin sebesar 15 m/s pada pengukuran setinggi 10 m. Berapakah kecepatan angin di daerah berikut? a. Pedesaan pada ketinggian 4 m (NIM ganjil) b. Tengah kota pada ketinggian 6 m (NIM genap) 2. Gambarkan pola pergerakan udara pada beberapa gambar di bawah ini dan berikan penjelasan!

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a. Arah angin: Dari utara (NIM ganjil), dari barat (NIM genap)

b. Arah angin: dari selatan (NIM ganjil), dari timur (NIM genap)

3. Dari kedua desain bangunan pada gambar di soal nomor 2, berikan kesimpulan, bentuk bangunan/tata massa yang mana yang lebih baik dalam menghantarkan udara? Berikan alasannya! 4. Gambarkan aliran angin pada bangunan berikut! a. Arah angin selatan (NIM ganjil) b. Arah angin barat (NIM genap)

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5. Bagaimana desain bukaan yang tepat pada bangunan di atas (no.4) supaya dapat mengalirkan udara ke seluruh ruang? Jelaskan dengan sketsa! 6. Berikan sketsa desain apartemen berlantai banyak yang mampu mengalirkan udara ke seluruh penjuru ruangan. Desain yang dimaksud antara lain: denah bangunan (susunan ruang) yang terlihat jelas posisi dan lebar bukaan, potongan bangunan yang terlihat jelas posisi dan lebar bukaan.

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3. THERMAL Heat

is a form of energy, contained in substances as molecular motion or appearing

as electromagetic radiation in space. Energy is the ability or capacity for doing work and it is measured in the same units.

Temperature is the symptom of the presence of heat in a substance. The celsius scale is based on water: its freezing point taken as 0oC and its boiling point as 100oC. The Kelvin scale starts with the absolute zero, the total absence of heat. Thus 0oC = 273,15oK.

The specific heat

concept provides the connection between heat and

temperature. This is the quantity of heat required to elevate the temperature of unit mass of a substance by one degree, thus it is measured units of J/kg.K

Latent heat of a substance is the amount of heat (energy) absorbed by unit mass of the substance at change of state (from solid to liquid or liquid to gaseous) without any change of temperature.

Thermodynamics is the science of the flow of heat and of its relationship to mechanical work. The first law: the principle of conservation of energy. Energy cannot be created or destroyed, but only converted from one form to another. The second law: heat (energy) transfer can take place spontaniously in one direction only: from a hotter to a cooler body, or generally from a higher to a lower grade state

Heat Flow Such heat flow can take place in three form 1. Conduction within a body or bodies in contact, by the spread of molecular movement. Conduction depends on a property of the material known as conductivity, measured as the heat flow density in a 1 m thick body, with a one degree temperature difference, in unit of W/m.K. Materials with low conductivity are referred to as insulating materials. These have a fibrous or porous structure and are very sensitive to moisture content. If the pores are filled with water, the conductivity will increase quite drastically. Conductivity is a material property, regardless of its shape and size. The corresponding property of a physical body is the conductance (C) measured between the two surfaces of the wall. For the single layer it is the conductivity, divided by thickness. It is rarely used quantity. Transmittance, or U-value includes the surface effects and it is the most frequently used measure.

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2. Convection from a solid body to a fluid (liquid or gas) or vice-versa (in a broader sense it is also used to mean the transport of heat from one surface to another by a moving fluid, which, strictly speaking, is mass transfer) The magnitude of convection heat flow depends on: • Area of contact (A, m2) between the body and the fluid • The different in temperature (∆ T, in K) between the surface of the body and the fluid • A convection coefficient (hc) measured in W/m2K, which depend on the viscocity of the fluid and its flow velocity as well as on the physical configuration that will determine whether the flow is laminar or turbulent 3. Radiation from a body with a warmer surface to another which is cooler. Therma radiation is a wavelength band of electromagnetic radiation Reflectance: is a decimal fraction indicating how much of the incident radiation is reflected by a surface. Absorptance: is expressed as a fraction of that of the ‘perfect absorber’, the theoretical black body, and its value is high for dark surfaces, low for light or shiny metallic surfaces. Emittance is also a decimal fraction, a measure of the ability to emit radiation, relative to the black body, the perfect emitter.

Thermal comfort The human body continuously produces heat by its metabolic processes. The heat output of an average body is often taken as 100 W, but it can vary from about 70 W (in sleep)to over 700 W in heavy work or vigorous activity. Comfort is defined as the condition of mind that expresses satisfaction with the thermal environment, it requires subjective evaluation. Factors of comfort environmental Air temperature Air movement Humidity Radiation

personal Metabolic rate (actiivity) Clothing State of health Acclimisation

Contributing factors Food and drink Body shape Subcutaneous fat Age and gender

Insulation means to control the heat flow, for which three different mechanism: Reflective insulation: where the heat transfer is primarily radiant, such as across a cavity or through an attic space. A shiny aluminium foil has both a low emittance and a low absorptance, it is therefore a good reflective insulator. In a hot climate, such a foil insulation under the roof skin is preferable to resistive insulation. It will reduce downward heat flow, but will allow the escape of heat at night, thus permitting building to cool down. A resistive insulation would affect the up and down heat flow almost equally.

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Resistive insulation: of all common materials, air has the lowest thermal conductivity, as long as it is still. The purpose of resistive insulation is just to keep the air still, dividing it into small cell, with the minimum amount of actual material. The most often used insulating material are expanded or extruded plastic foams, such as polystyrene or polyurethane of fibrous materials in the form of batts or blankets, such as mineral wool, glass fibres,, or even natural wool. Capacitive insulation: material layers of a high thermal capacity (massive construction) affect not only the magnitude of heat flow, but also its timing. Both reflective and resistive insulation response to temperature changes instantaneously. Capacitive insulation relies on the themal capacity of material and their delaying action on the heat flow.

Design Variables The four design variables that have the greatest influence on thermal performance are: shape, fabric, fenestration, and ventilation. Shape a. Surface to volume ratio: as the heat loss or gain depends on the envelope area, it is advisable to present the least surface area for a given volume b. Orientation: in most instances, the N&S walls should be longer than the E&W walls, depending on the temperature and radiation condition. It can be optimised in term of solar incidence and wanted or unwanted solar heat gain or heat dissipation Fabric a. Shading of wall and roof surfaces can control the solar heat input. The west facing wall should be shaded to eliminate the late afternoon solar input. If the plan shape is complex, then the shading of one surface by another wing should be considered. b. Surface qualities: absorptance/reflectance will strongly influence the solar heat input; if it is to be reduced, reflective surfaces are preferred. A white and a shinny metal surface may have the same reflectance, but the white would have an emittance similar to a black body. Thus if heat dissipation is the aim, a white surface would be preferred. c. Resistive insulation control the heat flow in both direction; it is very important in very cold climates or in very hot climates. d. Reflective insulation: the best effect is achieved if the foil is suspended in the middle of a cavity, so that both the high reflectance and low emittance are utilised. e. Capacitive insulation provide a very powerful control of the timing of heat input especially in climates with a large diurnal temperature swing, as it can store the surplus heat at one time, for release at another time, when it is needed Fenestration a. Size, position, and orientation of windows affect sun penetration, thus solar heat input, but also affect ventilation, especially where cross ventilation is desirable. b. Glass: single, double, multiple, and glass quality: special glass (heat absorbing or heat reflecting glasses) may be used to ameliorate an otherwise bad situation, by reducing the solar heat input.

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c. Closing mechanism: fixed glass, louvres, opening sashes, type of shases used d. Internal blinds and curtains can slightly reduce the solar heat input, by reducing the direct radiation, but they become heated and will re-emit that heat, thus causing convective gains e. External shading devices are the most positive way of controlling solar heat input. The effect of such devices on wind and on daylighting and views must be kept in mind f. Insect screen may be necessity in hot humid climate, but their effect on air flow and on daylighting must be recognised Ventilation a. Air-tight construction to reduce air infiltration is important both in a cold climate and in a hot climate in air conditioned buildings b. Beyond the provision of fresh air, ventilation can be relied on to dissipate unwanted heat c. Physiological cooling can be provided even when To>Ti and for this not the volume flow but the air velocity is important. This can only be achieved by full cross-ventilation and it may be the main determinant of not only fenestration and orientation but also of internal layout.

Thermal behaviour of building A building can be considered as a thermal system, with a series of heat inputs nd outputs for the human body: Qi = internal heat gain Qc = conduction heat gain or loss Qs = solar heat gain Qv = ventilation heat gain or loss Qe = evaporative heat loss

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Analisa thermal Comfort Analisa thermal comfort menggunakan psychrometric chart.

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Zona nyaman dapat ditentukan pada psychrometric chart dengan cara (Szokolay, 1987): 1. Mencari suhu udara luar rata-rata. 2. Menentukan thermal neutrality (Tn) dengan menggunakan rumus Tn = 17,6 + (0,31 x Tav) 3. Menentukan Tn di dalam grafik pada kurva RH 50%. 4. Tandai batas bawah suhu nyaman: L=Tn-2, dan batas atas U=Tn+2 pada kurva RH 50%. 5. Menggambar garis SET sebagai batas samping. Rumus kemiringannya menjadi: 0,025x(L-14) dan 0,025x(U-14) Dari psychrometric chart AH(L) dan AH(U) Dua batas samping sebagai pertemuan dengan garis dasar adalah: L + (AH(L) x kemiringan L) dan U + (AH(U) x kemiringan U) 6. Tandai batas atas AH pada level 12 g/kg dan batas bawah pada level 4 g/kg.

Thermal Calculation Tujuan dari perhitungan thermal adalah untuk mengetahui atau memperkirakan temperatur di dalam bangunan dari data iklim yang ada. Hal ini bisa dilakukan pada bangunan yang sudah terbangun maupun yang masih dalam proses rancang. Faktor penentu perhitungan termal: Dimensi bangunan: luas permukaan bangunan, orientasi bangunan Material Properties: U-value, sgf (solar gain factor), abs (absorption), Rso (Resistance outside) Data iklim: suhu udara luar rata-rata, kecepatan angin, Gav (global irradiance average) Menghitung suhu udara rata-rata di dalam ruangan 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 = 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 + �

(𝑄𝑄𝑄𝑄 + 𝑄𝑄𝑄𝑄) � 𝑄𝑄𝑄𝑄 + 𝑄𝑄𝑄𝑄

Tiav : suhu udara rata-rata dalam ruangan Toav: suhu udara rata-rata luar ruangan (data iklim) Qi = internal heat gain Qc = conduction heat gain or loss Qs = solar heat gain Qv = ventilation heat gain or loss

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Qs (Solar heat gain) Qs = jumlah Qs dari seluruh elemen bangunan (dinding, pintu, jendela, atap, yang mendapat sinar matahari langsung) 𝑄𝑄𝑠𝑠 (𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒) = (𝐴𝐴 𝑥𝑥 𝑈𝑈)𝑥𝑥 𝑎𝑎𝑎𝑎𝑎𝑎 𝑥𝑥 𝑅𝑅𝑅𝑅𝑅𝑅 𝑥𝑥 𝐺𝐺𝐺𝐺𝐺𝐺 𝑄𝑄𝑄𝑄 (𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡) = 𝐴𝐴 𝑥𝑥 𝑠𝑠𝑠𝑠𝑠𝑠 𝑥𝑥 𝐺𝐺𝐺𝐺𝐺𝐺 A : luas permukaan elemen bangunan U : U-value Abs : absorption Rso : Resistance outside Gav : Global irradiance average Sgf : solar gain factor

Qi (internal heat gain) Jumlah panas elemen internal (manusia, lampu, kompor, dll) 𝑄𝑄𝑄𝑄 = 𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗ℎ 𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 (𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤)𝑥𝑥

Qc (Conduction Heat Gain or Loss)

𝑗𝑗𝑗𝑗𝑗𝑗 𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 24 𝑗𝑗𝑗𝑗𝑗𝑗

𝑄𝑄𝑄𝑄 = 𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗ℎ (𝐴𝐴 𝑥𝑥 𝑈𝑈)𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙

Qv (Ventilation Heat Gain or Loss)

𝑄𝑄𝑄𝑄 = 0,33 𝑥𝑥 𝑁𝑁 𝑥𝑥 𝑉𝑉

N : jumlah pertukaran udara dalam ruang V: volume ruang

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Material Properties

56

57

58

59

60

61

62

63

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ASSIGNMENT 1. Berikan contoh heat flow (conduction, convection, radiation) pada bangunan! 2. Gambar thermal comfort 3. Pada setiap jenis insulasi (resistive, reflective, capacitive) cocok untuk jenis iklim yang mana? Jelaskan! 4. Gambar di bawah adalah gambar bangunan yang memiliki volume yang sama dengan luas permukaan yang berbeda. Dari kedua gambar di bawah, mana yang area di dalamnya terasa lebih panas? Lalu berikan orientasi yang tepat supaya bangunan tidak terlalu panas!

5. Di antara internal blinds dan external shading device, lebih efektif mana dalam mengurangi panas? Jelaskan! 6. Berapa perkiraan suhu dalam ruang rata-rata (Tiav) pada ruangan di bawah ini?

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7. Apakah nilai Tiav di atas masuk ke dalam zona comfort? Tunjukkan pada psychrometric chart di bawah ini!

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4. SUNLIGHT & DAYLIGHT Light outdoors can arrive directly from the sun, which is referred to as sunlight, or can be diffused by the atmosphere, e.g. by clouds. The term daylight, in a loose sense is often used for both, but in technical language, it means only the diffused light. For design purposes, daylight sources can be characterized as direct (direct sunlight and diffuse skylight) and indirect (light from reflective or translucent diffusers that were originally iluminated by primary or other secondary sources). Sky condition The available light is determined by sky condition. A fully overcast sky acts as a diffuse light source, i.e. the whole sky hemisphere is a source of light. The illuminance produced by an overcast sky strongly depends on the solar altitude angle (ALT) behind the clouds. In the absence of measured data, it can be estimated as E ≈ 200 x ALT Under clear sky conditions, direct sunlight can give an illuminance of 100 klx (1 kilo-lx = 1000 lx), but if the sunlight itself is excluded, the sky luminance is taken as uniform. In many climates, intermediate sky conditions occur most of the time. The average illuminance produced by such a sky (excluding direct sunlight) can be estimated as E ≈ 500 x ALT

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Luminance distribution Glare occuring in daylighting can be reduced by the following measures: 1. Reduce luminance of the view by using low-transmittance glass at least for critical (upper) parts of the window, or by the use of blinds and curtains 2. Increase the luminance of areas near the high luminance view, e.g. by having windows in other walls to iluminate the surfaces adjacent to the window considered or by using supplementary top lighting 3. Increase the luminance of the window’s surrounds by using light colour surfaces and contrast grading, i.e. having high reflectance surfaces next to the window, reducing away from the window. With very large windows, this measure will not work 4. Use external protective devices (similar to shading devices) to block out the view of the brightest problem area, most often the sky In daylighting design, for the positioning and sizing of apertures, there are three main issues to be considered: • To satisfy the visual task (provide enough daylight) • To create the desired ‘mood’ and provide visual focus • To integrate daylighting with the architecture Vision Light is perceived by the eye. Its diagramatic section can be compared to a camera: • Aperture, controlled by a light meter: the pupil, the size of which is varied by the iris (and controlled by the retina) is the eye’s main adaptation mechanism • Focusing, controlled by a coupled range-finder: changing the shape of the lens by the ciliary muscles, thus varying its focal length, which is the accommodation mechanism • The adaptability of the retina can only be likened to using films of different ‘speed’ or ISO rating Photometry The four measurable photometriic quantities are: 1. I, the luminous intensity of a source, measured in units of candela (cd), is defined as the intensity of a black body of 1/60 cm2, when heated to the melting point temperature of platinum. 2. ɸ (phi), the luminous flux (or flow of light), is measured by unit lumen (lm) 3. E, or illuminance is a measure of the illumination of a surface, the unit is lux (lx) 4. L, or luminance, is a measure of brightness of a surface, when looked at a given direction. Its unit is cd/m2, which is unit intensity of a source of unit area Lighting Requirements The suitability of lighting is a qualitative requirement and has at least four component factors: 1. Colour appearance and colour rendering

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2. Colour appearance of an environment is associated with mood and the expected ‘atmosphere’. These are psychological and aesthetic effects. 3. Directionality of light must suit the functional as well as the psychological requirements of a visual task 4. Glare should be avoided Glare Glare can be caused by a saturation effect or by excessive contrast. We can distinguish discomfort glare and disability glare, depending on the magnitude of the effect. Saturation glare can be caused when the average luminance of the field of vision is in excess of 25.000 cd/m2. This can be happen on a white sandy beach with full sunshine or by looking directly into a bright light source. Some sources distinguish ‘direct glare’ caused by a light source itself and ‘indirect glare’ caused by reflective illuminated surfaces. Glare is caused by contrast, and if the luminance ratio (Lmax/Lmin) within a visual field is greater than about 15, visual efficiency will be reduced and discomfort may be experienced. Glare can be categorized on the basis of its effect on the observer as: 1. Disability glare, result from areas in the field of viewof such brilliance that they cause a scattering of light within optical matterof the eye. Causing a veiling effect. This veiling effect reduces visual contrast to such a degree that seeing is reduced. Example: driving at night 2. Discomfort glare, is glare that produces discomfort, but does not necessarily interfere with visibility or visual performance. It may result from bright sources within the field of view that are not inherently distressing, but are seen in much darker surroundings. The most widely used measure of discomfort glare in daylighting is the glare index. While the calculation of the glare index is complex, the important variables are: • The luminance of the sky as seen through the window (the larger the window, the higher the index) • The apparent size of the visible area of sky (the larger the area, the higher the index) • The position of the visible sky within the field of view (the closer to the center of vision, the higher the index) • The average luminance of the room excluding the visible sky (the darker the room, the higher the index) Glare can also be categorized on the basis of the path of the light. Direct glare is caused by sources directly visible within the field of view. Reflected glare is glare from a glossy surface that reflects an image of the light source.

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Pencahayaan dari Atap (Top Lighting) Top lighting beroperasi seperti pencahayaan lampu listrik yang memancarkan cahaya secara langsung dengan arah cahaya ke bawah. Berikut adalah beberapa prototipe klasik dari top lighting: • Skylight, atau kaca horizontal, memungkinkan masuknya cahaya matahari langsung dengan pancaran cahaya langit melalui bukaan • Single clerestory, menghasilkan pencahayaan matahari langsung dan tidak langsung melalui jendela clerestory vertikal • Sawtooth single clerestory, menghasilkan pencahayaan matahari langsung dan tidak langsung, namun dengan memantulkan cahaya dengan persentasi tinggi pada plafon miring di sebelahnya sehingga meningkatkan cahaya yang jatuh ke arah bawah dan meminimalkan jumlah cahaya matahari langsung • Monitor atau double clerestory, memungkinkan cahaya matahari yang banyak, terutama pada bangunan di mana orientasi matahari atau cuaca tidak memungkinkan dibuatnya langit-langit miring atau desain khusus lainnya

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Pencahayaan dari Dinding (Side lighting)

Total flux Method The building (or a room in the building) is considered as a closed box, with an aperture (a window) that will admit a light flux. The illuminance on the plane of the window (Ew) must be known. If this is multiplied by the window area (A), the total flux entering the room is obtained. ɸt = Ew x A (lm) this will however be reduced by three factor (D.2.2.): 1. M, the maintenance factor, which allows for dirt or other deterioration of the glazing in use 2. G, or glass factor, allowing for the type of glazing, other than clear glass 3. B, ‘bars’ or framing factor, allowing for obstruction due to solid elements of the frame and sashes, that would reduce the effective area Thus, the effective flux entering will be ɸe = ɸt x M x G x B (lm)

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if this flux were to be uniformly distributed over the floor area, the illuminance would be Eav = ɸe /A (where A is the floor area) Which is not the case, but it can be taken as the average illuminance. The actual illuminance at any particular point in the room (on the work plane) will depend on the utilization factor (UF) at that point. This is determined by 1. Geometrical proportion of the room, expressed by the room index: RI 𝑅𝑅𝑅𝑅 =

𝐿𝐿 𝑥𝑥 𝑊𝑊 ℎ𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠/2 = (𝐿𝐿 + 𝑊𝑊) 𝑥𝑥 𝐻𝐻 𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 /2

Where L,W, and H are length, width, and height of the room 2. Reflectance of ceiling and wall surfaces 3. Type of fenestration 4. Position of the point relative to the window (s) Daylight Factor

It has been observed that although overcast sky illuminance may vary between quite wide limits, the ratio between illuminance at a point indoors to that outdoors remains constant. This ratio is the DF expressed as a percentage. 𝐸𝐸𝐸𝐸 𝑥𝑥 100 (%) 𝐸𝐸𝐸𝐸 Daylight can reach a point of the work plane by three routes, thus three component of DF are distinguished: 1. SC, the sky component: light from a patch of sky visible from the point considered 2. ERC, the externally reflected component: light reflected by outdoor objects, e.g. other buildings 3. IRC, the internally reflected component: any light entering the window, but not reaching the work plane directly, only after reflection(s) by internal surfaces, notably the ceiling 𝐷𝐷𝐷𝐷 =

Thus, DF = SC + ERC + IRC

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SC & ERC

Pada potongan

Pada denah

The sky component will be: the result from protractor 1 x the result from protactor 2

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IRC The IRC can be determined by using the nomogram: 1. Find the ratio of window area to total surface area of the room (ceiling + floor + walls, including the window) and locate this value on scale A 2. Find the average reflectance of room surface, which should be the area-weighted average. First find the ratio of wall area (including the window) to the total surface area (as in 1 above) and locate this value in the first column. The average reflectance is then read in the column headed by the wall reflectance. Locate this on scale B 3. Lay a straight-edge across these two points and it will give the IRC on scale C 4. If there is an obstruction outside the window, determine the altitude angle of its top edge and locate this on scale D 5. A straight-edge laid across this point (D) and the point on C previously determined will give the IRC on scale E

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A correction factor should be applied to this IRC for the deterioration of internal decoration (Dfactor), which depends on location and room usage.

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Nilai Keseragaman Iluminan Contoh Soal: Lokasi A A E B

A

D

C

Nilai E (lux)

Titik A

1456.93

B

2370.54

C

1357.44

D

891.81

E

Tabel 4. Nilai Iluminasi Pada Titik-titik ukur di lokasi A

1300.42

Lokasi A adalah lokasi yang dekat dengan tangga dan sumber cahaya utama. Meja diletakkan di titik A di mana nilai iluminasinya adalah sebesar 1456.93 lux. Nilai ini sudah berada di atas nilai standart, yaitu 200 lux. Untuk titik-titik di sekitarnya yaitu titik B,C,D, dan E, semuanya juga memiliki nilai di atas standart. Sehingga bisa dikatakan lokasi A memiliki nilai iluminasi yang baik. Keseragaman

Titik

E min

E max

A-B

1456.93

2370.54

0.614598362

891.81

1456.93

0.612115888

A-C A-D A-E

1357.44 1300.42

E min E av

=

1456.93 1456.93

1456.93

1007.31 =

Iluminan

0.931712574

Tabel 5. Nilai keseragaman iluminan pada lokasi A

0.892575484

1.446357

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Persyaratan nilai keseragaman iluminan adalah Emin/Emax > 0,7. Dari tabel 5 bisa dilihat bahwa 50% dari titik-titik tersebut memiliki nilai di atas 0,7, dan 50% yang lain di bawah 0,7. Untuk nilai Emin/Eav memiliki persyaratan >0,8. Nilai Emin/Eav di titik A memenuhi persyaratan ini. Dari kedua nilai ini bisa dilihat bahwa nilai keseragaman iluminan di lokasi A adalah baik. ASSIGNMENT 1. Jelaskan apa perbedaan daylight & sunlight! Yang harus dimasukkan ke dalam bangunan adalah sunlight atau daylight? Jelaskan! 2. Sebuah jendela memiliki ukuran 1 x 2 m. Desainlah sebuah shading device yang mampu memotong sinar matahari tidak nyaman sepanjang tahun! Adapun posisi jendela adalah sebagai berikut: a. barat b. timur c. utara d. selatan 3. Hitunglah nilai keseragaman iluminan dari ruang kelas Anda sekarang! Apakah ada kemungkinan terjadi silau pada ruang kelas tersebut?

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5. ARTIFICIAL LIGHTING Luminaire Lampu Sebuah luminair lampu meliputi rumah lampu dan alat listrik lain yang mendukungnya. Perlengkapan lampu permanen (fixtures) adalah luminair yang terpasang pada bangunan secara tetap. Luminair lampu dikelompokkan oleh cara pendistribusian cahaya lampunya, yaitu: • Luminair langsung memancarkan cahaya ke arah bawah. Jenis ini meliputi sebagian besar jenis luminair tersembunyi, termasuk downlight dan troffer • Luminair tidak langsung memancarkan cahaya ke atas, memantulkan cahaya dari langit-langit ke ruangan. Jenis ini meliputi banyak perlengkapan lampu gantung, sconce, dan beberapa model lampu portable • Luminair pancar memancarkan cahaya ke segala arah dengan intensitas cahaya yang sama. Jenis ini meliputi sebagian besar dari jenis lampu terbuka, lampu bulat, chandelier, dan beberapa model lampu meja dan lampu berdiri • Luminair langsung/tidak langsung memancarkan cahaya ke arah atas dan ke bawah tetapi tidak ke samping. Jenis ini meliputi banyak jenis perlengkapan lampu gantung dan beberapa model lampu meja dan lampu berdiri. Perhatikan bahwa luminair • Luminair asimetris biasanya didesain untuk aplikasi khusus. Pencahayaan asimetris arah atas adalah perlengkapan lampu yang mendistribusikan cahaya tidak langsung lebih kuat ke satu arah, misalnya menjauh dari dinding. Wallwasher adalah bentuk dari perlengkapan lampu dengan distribusi pencahayaan yang lebih kuat ke satu sisi untuk menerangi dinding • Perlengkapan lampu yang dapat disetel adalah perlengkapan lampu dengan pencahayaan langsung yang dapat diubah-ubah arah cahayanya. Perlengkapan ini meliputi lampu track, lampu banjir, dan lampu sorot. Pertimbangan memilih jenis luminair dasar: • Luminair langsung cenderung lebih efisien karena mendistribusikan cahaya secara langsung ke area kerja. Pada umumnya dapat menciptakan langitlangit yang gelap dan dinding yang lebih tinggi secara dramatis tetapi juga tidak nyaman karena terlalu kontras. Pencahayaan langsung biasanya digunakan pada lobi bangunan, kantor eksekutif, restoran, dan ruang-ruang lain di mana perancang ingin memberikan kesan yang dramatis. Ruangruang dramatis bisa melelahkan, sehingga, pencahayaan langsung biasanya tidak dianjurkan untuk digunakan pada ruang kerja. • Luminair tidak langsung cenderung menciptakan ruang yang nyaman, bercahaya lembut, dan tidak terlalu kontras yang secara psikologis memberi kesan luas. Pencahayaan tidak langsung biasanya lebih sering digunakan

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untuk ruang-ruang di mana orang menghabiskan banyak waktu untuk bekerja. Luminair menyebar cenderung menciptakan pencahayaan umum yang luas dan seringkali dianggap silau karena kurang tertutup. Kebanyakan chandelier dan sconce adalah luminair yang mendistribusikan cahaya secara menyebar, dan umumnya dipilih sebagai ornamen atau aplikasi hiasan Luminair langsung atau tidak langsung seringkali adalah perpaduan yang baik antara keefisienan dari pencahayaan langsung dan kenyamanan dari pencahayaan tidak langsung. Luminair asimetris dipilih untuk pencahayaan khusus dari sebuah benda atau bidang

GAYA LUMINAIR Downlight Downlight sering disebut tabung atau top hat. Termasuk jenis luminair langsung, biasanya berbentuk bulat dan tersembunyi di plafon. Prinsip pemakaiannya adalah untuk pencahayaan umum. Downlight dapat dipasangi lampu pijar, lampu halogen, lampu pijar bertegangan rendah, lampu fluorescent ringkas, atau lampu HID. Downlight terdiri dari 2 bagian: • Tabung yang berada di plafon • Trim yang dipasang di bawah plafon Jenis-jenis tabung: • Luminair yang terlindungi secara termal/thermally protected biasa digunakan pada sebagian besar aplikasi pencahayaan pada area komersil yang memiliki plafon gantung tanpa adanya sekat di sekitar area yang akan diterangi • Aplikasi plafon bersekat/insulated ceiling (IC) dipakai bila luminair dirancang menempel dengan sekat tabung IC secara khusus digunakan di perumahan, terutama plafon dengan loteng di atasnya • Luminair untuk tempat yang lembab dapat dipasang pada tempat-tempat yang lembab namun tidak terkena siraman air atau hujan • Perlengkapan lampu permanen untuk tempat basah dapat dipasang pada tempat yang langsung terkena siraman atau hujan • Perlengkapan lampu darurat dilengkapi dengan daya listrik cadangan sehingga dapat menghasilkan cahaya paling sedikit 90 menit selama daya listrik padam

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Troffer Troffer banyak digunakan di perkantoran, toko, sekolah, fasilitas institusional, dan komersial lainnya untuk penerangan umum pada area kerja dan penjualan. • Troffer berlensa menggunakan lensa plastik untuk memantulkan cahaya dan mendistribusikannya ke daerah yang diinginkan. Lensa berfungsi untuk menghilangkan dan meminimalkan pendaran cahaya yang menyilaukan. Lensa troffer dapat dilengkapi dengan lapisan pemantul internal berkualitas tinggi untuk memperoleh efisiensi energi yang tinggi • Troffer parabola menggunakan kisi-kisi plastik atau aluminium berbentuk parabola untuk melindungi lampu agar memberikan pandangan yang nyaman • Troffer tersembunyi dan tidak langsung adalah luminair terbuka, dan cahaya dari lampu flourescent dipantul oleh bagian dalam kotak troffer Kebanyakan troffer tersembunyi dan didesain untuk dipasang dalam panel plafon akustik, di mana perlengkapan lampu permanen ini memiliki ukuran yang sama dengan panel plafon.

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PERLENGKAPAN LAMPU PERMANEN ARSITEKTURAL Wallwasher Wallwashing adalah pencahayaan yang menerangi dinding secara merata. Wallwashing cenderung untuk disembunyikan di dalam dinding. Wallwasher tersedia dalam beberapa jenis: • Eyelid wallwasher, merupakan downlight dengan pelindung berbentuk seperti kelopak mata yang mengarahkan cahaya ke satu sisi dari sebuah ruangan • Wallwasher tersembunyi hampir sama dengan downlight namun menggunakan lensa bersudut untuk mengarahkan cahaya ke satu sisi dinding

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Wallwasher berlensa di permukaan dan semi tersembunyi serta wallwasher terbuka mengarahkan cahaya ke dinding di dekatnya dan biasanya bekerja paling baik Downlight wallwasher didesain lebih untuk pencahayaan ruangan daripada untuk menerangi dinding, dan tidak cukup baik untuk tujuan pencahayaan pameran

Wall Grazing Fixture Wall grazing fixture, kadang disebut wall slot, digunakan untuk menerangi dinding pada lobi, koridor, dan area penting. Sangat baik untuk menerangi permukaan yang bertekstur dan permukaan yang berlapis.

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Perlengkapan lampu sorot permanen Perlengkapan lampu sorot permanen memungkinkan cahaya untuk fokus pada permukaan bangunan dan benda seni • Lampu sorot tersembunyi tampil sebagai downlight namun secara internal memungkinkan rotasi dan elevasi dari cahaya yang dipancarkannya • Lampu sorot berbentuk bola mata dan dapat ditarik ke bawah seperti downlight, namun penampilannya dapat diubah-ubah • Sistem pencahayaan lampu track didesain untuk menyorot pameran benda seni dan produk retail

Lampu cove Cove memungkinkan pencahayaan ke arah atas dari ceruk dinding atau elemen arsitektur lainnya secara lebih efisien daripada lampu yang berbentuk memanjang, dan dapat memberikan pencahayaan tanpa adanya bayangan rumah lampu.

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Lampu kerja Perlengkapan lampu secara khusus didesain untuk menerangi area meja kerja sedangkan cahaya pantul diminimalkan.

Pencahayaan Dekoratif • Chandelier adalah perlengkapan lampu hias yang biasanya terdiri dari banyak lampu pijar kecil yang menyerupai efek cahaya dari nyala lilin. Chandelier digantung dan biasa digunakan untuk penerangan di ruang makan, foyer, dan ruang formal lainya • Lampu gantung juga merupakan lampu permanen dekoratif yang digantung di plafon. Kebanyakan perlengkapan lampu gantung menggunakan lampu pijar, walaupun variasi perlengkapan lampu gantung juga tersedia dengan menggunakan lampu HID dan lampu fluorescent • Luminair lampu gantung pendek serupa dengan lampu gantung biasa tetapi terpasang lebih dekat ke plafon yang memungkinkan penggunaan pada kebanyakan ruang dengan ketinggian plafon konvensional • Sconce adalah luminair hias atau dekoratif yang dipasang pada dinding. Seringkali, sconce dipasangkan dengan chandelier, di waktu lain sconce menjadi satu-satunya elemen pencahayaan dekoratif. • Torchier adalah lampu berdiri didesain secara khusus untuk memancarkan cahaya ke arah atas. Kebanyakan trochier menggunakan lampu pijar atau lampu halogen • Lentera adalah luminair ruang luar yang dipasang pada plafon, dinding, papan, atau tiang

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LAMPU STANDAR UNTUK TEMPAT INDUSTRI Troffer dengan pola 12 lensa akrilik

Troffer dengan kotak besar kisi parabola

Luminair fluorescent tertutup

Luminair fluorescent panjang

Luminair lampu fluorescent industri

Luminair lampu HID downlight industri

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Luminair fluorescent downlight industri ringkas

Luminair fluorescent gantung cahaya tidak langsung

Luminair fluorescent gantung cahaya langsung-tidak langsung

Troffer tertutup cahaya tidak langsung

Downlight bidang dan tersembunyi

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Luminair downlight yang dapat disetel

Sconce dinding

Lampu gantung (pendant)

Lampu plafon bentuk drum

Lampu meja dan lampu berdiri

Lampu yang dipasang dalam lemari

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Lampu rias (vanity)

Lampu tanda pintu keluar

Gambar Rencana Pencahayaan

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DESAIN LAYER PENCAHAYAAN

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Layer Pencahayaan Ambient

Pencahayaan ambient tidak menerangi area kerja yang spesifik.

Layer Pencahayaan pada Area Kerja

Di antara banyak kegiatan visual dalam sebuah ruang, banyak kegiatan di atas meja kerja, biasanya diberikan pencahayaan pada area kerja di lokasi di mana pekerjaan dilakukan

Layer lampu Sorot

Merupakan pencahayaan estetika yang biasanya hanya digunakan pada proyek yang membutuhkan gaya dan penampilan. Tujuannya untuk menerangi fitur dan benda pameran seperti benda seni

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The Lumen Method The lumen method (or total flux method) of general lighting design is applicable where a regular array of luminaires produces a uniform lighting over the work plane. The total lumen output of lamps is calculated for a given system, which is referred to as the installed flux (ɸi) and the flux received on the work plane will be: ɸr = ɸi x UF x MF then the illuminance is 𝐸𝐸 =

ɸr 𝐴𝐴

where MF is the maintenance factor, to allow for the deterioration of the lamp, luminaire and room surface. In the absence of more accurate data, this is taken as 0,8. UF is utilisation factor and the method hinges on finding the appropriate UF value. The magnitude of UF depends on the following factors: 1. Properties of the luminaire: an enclose luminaire or one with less than perfect internal reflectance will have a value much lower than an exposed lamp 2. The downward light output ratio (DLOR) of the luminaire. Light emitted upwards will reach the work plane only after reflection(s) from room surfaces and some of it is absorbed in these surfaces. A larger DLOR normally means a higher UF 3. Reflectance of room surfaces, which is more important if the DLOR is smaller, influence the lighting even with high DLOR values 4. Geometrical proportions of the room, as expressed by the room index, the ratio of horizontal areas: L x W x 2 and vertical areas (L+W) x 2 x Hm, where Hm is the mounting height, from the work plane to the luminaire (the multiplier 2 cancels out) 𝑅𝑅𝑅𝑅 =

𝐿𝐿 𝑥𝑥 𝑊𝑊 (𝐿𝐿 + 𝑊𝑊)𝑥𝑥 𝐻𝐻𝐻𝐻

5. Direct ratio: How much of the downward emitted light reaches the work plane directly. This has a low value with a narrow and high room (small room index), but a high value for a wide room (large RI) and downlighter type luminaires

If an installation is to be designed, the above equations are inverted: • If an illuminance E is required, this is multiplied by the work plane area to get the flux to be received, ɸr

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The type of luminaire is selected and the UF is found The MF is taken as 0,8 (higher in very clean spaces, lower in dusty or dirty situations, or in the absence of regular cleaning) Thus the flux to be installed will be ɸ𝑟𝑟 ɸ𝑖𝑖 = 𝑈𝑈𝑈𝑈 𝑥𝑥 𝑀𝑀𝑀𝑀 Combining this steps, we have a single expression: ɸ𝑖𝑖 =

𝐸𝐸 𝑥𝑥 𝐴𝐴 𝑈𝑈𝑈𝑈 𝑥𝑥 𝑀𝑀𝑀𝑀

Then we have to work back, divide the ɸi by the output of one lamp to get the number of lamps required, decide wether single or double lamp luminaire would be used, devise a luminaire layout (a ceiling plan) and check the spacing limits.

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Example A general office space is 12 m x 9 m and 2,7 m high. The illuminance required is 400 lux. Reflectance are: ceiling 0,7, walls 0,5. If the work plane is at 0,8 m and ceilingmounted luminaires are to be used, then Hm = 2,7-0,8 = 1,9 m. Therefore, the room index will be: 12 𝑥𝑥 9 = 2,7 𝑅𝑅𝑅𝑅 = (12 + 9) 𝑥𝑥 1,9

We select an enclosed plastic diffuser type luminaire, which has a DLOR of 0,5. We locate the coloumn headed ρ ceiling 0,7 and within this the subheading for ρ walls 0,5. There are lines for RI 2,5 and 3, so we make a note of both UF values of 0,55 and 0,58 and interpolate: 0,58 − 0,55 𝑥𝑥 0,2 = 0,012 3 − 2,5 Which is to be added to the lower value. Thus, UF = 0,56 The flux to be installed is: ɸ𝑖𝑖 =

400 𝑥𝑥 12 𝑥𝑥 9 = 96429 𝑙𝑙𝑙𝑙 0,56 𝑥𝑥 0,8

For uniformity, the spacing limit is 1,5 x 1,9 = 2,85 m

1200 mm fluorescent lamps are available from 1120 to 2800 lm output and select a medium quality for good colour rendering: the Kolor-rite lamp with a flux output of 1800 lm. Of these, we may need 96429/1800 = 54 lamps. We can have twin-tube luminaires, so we need 27 of these. We may have 7 rows of 4 luminaires, so the spacing may be 1,7 m in the 12 m length (0,9 m from the walls) and in the 9m width, the spacing would become 2,25 m (giving just over 1 m between ends of luminaires). Both are well within the 2,85 m limit. ASSIGNMENT 1. Berikan analisa layer pencahayaan pada gambar interior berikut ini!

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2. Desainlah sebuah pencahayaan dari ruang-ruang berikut ini! Berikan gambar kerja dan gambar arsitekturalnya! a. Gedung konser b. Galeri/museum c. Lobi hotel 3. Berapa jumlah lampu yang dibutuhkan pada sebuah ruang studio gambar berukuran 10 x 10 m dengan ketinggian plafon 4 m?

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6. ROOM ACOUSTIC ISTILAH-ISTILAH BUNYI Bunyi terjadi karena adanya benda yang bergetar yang menimbulkan gesekan dengan zat di sekitarnya. Gelombang bunyi dapat diukur dalam satuan panjang gelombang, frekuensi, dan kecepatan rambat. Panjang gelombang dinotasikan sebagai lambda (λ) adalah jarak antara 2 titik pada posisi yang sama yang saling berurutan. Panjang gelombang diukur dalam satuan meter dan merupakan elemen yang menunjukkan kekuatan bunyi. Semakin panjang gelombangnya semakin kuat pula bunyi tersebut. Frekuensi adalah jumlah atau banyaknya getaran yang terjadi dalam setiap detik. Frekuensi dihitung dalam satuan Hertz (Hz). Jumlah getaran yang terjadi setiap detik tersebut sangat tergantung pada setiap jenis obyek yang bergetar. Setiap benda akan memiliki frekuensi tersendiri yang berbeda dengan jenis benda lain. Frekuensi yang dapat didengar manusia adalah 20 Hz – 20.000 Hz. Bunyi di bawah 20 Hz disebut infrasonik, bunyi di atas 20.000 Hz disebut ultrasonik. Kecepatan rambat (v) bunyi adalah jarak yang mampu ditempuh oleh gelombang bunyi pada arah tertentuu dalam waktu satu detik, satuannya adalah m/dt. Banyaknya getaran tiap detik menunjukkan total panjang yang berpindah dalam satu detik. V=fxλ v = kecepatan rambat (m/dt) f = frekuensi (Hz) λ = panjang gelombang (m) kecepatan rambat bunyi di udara = 340 m/dt amplitudo menunjukkan keras dan lemahnya bunyi. Resonansi adalah peristiwa ikut bergetarnya obyek yang berada pada jarak tertentu dari sebuah obyek sumber bunyi yang bergetar, karena obyek yang bergetar tersebut memiliki kesamaan atau kemiripan frekuensi dengan obyek sumber bunyi yang bergetar. Kekuatan bunyi dapat diukur melalui tingkat bunyi (sound levels). Pengukuran kekuatan bunyi adalah dengan satuan decibell (dB). Tingkat kekuatan atau kekerasan bunyi diukur dengan alat yang disebut Sound Level Meter (SLM).

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Ketika sebuah obyek sumber bunyi bergetar dan tidak ada obyek lain yang menghalanginya, gelombang bunyi tersebut akan merambat ke segala arah, menempuh jarak tertentu, melemah, dan kemudian menghilang. AKUSTIKA DALAM RUANGAN Gelombang bunyi memiliki sifat yang hampir sama dengan cahaya, yaitu memantul dengan posisi sudut datang sama dengan sudut pantul bila mengenai obyek yang licin dan sempurna dan memiliki luasan yang melebihi dimensi gelombang bunyi yang datang, memantul ke arah tidak beraturan bila mengenai obyek dengan permukaan tidak teratur, serta terserap dan diteruskan atau ditransmisikan saat mengenai obyek yang terbuat dari material tertentu. Ketika mengenai obyek yang memiliki retak atau celah, gelombang cahaya maupun bunyi akan berusaha menerobosnya. Pada bunyi, keberadaan celah, lubang, atau retak kecil pada obyek penghalang justru dapat menyebabkan terjadinya duplikasi sumber. Refleksi Refleksi atau pemantulan bunyi oleh suatu obyek penghalang atau bidang batas disebabkan oleh karakteristik penghalang yang memungkinkan terjadinya pemantulan. Pemantulan yang umumnya terjadi dapat digambarkan sebagai: • Near field, yaitu area yang terjadi di dekat sumber bunyi, yang jaraknya diukur sekitar satu panjang gelombang dari frekuensi tersebut.

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Reverberant field, yaitu area yang terjadi di dekat bidang batas, berseberangan dengan sumber bunyi. Free field, yaitu area yang berada di antara near dan reverberant field.

Absorpsi Sesuai dengan karakteristik materialnya, sebuah bidang batas selain dapat memantulkan kembali gelombang bunyi yang datang, juga dapat menyerap bunyi. Tingkat penyerapan suatu material ditentukan oleh koefisien absorpsi. Koefisien absorpsi adalah angka yang menunjukkan jumlah/proporsi dari keseluruhan energi bunyi yang datang yang mampu diserap oleh material tersebut. Nilai maksimum α

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adalah 1 untuk permukaan yang menyerap sempurna, dan 0 untuk permukaan yang memantulkan sempurna. Jenis absorber yang sering dijumpai: 1. Material berpori (soft board, selimut akustik, acoustic tiles) 2. Panel penyerap 3. Rongga penyerap

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Reverberation Bila sumber bunyi dihentikan secara tiba-tiba, bunyi tidak serta merta ikut berhenti. Terjadi perpanjangan bunyi yang disebut reverberation (dengung). Pengukuran tingkat reverberation dalam sebuah ruang menggunakan waktu dengung (reverberation time). Waktu dengung adalah waktu yang dibutuhkan oleh suatu sumber bunyi yang dihentikan seketika untuk turun intensitasnya sebanyak 60 dB dari intensitas awal. Waktu dengung sebuah ruangan bergantung pada: volume ruangan, luas permukaan bidang pembentuk ruangan, tingkat penyerapan permukaan bidang, dan frekuensi bunyi yang muncul dalam ruangan. Melalui waktu dengung, kualitas akustik sebuah ruangan dapat ditentukan.

𝑅𝑅𝑅𝑅 =

0,16 𝑉𝑉 𝐴𝐴 + 𝑥𝑥𝑥𝑥

A = (S1 x α1) + (S2 x α2) + ...

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A : Penyerapan ruang total V : Volume X ; koefisien penyerapan udara = 0,3 S: luas material

α: koefisien penyerapan material

Difraksi Difraksi adalah peristiwa menerusnya atau membeloknya perambatan gelombang bunyi akibat ketidakmampuan penghalang berdimensi kecil untuk menahannya. Refraksi Refraksi adalah membeloknya gelombang bunyi karena melewati atau memasuki medium perambatan yang memiliki kerapatan molekul yang berbeda. Difusi Difusi adalah gejala terjadinya pemantulan yang menyebar, karena gelombang bunyi menerpa permukaan yang tidak merata. Transmisi bunyi Pada kondisi tertentu, kemungkinan besar elemen bidang batas ruangan mampu meneruskan atau mentransmisikan bunyi yang muncul dari sebuah ruangan ke ruangan lain di sebelahnya.

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CACAT AKUSTIK Gema (echo) Bila bunyi dipantulkan oleh suatu permukaan batas dalam jumlah yang cukup dan tertunda cukup lama untuk dapat diterima sebagai bunyi yang berbeda dari bunyi yang merambat langsung dari sumber ke pendengar. Gema terjadi jika selang minimum sebesar 1/25 sekon untuk pembicaraan terjadi antara penerimaan bunyi langsung dan bunyi pantul yang berasal dari sumber yang sama. Selang waktu kritis yang ditetapkan di atas sesuai dengan beda jejak minimum antara bunyi langsung dan bunyi pantul sebesar 14 meter untuk pidato. Sebuah dinding belakang yang berhadapan dengan sumber bunyi dan memantulkan bunyi, merupakan penyebab gema yang potensial, kecuali bila dinding tersebut diatur secara akustik. Long Delayed reflection Pemantulan yang berkepanjangan (Long Delayed Reflection). Ini adalah cacat yang sejenis dengan gema, tetapi penundaan waktu antara penerimaan bunyi langsung dan bunyi pantul agak lebih singkat Gaung Gaung terdiri dari gema-gema kecil yang berturutan dengan cepat dan dapat dicatat serta diamati bila ledakan bunyi singkat dilakukan di antara permukaanpermukaan pemantul bunyi yang sejajar, walaupun kedua pasangan dinding lain yang berhadapan tidak sejajar, menyerap, atau merupakan permukaanpermukaan difus. Gaung juga dapat terjadi antara permukaan-permukaan pemantul bunyi yang tidak sejajar, bila sumber bunyi diletakkan di antara permukaan-permukaan ini. Pemusatan Bunyi kadang disebut sebagai ‘hotspot’, disebabkan oleh pemantulan bunyi pada permukaan-permukaan cekung. Intensitas bunyi di titik panas sangat tinggi dan selalu terjadi dengan kerugian pada daerah lain, atau ‘dead spots’, di mana kondisi mendengar adalah buruk. Adanya hotspot dan deadspot menyebabkan adanya distribusi energi bunyi yang tak merata dalam ruang. Couple Space Bila suatu auditorium dihubungkan dengan ruang di sampingnya yang dengung lewat sarana pintu keluar masuk yang terbuka, maka kedua ruang itu membentuk ruang gandeng. Selama rongga udara itu saling berhubungan, maka masuknya bunyi dengung dari ruang tetangga ke dalam auditorium akan terasa.

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Distorsi Distorsi adalah perubahan kualitas bunyi yang tidak dikehendaki, dan terjadi karena ketidakseimbangan atau penyerapan bunyi yang sangat banyak oleh permukaanpermukaan batas pada frekuensi yang berbeda-beda. Resonansi Ruang Resonansi ruang, atau disebut dengan kolorasi terjadi bila bunyi tertentu dalam pita frekuensi yang sempit mempunyai kecenderungan berbunyi lebih keras dibandingkan dengan frekuensi lain. Bayangan Bunyi Gejalanya dapat diamati di bawah balkon yang menonjol terlalu jauh ke dalam ruang udara suatu auditorium. Whispering Gallery Frekuensi bunyi yang tinggi mempunyai kecenderungan untuk merangkak sepanjang permukaan-permukaan cekung yang besar, seperti kubah setengah bola

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AKUSTIK PADA BANGUNAN Auditorium Berdasarkan jenis aktivitas, auditorium dibedakan jenisnya menjadi 3: • Auditorium untuk pertemuan (speech) • Auditorium untuk pertunjukan seni (music) • Auditorium multiifungsi (speech & music) Persyaratan akustik: 1. Harus ada kekerasan yang cukup dalam tiap bagian ruang 2. Energi bunyi harus didistribusi secara merata dalam ruang 3. Ruang harus bebas dari cacat akustik 4. Bising dan getaran harus dihindari 5. Jejak gelombang bunyi langsung harus sependek mungkin, agar mengurangi hilangnya energi bunyi di udara 6. Bunyi pembicaraan yang tak diperkuat, yang merambat secara langsung dari sumber ke pendengar hampir tak dapat dimengerti di atas jarak 9-12 m 7. Tempat duduk harus diatur sedemikian rupa hingga berada dalam sudut sekitar 140 derajat dari posisi pembicara 8. RT harus sedekat mungkin dengan kondisi ideal di seluruh jangkauan frekuensi 9. Pengendalian bising

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7. NOISE Background noise (bising latar belakang) adalah bunyi di sekitar kita yang muncul secara tetap dan stabil pada tingkat tertentu. Bising latar belakang yang nyaman berada pada tingkat kekerasan tidak lebih dari 40 dB. Noise adalah bunyi yang muncul secara tidak tetap atau seketika dengan tingkat kekerasan melebihi noise latar belakang pada daerah tersebut. Ambient noise adalah tingkat kebisingan di sekitar kita, yang merupakan gabungan antara noise latar belakang dan noise.

Kebisingan masuk ke bangunan dipengaruhi 3 faktor: 1. Sumber kebisingan, yang meliputi: jarak sumber kebisingan dari bangunan, tingkat kebisingan sumber, frekuensi, durasi munculnya kebisingan, dan waktu munculnya kebisingan 2. Medium yang dilalui kebisingan, yang meliputi: kondisi udara, jarak tempuh gelombang bunyi kebisingan, dan ada tidaknya obyek dalam medium 3. Bangunan sebagai penerima, yang meliputi: tingkat kerapatan elemen bangunan secara keseluruhan (berupa dinding, lantai, plafon, dan atap) serta kemungkinan ruang-ruang yang menderita kebisingan serta yang dapat dilindungi dari kebisingan Kebisingan yang diderita oleh bangunan dapat berasal dari: • Luar lahan bangunan, misalnya dari jalan atau dari titik lain di luar lahan seperti lahan atau bangunan sekolah • Dalam lahan tetapi di luar bangunan, misalnya area parkir bangunan • Dalam bangunan sendiri • Dalam ruangan sendiri Jenis perambatan kebisingan dapat dibedakan menurut medium yang dilalui gelombang bunyi, yaitu: 1. Airborne sound, adalah perambatan gelombang bunyi melalui medium udara 2. Structurebone sound, adalah proses perambatan gelombang bunyi melalui benda padat

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Cara yang paling tepat untuk menanggulangi penyebaran kebisingan adalah dengan cara insulasi. Prinsip ini merupakan penggabungan dari refleksi, absorpsi, dan peredaman getaran yang mengikuti kebisingan. obyek yang akan bertugas sebagai insulator harus memenuhi persyaratan sebagai berikut: • Berat • Keutuhan material • Elastisitas • Prinsip isolasi

Ketika sebuah obyek dipasang untuk menjadi insulator, maka untuk mengukur tingkat kemampuannya sebagai insulator, dipakai kriteria yang disebut Sound Reduction Index (SRI). Selain itu, kemampuan insulasi suatu material juga diukur dalam sistem Sound Transmission Class (STC). STC suatu material adalah kemampuan material dalam meredam bunyi (sound proof) ketika digunakan sebagai konstruksi. Selain itu, material juga memiliki nilai Transmission Loss (TL) yang diukur dalam satuan dB, yaitu kemampuan material/konstruksi untuk mengurangi terjadinya transmisi atau merambatnya gelombang bunyi ke balik material/konstruksi karena diserap oleh material/konstruksi tersebut.

NR = TL + 10 log

A S

NR = noise reduction (dB) TL = transmission loss A = total penyerapan ruang S = luas bidang batas kedua ruangan

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ASSIGNMENT 1. Hitunglah nilai reverberation time (RT) pada ruang kelas Anda saat ini! Apakah nilainya sudah sesuai dengan standar RT yang diperlukan? Kalau tidak sesuai, apa yang harus dilakukan? Menambah/mengurangi bidang pantul/serap? 2. Hitunglah nilai noise reduction (NR) pada ruang kelas Anda saat ini, dari bidang dinding yang berbatasan dengan jalan raya, dan bidang dinding yang berbatasan dengan koridor! Apabila bunyi dari jalan raya adalah 80 dB, dan bunyi dari koridor adalah 40 dB, berapakah bunyi bising yang terdengar dari dalam ruang kelas?

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