LIGHTING IN THE HOME HOME SCIENCE FACILITATOR JASMINAS

Importance of Light/ Purpose of light Light is required; - For visibility - Light enhances the beauty of design and materials in a house. - Light is required for health. Sunlight produces vitamin-D in the body. Proper light is good for eyesight. - Light is needed for different activities like writing, reading, cooking etc. HOME SCIENCE FACILITATOR JASMINAS

The light is a kind of energy through which the things become visible. Good day light and artificial lighting can enhance the beauty of design and materials in a house, and create a good living environment. During the day, the sun is the natural and the most important source of light. There are many other different source of artificial lights like candle, diya, lantern,electricity- tube lights etc. Let us study the different sources of light in detail: HOME SCIENCE FACILITATOR JASMINAS

(i) Natural Source of light The main sources of light is SUN. Clouds interfere with the passage of light. Following factors affect the intensity of light in the room: - The admittance of light in the room. - Use of proper surface reflections within a room, and - Control of glare HOME SCIENCE FACILITATOR JASMINAS

(ii) Artificial Light: It includes the DIYA (earthen lamps), lamps, tube light etc. The most common sources of light at present used in our homes are incandescent bulbs and fluorescent tubes. The efficiency of each source or the size or voltage of the lamps required to produce the given amount of light, is common to both. HOME SCIENCE FACILITATOR JASMINAS

Lighting Measurement Terminology Unit of luminous intensity of a light source in a specific direction. Also called candle. Wattage : The amount of electricity consumed by a light source/power used Lumens: The amount of light that a light source produces/Unit of light flow/emitted Efficacy: Lumens per watt. Power or capacity to produce a desired effect. Foot candles: The amount of light reaching a subject. Lux-Unit of illumination equal to one lumen per square metre. HOME SCIENCE FACILITATOR JASMINAS

It denotes the ratio of the amount of power used to the amount of light emitted from the source. The unit of measurement of power is Watt. Our light bill is made on the basis of how many watts of power we use. The Lumen is the measurement of the amount of the light emitted by the bulb or tube. A bulb of high power consumption (watts), yields more lumens of light and provides better illumination of objects.. HOME SCIENCE FACILITATOR JASMINAS

A plain household candle gives off about 12 lumens. A std 100 watt bulb =1630 lumens About 70 lumens per square foot of floor space is considered average for entire home. Kitchen, Bath and living room needs more light than the bed rooms and passages. HOME SCIENCE FACILITATOR JASMINAS

The power of bulb or tube suitable for a room can be calculated by the formula given below: no.of lumen required for good lighting= Area of room in sq.foot __________________ Lumens required per sq.foot HOME SCIENCE FACILITATOR JASMINAS

The approximate wattage (power) of bulb can be estimated on the basis that a 100 watt bulb emits about 1600 lumens of light. RECOMMEND LUMENS FOR DIFFERENT AREAS IN A HOME LumensPer sq. feet 1.Livingroom80 2.Kitchen80 3.Bedroom70 4.Diningroom45 5.Bathroom65 6.Passages35 HOME SCIENCE FACILITATOR JASMINAS

Sources of Artificial Light: 1) Incandescent Bulb: It is used in table lamps, floor lamps, wall brackets and hanging fixtures. The bulb produces more heat and less light in proportion to the power used. The ordinary bulb lasts from 750 to 1,000 hours. That is why more people are now using fluorescent tubes. HOME SCIENCE FACILITATOR JASMINAS

The ordinary filament tungsten filament bulb which glow inside the bulb is available in 4 varieties: a) Cleanb) Pearl c) Silicad) Colored a) Clean Bulb: It gives out bright light. It creates shadows and glare. b) Pearl Bulb: This is milky that is why its illumination is soft. Mostly this type of bulb is used in our homes. c) Silica coated bulb gives soft light. d) Colored lamps are used for decoration. HOME SCIENCE FACILITATOR JASMINAS

2) Fluorescent tubes: These are long cylindrical tubes which emit 3-4 times as much light as tungsten bulb of equal watt. It has a fine filament called electrode. It is used mainly in homes as a source of indirect lighting for general illumination. The life of a fluorescent tube depends, to a considerable degree, on the number of times the power is turned on and off. This also emit relatively high lumens, and light distribution is better and uniform along the length of the tube. HOME SCIENCE FACILITATOR JASMINAS

3) Ecotone: This new addition in the market has ultra long life of 10,000 hours. It lasts 10 times longer than standard incandescent bulb. It saves 80% energy as compared to ordinary incandescent bulb. It is fluorescent lamp. HOME SCIENCE FACILITATOR JASMINAS

Methods/Types of Lighting: To ensure adequate light of good quality in all rooms. It is generally recommended that careful attention be given to the proper distribution of light. The distribution depends on the type of lighting fixtures used. Methods of lighting is divided into : 1) Direct lighting 2) Indirect lighting 3) Semi-direct lighting 4) Semi-indirect lighting HOME SCIENCE FACILITATOR JASMINAS

Types of Light HOME SCIENCE FACILITATOR JASMINAS

1) Direct Lighting: If the light falls directly over an object, it is said to lighted by direct light. The source of light emits the highest percentage of light downward, thus providing the highest foot candles per watt over beneath the source but creates harshness of shadow, and causes discomfort, eye fatigue, and frequently interferes with clear vision because of glare. The glare is caused because of: - Brightness of sources. - The total volume of light. - Location of the field of view. - Contrast with background. - Time exposure. To reduce the glare, frosted or opalescent glasses are used, which in fact diffuse which is softened and also shadow less. HOME SCIENCE FACILITATOR JASMINAS

2) Indirect Lighting: The light shines not on the object being viewed, but on other surfaces which in turn reflect light and makes the object visible. In this method almost all the beams of light are directed from source to the wall of ceiling and from reflected light is now diffused and it is soft, uniform and shadow less. Used only in those rooms where no reading or precise work will be done. For critical work use the portable lights which emit some light to the ceiling and provide diffused light directly upon the object or work piece. The shades of such lamps should not be completely opaque of highly translucent. Moreover, the light source should be located well above the eye level. HOME SCIENCE FACILITATOR JASMINAS

Difference : Direct & Indirect light Direct: provides a strong illumination toward a specific task or area. creates sharp shadows and highlights. the light source illuminates below the horizon surface of the luminary or fixture. Indirect: provides an illumination to the surrounding areas. helps prevent excessive brightness and contrast. the light source illuminates above the horizon surface of the luminary or fixture HOME SCIENCE FACILITATOR JASMINAS

3) Semi direct Lighting: Usually the diffused lighting system emits light in fairly proportions in all directions and up and down. The fixture providing diffuse lighting is usually of globe variety and made of glass. To prevent glare, the globe should be large and translucent enough to completely conceal the lighting source. 4) Semi indirect Lighting: This type also emits light in maximum percentage upwards to the ceiling for diffusion back downwards. It provides less foot candles per watt in the center of the room but illumination is spread over a larger area than others and has less of soft shadow. Structural or translucent glass is used to deflect and diffuse the light downwards. HOME SCIENCE FACILITATOR JASMINAS

Measurement of Intensity of Light: The measurement of light is measured in terms of its brightness or intensity. It depends upon the lighting equipment as well as upon the walls, ceilings,floors, furniture and every object present in the room. It includes the color, texture, finish, size, form, glare etc. We see objects in diffused light. The diffusion power of surface refers to the percentage of the light it reflects. The white surfaces reflect the highest percentage whereas the black or dark surfaces diffuse the least. HOME SCIENCE FACILITATOR JASMINAS

- All surfaces should have a dull or matte finish as these diffuse light better than a bright or shining finish. - The more light a surface is able to reflect, the more light diffused from it, in proportion to the amount of light it receives. - Getting more light does not always depend upon the power of the source. But the distance between light source and the reflecting surface is another contributing factor. - The intensity of light decreases rapidly as the distance amounts light and also differ in their reflectance. HOME SCIENCE FACILITATOR JASMINAS

- Extreme brightness causes eye fatigue. Care must be taken to conceal the light source by using shade to eliminate the glare to the eyes and enhance diffusion. - About half of the light in a room should come from direct lighting. - Table lamps provide proper intensity of light for any task. To avoid glare, the light source should never be visible directly to eyes, when in use. HOME SCIENCE FACILITATOR JASMINAS

Portable Lamps The term portable lamp refers to all moveable lighting devices as desk lamps, reading lamp, floor lamps and table lamps. Included in the category are also wall lamps and wall brackets. HOME SCIENCE FACILITATOR JASMINAS

Light and Color: Colors change as light changes. Artificial light softens colors. Colors that appear attractive under artificial light, might not be pleasing in the day- light. The matching of fabrics should be avoided inside the shop. The mercury lamps in shops do not have red rays in it. Therefore, in this light red color will not appear red. They will appear blue or purplish. That is why fabric matching should be done in daylight instead of artificial light. HOME SCIENCE FACILITATOR JASMINAS

Fixtures and Fittings: - Fixtures here refers to the holder's, brackets, knobs and accessories. The type of fixtures and fittings should complement the style and look good. - Consider how the fittings will distribute the light. This will depend in part on where you put them and whether you conceal or make a feature of them. Look at the light when its off as well as on-it can appear quite different. - More light will get through transparent shades than opaque ones, which give more localized pools of light. - Switches play important role in aesthetics, ergonomics etc. HOME SCIENCE FACILITATOR JASMINAS

Light and Rooms: - The light fixtures should be functional as well as decorative. In homes, we opt two kinds of lighting general and local. - Kitchens should be particularly well lighted. Wall or ceiling light over the working places, tube-lights fixed under the cabinets and over cooking range. - Bedroom lights should usually be local lights. One tube light may be placed at the top of the dressing table mirror. The lamp for reading in bed, should be adjustable so light falls on the book. Bright light over the front and rear entrance are necessary. If the garden is big some flood lights can be installed there, for proper illumination. HOME SCIENCE FACILITATOR JASMINAS

Fixtures Light fixtures Central heating systems (inc. radiators) Kitchen units Bathroom suites Built in wardrobes Plugs & sockets Fittings Paintings, pictures and mirrors (hung to wall) Curtains and rails Free standing kitchen appliances (i.e fridge) Other free standing furniture (i.e. sofa) TV aerials & satellite dishes HOME SCIENCE FACILITATOR JASMINAS

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