bs ii-electricity-unit-iv-2012-four

AR 4.5 BUILDING SERVICES - II:ELECTRICAL SERVICES:

Unit – IV:

Building Lighting System: Artificial Illumination, various types of lamps, advantages and disadvantages, method of lighting, direct, semi direct, indirect, concealed lighting, spot lighting, task lighting, decorative lighting, rope lights, neon lights, flood lighting, yard lighting, under water lighting.  

ARTIFICIAL ILLUMINATION:What do we understand by Artificial Illumination ?Illumination provided by Electrical Light Fixtures or other means, other than Natural Sun Light.What was the earliest form of electric light which was invented ?

The earliest invention was the electric arc which was

followed by carbon filament lamp which was developed by Thomas Alva Edison in 1879. It had carbonised fibres for filament and was mounted within a glass bulb. Since its filament temperature is low, has poor efficiency and is rarely used now-a-days. On the other hand Arc lamps are widely used even today for film projection, in television studios etc.,

TUNGSTEN LAMP:1) Outline of Glass bulb.

2) Low pressure inert gas (argon, nitrogen, krypton, xenon)

3) Tungsten filament.

4) Contact wire (goes out of stem)

5) Contact wire (goes into stem)

6) Support wires (one end embedded in stem; conduct no current)

7) Stem (glass mount)

8) Contact wire (goes out of stem)

9) Cap (sleeve)

10) Insulation (vitrite)

11) Electrical contact.

TUNGSTEN LAMP:These are the standard bulbs that most people are familiar with. Incandescent bulbs work by using electricity to heat a tungsten filament in the bulb until it glows. The filament is either in a vacuum or in a mixture of argon / nitrogen gas. Most of the energy consumed by the bulb is given off as heat, causing its Lumens per Watt performance to be low. Because of the filament's high temperature, the tungsten tends to evaporate and collect on the sides of the bulb. The inherent imperfections in the filament causes it to become thinner unevenly. When a bulb is turned on, the sudden surge of energy can cause the thin areas to heat up much faster than the rest of the filament, which in turn causes the filament to break and the bulb to burn out.

TUNGSTEN LAMP:Incandescent bulbs produce a steady warm, light that is good for most household applications. A standard incandescent bulb can last for 700-1000 hours, and can be used with a dimmer. Soft white bulbs use a special coating inside the glass bulb to better diffuse the light; but the light color is not changed.

COMPACT FLUORESCENT LAMPS:Compact Fluorescent Lamps

(CFLs) are a modern type of light bulbs, that work like fluorescent bulbs, but in a much smaller package. Similar to regular fluorescent bulbs, they produce little heat and are very efficient. They are available to fit screw type base fittings and pin type (snap-in). Most CFLs either consist of a number of

short glass sticks, or two or three small Tubular loops. Sometimes, they are enclosed in a glass bowl, made to look similar to a regular incandescent bulb.Most CFLs cannot be used with dimmers. They normally last up to 10,000 hours.

COMPACT FLUORESCENT LAMPS:

Approximate Equivalents to Incandescent Bulbs.

CFL. Incandescent.

7–10 Watts. 40 Watts.

15-18 Watts. 60 Watts.

20 Watts. 75 Watts.

20-25 Watts. 100 Watts.

32 Watts. 150 Watts.

HALOGEN LAMPS:Halogen has the advantage of being more efficient (although not by much) and having longer life than the tungsten bulb. They are relatively small in size and are dimmable, high intensity more lumens per watt). The disadvantages are that they are more expensive, and burn at a much higher temperature, which could possibly be a fire hazard in certain areas.

HALOGEN LAMPS:A halogen lamp, also known as a tungsten halogen lamp or quartz iodine lamp, is an incandescent lamp that has a small amount of a halogen  such as iodine or bromine added. The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical reaction which redeposits evaporated tungsten back on the filament, increasing its life and maintaining the clarity of the envelope. Because of this, a halogen lamp can be operated at a higher temperature than a standard gas-filled lamp of similar power and operating life, producing light of a higher luminous efficacy and color temperature. The small size of halogen lamps permits their use in compact optical systems for projectors and illumination.

HIGH-INTENSITY DISCHARGE LAMPS:High Pressure Sodium (HPS), Metal Halide, Mercury Vapor and Self-Ballasted Mercury Lamps are all high intensity discharge lamps (HID). With the exception of self-ballasted lamps, auxiliary equipment such as ballasts and starters must be provided for proper starting and operation of each type bulb. Compared to fluorescent and incandescent lamps, HID lamps produce a large quantity of light from a relatively small bulb.

HIGH-INTENSITY DISCHARGE LAMPS:HID lamps produce light by striking an electrical arc across tungsten electrodes housed inside a specially designed inner glass tube. This tube is filled with both gas and metals. The gas aids in the starting of the lamps. Then, the metals produce the light once they are heated to a point of evaporation.

Office building illuminated by high streetlight. 250-watt mercury vapor pressure sodium lamps.

HIGH-INTENSITY DISCHARGE LAMPS:Standard high-pressure sodium lamps have the highest efficacy of all HID lamps, but they produce a yellowish light. High-pressure sodium lamps that produce a whiter light are now available, but efficiency is somewhat sacrificed. Metal halide lamps are less efficient but produce a whiter, more natural light.

HIGH-INTENSITY DISCHARGE LAMPS:Colored metal halide lamps are also available. HID lamps are typically used not only when energy efficiency and /or long life are desired, but also when high levels of light are required over large areas. Such areas include gymnasiums, large public areas, outdoor activity areas, roadways, pathways, and parking lots. Lately, metal halide is successfully being used in residential environments.

metal-halide lighting pole, at a baseball field.

NEON LIGHTING / LAMPS:Neon lighting is created by

brightly glowing, electrified glass tubes or bulbs that contain rarefied NEON or other gases. Georges Claude, a French engineer and inventor, presented neon tube lighting in essentially its modern form. Neon lighting was an important cultural phenomenon in the United States in 1940.  The popularity, intricacy, and scale of neon signage for advertising declined in the U.S. following the Second World War, but development continued vigorously in Japan, Iran, and some other countries. In recent decades architects and artists, in addition to sign designers, have again adopted neon tube lighting as a component in their works.

NEON LIGHTING / LAMPS:A second technology for neon

lighting, the miniature neon glow lamp,  was developed in 1917, about seven years after neon tube lighting. While neon tube lights are typically meters long, the lamps can be less than one centimeter in length and glow much more dimly than the tube lights. Through the 1970s, neon glow lamps were widely used for displays in electronics, for small decorative lamps, and as electronic

devices in of themselves. While these lamps are now antiques, the technology of the neon glow lamp

developed into plasma displays and televisions.

NEON LIGHTING / LAMPS:The mid to late 1980s was a

period of resurgence in neon production. Sign companies developed a new type of signage called channel lettering, in which individual letters were fashioned from sheet metal.While the market for neon lighting in outdoor advertising signage has declined since the mid 20th Century, in recent decades neon lighting has been used consciously in art, both in individual objects and integrated into architecture.

FLOOD LIGHTING:Floodlights are broad-beamed, high-intensity artificial lights often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions. 

A floodlight used on a A floodlight in a cricket football field. field.

FLOOD LIGHTING:In the top tiers of many

professional sports, it is a requirement for stadiums to have floodlights to allow games to be scheduled outside daylight hours. Evening or night matches may

suit spectators who have work or other commitment earlier in the day.

The most common type of floodlight is the Metal Halide which emits a bright white light, however most commonly used for sporting events are high pressure Sodium floodlights which emit a soft orange light, similar to that of street lights; SON lamps have a very high lumens-to-watt ratio making them a cost effective choice where certain lux levels have to be met.

LED – LIGHT EMITTING DIODES:Light Emitting Diodes (LED) are bulbs without a filament, that are low in power consumption and have a long life span. LEDs are just starting to rival conventional lighting, but unfortunately they just don't have the output (lumen) needed to completely replace incandescent, and other type, bulbs just yet. Never the less, technology is advancing everyday, and it will not be long until the LED bulb will be the bulb of choice for most applications in the home and work place.

LIGHTING SYSTEMS:LAMP FITTINGS IN COMMON USE:The variety is so large that it cannot be documented or known in a realistic manner. Fittings and lamps meant for home are designed to appeal to the eye, it is artistic and ornamental also. However there is wide choice of fittings intended for the use as per requirement consisting of tungsten or other filament lamps, fluorescent tubes, mercury vapour or sodium vapour etc.,Basically there are three systems of lighting:1) DIRECT LIGHTING.2) INDIRECT LIGHTING.3) SEMI-INDIRECT.

LIGHTING SYSTEMS:1) DIRECT LIGHTING:The light from the lamp directly reaches the working plane. These are largely used in industrial installations, offices, showrooms, commercial establishments etc., The lamp is enclosed in diffusing globes or enclosures to reduce the surface intensity of the light source.2) INDIRECT LIGHTING:The lamp fitting is hidden and the light rays reach the working plane indirectly by reflection from the walls, ceiling or any other surface.3) SEMI-INDIRECT:It is a combination of the above two methods.

COVE LIGHTING:I. INTRODUCTION

Cove Lighting is hiding of a luminaire behind a panel or a special construction to create glowing edge or indirect soft light or surface illumination. It is a light installation that can bring a strong result in terms of perception of the space and atmosphere creation.

Cove Lighting takes into account many variables to have good results and great impact. Satisfying the “inspirational” aspects of the architect, the lighting designer, the customer and the end user involves selection of right product and follow simple design rules.

COVE LIGHTING:II. DEFINITIONSA. Wall Washing & GrazeWall Washing is perceived effect of uniform illumination on the surface. It typically involves Grazing Effect revealing texture of the surface.

COVE LIGHTING:B. GlowGlow is a perceived effect of a line of light that can be wide or narrow but stops at a certain height with a softer gradient.

COVE LIGHTING:III. APPLICATION AREASA. Home

A Cove Lighting System in a home is defined by need of aesthetics, soft illumination and controlled lighting.

COVE LIGHTING:III. APPLICATION AREASB. Hospitality

Cove Lighting Systems are widely used in Hotel rooms and common areas because of their flexibility, softness & elegance.

COVE LIGHTING:III. APPLICATION AREASC. Office

In Offices, coves are used to create indirect lighting, surface illumination and natural light simulation.

COVE LIGHTING:III. APPLICATION AREASD. Retail & Entertainment

Cove systems in Retail can create attention points and range of effects.

COVE LIGHTING:IV. SELECTION CRITERIATo create cove lighting, there are many variables to take into account e.g. type of luminaire, position of the product inside the cove, shape of the cove and light effect generated / desired.A. Product Positioning

COVE LIGHTING:IV. SELECTION CRITERIAWhen the luminaires are in a horizontal position, pointing upwards, an “uprise” is needed to screen off direct light. The height of such screen must be at the same level as the LED lamp. In this situation, some distance from the ceiling is recommended to avoid dark spots and a good color mixing.

COVE LIGHTING:IV. SELECTION CRITERIAWhen the luminaires are in vertical position, pointing to the wall, they must be placed on edge of the cove to avoid harsh shadows and weird color lines. Here too, some distance from the ceiling is recommended to avoid dark spots and a good color mixing.

COVE LIGHTING:B. Wall Washing and Glow

By increasing the size of the opening, the light effect changes from Glow to Wall Washing.Placing the luminaire in a vertical position allows to use much more direct light and the brightness is increased compared to horizontal position.

COVE LIGHTING:C. Brightness Contrast and Color ContrastA Cove Lighting effect also depends on the contrast that is generated by the General Lighting.

In case of White Cove Lighting, general lighting gives contribution to the uniformity of the wall illumination. It can make a glow effect be perceived as a wall washing effect and decrease impact of the cove.

COVE LIGHTING:

In case of Colored Cove, the general lighting gradually turns the cove effect from wall washer to glow and generates a color contrast.

COVE LIGHTING:VI. EXAMPLES

Gentle Highlighting

COVE LIGHTING:VI. EXAMPLES

Illuminating Entire Space

COVE LIGHTING:VI. EXAMPLES

Impressive Dynamic Effect

COVE LIGHTING:VI. EXAMPLES

Mould The Space

COVE LIGHTING:VIII. CONCLUSIONS

Cove Lighting involves thorough understanding of application area, desired effect and selection of appropriate product.

Installation Complexity and Maintenance Ease are important factors to be considered while selecting Cove Lighting products.

DETAILS OF LAMP FITTINGS:The following table gives the shape of lamp, type of lamp, lamp details with its description and its application. The following abbreviations are used:

D Direct Lighting. GF Gas Filled Lamp.

DD Direct Diffused. MV Mercury Vapour Lamp.

ID Indirect. SO Sodium Lamp.

H/S Height-to-spacing ratio.

FL Fluorescent Tube Lamp.

MVF Mercury Vapour (Fluorescent) Lamp.