Unit-11 Building Facilities- I

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UNIT 11 BUILDING FACILITIES- I

Structure 11.0 Objectives 11.1 Introduction

11.2 Basic Terminologies 11.3 Source of Electricity 11.4 Types of Electricity

11.5 Source of Lighting (Decorative Lighting) 11.6 Maintenance of Light Outputs

11.7 Let Us Sum Up 11.8 Further Readings 11.9 Key Words

11.10 Clues to Answers 11.11 Activities

11.0 OBJECTIVES

After reading this unit you will be able to:

 know the basic terminology used in electrical network and able to understand the sources and types of electricity.

 know the sources of lightning and maintenance of decorative lighting fixtures.

11.1 INTRODUCTION

India is the third largest producer of electricity in the world. The national electric grid plays a vital role in supply & distribution of electrical energy in the country. Approximate 58% of electrical power generated by using fossil fuel for e.g. coal, lignite, gas & diesel, 11% by hydro, 29% by wind & solar, 2% by nuclear.

Electricity can be supplied where you want it, as long as you have enough outlets. You can install new power points or move existing ones yourself.

Appliances and devices may require different electric-energy sources. Small buildings may have very limited electric-energy capabilities, while larger buildings (hotels, institutional buildings, and health-care facilities) may provide several electric-energy sources.

11.2 BASIC TERMINOLOGIES

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 Conductor: A conductor is a substance through which electricity flows freely, e.g.

copper, aluminium, water or the wiring system of a building.

 Insulator: An electrical insulator is a material in which electric current does not flow freely.

 Voltage: This term denotes the pressure exerted by the electricity supply. Volt measures the pressure of flow of an electric current. Before electricity can flow through a wire, the electric pressure at one end of the wire must be greater than at the other end: this is known as “potential difference”.

 One volt: One volt is defined as potential difference necessary between the ends of a conductor whose resistance is 1 ohm, to produce a current of 1 ampere. 220 volts is introduced as the standard for domestic use and 415 volts for industrial use throughout the country.

 Ohms: it measures the resistance of a conductor to the flow of a current. All conductors offer some resistance, but the lower the resistance the better the conductor.

A thin wire offers more resistance (causing voltage drop) than a thick cable of same material, and therefore long runs of the former should be avoided when planning the electrical wiring of a building.

 Ohm’s Law: The Ohm’s Law defines the relation between the above three parameters of the electric circuit as follows:

o “The voltage drop across the load resistance of the circuit is directly proportional to the current flowing through it; provided the physical parameters viz. length, cross-section, temperature and material of the load resistance remains same.”

Mathematical representation:

o V  I

o = [R] * I[where R is a constant of proportionality and known as ‘Resistance’

responsible for energy waste]

Unit of ‘V’ expressed in Volts.

Unit of ‘I’ expressed in Ampere.

Unit of ‘R’ expressed in Ohm unit.

The ‘V.I.R.’ triangle easily recalls the circuit parameters.

Illustration : If the domestic AC supply is at about 240 Volt & the safety limit for an electrical appliance is set at 15 Ampere then the minimum resistance for that circuit will be R=V/I = 240/15 = 16 Ohm’s

 Ampere: it measures the rate of flow of a current, i.e. the amount of electricity that is passing through the circuit. If an electric wire using 10 amps is plugged into a 5 -amp.

Socket, the demand will overstrain the circuit and should blow the fuse.

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One Ampere = 1Coulomb /second = 1 / 1.6x10^-19 electrons /second = flow of 6.25x10¹⁸ electrons /second.

 Watts: The work that electricity does is measured in watts. It measures power- that is to say, the amount of electricity used by an appliance.

One thousand watts equals to one kilowatt & electricity consumed over a period of one hour is called a kilowatt hour.

1000 watts = 1 kilowatt (“kW”)

 One B.T.U.: It is the quantity of heat required to raise the temperature of 1 Pound (lb represents Pound) of water through 1 degree Fahrenheit.

Simple Relationship Between Volts, Ohms, Amperes and Watts

There is a simple relationship between volts, ohms, amperes and watts that can be expressed by the following equations:

1. volts / ohms = amperes

For example: when the voltages of the main supply is 240 volts and the wire and other connections leading to a socket outlet have a resistance of 20 ohms, the socket outlet is able to supply 12 amps.

2. watts = amperes x volts

For example: a 15 amp. Socket using a current of 440 volt can supply an electrical appliance rated at 6,600 watts

3. amperes = watts / volts

For example: four 100- watt lamps using 220 volts could be safely supplied by a 2 - amp plug.

The abbreviations used by electrical engineers are: E= volts, I= amperes, R = ohms, W = watts.

 Electric Circuit is path of an electric current. The term is usually taken to mean a continuous path composed of conductors and conducting devices and including a source of electromotive force that drives the current around the circuit. A circuit of this type is termed a closed circuit.

 Open circuit in which the current path is not continuous or current flow is interrupted is called an open circuit.

 A short circuit is a closed circuit in which a direct connection is made, with no appreciable resistance, inductance, or capacitance, between the terminals of the source of electromotive force. No serious damage is likely to be done beyond the blowing a fuse.

 Series connection A series circuit is one in which the devices or elements of the circuit are arranged in such a way that the entire current (I) passes through each element without division or branching into parallel circuits. When two or more resistances are in series in a circuit, the total resistance may be calculated by adding the values of such resistances.

 R = r1 + r2 + r 3

 Parallel connections If the resistances are in parallel, the total value of the resistance in the circuit is given by the formula:

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Formula of Electric Circuit and Precautions

Quantity Formula Notations

Electric current I = Q/t I is the current Q is the charge flow T is the time Resistance R = ρ (L/A) R is the resistance

Ρ is the resistivity of the wire L is the length of the wire A is the area of the wire

Voltage V = IR V is the voltage; it can also be potential difference

Power P = E/t P is the power

E is the energy gain or loss t is the time

Series circuit Req = R1 + R2 + R3 +…

Req is the equivalent resistance of the circuit R1, R2,… are the resistances placed in the series circuit

Parallel circuit 1/Req = 1/R1 + 1/R2 + 1/R3 +…

Req is the equivalent resistance

R1, R2,… are the resistances placed in the parallel circuit

 Capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a capacitor is known as capacitance.

 Choke In electronics, a choke is an inductor used to block higher-frequency alternating currents while passing direct current (DC) and lower-frequencies alternating current (AC) in an electrical circuit.

 Coil in an electric circuit, one or more turns, usually roughly circular or cylindrical, of current-carrying wire designed to produce a magnetic field or to provide electrical resistance or inductance.

 Transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

 Color Code To enable wires to be easily and safely identified, all common wiring safety codes mandate a colour scheme for the insulation on power conductors.

 Fuses These are safety devices and provided at every distribution board. They take the form of a short piece of thin wire which melts or blows, thus disconnecting the supply, if the current load becomes too heavy. Most common types of fuses are as follows:

(A) Rewirable Fuses In these fuses a length of wire is screwed to a porcelain carrier;

blown fuses are repaired by replacing the wire, which should be properly secured

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under the washer or screw head. Kit- kat type of fuse is most commonly used fuse device in domestic installation.

(B) Cartridge Fuses are self contained units with the link wire bedded in unburnable powder; they cannot be repaired; they usually give a visual indication when blown. Cartridge fuses are safer, as they smother the arc that is momentarily formed when the circuit breaks.

(C) H.R.C. Fuses consist of outer ceramic body, sealed at both ends by metallic caps.

To these caps are welded a number of silver wires in parallel. The space surrounding these wires is filled with compacted quartz sand which acts as a quenching medium. To the end caps are fixed tags for the purpose of fixing the fuses.

(D) Circuit Breakers consist of an electro-magnetic trip which breaks the circuit automatically when there is an overloading of, or a defect in, the circuit. They can be reset by hand to restore the current. If, however, the fault persists; an automatic device prevents resetting until the cause of the trouble has been remedied. Circuit breakers can be used either in place of fuses or for the earth –continuity circuit in buildings where it is difficult to obtain an effective earth connection.

 Earthing: The risk of shock can arise from damage to insulation, the presence of water, or the working looses a connection. Electricity always takes the path of least resistance to the earth. It will therefore pass through the body of a person who is in effective contact with the earth, e.g. by touching a metal pipe or stone floor.

 Switch: Switch is manually operated device for closing, opening or changing the connection in a circuit.

 Surface or Tumbler Type Switches project out of the switch board and are most commonly used.

 Flush Switches Flush switches are some time also called as piano switches or tiny switches and mounted with only its face exposed and with its sides and surrounded by a box or case.

 One Way Switches have two terminals and are connected in series with the points.

 Two Way Switches have four terminals two of them are connected inside.

These switches are used in controlling one point from two places such as in stair case wiring,.

 Two Pole Switches are actually two single way switches linked together which control both live and neutral wires simultaneously. These switches are used as main switches for domestic installations.

 Push Button Switches used for electric bells, table lamp and bed on-off switches.

 Ceiling Rose It forms the tapping point from electrical installation for supplying power to fans, pendants or tube lights by means of flexible cords.

 Lamp Holder Lamp holder connects the filament lamps to the electrical installation.

These may be of brass or bakelite type.

 Edison Screw Type Holder has centre contact which is connected to the live wire and outer or screw contact is connected to the neutral wire.

 Bayonet Lamp Holder may be pendant type, bracket type or batten holder straight type or batten holder angle type.

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 Socket Outlets and Plug Tops Portable appliances are connected to electrical installation by means of these. These may be surface type of flush type.

 Two Pin Type Sockets and Plug Tops are used for feeding portable appliances having al insulated body such as garden standard lamp. For feeding portable appliance having metallic body it becomes necessary to earth the metallic body which ensures safety to operating personnel.

 Socket Outlet and Plug Top are used for feeding such appliances have necessarily to be one of three pin type. Two pins are of equal size. These are connected to live and neutral wire. The third pin is thicker and longer than other two pins and is connected to earth wire in case of any leakage from the element of appliance to the metallic body; heavy current will flow through earth wire.

 Thermal Effect: The flow of electric current produces heat and causes rise of the temperature of the resistive conductor.

 Luminous Effect: Due to the thermal effect at high temperature the resistive conductor radiates light.

 Magnetic Effect: The current flow in a conductor always accompanies with the production magnetic lines of force.

 Chemical Effect: Electric current flowing through electrolytes (water solution of salts) or molten salts causes a chemical change.

 Cables: Several conductors, each with its separate insulation, can be combined with additional insulation to form a cable. Cables must be protected against physical damage such as pressure, cutting, rubbing, dampness or attack by rodents. One method is to cover them with a strong, protective sheath.

 T.R.S. (Tough rubber sheathed) also known as cab-tyre sheathed (C.T.S.) - because of outer sheath of tough rubber or cab- tyre. These wires are used in 400/ 230 V grades only. It is cheap, easy to install, and fairly strong.

 L.A.S. (Lead- alloy sheathed) – neat and convenient for earthing, but vulnerable to damage.

 M.I.C.S. (Mineral insulated copper sheathed) – very strong, will withstand extremes of heat, moistures, and fumes, etc; fairly expensive.

 Aluminium – light and stiff, self supporting on bends.

 P.V.C. (Polyvinyl chloride) these cables resist successfully the action of acid, alkali ultraviolet radiations, ozone, sun etc and are Very flexible and waterproof. These are very difficult to ignite. These wires are made in both 400 /230 V and 1100/ 600 V grades.

 V.I.R (Vulcanized Rubber Insulation) is applied over tinned copper wires to prevent attack of sulphur in the vulcanized rubber over bare copper. Although vulcanized rubber is relatively strong, it is further covered with cotton tape with braiding spun on its top. The cable is then dipped in the solutions of bitumen or wax to make it moisture proof. These wires are made in both 400 /230 V and 1100/ 600 V grades. These wires are used in casing capping and conduit wiring.

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 Ducts consist of shallow tubes or channels in the concrete, can be incorporated in the floors of a building at the construction stage.

 Conduits can be fixed to the surface of walls, floors or ceilings, or buried in plaster or other finishing material. Because of its poor appearance, surface fixing is not recommended for the public parts of a hotel building. Ducts and conduits have junction boxes at intervals to enable the electric cable to the inserted or withdrawn as required, thus facilitating repairs.

 Steel Conduit it can be either light – gauge or heavy – gauge. Light gauge, with joints clipped together, is cheap but not very reliable from the point of view of earthing, heavy- gauge, with screwed joints, is strong, easy to re-wire, and has good earthing qualities.

 Plastic or Fibre Conduit can also be used. It should be firmly fixed to give rigidity and usually requires a separate earth – continuity wire.

Electronics Symbols

Wires Symbols

Symbol Name Description

Electrical Wire It is the symbol that is used to represent a wire.

Connected Wires This Symbol represents the wire connected crossing.

Not Connect Wires

This Symbol shows that wires are not connected on crossing.

Switches Symbols

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SPST Toggle Switch

It is the symbol of a switch that disconnects current when open.

SPDT Toggle Switch

This Symbol of switch selects between two connections.

Push Button (N.O) It is a symbol that denotes Momentary switch - normally open.

Push Button Switch (N.C)

This denotes the symbol of a Momentary switch - normally closed.

DIP Switch It is the symbol of the DIP switch which is used for onboard configuration.

Relays

SPST Relay This shows the symbol of relay that close connection by an electromagnet.

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SPDT Relay This shows the symbol of relay that open connection by an electromagnet.

Earthing

Earth Ground This Symbol is used for zero potential reference and electrical shock protection.

Chassis Ground

This symbol shows the wire Connected to the chassis of the circuit.

Digital Ground It refers to the reference voltage of digital-analog if.

Inductors

Indicator Symbol of a Coil / solenoid that generates a magnetic field.

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Iron Core Inductor

It is the symbol of the iron core Inductor Which Includes iron.

Variable Inductor It is the coil or solenoid that has a Variable magnetic field.

Motor and Transformer

Motor Symbol of motor, which changes electric energy to kinetic energy.

AC Transformer Transformer changes AC voltage from high to low or low to high.

Electronics Symbols Resistance

Variable

Resistance It is the symbol of an adjustable resistor which has 2 terminals.

Potentiometer It is the symbol of an adjustable resistor that has 3 terminals.

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Trimmer Resistor It is the symbol of a trimmer which is also known as a Preset resistor.

Thermistor It is the symbol of a Thermal resistor that changes the resistance when temperature changes.

Photo resistor It is the symbol of Photo-resistor - change resistance with light intensity change.

Diode

Diode Diode allows current flow in one direction only - left (anode) to the right (cathode).

Zener Diode It allows current flow in one direction, but also can flow in the reverse direction when above breakdown volt.

Schottky Diode Schottky diode is a diode with a low voltage drop.

Varicap Diode This represents the varicap diode. Variable capacitance diode.

Light Emitting

Diode LED emits light when current flows through it.

Photodiode This is the symbol of Photodiode that allows current flow when exposed to light.

Capacitor

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Capacitor Capacitor is used to store electric charge. It acts as a short circuit with AC and an open circuit with DC.

Variable

Capacitor The Symbol represent the adjustable capacitance.

Sources

Voltage Source It is the symbol of a voltage Source which generates constant voltage.

Current Source It is the symbol of a current Source which generates constant current.

AC Voltage Source This symbol shows the AC Voltage Source.

Battery Cell It is the symbol of single cell use to generate constant volt.

Battery It is the symbol of a battery which is the combination of two or more cells.

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Controlled Voltage Source It is the symbol of a constant voltage Source that gives controllable voltage at the output.

Controlled Current Source

It represents the controlled Current source which gives controllable current at the output.

Meter Symbols

Voltmeter It is the symbol that shows Voltmeter which is used to measure the voltage.

Ammeter It represents the ammeter whose work is to measure the current in the circuit.

Ohmmeter It is the symbol of the ohmmeter which is needed to measure the value of a resistor.

Wattmeter This represents the power meter which shows the power consumption.

Converter and Amplifier Symbols

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Operational Amplifier This operational gives Amplify input signal.

Analog to Digital Converter This is the symbol of ATD converts analog signal to digital numbers.

Digital to Analog Converter This is the symbol of DTA converts digital numbers to analog signals.

Transistors Symbols

NPN Bipolar Transistor It allows current flow when the high potential is at the base (middle).

PNP Bipolar Transistor It allows current flow when the low potential is at the base (middle) of the symbol.

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Darlington Transistor It is made from 2 bipolar transistors. Has total gain of the product of each gain.

JFET-N Transistor Symbol of JFET N-channel field effect transistor.

JFET-P Transistor This is the symbol of JFET P which is a P- channel effect transistor.

NMOS Transistor This is a symbol of Mosfet N-channel MOSFET transistor.

PMOS Transistor This is a symbol of Mosfet P-channel MOSFET transistor.

Utility Symbols

BUZZER Produce a buzzing sound when current flows through it.

Electric Bell This is the symbol of Bell which Rings when activated.

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Fuse

The fuse disconnects when current above the threshold---used to protect a circuit from high currents.

Bus The bus symbol contains several wires. usually for data / address.

Loudspeaker Convert electrical signal to sound waves.

Microphone Microphone Converts sound waves to the electrical signal.

Lamp/Light Bulb

This is the symbol of a lamp that glows when current flows through it.

Source: Wondershare Edraw Max, retrieved on 20-Nov-22 @ 5:00 pm.

Check Your Progress-1

1) Define the following terms:

 Potential Difference

 Ampere

 Power

 Circuit

 Earthing

2) Write SI units of following:

 Power

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 Current

 Voltage

3) Differentiate between the following:

 Open circuit & closed circuit

 Series & parallel connection

4) Find the equivalent resistance if 3 resistance of 3ohm, 4ohm, 5ohm are connected in series & parallel?

5) If the domestic AC supply is at about 220 Volt & the safety limit for an electrical appliance is set at 10 Ampere then what will be the minimum resistance for that circuit?

11.3 SOURCE OF ELECTRICITY

Earlier, electricity is produced by using non- renewable sources of energy such as natural gas, nuclear energy & coal. But now-a-days electricity is also produced from renewable sources such as wind, hydropower, solar power, biomass, wind, and geothermal. The various sources of electricity are:

 Natural Gas- Natural gas combustion alone, or as part of a furnace/boiler system, propels turbines to create energy.

 Coal- Most power plants use coal-fired steam turbines to generate power, though a few convert coal to a gas before using it in turbines.

 Petroleum- Petroleum can also be burned to produce combustion gases or steam to power turbines.

 Nuclear Power- With nuclear power, nuclear fission produces the energy-generating steam necessary to spin turbines and generate electricity.

 Hydropower- Hydropower from dams and other setups power turbines via flowing water.

 Wind- Like giant pinwheels, turbines capture energy from the wind for conversion into electricity.

 Biomass- Derived from plant and animal waste, materials are burned directly and used as other fuels to power turbines or internal combustion generators.

 Solar- Energy from the sun is captured in photovoltaic solar cells, heating fluids to produce steam and drive turbines.

 Geothermal- Heat from within the earth is harnessed to for heating water into steam to power turbines.

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 Hydrogen Energy- Hydrogen is a great source of energy and can be used as a source of fuel to power ships, vehicles, homes, industries, and rockets. It is completely renewable, can be produced on demand, and does not leave any toxic emissions in the atmosphere. Hydrogen is available with water (H2O) and is the most common element available on earth. Water contains two-thirds of hydrogen and can be found in combination with other elements. Once it is separated, it can be used as a fuel for generating electricity.

 Tidal energy- Tidal energy uses the rise and fall of tides to convert the kinetic energy of incoming and outgoing tides into electrical energy. The generation of energy through tidal power is most prevalent in coastal areas. Tidal energy is one of the renewable sources of energy and produces large energy even when the tides are at low speed.When there is an increased height of water levels in the ocean, tides are produced, which rush back and forth in the ocean. In order to capture sufficient power from the tidal energy potential, the altitude of high tide needs to be at least five meters (around 16 feet) greater than low tide.

11.4 TYPES OF ELECTRICITY There are mainly two types of electricity.

1. Static Electricity 2. Current Electricity

1. Static Electricity Static electricity is when electrical charges developed on the surface of the material. It is usually caused by friction when two or more than two materials rubbed together. Then, as a result, static electricity builds up and due to this these objects may be attracted to each other or may even cause a spark.

2. Current Electricity Current electricity is the flow of electric charge across an electric field.It is produced by moving free electrons and it is measured in amperes (A). There are two main types of electric current:

 Direct current (DC)

 Alternating current (AC).

Direct Current Direct current provides a constant flow of amperes when a constant voltage is impressed on the amperes. Amperes change only if the electrical load changes or if the impressed voltage changes. Direct change is used in some security systems and for limited emergency energy use for selective devices, such as exist lighting.

Alternating Current Around the world a large percentage of the electrical energy used is generated by alternating current generators. It is therefore necessary to understand the principles of electricity and magnetism as they apply to alternating current. The extensive use of alternating current has not eliminated he use of direct current. There are many applications where direct current essentially be used or it performs better than alternating current.

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Differentiation between AC and DC

KEY WORDS ALTERNATE CURRENT (AC) DIRECT CURRENT (DC)

Amount of energy that can be carried

Safe to transfer over longer city distances and can provide more power.

Voltage of DC cannot travel very far until it begins to lose energy Cause of direction of

Electrons

Rotating magnet along the wire. Steady magnetism along the wire.

Frequency The frequency of alternating current is 50Hz or 60Hz depending upon the country.

The frequency of direct current is zero.

Direction It reverses its direction while flowing in a circuit.

It flows in one direction in the circuit.

Current It is the current of magnitude varying with time It is the current of constant magnitude.

Flow of Electrons Electrons keep switching directions - forward and backward.

Electrons move steadily in one direction or 'forward'.

Obtained from A.C Generator and mains. Cell or Battery.

Passive Parameters Impedance. Resistance only

1: Write 2 examples of renewable & non-renewable sources of electricity each?

2: Enlist five sources of electricity?

3: Differentiate between the following:

 Static & Current Electricity

 Alternate Current & Direct Current

11.5 SOURCE OF LIGHTING (DECORATIVE LIGHTING)

NATURAL LIGHTS

Natural sources of light include sunlight, the stars, volcanoes, meteorological lightning and biochemical sources. These types of light are naturally occurring and do not necessarily need humans to create light. Sunlight is one of the most obvious and prominent sources of natural light for humans. It is constantly present in the Earth and provides a large amount of light for people to see by on a daily basis. It is also the largest source of light available to humans.

Starlight is similar to sunlight in that it comes from stars that are within the galaxy and beyond, although these stars are much smaller and further away than the sun.

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Natural Light Sources and Types Daylight is the natural light sources which are obtained as daylight directly or through various openings in building like windows, door, glass roofs and atrium.

Day lighting is the practice of placing windows, other openings, and reflective surfaces so that sunlight (direct or indirect) can provide effective internal lighting. Particular attention is given to day lighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Provisions of day lighting can be made by adding below features to the building:

 Window Windows are the most common way to admit daylight into a space. Their vertical orientation means that they selectively admit sunlight and diffuse daylight at different times of the day and year.

 Clerestory Windows These are high, vertically placed windows. They can be used to increase direct solar gain when oriented towards the equator.

 Sawtooth Roof It is a vertical roof glass facing away from the equator side of the building to capture diffused light. The sawtooth roof's lighting concept partially reduces the summer "solar furnace" skylight problem, but still allows warm interior air to rise and touch the exterior roof glass in the cold winter, with significant undesirable heat transfer.

Figure-1: Sawtooth Roof as a source of natural light

Source: https://build.com.au/sawtooth-roofs; retrieved on 20-11-2022 @ 5 pm.

 Atrium An atrium is a large open space located within a building and is used to light a central circulation or public area by daylight admitted through a glass roof or wall.

Atria provide some daylight to adjacent working areas, but the amount is often small and does not penetrate very far. The main function of an atrium is to provide a visual experience and a degree of contact with the outside for people in the working areas.

Figure-2: Natural Lighting brings an outdoor feel to interior atrium

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Source: https://www.ledsmagazine.com/company-

newsfeed/article/14173311/lighting-brings-an-outdoor-feel-to-interior-atrium;

retrieved on 20-Nov-22 @ 5 pm

 Translucent Walls Walls made of glass brick are translucent to transparent.

Traditionally, they are hollow and grouted with a fine concrete grout, but some modern glass brick walls are solid cast glass grouted with a transparent glue.

ARTIFICIAL LIGHTS

Artificial light, as opposed to natural light, refers to any light source that is produced by electrical means. Artificial lighting has many different applications and is used both in home and commercially. Artificial lights are available in a wide variety of shapes, sizes, colours of light emitted, and levels of brightness.

There are several different types of artificial light sources. Some of these sources are incandescent bulbs, halogen lamps, metal halide, fluorescent tube, compact florescent light, and LEDs.

Artificial Light Sources and Types

Artificial light sources are categorized by the technology used to produce the light. There's dozens of sources, with a few common in household applications and others more suitable for industrial uses. The five most common light sources are as follows:

 Incandescent Lamp: Until recently the most common electric light source was the incandescent lamp. This is still widely used, although its relatively low energy efficiency is leading to its replacement by other more efficient lamps such as the CFL.

 Compact Fluorescent Lamp: The compact fluorescent lamp (CFL) was designed as a more efficient replacement for incandescent lamp. It is supplied with the same fixing system (screw or bayonet), and can be used in many light fittings designed for incandescent lamps.

 Fluorescent Tube: Fluorescent tubes are the main form of lighting for offices and commercial buildings. They are a form of gas discharge lamp, and are formed in a long thin glass cylinder with contacts at either end that secure them to the fitting (or luminaire) and provide the electrical connection.

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 Discharge Lamps: Discharge lamps work by striking an electrical arc between two electrodes, causing a filler gas to give off light. Different metals and filler gasses can be used to provide a range of colour and brightness. Discharge lamps provide high luminous efficacy combined with long life, resulting in the most economical light source available.

Figure-3: Discharge Lamp

Source:https://www.shutterstock.com/search/mercury-vapor- lamp?image_type=illustration; retrieved on 20-Nov-22 @ 5 pm.

 Light Emitting Diode (LED): LEDs use semi-conductors to convert electrical energy directly into light. They are only recently becoming available as a light source for lighting purposes, and are highly efficient and long lasting. LED torches are becoming very popular, as they provide a far longer battery life than other.

Figure-4 : LED Bulb

Source: https://shop.bajajelectricals.com/Home-Essentials/Lighting/LED-Lights/c/m-led- lights;

Retrieved on 20-Nov-22, @ 5 pm

Types of Decorative lighting fixtures (on the basis of function)

There are five basic types of light fixtures according to the function or aim of using it as follows:

 Ambient Lighting/ General Lighting -Ambient lighting provides an area with overall illumination., it radiates a comfortable level of brightness without glare and allows safety. Ambient lighting is often provided by traditional pendant type fixtures, down lights, chandeliers, or ceiling mounted fixtures etc. The general decor and aspect of the room will affect the amount of general lighting required. Having a central source of ambient light in all rooms is fundamental to a good lighting plan.

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 Task Lighting/ Directional Lighting -As the name suggests these lights are aimed at a specific task, provide more light on a specific area to perform a task that requires more light than the ambient fixtures can give. It can be provided by recessed and track lighting, pendant lighting and under cabinet lighting, as well as by portable floor and desk lamps. Task lighting should be free of distracting glare and shadows and should be bright enough to prevent eye strain.

Figure-5: Task Lighting/ Directional Lighting

Source:https://www.architonic.com/en/product/amos-design-lighthouse-system-hotel- signage-emergency/1186584; retrieved on 20-Nov-22,@ 5 PM.

 Accent Lighting: Accent lighting is also a sort of a directional lighting that adds drama to a place by creating visual interest. As part of an interior design scheme, it is used to draw the eye to houseplants, paintings, sculptures and other prized possessions. It can also be used to highlight the texture of a brick or stone wall, window treatments or outdoor landscaping. To be effective, accent lighting requires at least three times as much light on the focal point as the general lighting surrounding it. Accent lighting is usually provided by recessed and track lighting or wall-mounted picture lights.

Figure-6 : Accent Lighting

Source: https://in.pinterest.com/pin/792703971888705179/; retrieved on 20-Nov-22, @ 5 Pm

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 Informational Lighting / Guidance Lighting -It is designed to help us see our way safely for example: The light in closet, by doorbell, and night lights. Path lighting and motion lights are all examples of informational lighting. Informational lighting can be beautiful as well as functional, and can create dramatic statements. Lights inset on stairs can create pathways that enhance architecture, while outdoor informational lighting can create.

 Decorative Lighting: Strips, pendants, chandeliers, and sconces are all examples of light fixtures that draw attention to themselves and add character to the place being lighted.

11.6 MAINTENANCE OF LIGHT OUTPUTS

Lighting fixtures accounts for an estimated 20 percent of the total energy used in commercial buildings. Most of the commercial and residential buildings in India do not have detailed lighting maintenance policy other than replacing burned-out bulbs. Poor lighting maintenance can lead to visual degradation, reduce worker productivity, and contributes to higher energy costs. Having an effective lighting maintenance schedule can include many things including scheduling, policies, and inventory control. A lighting maintenance policy is a set of written procedures designed to serve as a guideline, not only for everyday maintenance practices, but for optimizing lighting systems on a year-round basis. Elements of an effective maintenance policy include:

 Blueprints of the facility

 Fixture and lighting controls schedule

 Equipment and service provider sources and contacts, including utility contacts

 Fixture cleaning and re-lamping schedule with service tracking log

 Procedures for re-lamping, re-ballasting, and cleaning fixtures

 Procedures for the adjustment of controls and occupancy sensors

Following practices are recommended to adhere while maintenance of lighting fixtures:

 Never clean an incandescent bulb while it is turned on. If the cloth is damp, the cooling effect of the liquid may shatter the hot bulb.

 Replace lenses if they appear yellow.

 Clean or repaint small rooms every year and larger rooms every 2-3 years because the dirt collected on these surfaces could reduce the amount of light they reflect.

 Consider group light replacement. Common lamps lose up to 30 percent of light output over their service life.

 Replacing all the lamps in a lighting system at the same time saves labour, keeps illumination high, and avoids stressing ballasts with lighting maintenance policies.

1. Write in brief about Natural & Artificial Lighting?

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………

2. Enumerate various sources & types of Natural & Artificial Lighting?

………

3. Explain types of Decorative lighting fixtures on the basis of their functions?

………

4. Write a short note on Maintenance of Light Outputs?

………

11.7 LET US SUM UP

This chapter has considered the fundamentals of Building Facilities-I focusing on the electrical engineering, lighting & electrical safety aspect and it is not expected that students of facility management need to become electrical engineers but however, they must have sufficient knowledge of the subjects dealt in this topic to enable them to understand source of electricity, familiarization with the electrical fixtures & types of lighting, illumination &

maintenance of light output. A careful examine of your expenditure on electricity may give you an insight to perceive in better manner about your decisions. The best understanding of the topic will help you to develop in planning safe and secure building facilities.

11.8 FURTHER READINGS

Basic Electrical Engineering- by C.L. Wadhwa, 2006 Publication - New Age International (P) Limited

Basic Electrical and Electronics Engineering- by Sabyasachi Bhattacharya, 2010 Publication - Pearson Education

Objective Electrical Technology- by V.K. Mehta, 2008 Publication - S. Chand Publishing

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Modern Control Systems- by Richard C. Dorf, 1967 Publication - Addison-Wesley Publishing Company

Standard Handbook for Electrical Engineers- by Donald G. Fink and H. Wayne Beaty1968

Publication - DA Information Services

Practical Electrical Engineering- by Reinhold Ludwig, 2016 Publication - Springer International Publishing

A Textbook of Electrical Technology – Volume I (Basic Electrical Engineering)- by B.L.

Theraja, 2005

Publication - S. Chand Publishing

Principles of Electrical Engineering- by V.K. Mehta, 2008 Publication - S Chand & Co Ltd

Fundamentals of Electric Circuits- by Matthew N.O. Sadiku, 1999 Publication – MCGraw Hill Education Limited

Fundamentals of Electric Circuits - Charles K. Alexander&Matthew N.O. Sadiku, 2004 Publication – MCGraw Hill

The Complete Guide to DIY & Home Maintenance, Edited by- Mike Lawrence, 1987 Publication – Orbis Publishing Ltd.

11.9 KEY WORDS

Decorative Light: A light fixture that is decorative in nature or design. The term. 'decorative lighting' covers all the traditional kinds of light fittings. (floor lights, pendants, chandeliers, etc)

Electricity: a form of energy resulting from the existence of charged particles (such as electrons or protons), either statically as an accumulation of charge or dynamically as a current.

Light: the natural agent that stimulates sight and makes things visible.

Light Output: Light Output means the luminous flux (measured in lumens) emitted by a Lamp or Luminaire.

Maintenance: The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installations.

Source: a body or process by which energy or a particular component enters a system.

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Terminology: the technical or special terms used in a business, art, science, or special subject. Nomenclature as a field of study.

11.10 CLUES TO ANSWERS

1: For details refer to 11.2 2: For details refer to 11.2 3: For details refer to 11.2

4: Equivalent resistance in series connection is R = r1 + r2 + r 3

R = 3+4+5

= 12 ohm Equivalent resistance in parallel connection is

1/R = 1/3+1/4+1/5 1/R=60/37 R = 1.62 ohm 5: R=V/I

= 220/10 = 22 ohm.

1. For details refer to 11.3 2. For details refer to 11.3 3. For details refer to 11.4

1. For details refer to 11.5 2. For details refer to 11.5 3. For details refer to 11.5 4. For details refer to 11.6

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11.11 ACTIVITIES

 Visit a mall and identify sources of natural lighting and how they using natural and artificial light together for appropriate/decorative lighting in the premises.

 Visit the lighting showroom/shop and collect catalogue for different decorative lights.

 Conduct an interview with an electrical engineer / project manager/ site manager and discuss on Electricity conservation practices need to be adhered.