Ebook Interior design principles and practice - M. Pratap Rao: Phần 1

Part 1 ebook present the content: idstory of interior design; basics of design composition; introduction to building materials; plumbing; natural ventilation; air conditioning; natural lighting; artificial lighting; acoustics; building protection; interior furnishing; painting interiors; Indian institute of interior designers. For more details please refer to the ebook.

" In India" we are.slowly accepting this fact In the process, many schools of interior desig-nare started offering dip mas an<!degrees.

- Most of the students nf interior desigfl are not very clear about the syllabus and method of study They are attracted to the profession for the glamour and glossy photographs in magazines There is no real 'textbook' which can guide the students of intenor design, and this

This book is divided into two sections as Theory and Drawing The theory part contains History of interior design, Basics of design composition, Introduction to building materials, Plumbing, Natural ventilation, Air-conditioning, Natural & Artificial lighting, Acoustics, Building protection, Interior furnishing and information on Indian Institute of Interior Designers The drawing part contains Lettering & Scales, Figures & Projections, Building material symbols, Space standards, External & Internal parts, Kitchen design, Staircases, Theory

of colours, Rendering techniques, Three dimensional views and Interior design method These are the most essential topics and drawing exercises a student of interior design should learn I tried to incorporate the latest information available on each subject suiting to Indian conditions.

I would have included many other topics, but then, it would become an encyclopedia than a textbook for easy reading and understanding However, I welcome suggestions to improve the text in the coming editions from the students and fellow professi~nals in

M PRATAP RAO

THEORY

!

CHAPTER 1 IDSTORY OF INTERIOR DESIGN

2 Emergence of professional interior designer, I

CHAPTER 2 BASICS OF DESIGN COMPOSITION

1 The elements, 3

2 The principles, 3

3 Golden mean rectangle, 6

CHAPTER 3 INTRODUCTION TO BUILDING MATERIALS

7 Plywood and related products, II

8 Plastics and related products, 12

9 Glass and related products, 12

10 Paints and related products, 13

11 Ferrous and Non-ferrous metals, 13

12 Gypsum and related products, 14

13 Adhesives (or Glues), 14

CHAPTER 4 PLUMBING

1 Water Supply, 15

2 Sanitation, 17

2 Atmospheric conditions for human comfort, 29

3 Process of air-conditioning, 30

4 Air-conditioning under lndianclimatic conditions, 30

5 Types of Air-conditioning methods, 30

7 Calculation of packaged systems, 32

. CHAPTER 7 NATURAL LIGHTING.

1 Daylight factor, 33

2 Recommended daylight factors for interiors, 33

3 Calculation of the openings for natural lighting, 34

4 Guidelines for good natural lighting, 36

CHAPTER 8 ARTIFICIAL LIGHTING

1 Different types of lighting arrangements, 38

4 Acoustic design of a hall, 55

5 Guidelines for good acoustic design, 56

CHAPTER 10 BUILDING PROTECTION

3 The painting process, 7]

4 Common painting defects and remedies, 72

CHAPTER 13 INDIAN INSTITUTE OF INTERIOR DESIGNERS

A Rules & Regulations, 73

B Code of conduct, 78

73-80

A LETTERING & SCALES

2 Plan Elevation and Section 28

3 Typical Wall cross-section, 30

4 Arches and Lintels, 33

3 Contrast Colour Scheme I, 72

4 Contrast Colour Scheme I, 74

2 Interior Layout of a Residence, 109

M INTRODUCTION TO COMPUTER AIDED DRAFING (CAD)

t Facilities in CAD system, 114

2 Advantages of using CAD, 114

3 Auto CAD (ReI 10) design software package~ 114

1 INTERIOR DECORATION AS A PROFESSION

The profession of 'Interior Design' did not exist before 20th century Traditionally the carpenter ,or the store-keeper used to advise the arrangement ofinteriors for their clients Until the First World War interior decoration was closely related to the trade of antiques The social and economic situation duringthe 20th century increased the importance of an interior decorator Interior decoration still remains a ld?'ury available only to the upper classes of the society.Certain status is attached in the society in taking professional advise on the appearance of home or'\vork-place The role of interior decorator is alwaysadvisary because of the consultative nature of the work It is one of the professions in which women did very well In America, women tried to establis,heconomic independence through interior decoration of existing buildings or rooms Interior decorators were mainly responsible for selecting suitable textiles,floor and wall coverings, furniture, lighting and colour schemes for rooms Interior decoration never enjoyed the status of architecture and the interiordecorator is rarely responsible for structural alterations It is regarded as a branch of fashion design because in interior decoration very few schemes remain.intact for a long time Interior decoration gained importance with the publication of the book, 'The decoration of houses' by novelist Edith Wharton andarchitect Ogden Codman in 1897 They identified the principles of proportion and harmony for the planning of interior schemes The criteria ~ 'good taste'

2 EMERGENCE OF PROFESSIONAL INTERIOR DESIGNER

The status of an interior designer did not improve further due to the Second World War shortages Then the emergence of interior designer with

, professionalqualificationstarted to dominatethe interiors.These designersworkedon non-domesticinteriorsbecausethe commercialsector realisedthe

worth of good interior design During and after the Second World War, modernisation was developed in America Among the prominent modem architects inAmerica, Mies Van der Rohe, designed exposed steel-frames and brick-and-glass infills Different functional areas were delimited by storage units notreaching the ceiling Many of the technical innovations of post-war interior design are widely used in the interi~rs

3 MODERN INTERIOR DESIGN FEATURES

Let us discuss some important interior design features in modem buildings The false ceiling of each floor conceals services such as air-conditioning andelectric cables They can be easily accessible for maintenance through the false ceiling The interior working space was opened with rows of desks and smallp~itions replacing corridors and office rooms The concept of an open-office was developed during the 1950's with large floor areas divided by partitions,

introduced with floor carpets, indoor plants and the use of sky lights Another interior design feature is to leave interior brickwork and concrete exposed Newt~hniques for moulding and glueing plywood were discovered by American manufacturer~ during the War forth~ Navy Th~se are used for furniture designhke plastics with fibre-glass reinforcements, plastic shell chairs on metal legs, wire chairs, stacking plastic chairs bent plywood chairs and black leather

2 INTERIOR DESIGNS PRINCIPLES AND PRACTICE

upholstery Open shelving, drawers, cupboards and desks replaced partition walls Thus a good interior design was defined as 'items in which the design wassimple of good proportions and without dust collecting features with stress on good construction' Manufacturers were allowed to produce their own designsand there was public demand for ornament and periodic design features Certain features of modem interiors are indoor plants, built-in furniture, animal skins

as floor coverings, Venetian blinds, open storage space and smooth organic forms There is a tendency to use different textures and patterns Free-standinglamps replaced wall and ceiling lamps The garden is integrated with the living space by a sliding glass door The discovery of new building materials led tomany more innovative interior design concepts

EXERCISE

1 Describe the emergence of professional interior designer?

2 What are the important features of modem interior design?

The main source of design has been nature for man and his creations From nature many aspects has been picked up for various designs To communicatethese thoughts, there is a need to develop a design language Broadly we can divide them into two groups .

These are basically visual components used in creating an object or a composition They can be classified into:

2 THE PRINCIPLES

These principles help us in determining an object, whether it is artificialty good or bad in appearance They can be classified into:

(E) Unity or Harmony

'

1 A Line - Line is the basic design element Too many lines of different nature in a room create an impression of visual chaos like too many beams,panelling on walls etc., Lines should be restricted to the minimum Equal heights in furniture bring in the impression of unity in the space Vertical linescreate the imPression of height and similarly horizontal lines create the impression of more length Vertical lines of door ways, draperies, windows, built-in

1 B Form.: It is also referred as shape, area or mass Forms are closely related to lines.,Forms unite with lines to achieve overall design of a given

space A long rectangular table or sofa helps in creating a line of unity in the room but at the same time too many shapes or formS of furniture create the

'

1 C Texture -Surface characteristics of any object is known as texture Text~aJ surfaces range from smooth to rough A rough texture absorbs light

and smooth surface reflects light Small and dark rooms should have smooth texture and large rooms can have rough texture, if needed Textures can be used

1 D Colour - We react emotionally to different colours in different ways Our national flags and political party flags are good examples of ourattachment to various colours We all know that colours are an integral part of our religion and culture, so the choice of colour is very important and relative

to the functional use of space Light is intimately linked with colour because light is the source of all colours in nature Bright colours should be used in darkareas and dark COIOurfcan be used in lighted areas There are wide variety of colours for interior surfaces A careful and thoughtful use of colours is veryessential for attractive interiors

1 E Pattern - Pattern is a kind of surface enrichment Any room will look dull without any pattern In interior design there are three types of motifs orunits of design

(a) Naturalistic motifs, which look like picture of flowers, fruits, animals or scenes.

(b) Stylised motifs, which depend upon the material as well as purpose of the article Ferns and leaves are the most commonly used pattemmodels forfabrics and other decorative articles

(c) Geometrical motifs, which are based on forms of circle, rectangle, triangle etc., Stripes, dot and checks are the most commonly seen geometrical

1 F Light - Light is an art and utilitarian element Light is closely related to colour and texture Daylight is very important in the overall appearance of

a room Artificial lighting has become common in interior design today due to the lack of natural light in the interiors There are many reasons for this Manydesigners prefer artificial light for dramatic effect of interiors However a good combination of natural and artificial lighting will save energy consumption.Artistic placement of lights can bring out important areas and keep subordinate areas in shadow There are several types of artificial lighting appliancesavailable today for interior designers

Now, let us discuss the 'Principles' in detail

2 A Balance - Balance is

equalisation of attraction on both

sides of the centre There are two

types of balance

(a) Symmetrical or Formal

-When articles of equal

weight are placed on each

side of the centre and at

equal distance from the

centre, then it is called as

symmetrical or formal

balance

(b) Asymmetrical or

Informal-If each side of balancing

point is ditferent and there

is no centre line

which-divides the composition

into two equal parts, t.l)en it

is called as asymmetrical or

informal balance

4

2 B Emphasis - Emphasis helps to centre the interest to the most important thing or spot in any arrangement It should be called as focal point or cenVe

of interest If there is one main emphasized point in a room then others will become subdued Few examples are a window, an arch a painting and a furnitUrepiece The point of emphasis should be decided by the interior designer

2 E Unity of Harmony - When all the elements of design are nicely related, then the design has unity or harmony For example if all items have samecolour or similar type of wood or similar furniture design or similar fabric design All forms, lines, textures and colours should be harmonious The coloursneed not be the same always, but they can be complementary or matching one another.

EXERCISE

1 What are the elements of design composition?

2 What are the principles of design composition?

3 What is 'Golden mean rectangle' ? Descri~ with an example 'J

J \J'Jl.J1 1r l., lUr ftl., ~L\.-lftl"'\JLL

\

The proportional system most associated with Greek architecture and design, and with classical architecture as a whole is called the 'Golden section orGolden mean' Gold is the most uncorruptable and perfect of all the metals, so similarly this propotional relationship is also believed to be perfect It can bedescribed as the relationship of two unequal parts, where the ratio of the smaller part to the larger pan is the same as that of the larger part to the whole The

ratio can be approximately assumed as 1:I.6~ It can also be wriuen algebraically Assume 'a' as the maller unit and 'b' as the larger unit, then the relationship

-

A G()lden mean rectangle can be generated from a given square First the square is divided into half, then the diagonal of one of these rectangles isrotated d6wn along the side of the original square From the end of the rotated diagonal the desired Golden mean rectangle is constructed

Example:

* Assume a square of 4.0 x 4.0 metres.

* Draw a square of ABCD 4.0 x 4.0 m in any convenient scale.

* Divide the square into two equal parts of A~D and PBCO.

I * Draw a diagonal of OB and calculate its length based on the formula OB

It is 4.47 m .

* Draw the diagonal arch OB cutting at F.

* Calculate area of larger part (b) or ABCD It is 16 sq m.

* Calculate area of smaller part (a) or BEFC It is 9.88 sq m.

* Add the areas of (a + b) or ABCD + BEFC It is 25.88 sq m.

6

Buildings are made of different kinds of mat~rials It i~ very important to know thes~ building materials The knowledge of different building materials,their properties and uses help in achieving economy and efficient use of materials The cost of materials in the construction of a building ranges from 60 to

70 percent of the total cost Some essential building materials are described below Many new building materials are combinations of these materials orfurther innovations of these materials However, there are many other new building materials in the market, so it is also necessary for the Interior Design~ to

1 STONE

There are many varieties of stones available in nature They can be broadly classified as below:

(A) Different types of stones

(a) Sand stone

(c) Slate

(e) Granite

(g) Laterite

(a) Sand stone - It is very easy tp dress and work It is extensively used in general ,building cQnstruction and ornamental carving.

(b) Limestone - Lime stone slabs are used for floor41g, paving and roolmg It is also used for general building purposes and manufacturing of lime

(c) Slate ~ Slates are used as a roofmg and flooring material Harder slates are used fot damp-proofmg and steps of staircases

(d) Marble -'-It is extremely suitable for ornamental and superior type of building work It is also used for flooring and other decorative works.

(e) Granite -It is very hard and durable stone suitable for bridge abutments, piers etc., It is not suitable for carving

(j) Basalt - It is hard and compact and hence very expensive to wor~ It is used in foundations of structures and superstructures also, but not used for

(g) Laterite - It is normally used for inferior type of stone masonry work.

B Stone aggregate - Aggregate is a general term applied to all inert materials which when bonded together with cement form concrete

C General properties

(a) A good building stone should be hard, tough, compact grained and unifonn in texture and oolour.

(b) Lime stone

(d) Marble'if) Basalt

8 INTERIOR DESIGNS PRINCIPLES AND PRACTICE

(b) Stone absorbing less water is stronger and more durable as it will have less action of rainwater.

(c) Stone should be properly seasoned by exposure to the air before they are put in a structure.

(d) They should be small enough to be lifted and placed by hand.

(e) Length should be three times of the height and breadth, and it should not be less than six inches Maximum height should be one foot.

(j) All stones should be wetted before use

D Stone masonry types

(a) Random rubble masonry

(b) Coursed random rubble masonry

(c) Square rubble coursed and uncoursed masonry

(d) Ashlar

(a) Random rubble masonry - The stones are hammer dressed on the face, sides and beds to such an extent that the stones will come into close proximity

with the neighbouring stones

Fig 3.1 Random Rubble Mason!)' (Uncoursf'.d)

(b) Coursed random rubble masonry - Stones are hammer dressed on the bed and LOPsurfaces until the stones give parallel faces No face stone should

'''be narrower or shorte.r than its height

Fig 3.2 R~dom Rubble Masonry (Coursed)

(C) Square rubble coursed and uncoursed masonry - Stones should be hammer or chisel dressed on all beds and joiilts so as to make rectangular shapes.

Fig 3.3 Square Rubble Masonry (Uncoursed) Fig 3.4 Square Rubble Masonry (Coursed)

INTRODucnON TO BUILDING MATERIALS 9

(d) Ashlar - Every stone should be chisel dressed on all beds and joints to be true and square giving perfectly vertical and horizontal joints with the

(A) Bricks -The manufacturing of bricks involves four distinct operations They are earth preparation for bricks, moulding, drying and buining The

(a) Brick properties

* The surface should not be too smooth because mortar will not stick to it.

* A brick should give a metallic ring when struck with a small hammer or another brick.

* A good brick should not break when struck against another brick or ,,,hen dropped flat from a height of about four

to five feet

* It should have a surface so hard that cannot be scratched by fingernail.

* All bricks should be soaked in water for about one hour before use.

(b) Bricks are extensively used for construction of building exteriors and interiors in India.

(B) TIles - They can be divided into two classes

(a) Common tiles used for rooImg, paving and draining,

(b) Encaustic tiles used for decorative purposes,

(c) Properties of tiles - TIles are made more Dr less in the same manner as bricks but they are.made thinner for the sake of lightness and width wiselarger so that the number of joints may be reduced

(d) TIles can be classified into:

10 INTERIOR DESIGNS PRINCIPLES AND PRACfICE

3 Quarry tiles - These are very dense and possess a good wear resisting property They are used for heavy wear or chemical resistance flooring.

4 Glazed earthenware tiles- The top side of the tile should be glazed and the underside should be completely free from glaze so that the tiles may stickwell to the surface The edges should be free from glaze These are generally used in finishing floors and walls of kitchens, bathrooms, water closets andhospitals,wherecleanlinessis important. .

5.Terracota - It is a kind of earthenware made from superior clay by burning Hollow terracota blocks are used as a substitute for stone in ornamentalparts Porous terracota is a fire resisting material

3 CEMENT

The best variety of artificial cement is known as 'Portland Cement' or 'Ordinary Cement' It mainly consists of three ingredients lime, silica and alumina.Lime 60 to 65 percent and silica 20 to 25 percent give the required strength, alumina 4 to 8 percent for quick setting and rest 2 to 16 percent are meant forhardness and colour Manufacturing of dment by wet process can be-divided into three stages First stage is mixing of raw materials, second stage is burningand third stage is grinding There are other varieties of cement apart from portland cement, they are as described below:

(A) Rapid hardening cement- This type of cement attains high strength in early days because of increased lime content in composition and bumingat

higher temperature and finer grinding This type of cement is used in concrete when earlyhigh strengths are needed either to remove form work quickly orspeedy construction or in cold weather conditions to reduce the period of protection against low temperature or to achieve economy for early higher strengths

(B) Quick selling cement - This type of special cement starts setting within five minutes of water addition and becomes bard like stone within thirty

minutes This is produced by adding small percentage of aluminium sulphate as an accelerator and also by reducing percentage of gypsum and fine grinding.This type of cement is used where the work has to be completed in a short time For example cement concreting in static or running water

(C) White cement - This is a variety of ordinary cement and prepared from such raw materials which are practically free from iron oxide It is more

I(D) Pozzalona cement- Pozzalona is a volcanic powder found in thermal plants It is mixed with cement clinker to prepare cement It is used for ~

structures, sewage works and other underwater works This can also be used for internal plastering for economical building construction

4 MORTAR

It is a mixture of binding material (like cement and lime), fine aggregates (like sand) and water This is used to bond masonry or other structural units.The uses of mortars are as mentioned below:

* To unite bricks or stones in the construction of brick and stone masonry.

* To form an even bed between different courses of masonry.work and to distribute the load evenly on the layers.

* To hold stone aggregate together and form a solid mass of concrete.

* To cover exposed surfaces of walls and joints with plaster to provide smooth and hard surface.

(a) Different varieties of m~rtar

* lime mortar - It is a mixture of lime, sand and water Lime acts as a binding material for preparing mortar when it is to be used in masonry work.Generally lime to sand ratio is 1:2

* Ce"rent mortar - It is a mixture of cement, sand and water Where cement acts as a binding material The proportion of cement to sand varies from

1:2 tC' 1:6 depending upon the desired strength

* Surkhi mortar - It is a mixture of lime, surkhi and water Here sand is substituted by surkhi for economy and strength Surkhi is a form of finely burnt

5 CONCRETE

It is the most versatile material for all types of construction It is mainly used in building construction for foundations, columns, beams, slabs, staircases,lintels, sunshades, door & window frames, storage water tanks etc., There are many varieties of concrete They are:

INTRODUCfION TO BUILDING MA'JERIALS

11(A) Plain cement concrete,

(B) Reinforced cement concrete

(C) Prestressed concrete

(D) Lime concrete

(E) Reinforced brick concrete

(A) Plain Cement Concrete - It is a mixture of cement, water and aggregate It has high compressive strength It has good workability as it can be

moulded into different shapes It has high durability value and not much affected by atmospheric conditions It is a good insulator and has a fairly good fire

(B) Reinforced Cement Concrete (RCC) - In reinforced cement concrete, both concrete and reinforcing metal (usually steel) are combined to act together

as one material and produce a more economical material than either acting alone A general proportion of mix is 1:2:4 for general work

(C) Presttessed Concrete - This is a modification over RCC in which steel provides high initial compressive stresses in the concrete so that it may resist

tensile stresses without cracking Prestressed concrete saves upto fifty percent of concrete and quantity of steel is also reduced as high

tens.!!~ steel is used

(D) Lime Concrete - It is a mixture of lime, fine and coarse aggregates and water in 1:2:4 proportion.

(E) Reinforced brick Concrete - It is known as RBC In reinforced brick concrete, steel rods are embedded inrement concrete which take teJlSion

6 TIMBER

Timber is that part of wood of a tree which is of sufficient size and can be used for builQing, carpentary and various other construction purposes Sometrade names of timber available in the market are Babul, Deodar, Teak, Sal and Walnut Timber is available in different forms They are:

* Converted timber, which is sawn and cut into suitable commercial sizes.

j Rough timber, which is ?btained after falling a tree

* Standing timber, which is available in a living tree.

(A) Properties of good timber

* Timber should have sufficient weight A timber with heavy weight is considered to be sound and strong.

* The structure of timber should be uniform, hard and compact.

* It should have favourable physical characteristics such as dark colour, straight fibres, and shining appearance It should be free from defects and goodsound rSl10UIdemit when struck

This is the process of drying of timber in order to remove all the plant juice and moisture out of it so that it will not decay Seasoning of timber may be

(C) Preservation of timber

It is the process of preserving the timber structure from the attack of destroying agents like moisture, fungi and insects to ensure increased life Some ofthe preservatives used are oil paints, coal tar and chemical salts

7 PLYWOOD AND RELATED PRODUCTS

Timber, which is scientifically prepared in factory to meet the desired shape, appearance, size and strength is termed as 'industrial timber' Industrialtimber is available in various varieties such as veneers, plywoods, laminated timber and block boards Such varieties are:

(A) Plywoods

(B) Fibre boards

(C) Block boards

12 INTERIOR DESIGNS PRINCIPLES AND PRACTICE

Veneers are thin sheets or slices of wood of superior quality, which are knife cut by various processes Thickness varies from 0.4 to 0.6 mm or evenmore Veneers are used to produce plywoods, batten boards and laminated boards This process is known as veneering

(A) Plywoods - These are prepared by cementing together thin boards or sheets or'wood into panels Three or more veneers, which are always odd in

numbers are placed one above the other so that the grain of each layer is at right angles to the grain in the adjacent layer The main advantage is uniformstrength and greater resistance to cracking and splitting with change of moisture content The veneers are held by suitable adhesives like synthetic resms.They are available in standard sizes and thickness It is used for interior partitions, doors and panelling

(B) Fibre boards -These are rigid boards, which are prepared after processing pieces of wood, cane and then pressing them together It is also known aspressed wood and available in various forms like laminated boards and hard boards They are used for wall panelling, suspended ceiling and partitions

(C) Block boards - Block board has a core made up of strips of wood glued or joined to form a slab, which is further glued between two or more outer

veneers in such a way that direction of the grain of the core blocks running at right angles to the adjacent outer veneers These boards are Qf two types,

Plastic is an organic material of high molecular weight, which is soft enouglf at some stage of its manufacture to be formed in various shapes by aptftymg

'

(A) Thermoplastics - These plastics are softened by heat during the manufacturing process and regain their original properties as they solidify duriQg

cooling to form the fInished product Some of the uses are PVC tubes, wall tiles, floor tiles and glazing

(B) Thermosetting plastics - These plastics change chemically when heated during manufacturing They solidify while still hot and assumetli~'iQrii1 of

finished product It is not possible to reshape these plastics by means of heat and pressure Some of the uses are Wash basins, water closets, vMves,haIidlesand wall panels

'~

9 GLASS AND RELATED PRODUCTS

Glass is a mixture of number of metallic silicates like pure sand, soda, chalk and one of which is usually an alkali metal Various varieties.~ gi~aredeveloped in recent tiiI}es Some of them are:

INTRODUCfION TO BUILDING MAlERIALS 13

10 PAINTS AND RELATED PRODUCTS

Paints.are the coating of fluid materials applied as a final finish to all surfaces like walls, ceiling, woodwork and metal work

(A) Characteristics of a good p~int

(a) It should possess good spreao~g or covering power

(b) It should be cheap and economical in the long run with easy applicability and drying capacity within a day.

(a) Aluminium paint - This paint c~sists of finely ground aluminium suspended in varnish and ~ evaporation of varnish spirit or oil, the particles ofaluminium form a thin coating on the surface It is used for metal roofs, gas tanks, eledtReal and telephone poles and machinery

(b) Anti-corrosive paint - It consists of oil, a strong drier and a pigment mixed with fine sand It gives black appearance to the surface It is sed to

'

(c) Bituminous and Tar paints - These paints consists of bitumen or tar dissolved in petroleum or spirit They are alkali resistant and possess high

(d) Cement paints - This consists of boiled linseed oil into which dry good cement (65 t075 percent) is mixed so that a paint of workable consistency is

obtained Cement paint is available in powder form in variety of shades It has Ibetter water proof qualities, strength, hardness, durability and

decorative appearance It is used for p,lastered brickwork, stone masonry and concrete It lasts minimum five to six years before renewed painting is

"

(e) Emulsion paint - This paint consists polyvinyl a~etate, synthetic resins etc., giving excellent quality of alkali-resistance It has good workability, high

'

if>Enamelpaint - This paint consists of metallic oxide ground with a small quantityof oil and mixed with petroleumspirit for holding the painttogether It is available in ready made form in variety of colours It dries slowly but after drying it forms a smooth surface It is not affected by hotand cold water and steam,and it is easilywashable.It is used both for internaland externalworks. ,

(g) Oil paint - This is the ordinary paint The oil paints are used in general for all types of surfaces such as'wood work, walls, ceilings and metal work

(h) Plastic paint - It consists of a variety of plastics as the base When this paint is thinned with water, it is known as 'plastic emulsion paint' It has

(i) Distempers - They are considered to be water-paints consisting of whiting or chalk powder, glue as a binder and suitable fast colouring pigments

These are cheap, durable and easily applied on plastered, cement concrete and wall board surfaces '

11 FE~ROUS AND NON-FERROUS METALS'

(a) Cast Iron ~ It is ItlaIlufactured by refining pig iron in a cupola furnace Carbon content in cast iron varies from 1.7 to 4.5 percent It is strong in

compression and weak in, tension It cannot be welded, rolled, puncheq or riveted but caD be melted and cast into various shapes and rusts slowly It

is used for making builcfu\g column brackets, spiral staircases, manhole covers, ra;.n water pipes and sanitary fittings .

(b) Wrought iron - It is the p1.\re~tform of iron with low carbon content (less than 0.15 percent) It is hard and can be bent, twisted, rusts more quickly

than cast iron It is replace~ brmild steel at present, so it is produced in small quantity It is used for making tough materials such as nails, bolts,chains, sheets, handrails an4 ornamental gates

"

(c) Steels - Steel is an alloy or compound of irOn and carbon in the form of carbide of iron The carbon percentage is limited to 1.5 There are three

1 Low carbon or mild steel

2 Medium carbon or hard steel

,.'

3 High carbon steel." ,

The increase of carbon percentage increases the tenacity and hardness Steel is used for trusses, beams, griiIs, mechanical devices and sheets

14 INTERIOR DESIGNS PRINCIPLES AND PRACflCE

(B) Non-ferrous- metals - These are the metals which do not contain iron as their main constituent They are of several types Three of these metals are

(a) Aluminium - It is silvery white lustrous metaIobtained from 'Bauxite' ore Pure aluminium is very soft and it is mixed with other metals like copper,magnesium, silicon, manganese and others to increase tensile strength and hardness while retaining the character of lightness and durability It is

. corrosion resistant and good conductor of heat and electricity It is used for roofmg, window frames, glazing bars, posts, panels., wires and in paintS

(b) Lead - It is bluish grey in colour with silvery lustre when freshly cut and available in free state It is resistant to atmosphere corrosion and not

affected by soil, sewage and industrial wastes It is used for roofmg, water service pipes, cable coverings and ornamental work

(c) Copper - Copper is extracted by smelting 'Copper Pyrites' which is an ore of copper Pure copper is of lustrous red colour, light, tough and good

(a) Brass - It is all alloy of copper and zinc Commercial brass contains 65 percent copper and 35 percent zinc Properties of brasses vary considerably

by changing these proportions It resists corrosion but needs regular cleaning It is used for door and window fittings, household utensils andhardware

(b) Bronze - It is an alloy of copper, zinc and tin containing 80 percent copper Bronzes are hardened copper They are stronger and superior to brass in

cOrrosionresistance It is difficult to work and niore expensive It is used for frames, grills and hardware

12 GYPSUM AND RELATED PRODUCTS

(A) Gypsum -It is a combination of calcium sulphate with water and the white substance is found in the form of rock in nature It is mainly used in th~

(B) Plaster of paris (POP) -When finely ground gypsum rock is heated to a temperature between 100°C and 140°C, three fourth of the combined waterpasses off as a steam The remaining product is known as 'plaster of paris' It is used for ornamental work and its products are hard-surfaced, can have sharpcontours and they are sufficiently strong Gypsum plaster is rendered more plastic by the addition of clay on hydrated lime Its cohesiveness is increased by

(C) Plaster board - It isa large sheet of gypsum plaster faced on both sides with stout paper as a reinforcement Depending upon the nature of facing

1 Gypsum lath board, when the facing paper is rough and provide adhesive grip for plaster finish

2 Plaster wall board, when facing paper is of self-finish type for decoration They have good insulation properties and used for ceilings and partitions.

(D) Asbestos - It is naturally occuring mineral substance composed of hydrous silicates and contains small amount of" iron oxide and alumina It islargely uSed for preparing Asbestos Cement, which is used for making pipes and roofing material Asbestos felt is used as damp' proof layer for insulation and

13 ADHESIVES (OR GLUES)

An adhesive is a substance which enables two surfaces to stick together and behave as a single unit They are classified into two types:

(A) Organic adhesives are made out of animal blood albumin, vegetables, milk and other organic wastes

(B) Synthetic adhesives are permanent, strong, water proof and made out of chemical resins

EXERCISE

1 Describe the properties and uses of the following building materials:

(a) Stone . (b) Clay

2 Describe the properties and uses of the following building materials:

(€i) Plywood (b) Plastics

(d) Paints (e) Metal.s

(c) Cement

(j) Timber (c) Glass if) Gypsum

In the present context, plumbing services mean Water supply and Sanitation including sewerage and drainage The importance of plumbing services iswell known in a building This knowledge helps an Interior Designer to plan the interiors efficiently keeping in view of these service requirements.

1 WATER SUPPLY

Public water supply system consists of collection, conveyance, treatment and distribution Water is distributed for consumption in a building throughinternal water distribution system Water supply in a building depends on the size :md height of the building Large and tall buildings create numerous

16 .INTERIOR DESIGNS PRINCIPLES AND PRACTICE

installation and design problems, whereas in low rise buildings they are not found Water piping system may be basically horizontal or vertical Systemsabove the main or pressure tank are called upfeed systems In tall buildings water is pumped to elevated tanks, so that it can flow down Adequate water isneeded for drinking, fire protection and general use Before designing a building water requirement should be calculated keeping the present and future needs

of the 9ccupants Availability of sufficient quantity of water sources like municipal water, ground water and surface water should be found Normallymunicipal water is treated and supplied, whereas ground and surface water should be properly treated as per the need of the users Distribution of water is

'Residential buildings are nOrmaHy-ooe t~<?or three storeyed constructions Individual residences are connected to the public water main by a servicepipe A water meter is connected to the service mm Once the service pipe emerges from the floor level of the building, it is referred as the rising main Thes(:rvice pipe can supply to upper floors depending upon the available water pressure If adeEluate pressure is not available, then water can be collected in asUmp, which can be constructed below the ground floor level and pumped up to the elevated water tanks with a motor From these tanks, water can bedistributed down with gravity pressure Water storage tanks located on the terrace should be properly covered and protected from contamination Plastic water, tanks are preferred for storage pU1Jl ose. '

B Water supply in multi storeyed buildings

Water supply pressure from the main will not be sufficient to reach the upper floors on many occasions, so it is necessary to pump it to reach the upperfloors The water requirement in such buildings is very high for both drinking and general use Thus there is a need to store water and supply it with gravitypressure The storage of water is possible only on the terrace of the building Pumping of water from the main becomes a necessity, but continuous operationwould be costly and difficult to maintain To avoid this, storage techniques are employed to prevent continuous pumping Most common storage systems usedare:

(a) The header storage system

(b) Enclosed tank system

(a) The header storage system - In this system, water is pumped through the rising main to the terrace of the building, where two storage tanks are

placed One is meant for drinking water, and the overflowing water from this tank is connected and collected in another storage tank for general use.The storage capacity of the drinking water tank is calculated as 5-7 litres per dwelling unit in the case of residential buildings The storage water issupplied with gravity pressure.in separate pipes for drinking and general use

(b) Enclosed tank system - Normally drinking water is directly taken from the main because storage can lead to contamination and bad taste However,storage of drinking water is inevitable due to various reasons for daily use So it should be stored in an enclosed, insulated and ventilated tanks toavoid contamination and bad taste There are two common storage systems adopted for this purpose In one system, two separate tanks are locatedfor drinking water and general use at the ground or basement floor level The capacity of the tanks at the roof level can be dwelling unit-wise orfloor-wise or one for all the dwelling units This calculation depends on the space and convenience In another system, a large tank is located in the

separately for drinking and general use From these storage tanks, water is supplied by gravity pressure in separate pipes for drinking and general

C Piping materials

Cast iron, steel, concrete and asbestos cement are the most common materials used in distribution pipes Copper, lead, Zinc, brass, bronze and plastic areused in small pipes, valves, pumps and 'other appurtenances Common pipe joint materials are lead, cement, sand, rubber, plastic and sulphur compounds.Stoneware pipes are mostly used for underground work Cast iron is the most common material for city water mains Steel is commonly used for large

pipelines and trunk mains but rarely used for distribution mains Concrete pipes may be precast in sections and assembled on the job or cast in place Hume .

pipes are RCC pipes used for drainage,irrigation,wells and culverts.Galvanisedpipes of steel or wroughtiron are widely used for distributionsystems .

Thes~ pipes are used where pipes are to be exposed to corrosive conditions such as salt water or air Lead pipes are not generally used for domestic watersupply They can be used for flushing and overflow pipes inside the buildings PVC pipes are more flexible, conosion resistant, light weight, easy to handleand install It is comparatively cheaper They are not suitable for hot water installations

2 SANITATION

Water after usage becomes waste water, which should be collected and conveyed through drain pipes to join the municipal sewers laid under the roads.The surface and rain water is also let into the sewers in the combined drainage system The waste water is let into the municipal sewers through undergroundchambers like manholes connected by traps like gully trap, intercepting trap, grease trap, silt trap and ventilating pipes The primary function of the trap is toseal the foul air entering the building

A Traps

Traps prevent entry of foul gases and odour from municipal sewers and drains Depending on the need, a water seal is created as a barrier The depth ofthe water seal can be between 35 rom to 75 rom These traps should be created as close to the unit as possible Efficiency of the water seal depends on thedepth of the water Traps should be made of non-absorbent material Entry inlet into a drain should be properly trapped with a water seal It should beprovided with a cap or plug for cleaning Traps can be made of different shapes Most conimon shapes of traps are p Q and S (See Fig 4.1,4.1.2, 4.1.3)

(a) Gully trap'- Gully traps disconnect the sullage drain of the house from the main drain They are employed to receive sullage or waste water from

wash basins, sinks and baths and pass it on to the house d'mns Gully traps should be fixed near the surface level of the flOQr.There should be a

grating on top of the tiap to block solid matter Pipes should be connected to the gully trap below the grating In combined system of sewage the rainwater is also passed into the house drains through the gully traps (See Fig 4.1.5).

(b) Intercepting Trap - It is also known as 'sewer'trap It disconnects the house drain from the street sewer It can be fixed in the last manhole of the

house or in a separate small chamber between tbe lowest end of the house drain and the street sewer It has a comparatively deeper water seal thanordinary trap and an opening at the top of the trap known as 'cleaning eye' This opening is closed with a plug The intercepting traps should beproperly flushed out otherwise they wilJ not be of much use (See Fig 4.1.4)

(c) Grease trap - Grease traps are used where large quantities of oily wastes are let out into the drain like hotels, restaurants and some industries These

oily substances deposit solids in the house drains and municipal sewers To avoid this, grease traps are used Grease trap can be a small cast iron ormasonry chamber with a bent pipe as on outlet The oily substances float to the surface to form a scum on top The bent pipe allows the sewage toflow out while retaining the scum This scum cari be removed out from the top (See Fig 4.1.6) .

(d) Silllrap - Washing of kitchen utensils, sometimes, involves ash and pulverised brick pieces These particles need steep slopes and higher velocities

PLUMBING 19

'.! ",

in the drain for movement These should be trapped and removed in silt traps These silt traps are required where extensive utensil washing is carriedout like hotels and restaurants Silt and grease traps can be combined.'

B Waste Water Disposal

Waste water Disposal is done through inspection chambers or manholes, septic tanks and with proper ventilation systems

(a) Inspection chamber or Manhole - For cleaning, repair and inspection of house drains masonry inspection chambers or manholes are constructed onhouse drains It is provided at every junction or change of direction or gradient and at 30 m intervals in the long straight lengths TIle drainage pipesare opened out in these chambers to form channels The bottom is given steep slope towards the open channel in the centre of the chamber Thisprevents blockages and deposits of soil in the pipes The chambers are closed from top with cast iron covers to prevent escape of foul gases The size

of the chamber depends on the underground depth and number of branches to be connected (See Fig 4.2.1)

(b) Septic tank - The function of a septic tank is to produce some biological changes of the human excreta and reduce the bulk of sewage This system

is useful where municipal sewerage system is not available In the septic tank lighter matter rises to the surface and form a thick layer called 'scum'while heavIer matter sinks to the bottom as 'sludge', The tanks are made air-tight, water-tight and excluded from light to help the sewagedecomposition process The layers of scum and sludge are not disturbed by the flow of water by making a vertical partition wall called as 'bafflewall' The size of a septic tank depends on the number of users A septic tank should be initially filled with water and constructed far away from thehouse The effluent may be disposed into a cesspool The size of the cesspool depends on the absorption capacity of the soil and the number of users

A cesspool is constructed with bricks or stones with open joints below the level of inlet pipe The cesspool may be filled with gravel or brickbats at

(c) Ventilation systems - Ventilation system is necessary to let out the foul gases developed inside the drains If the foul gases does not escape into the

air, they may break the water seal of the traps The ventilation ducts dilute the foul gases and their poisonous effects These fresh air inlets can beprovided by an outlet pipe directly connected to the underground drain or over the manhole and rise above the roof level of the building The freshair inlet should be vertical, about 100 mm diameter, atleast 3 m above ground level and with a slotted cast iron head on top A long 30 to 50 nundiameter cast iron pipe is used as an outlet pipe

In addition to this, ventilation system should be provided on every soil and waste pipe of every water closet and bath When wc's of more than one floorare connected with the same soil pipe, an anti-siphonage pipe or vent pipe is fixed to the outlet side to both the traps to prevent siphonic action and emptying

of the sealed traps in the lower water-closets when the upper water-closet is flushed The vent pipe should have a diameter of not less than 50 mm andconnected at an angle of 45° from the highest part of the trap The vent pipe can be taken up to the top of the soil pipe and provided with a wire globe Thisvent pipe should be taken above the level of the building roof (See Fig 4.2.2)

c Sanitary appliances

There are various types of sanitary appliances available in the market Most commonly used sanitary appliances are

(g) Water closets

(a) Wash basins - There are various types and shapes of wash basins for different uses They are made of cast iron, steel, porcelain and plastic materials.

The standard wash basin consists of a bowl, soap tray and holes for tap and water overflow TIley may be supported on cast iron brackets screwed tothe wall or on a pedestal concealing the pipework They 'are normally fixed at 0.80 m above the floor level for convenience (See Fig 4.3.1)

(b) Sinks - Sinks are normally used in the kitchens or at places where frequent cleaning is required Sinks are made of porcelain, steel and plasticmaterials There are three types of sinks They are Belfast type, ordinary type and stainless steel type The belfast type has water overflow whichpasses water to the waste pipe A drain board may be fixed on either side of the sink or the drain can be integrated into the sink Ordinary sink issimilar to Belfast type but it does not have proVision for water overflow Stainless steel sinks have drain board on either side or on one side withsingle or double bowls as per the need (See Fig 4.3.2)

(c) Showers - Shower is most commonly used in the residences It is more hygienic and takes less space and water The mixer may be thermostatic or

non-thermostatic The shower tray is made of plastic and porcelain materials The bore of the supply pipes is 13 mm and the pipes should be as short

as possible to avoid frictional losses The minimum height above the shower outlet should be 1.0 m In place of a shower tray, hU'ger tiled space isalso used for taking shower on some occasions (See Fig 4.3.4)

(d) Bath tubs - Bath tubs are used in western type of toilets Bath tubs are used for relaxed bathing They are made of porcelain, steel and plastic

materials These tubs are provided with holes for hot and cold water pipes for mixing before taking bath Provision is also made for water overflowand waste outlet These bath tubs can be made of different fancy shapes and sizes Normally the length varies from 165 to 180 cm, width varies from

55 to 58 cm and depth 40 to 45 cm The bottom of the tub is supported with short legs on the floor (See Fig 4.3.3)

(e) Urinals - There are four types of urinals called as Bowl type, slab type, stall type and squatting plate type used by ladies Slab and stall type urinals

are used in public toilets The bowl type is screwed to the wall and if two or more bowls are fitt~d division pieces may be fixed between them Theslab type consists of flat slabs fixed against the wan with projecting end slabs an~ common channel The stall type consists of curved stalls withdividing pieces and glazed channel The foot rests should be non-slippery and sloping towards the channels Ordinary brick walls with cementplastered surfaces are not suitable for urinals They should be cladded with glazed tiles and joints should withstand the chemical reaction The urinalwaste pipes can be in plastic or lead with 50 mm diameter Not more than seven urinals should drain into one outlet Urinals are normally made ofglazed tiles porcelain and plastic materials

(j) Flushing cistern - Flushing cistern is a tank which discharges water for flushing out a water closet or urinal Flushing cisterns are made of cast iron,

porcelain and plastic materials There are two types of cisterns, the bell type and the disc type, which are most commonly used The bell type offlushing cistern is noisy The cistern is operated by pulling down the chain and lifting the bell When the water runs down it takes away some air and

it results in vaccum on the tDp of the bell The water gets empty within few seconds due to the syphonic action The water to the cistern is suppliedthrough ball valve arrangement (See Fig 4.4.3)

The disc type flushing cistern is commonly used in all types of buildings The cistern is operated by a lever which lifts the piston and water istlushed by siphon action (See Fig 4.4.4)

There arc other types of Ilushing cisterns like flushing trough and automatic flushing cisterns and valves A flushing trough is used as analternative to separate nushing cisterns for the flushing of more number of wc's Automatic flushing cisterns and valves are also used for similarpurpose in puolic toilets

(g) Water closets Waler closets can be classified into Indian and western types In Indian type of wc, squatting pan is used In western type of ~c,siuing pan is used There arc two types of flushing systems adopted They are wash down type and syphonic type In the wash down type a highlevel tlushing cistern ahove the door level is used for flushing In the syphonic type, a low level flushing cistern is used The surfaces ofthe bowl are

designed to slow down the flow of water and the pipe is filled with water causing siphonic action The siphonic wc's are comparatively quieter inoperation (See Fig 4.4.1 & 4.4.2)

(h) The following tables gives the different sizes of pipes for fixture supplies.

Table 4.3 Different sizes of pipes

D Plumbing systems

(a) One pipe appliances - In this system only one main pipe collects both soil waste and waste water from different appliances In multistoreyed

buildings the lavatory blocks on different floors are placed above one another so that the waste water from different units can be carried throughcommon vertical pipes connected by short branch drains Thus only one main pipe collects both soil and waste water from different appliances This.main pipe is directly connected to drainage system All traps of wc's and wash basins are completely ventilated whereas gully traps and waste pipesare not provided

(b) Single stack system - This is same as one pipe system but no ventilation of traps is provided.

(c) Single stack-partially ventilated system - This is a compromise between one pipe system and single stack system There is only one soil pipe for

colfecting the discharge from all water closets, baths, sinks and basins A relief vent pipe for ventilating only the traps of wc's is provided

(d) Two pipe system - In this system separate soil and waste pipe are provided The soil pipes are directly cOIlllected to the drain, whereas waste pipes

are coIlllected through a trapped gully All traps are completely ventilated

In India, the two pipe system is comparatively more convenient because close grouping of fixtures is not necessary However in multistoreyed buildingsone pipe system is preferable because close grouping of toilets is necessary for convenience and economy

E Residence drainage plan

The Fig 4.5 shows residence drainage plan It is assumed that the drainage and sewer lines are combined

EXERCISE

1 Describe the water supply systems in multi-storeyed buildings?

2 Describe various traps used in the sanitation of buildings?

3 What are the different wa.'Ite water disposal systems ?

4 Describe the important sanitary appliances?

S What are the various plumbing systems adopted in buildings?

Ventilation means supply of fresh air and removing dust, heat and other pollutants for human comfort Natural ventilation is very important for healthyliving 1bere are many buildings, which we see around us are very poorly ventilated These poorly ventilated buildings' are not in city slums, but in denselybuilt up areas, particularly in the centre of the city As an Interior Designer, it is essential to ensure good natural ventilation in any building interior Natural 'ventilation helps in improving hygienic conditions For any type of interior design and planning, it is important to create healthy living conditions otherwisethere is no difference between old and new buildings Everything stands next only to this primary concern.

A The following factors should be taken into consideration for natural ventilation

(a) Room or building size.

(b) Activity performed in a room or building.

(c) Number of occupants.

(d) Heat and relative humidity

(e) Other pollutants like smoke, dust and fuw es.

B AtIeast one window should be provided on the windward wall and another window on the opposite side of the wall

C In case of a room with only one wall exposed outside, two windows are preferable' than a single window

E Maximum air movemeIit is achieved by keeping the silI height at 0.75 m to 0.90 m from the floor level

G The average wind velocity inside a room may be around 27 percent of the out door air velocity

H Openings of equal size are preferred in regions having fairly constant wind direction

A Ventilation with fans

Mechanical ventilation is necessary, where natural ventilation is not possible and to remove pollutants The use of mechanical ventilation will allow forprovision of air temperature control, humidity and purity Buildings of different use demand different quantities of fresh air for their occupants It is expressed

in terms of air changes per hour For air motion, fans and exhaust fans are used Fans should be chosen based on the area to be ventilated and not on the size

of the room alone They should be uniformly distributed for proper ventilation The following table can be used as a thumb rule, but precise ventilationrequirements should be calculated based on the activity performed in the room or building.

Table 5.1 Fans for rooms of different sizes

Source: Central Building Research Institute, India.

Note: Room length & width and fan sizes are in meters

B Ventilation with ducts

While designing ducts for air, number of features should be incorporated The duct should be smooth The number of changes of directions of the ductshould be minimised Branches from main ducts should be made with a gradual curve and should not be sharp Galvanised mild steel is the most widely usedduct material This may be pressed into rectangular sections and bolted or riveted Circular ducts can also be made with wrapped flat sheets As the size of; theduct increases, there is a possibility of the wall vibrating due to the air movement Efficient delivery of air to rooni spaces involves detailed calculation oeairflow velocities At the points of delivery, the cross sectional profile of the duct may become smaller Conical diffusers are best for efficient throw of air intothe space Dampers within the ducts will control the flow of air and resists spread of fire Ventilation ducts may extend to all areas of a building creatingpotential routes for noise transfer Proper care should be taken to contain it

3 RECOMMENDED FRESH AIR SUPPLY

Recommended minimUm rates of fresh air supply to buildings for human habitation: ,

Table ~.2 Minimum Rates of Fresh AirSupply

A =Area of openings provided on wall in m2.

Q =Desired rate of air flow in m3lb

V=Prevailing outdoor wind speed in m/h

K=Co-efficient of flow, which can be taken as

* 0.6 for wind perpendicular to the openings

* 0.3 for wind incident at 45° to the openings

* 0.025 for windows on one external wall only

EXERCISE

1 What are the guidelines for good natural ventilation?

2 Describe the methods of mechanical ventilation?

3 How do you calculate the size of openings for good natural ventilation?

4 SIZE OF THE OPENINGS FOR NATURAL VENTILATION

Normally fifteen to twenty percent of the floor area is taken for the openings like windows and ventilators to provide light and air However, there is ascientific method of calculating the openings for permanent ventilation based on Bureau of Indian Standards, 1988

A.Openings of the size obtained by the following equation should be provided on wind facing wall and also on the opposite wall

Source: Bureau of Indian Standards, 1988.

Note: Air change per hour is the volume of outside air allowed into a room in one hour compared with the volume of the room.

30 IN1ERIOR DESIGNS PRINCIPLES AND PRACftCE

C Humidity

The control of humidity in the air is very important Dry air puts strain on the nasal vassages of the nose making them dry and irritating To avoid thismoisture is added to the heated' air This process is called 'Humidification', and it is done d;11fingthe winter season The moisture is extracted from the cOOledair during summer This process is called 'Dehumidification' Normal relative humidity should be between 40 to 60 percent in the air The desirable relativehumidity for human comfort is 40 to 50 percent during summer and 50 to 60 percent during winter

3 PROCESS OF AIR-CONDITIONING

Air is a mixture of various substances composed of gases like nitrogen, oxygen, heliuIIl etc., It can absorb moisture in the form of vapour The amount ofmoistur~ it can absorb depends on air temperature Apart from these, air can have suspension dust particles, bacteria etc., In summer air-conditioning involvesair cooling, dehumidifying, air cleaning and air distribution In winter the cycle involves air heating, humidification, air cleaning and air distribution Boththese operations should be done for a whole year use in the case of composite air conditiorring, The following filters are used for air cleaning

The impurities in the air are trapped and retained in the filter element The materials normally used are glass fibre, steel wool, bronze or copper wool etc.,

B Dry strainer filters

These fIlters have collecting surfaces made of cloth, felt, glass fibre etc.,

The earlier method is by diluting with outdoor air The present method is to use chemiCaldeodarants to reduce odour

4 AIR-CONDITIONING UNDER INDIAN CLIMATIC CONDITIONS

In India, authentic research is not available on this subject However, comfort zone for hUIllan activity can be presumed as 25°C to 30°C temperature and

45 to' 60 percent relative humidity For health reasons, ror-conditioned spaces which are ftequently used by people, should have entrance lobbies where th~temperatures are kept midway between exterior and interior spaces to avoid sudden changC of atmosphere All structural elements used in the buildings like

5 TYPES OF AIR-CONDITIONING METHODS

A The foUowing cycle is involved in air-conditioning of any system

(a) Sucking the outside air through a fIltering media.

(b) Heating Of cooling the air.

(c) Humidifying the air while heating is needed, and dehumidifying the air whil.e cooling is needed

(d) The air is passed through ducts for circulation to the designed spaces.

1 Cleaning of air

2 Cooling or heating of air

3 Humidification or Dehumidification of air

4 Circulation of air tllfOUgh ducts

5 AC space

7 Mixing of outside and used air

B The followingtenns are cODimonly used in air-conditioning systems:

(b) Wet bulb temperature - The temperature of air recorded by a thermometer whose bulb is covered with a wetted wick and exposed to a current of

(c) Dew point temperature - The temperature at which condensation of moisture begins when air is cooled.

(d) Relative humidity - The ratio of actual water vapour pressure of the air to the saturated water vapour pressure of the air at the same temperature.

C Complete air-conditioning is used where the temperature and humidity are controlled by a mechanical system; There are basically two types ofsystems:

(a) Centralised system

(b) Self-contained or packaged system

(a) Centralised system - In this.system all the equipment for air-conditioning is installed at one place and the conditioned air is distributed tllfough

ducts The necessary equipment is assembled on the spot than in the factory The entire space to be air-conditioned is divided into different areas Thetemperature and humidity can be adjusted according to the specific requirements of each area This system is economical because one system serves

(b) Self-contained or packaged system - A self-contained system comes with complete equipment of compressor, condenser, evaporator, fan, ftlter and

controls Smaller units are kept within the room and larger units are placed at a different place and connected by ducts This system is designed forapplication in smaller establishments like shops, restaurants etc., Room air-conditioJ1ers are small self-contained units Most of them are air-cooledunits to be placed on a window sill or near a source of outside air Some of them are available for winter heating also These units are self-containedand the conditioned air is formed inside the unit and directly opened into the room without any help of ducts .

Sometimes a combination of the two systems is preferred The choice of a particular system depends on several factors like size of the structure, heatingand cooling requirement, spa<?eavailability, cost and similar other factors

32 IN1ERlORDESIGNS PRINCIPLES AND PRACfICE

Summer air-conditioning needs the use of cooling medium, so it requires some artificial method of cooling The major refrigeration methods used for

air-conditioningare: .

A Mechanical vapour compression system

B Vapour absorption system

Any liquid requires heat to be transformed into its gas or vapour state Generally, if the pressure is increased then the transformation also increasesquickly The refrigerants normally used for cooling are Freon 11, 12 & 22 and in some cases ammonia is also used The refrigerant at a pressure andtemperature can be made to evaporate by allowing it expand to a lower pressure with the help of a throttle It will have to absorb heat from the surroundings

B Vapour absorption system

In this process, the refrigerant used is water Water absorbs heat while boiling The evaporation is absorbed by a solution of lithium bromide The weaklithium bromide solution is pumped into a generator where steam heats the solution This heating bOils the lithium bromide solution giving away the water

Most commonly used equipment in refrigeration and air-conditioning system are compressors, evaporators, condensers, cooling towers, spray ponds,expansion valves, air handling units and dUCl-;.Air-conditioning has become a specialised area requiring the services of a specialist for design, particularly forlarge spaces like cinema theatres, auditoriums, hospitals etc., For an interior designer it is essential to know the various units and arrangements iilair-conditioning so that proper care is taken in designing the interiors for air-conditioning

i

7 CALCULATION OF PACKAGED SYSTEMS

The air-conditioning equipment should have the capacity to maintain comfort conditions inside Ii room with minim~ energy consumption In decidingthe type of system for cooling, there arc many factors which should be taken into consideration like number of windows, occupants, floor level, buildingorientation etc., However the package systems available in the market arc made of standard capacities The following table is meant for average climatic

Table 6.1 Capacity of systems for cooling

EXERCISE

1 What are the atmospheric conditions required for human comfort? What is the need for air-conditioning?

2 Describe the process of air-conditioning? . ' .

3 What are the different methods of air-conditioning?

4 What are the refrigeration methods ?

Natural lighting is the light available in nature We perform all our activities in this daylight Daylight is nothing but sunlight on earth Intensity ofsunlight varies depending upon the atmospheric conditions Sunlight is very bright in the morning and dull in the evening Its brightness is more in theafternoon causing glare, and we try to protect our eyes with a shade from this glare When we construct buildings we try to make use of this daylight toperform our activities inside a sheltered space The availability of the daylight within a building will not be the same as it is outside because of the roof andwalls of the structure The admission of daylight into the building depends upon the number of openings provided in the building If the building -isopen onall thefour sides then the daylight is not cut-off by any obstruction, but such a situation is uncommon in the densely populated areas 'Qfthe city In India, it ispreferable to use as much daylight as possible to save energy However, it is not possible on many occasions to provide totaldaylight'inside the building Onsuch occasions, a combination of artificial and natural lighting is preferable This will help to save energy without sacrificing lighting requirements .It isdifficult to measure the availability of daylight inside a building, but certain factors can be taken into consideration to measure it.

1 DAYLIGHT FACTOR

The daylight received inside a building is measured as "the ratio of illumination at the working place inside a room to the total light available outside".This is called as 'Daylight Factor (DF)', which is expressed in percentage The daylight factor includes the following:

(a) Sky component (SC) - light received from the sky excluding direct sunlight

(b) t.xternal reflected component (ERC) -light received from exterior reflecting surfaces ,

(c) Internal reflected component (IRC) -light received from internal reflecting surfaces .

Thus the daylight available inside a building is only filtered and reflected sunlight The value of sky Component (SC) is zero, when there is a completeroof over a building It receives only ERC & IRe Light coloured surfaces have high reflection factor and dark coloured surfaces have low reflectioh factor.The other parameters essential in interior daylighting design are outdoor atmospheric conditions room size & shape internal finishes, external obstructions &finishes and openings like windows & ventilators

3 CALCULATION OF THE OPENINGS FOR NA~ LIGHTING

The amount of daylight needed for perfonning an activitJ can be derived from the above table The required number of openings can be derived from theFig 7.1 The following assumptions are made, forcalcu1ating the openings for natural lighting in the Fig 7.1

(a) Window areas are fo~ metal sasbes with usual dirt collection on glass.

(b) For windows with wooden sashes these areas sbould be increased by ten percent.

(c) External reflected light is accounted.

(d) The \;Vin49w areas are for room depths upto ten meters

(e) The windows should be located to have uniform spread of light.

if) Sill level should be 1.0 to 1.2 meters

(g) The height of window should be 1.2 m or more.

(h) External shading means sunsl;wJes or similar other shades.

(i) ':l1e graph gives window areas for lS6lated buildings only.

\\i\.'r ;tdji)ining huildings are QUite high and obstruct the light the values should be increased as given below

!{;llio =Distance between the buildings I Height of the obstructing building