replacement of vitiated air by a supply of fresh outdoc t but also control of the quality of incoming air with regard of infection. Standards of ventilation The fixing of standards of ventilation is a matter of difficulty. Most of the standards of ventilation have 6 based on the efficiency of ventilation in removing Bo odour, (1) Cubic space ; Different workers have advocal standards for the minimal fresh air supply ranging fromd to 3,000 c.ft. per hour per person (1). The widely quol standard is that of De Chaumont who advocated a fres supply of 3,000 c.ft. per person per hour on the fo grounds: It was observed that so long as the amo carbon dioxide due to respiration was not more than 2 ‘n 10,000 parts of air, the air of the rooms seemed fresh al did not sensibly differ from outdoor air. Assuming tha average person expires 0.6 c.ft. of carbon dioxide per hot and that 0.0002 c.ft. of CO. in one c.ft. of air as” ssible impuVENTILATION, 3,000 eft. of air would be required by a man at 1 3or This standard of ventilation is no longer folew ont {2) Air change : It is now established that the carbon dioxide fheory is not quite correct because even if the CO, content of ait i raised to over 5 per cent and the O, content rechiced 28 per cent, there were no deleterious effects so long as the “cooling power” of the air was satisfactory. Air change Is iNsre important than the cubic space requirement. It is Teommended that in the living rooms, there should be 2 or 3 ai changes in one hour; in work rooms and assemblies 4 oat changes, the ats changed moe equi ie more than 6 times in one hour, it is likely to produce a Talat which should be avoided. Based on this Concept, {how considered that a space of 1,000 to 1,200 et. per person is quite sufficient. The number of air changes per four is calculated by dividing the total hourly ait supply to the room by the cubie capacity of the room (1), (3) Floor spoce : Floor space per person is even more important than Gubic space. Heights in excess of 10 to 12 feet are ineffective fom the point of view of ventilation, as the products of respiration tend to accurnulate in the lower levels. Therefore, yp calculating cubic space requirements, heights over 10 to 42 {ect are not taken into account. The optimum floor space requirements per person vary from 50 to 100 sact. ‘Types of ventilation 1, NATURAL VENTILATION Natural ventilation is the simplest system of ventilating small dwellings, schools and offices. In this method, reliance ‘on certain forces which operate in nature. These THE WIND : The wind is an active force in When it blows through a room, it is called ‘n. When there is an obstruction, it bypasses and o suction action at its tail end ~ this is called tion, Doors and windows facing each other provide scoss-ventilation”. Back to back houses do not permit cross Ventilation and therefore, their construction is not allowed, (2) DIFFUSION : Air passes through the smallest openings or iffusion, This is a slow process and therefore. is spac pot relied upon as the sole, means of ventilation. (3) INEQUALITY OF TEMPERATURE : Air flows from high density 10 low density; it rises when slightly heated and teens om openings provided high up in the room. The eee, eee it fooler and more dense will enter the Soo en eee placed low. The greater the temperature difference between outside and inside air, the greater the i'n the tropies he ouside ai Wvelocity of the incoming may be hotter than the inside and the reverse may take place (2). These properties of air are utilized to best fdvantage by the proper location of windows, doors, The chief drawback of natural enilators and skylights vial velocity of ventilation is that itis not possible to regulate the he incoming air nor to adjust its temperature or humidity 2. MECHANICAL VENTILATION ventilation may be of the Mechanical or artificial following types, (1) Exhaust ventilation. (2) Plenum ventilation ) Balanced ventilation, (4) Air conditioning, In this system, air is (1) EXHAUST VENTILATION Bxtracted or exhausted to the outside Bsually driven by eleciticiy. As air is exhaust Freatedl which induces fresh air to enter the room through Windows, doors and other inlets. Exhaust ventilation is by exhaust fans generally provided in large halls and auditoria for removal Of vitiated air, The exhaust fans are housed in apertures in the external walls, high up near the roof which facilitate removal of the upper layers of the heated light air. The ventilation may be regulated by adjusting the speed of the fans. Local exhaust ventilation is widely used in industries to remove dusts, fumes and other concentrated contaminants at their source, (2) PLENUM VENTILATION : In this system, fresh air is blown into the room by centrifugal fans so as to create a positive pressure, and displace the vitiated air Plenum or propulsion system is used for supplying air to air conditioned buildings and factories. Air is delivered through ducts al desired points. This system is of limited utility (3) BALANCED VENTILATION: This is a combination of the exhaust and plenum systems of ventilation. The blowing fan must balance the exhaust fan. When this system is employed. the natural system of ventilation is entirely dispensed with, (4) AIR CONDITIONING : Air conditioning {s defined as “the simultaneous control of all, or at least the first three of those factors affecting both the physical and ions of the atmosphere within any confined Space or room. These factors include temperature, humidity, air movement, distribution, dust, bacteria, odours and toxic gases, most of which affect in greater or lesser degree the fuman health and comfort". Air conditioning is popular in large institutions, hospitals, industries and dwellings. Its use in operation theatres is of particular value in control of pathogenic organisms in the air. The air is filtered when ‘iawn into an airconditioner system from the room. Excess humidity is removed and the air is cicculated back into the room after heating or cooling it, to bring room temperature to required comfort zone. Mixing some percentage of fresh air with recirculated air is regulated. Large institutions or hospitals often install central airconditioning system for entire building, instead of installing equipments for individual rooms. Better controls and economy is achieved in central airconditioning. Where the temperature difference is large between outside atmosphere and airconditioned room, “transition room” is sometimes provided, which maintains temperature in between the two, so as to prevent sudden exposure to high or low temperature. ‘chemical condi References 1. Bedford, T (1964), Base Principles of Ventilation and Heatin London, Wilkie W, (1965), Jordan's Tropical Fiygiene and Sanitation, Bailie Tindall & Co Ee LIGHT The requirements of good lighting ng is essential for efficient vision. Ifthe lighting, fe not ideal, the visual apparatus is put to strain Good igh tihich may lead fo general fatigue aid loss of elilency. For {1) SUFFICIENCY! The lighting should be sulfiient to enable the eye to discern the details of the oblect as well as the 20 fool candles (1 foot candle = 10,76 Lux) is accepted asa base inn for sas von the tmination requlrements vary from ete as foot candles in stalrvays find coridors to. 100 foot candles. in some. industries (2) DISTRIBUTION «The distibution of hght should. be Uniform, having the same intensity, over the whole feld ofin the modern concept includes not ‘ure’ providing shelter, but also the imm ‘and the telated community. services furinies, It has become part of the concept of ‘eeflement”, which is defined as “all places in which a gro Ble reside and pursue their Ife goals: the size of Petlement may vary froma single family to millions of pe 'AWHO Expert Group (1961) on public health asp howeing prefers to use the term “residential environ ie Refined as the physical structure that man uses Ye environs of the structure including all necessary se Sites, equipment and devices needed or desired fo physical and mental health and the social well-being of Family and the individual (1). The immediate surrounding ot residential building are often referred to as neighbourhood or microdistriet. “Housing”, ‘physical struc surroundings, Social goals of housing Goals are statements about desirable or proj conditions. The generally accepted goals of housing (2) Shelter > That the house should provide a sanita Shelter, which is a basic need. (2) Family life: That the hous Should provide adequate space for family life and relat activities, viz preparation and storage of food, meetin Scoping, individual activities and other basic activities. T adequacy of housing at this level has been found to have direct impact on such things as worker productivity family stability, (3) Access to community facilities : A clement of housing is accessibility to community servi Snd facilities such as health services, schools, shopt seas, places of worship etc. (4) Family participation Community life < Family is part of the wider commu Community is important to family in many ways ~ it Ser help in times of need: it is an important source ¢ friends, Communities are able to pool thelr efforts a improve their living conditions. (5) Economic stability Housing is a form of investment of personal savings.” provides for economic stability and well being of the fa The implementation of social goals in housing requlfe that government should (1) introduce social housl schemes: (2) establish both minimum and maxim Sfandards: (3) create financial and fiscal institutions gea to helping low income people obtain credit for building improving their houses CRITERIA FOR HEALTHFUL HOUSING An Expert Committee of the WHO (3) recommended following criteria for healthful housing similar to the Bt Principles of Healthful Housing published by the Amerie Public Health Association (4) 1, Heahihfal housing provides physical protes shelter 2, provides adequately for cooking, eating, and excretory functions; 3, is designed, constructed, maintained an manner such as to prevent the communicable diseases; 4. provides for protection from hazards of exposute noise and pollution: 5. is free from unsafe physical arrangements die ty construction or maintenance, and from tHe harmful materials; and ction @ wash sprea\6, encourages personal and community developmen promotes social relationships, reflects 9 roy or ecological principles, and by these means tanconce mental health, tk Lae ‘Housing standards With the broadening concept of housing, the concept of hovsing standards has also hanged The siandards ae no Ionger confined to narrow health criteria like per capri space and floor space. Social and economic ehatacteriee Sich ax family income, family size and composition, Sardard of living, life stule, stage tn life eyele, education andl Gultural factors must be taken’ into consideration. in determining housing standards, Because of cultural diversity ani other factors such as climate and. social traditions, nc of housing must vary rom county to eounty and from region to region. In short, there cannot be rig uniform standards. a ce However. minimum standards are still maintained by building regulations, the aim being improvement of housing anc environmental conditions for the majority of families within the limits set by available resources and objectives ‘The standards in India are those recommended by the EHC (1947), These are as below (a) The site should be elevated from its vundings so that itis not subject to flooding during rains site should have an independent access to a steet of ‘ate width (c) it should be away from the breeding of mosquitoes and flies (d) it should be away from huisences such as dust, smoke, smell, excessive noise and trai: 1) it should be in pleasing surroundings (f) the soil Should be dry and safe for founding the structure and should be well drained. "Made-soil”,ie,, ground that i levelled by dumping refuse is very unsatisfactory for building purposes for 2 least 20 to 25 years, The subsoll water should be below 10 feet (2 metres) T BACK : For proper lighting and ventilation, there should be an open space all round the house ~ this is called se: back” In rural ateas Its recommended that the built-up area should not exceed one-third of the total areas in urban area: where land is costly, the builtup area may be upto {wo-thirds. The set back should be such that there is no ‘on to lighting and ventilation LOOR ; The floor should be pucca and satisly the following criteria: (a) t should be impermeable so that it can be easily washed and kept clean and dry. Mud floors tend to break up and cause dust they are not recommended) (b) the focr mst be smooth and free from cracks and crevices {0 Prevent ihe breeding of insects and harbourage of dus Ac} the floors should be damp-proof, (d) the height of the Plinth should be 2 to 3 feet (0.6 to 1 metre) WALLS + The walls should be (a) reasonably strong {b) should have a low heat capacity ie., should not absorb heat and conduct” the. same (c) weather resistant {d) unsuitable for harbourage of rats ind aD {e) net easily damaged and (f) smooth, These standards can be attained by 9-inch brick-wall plastered smooth and coloured éieam or white ROOF : The height of the « 20 feet (3 m) in he absence of airconditioning foro The rool should have a low heat ansmitiance coefficient ROOMS : The numberof living rooms should not be less than two, at least one of which can be closed for security. The other may be open on one side if that side is a private roof should not be less than i wousme | BL courtyard. ‘The number and area of rooms should be Bibedi ac size of family, so that the incteased according to recommended floor space per person may be m: FLOOR AREA : The floor area of a living room should be at least 120 sq.ft. (12 sq.m.) for occupancy by more than ne person and at least 100 sq.ft. (10 sq. m.) for occupancy by a'single person. The floor area available in living rooms per person should not be less than 50 sq.ft; the optimum is 100 sa. CUBIC SPACE : Unless means are provided for mechanical replacement of air the height of rooms should be Such as to give an air space of at least 500 c.ft. per capita preferably 1,000 « ft. WINDOWS : (a) Unless mechanical ventilation and anificial lighting are provided, every living room should be provided with at least 2 windows, and at least one of them Should open directly on to an open space, (b) the windows Should be placed at a height of not more than 3 feet (1 rm) above the ground in living rooms (c) window area should be Usth of the floor area. Doors and windows combined should have 2/5th the floor area. LIGHTING : The daylight factor should exceed 1 per cent cover hal the floor area KITCHEN : Every dwelling house must have 2 separate kitchen. The kitchen must be protected against dust and stoke; adequately lighted: provided with arrangements for storing food, fuel and provisions; provided with water supply; provided with a sink for washing utensils and fitted with arrangements for proper drainage. The floor of the Iuitchen must be impervious, PRIVY : A sanitary privy is a MUST in every belonging exclusively to it and readily accessible. In the more developed areas of the world, the majority of dwelling Units are equipped with water carriage systems GARBAGE AND REFUSE = These shoul from the dwelling atleast daily and disposed of BATHING AND WASHING : The house should have facilites for bathing and washing belonging exc ‘and providing proper privacy: WATER SUPPLY : The house should have a safe and adequate water supply available at all times, jade available. Rural housing In rural areas, the “approved” standards may be lowe suggested : (1) there should be at least two living rooms (2) ample verandah space may be provided (8) the bulla atea should not exceed one-thitd of the total ea (4) thete shoul be a separate hitehen with a paved sik of plaiorsn for washing utensils (6) the houne shouldbe provided wth & Sanitary lattine (6) the window area should be st leset 10 per cent ofthe flor area (7) there shou! be @ santa well ora insanity to keep cattle and livestock tn dueling houses Cattle sheds should be at least 25 leet away hone dente Houses. 4 catle shed should be open on all sider; eng 2 tsi for each head of cate (3) here water nd garbage (5). Pea caer ing and health Housing is part of the total environment of man and‘of environment. relationship, can be ‘and the following Common cold bronchitis, measles en | cough, ete. : + Scabies, ringworm, impetigo. “leprosy. (3) RAT INFESTATION : Plague. (4) ARTHROPODS : Houseflies, mosquitoes, fleas and bugs. (5) ACCIDENTS = A substantial proportion of house accidents are caused by some defect in the home and its environment. (6) MORBIDITY AND MORTALITY : High morbidity and mortality rates are observed where housing conditions are sub-standard. (7) PSYCHOSOCIAL EFFECTS : These effects must not be ‘overlooked. The sense of isolation felt by persons living in the upper floors of high buildings is now well known to have harmful effects. Often, also, people living in ensely populated urban areas feel a similar sense of isolation which may lead to neurosis and behaviour disorders. If the definition of health given by WHO is applied. we have also to take into consideration the broader aspects of mental and social well-being of individuals and families, i... factors related to satisfaction of physiological, psychological and social needs. Overcrowding Overcrowding refers to the situation in which more people are living within a single dwelling than there is space for, so that movement is restricted, privacy secluded, hygiene impossible, rest and sleep difficult (8). In general the risks as regards physical health are clear enough - infectious diseases spread rapidly under conditions of overcrowding, The effects on psychosocial health are not so clear-cut, viz. irritability, frustration, lack of sleep, anxiety, violence and mental disorders. Children are said to be more affected. In short, it is a psychosocial stress, leading to unhappiness and very probably to psychosomatic and mental disorders. Overcrowding is a health problem in human dwellings. It may promote the spread of respiratory infections such as tuberculosis, influenza and diphtheria. High morbidity and mortality rates are observed where housing conditions are substandard. The accepted standards with respect to overcrowding are as below (1) PERSONS PER ROOM : The degree of overcrowding can best be expressed as the number of persons per room, ie., number of persons in the household divided by the number of rooms in the dwelling. The accepted standards 1room 2 persons 2 rooms persons 3 rooms 5 persons 4 rooms 7 persons. 10 persons (additional 2 5 or more rooms for each further room) “110 sq.ft. (11 sq. m.) or more 90-100 sq.ft. (9-10 sa. m.) 70-90 sa.t. (7-9 54m.) 50-70 sq.t. (5-7 sa. m.) Under 50 sq.ft (5 34. m.) ‘A baby under 12 months is not counte beeen 1 to 10 years counted as half a unit), hilar, SLX SEPARATION : Overcrowding is considere, i1 2 persons over 9 years of age, not husband ond gee erste aexeo are obliged 10 sleepin the same ropm sc Indicators of housing Tn recent yes the ure Of Indira a, in ee ofthe: measurement of ualty of jpetae widespread Mhrousing may be classified as: M® The (1) Physical: These are based on floor space, cubic pag disposal, ete). age 2) Economic indicators : These are cost of the bu rental levels, taxes, expenditure on housing, etc he, social indicators : The following were proy in esl nr on the Soc Arpecs 0 Hass organized by the UN in 1975, {a} Indicators related to prevention of illness : (1) Frequency of illness due to inadequate sews: Td gartae colon (2) Frequency of illness associated with contaminate: (3) Frequency of insect borne diseases (4) Frequency of illness due to overcrowding, (6) Frequency of illness due to proximity to animals, (7) Acoust medial ait (b) Indicators related to comfort = (1) Thermal comfort (2) Acoustic comfort (3) Visual comfort (4) Spatial comfort. (c) Indicators related to mental health and social well-being (1) Frequency of suicides in the neighbourhood (2) Neglected and abandoned youth in neighbourhood (8) Drug abuse (including alcohol) in neighbourhood, Public policy ner 2° In every country where housing conditions in genet ®* unsatisfactory the need for government intervention 2 been recognized, The approach to public policy 0” Mss", in India is indicated in the Five Year Plans. In W3,. separate Ministry of Works and Housing was ctealel® Centre. The Government Housing Programmes 6° wo categories ~ public sector housing and social HO schemes. The former provides mainly for gov@tt, employees, while the latter attempts to provide 2) yh Particularly to low and middle income gr0UPS fh various housing schemes. For promoting housit statutory Housing Boards have been establishs hes| Four organizations, viz The Nationa Pe ation (NEO), Netionel Buildirgs Cone fon Lid., “Housing and Urban Downes ion (HUDCO) and the Hindustan Housing Fretory GeManetioning winder the aeais of the Union Ministy of Hand Housing fo deal with various aspects ot honsion,, © According to an assessment by NBO, the housing stock Hrs estimated to be 14,1 milion in urban areas and RS increased trillion in 1971, 116.7 million in 1981 and 148.8 million fo 7901 (6). In 2001 census, the total Reber o hoe ‘were 249 ion (10) and according to 2011 census. total number of houses counted were 330.84 million Includes 220.7 million houses in rural areas and ).14 million houses in urban areas (11). Urban housing has manifested itself in many ways of which the most ificant is the growth of slums and squatter settlement. It ‘as estimated that about 48.8 million persons were living in Jams in 1990, About 40 per cent of this population was in oe cities. The overall rate of construction of new ings es recommended by the expert body of the UN is hhouses per 1000 persons per year (7) + The Eighth and subsequent Five Year Plans have strateay for the National Housing Policy consisting of creating an bling environment for housing activity, viewed as an portant component of the national economy. by inating various constraints and providing direct stance to the specially disadvantaged groups including Mural and urban poor household, SC/ST, physically Hhandicapped, widows and single women (6) "House site and construction assistance : The feme was included in the State Sector as a part of inimum Needs Programme and formed the core of the fal housing programme during Seventh and subsequent Year Plans. This scheme has two components — vision of free house sites and construction assistance fh varying proportion of subsidy and loan in different tes. Construction assistance is planned to benefit ‘million families directly as part of MNP. This is exclusive ‘other special rural housing programmes intended for ecific beneficiary groups. Indira Awas Yojana (IAY) : The Indira Awas Yojana introduced in the Central Sector in 1985-86 as part of Rural Landless Employment Guarantee Programme is type of houses have one room, one kitchen attached ith latrine, bathroom and a smokeless chullah (9) ferences WHO (1961). Techn. Rep. Ser, No:225 WHO (1965). Techn. Rep. Ser, No.297 WHO (1974), Techn, Rep. Ser, No.544 Jartartenn Publis Health Association (1959). Am. Public Health, 59. Ba Br ti in (1640), Report of the Environmental. Hualen Committee, Ministry of Health, New Delhi Oe art rie veor Plan (1992-92) by E, Chandran, lees of Curent interest series No F @ Social Impact of Housing, Re UN (1977). The Social Impact of Hé Mtaits, ESA(OCT SEM) Seminar, Department of Economic and Soci 77f2, New York , 40 (1975), Promoting Health in the human Enelronment P26 Social Welfare, Housina Feb. 1987 Fe chaise, Census of india 2001 series 1. tables on Louse PR ee Cire’ tnd oneal, Reatstrer General ancl Census Commissioner of India. Commoner tte a compendium (2018), Gov. of India, NBO.