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Dr R.K LudamDept Of Community MedicineV.S.S.M.C.H Burla

Housing And Ventilation

HousingHousing in modern concept includes not only the physical structure providing shelter but also the immediate surroundings and the related community services and facilities.It may be defined as- all places in which a group of people reside and pursue their life goals; the size of settlement varies from a single family to millions of people.The immediate surroundings of residential building are often referred as neighborhood or microdistrict.

WHO expert group (1961) on public health aspects of housing prefers to use the term ;residential environmentSocial Goals Of Housing-: a) Shelter b) Family Life c) Access to community facilities d) Family participation in community life e) Economic Stability

The Implementation of social goals in housing requires that govt. should-- Introduce social housing schemes- Establish both minimum and maximum standard- Create financial and fiscal institutions geared to helping low income people obtain credit for building and improving their house.

Criteria for healthful housing-:Healthful housing provides physical protection and shelterProvides adequately for cooking,eating,washing,and excretory functionsIs designed,constructed,mantained and used in a manner such as to prevent the spread of communicable diseasesProvides for protection from hazards of exposure to noise and pollutionIs free from unsafe physical arrangements due to construction or mantainance,and from toxic or harmful materialsEncourages personal and community development, promotes social relationships ,reflects a regard for ecological principles and finally promotes mental health

Housing Standard-:Social and economic characteristics such as family income, family size and composition, standard of living,lifestyle,stage in life cycle, education and cultural factors are taken into account.Because of cultural diversity and other factors such as climate and social traditions, standard of housing varies from country to country and from region to region.In short-there cannot be rigid, uniform standardsThe standards in India are those recommended by the EHC(1947)

Site-: - should be elevated from its surroundings - should have an independent access to a street of adequate width - should be away from breeding places of mosquito and flies - should be away from nuisances such as dust,smoke,smell,excessive noise, and traffic. - should be in pleasant surrounding - soil should be dry and safe for founding the structure and should be well drained. - The sub-soil water should be below 1o feet

Set Back-: -It is the open space all around the house which allows proper ventilation and lightening - In rural areas it is recommended that the built-up area should not exceed one third of total area. - In urban areas it is allowed upto two-third of total area. - The set back should be such that there is no obstruction of lighting and ventilation. - e.g.

Floor-: -Should be Pucca and satisfy the following criteria-: - should be impermeable ,so that easy to clean and dry - must be smooth and free from cracks and crevices to prevent the breeding of insects and harbourage of dust - it should be damp-proof - the height of the plinth should be 2-3 feet(0.6 t o 1 mtr)Walls-: - reasonably strong - should have a low heat capacity - weather resistance - unsuitable for harbor of rats and vermin - not easily damaged - smooth ( 9 inch brick with wall plastered smooth and colored cream or white)

Roof-: -Should not be less than 10 feet (3 mtr) in the absence of air-conditioning for comfort. - should have a low heat transmittance co-efficientRooms-: - should not be less than two,atleast one of them can be closed for security - the other may be open on one side if that side is a private courtyard - No. should be increased as per the family membersFloor Area-: - should be at least 120 sq ft for more than one person and at least 100 sq ft for single person - floor area per person should not be less than 50 sq mtr

Cubic Space-:at least 500 c.ft per capita preferably 1000 c.ft

Windows-: every living room should be provided with atleast 2 windows and one of them should open directly on to an open space- the windows should be placed at a height of more than 3 feet(1 m) above the ground in living rooms- windows area should be 1/5th of the floor area doors and windows combined should have 2/5th the floor area.

Lighting-:the daylight factor should exceed 1 % over half the floor area.Kitchen-: Must have a separate kitchen- Must be protected against dust and smoke, adequately lighted, provided with water supply, provided with a sink for washing utensils and fitted with arrangements for proper drainagePrivy-: A sanitary privy is a must for every house, belonging exclusively to it and readily accessible.Garbage and refuse-:Should be removed from the dwelling at least daily and disposed of in a sanitary manner

Bathing and Washing-: house should have facility for bathing and washing belonging exclusively to it and providing proper privacyWater Supply-: House should have a safe and adequate water supply available at all times.RURAL HOUSING-: Minimum standard suggested-:There should be at least two living roomsAmple verandah space may be providedThe build-up area should not exceed one-third of total areaThere should be a separate kitchen with a paved sink or platform for washing utensils

The house should be provided with a sanitary latrine The window area should be at least 10% of the floor areaThere should be a sanitary well or a tube well within a quarter of a ample from the houseIt is insanitary to keep cattle and livestock in dwelling house. Cattle sheds should be at least 25 feet away from dwelling houses. A cattle shed should be open on all sides an area 8ft4ft is sufficient for each head of cattle There should be adequate arrangement for the disposal of waste water, refuse and garbage.

Housing and Health- Poor housing is associated with the following health conditions-:Respiratory InfectionSkin infectionRat infestationArthropodsAccidentsMorbidity and MortalityPsychological effects

OvercrowdingIt refers to the situation in which more people and living within a single dwelling than there is space for, so that movement is restricted, privacy secluded, hygiene impossible rest and sleep difficult.Overcrowding is a health problem in human dwelling.It may promote the spread of respiratory infections such as TB,Influenza and Diphtheria.

Public PolicyHouse site and construction assistance

Indira Awas Yojna (IAY)-: Introduced in central sector in 1985-86 as part of the rural landless employment guarantee programme.-one room, one kitchen attached with latrine, bathroom and a smokeless chullah.

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VENTILATION

It not only means the replacement of vitiated air by a supply of fresh outdoor air but also control of the quality of incoming air with regard to its temperature, humidity and purity with a view to provide a thermal environment that is comfortable and free from risk of infection.Standards Of Ventilation-: Most of the standards of ventilation have been based on the efficiency of ventilation in removing body odour. 1) Cubic Space-: minimal fresh air supply ranging from 300 to 3000' c.ft. per hour per person - De Chaumont advocated a fresh air supply of 3000 c.ft per person per hour.

2) Air Change-: Air change is more important than the cubic space requirement.It is recommended that in the living rooms, there should be 2 to 3 air changes in one hour; in work rooms and assemblies 4 to 6 air changes.If the air is changed more frequently. i.e. More than 6 times in one hour, it is likely to produce a draught and should be avoided.The number of air changes per hour is calculated by dividing the total hourly air supply to the room by the cubic capacity of the rooma space of 1,000 to 1,200 c.ft. per person is quite sufficient.

3)Floor space-:Floor space per person is even more important than cubic space. - The optimum floor space requirements per person vary from 50 to 100 sq.ft.Types Of Ventilation-:Natural Ventilation-: Natural ventilation is the simplest system of ventilating small dwellings, schools and offices. A)The Wind-: The wind is an active force in ventilation. - when it blows through a room, it is called perflation. - When there is an obstruction, it bypasses and exerts a suction action at its tail end - this is called aspiration. - Doors and windows facing each other provide "cross ventilation".

B) DIFFUSION : Air passes through the smallest openings or spaces by diffusion. - This is a slow process and therefore, is not relied upon as the sole means of ventilation. C) INEQUALITY OF TEMPERATURE : Air flows from high density to low density - The greater the temperature difference between outside and inside air, the greater the velocity of the incoming airThese properties of air are utilised to best advantage by the proper location of windows, doors,ventilaiors and skylights.The chief drawback of natural ventilation is that it is not possible to regulate the velocity

Mechanical Ventilation-: - Types-: 1) Exhaust ventilation (2) Plenum ventilation 3) Balanced ventilation (4) Air conditioning. 1)Exhaust Ventilation-: In this system, air is extracted or exhausted to the outside by exhaust fans driven by electricity. - As air is exhausted, a vacuum is created which induces fresh air to enter the room through windows, doors and other inlets. - Exhaust ventilation is 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.

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 - plenum is used for supplying air to air-conditioned buildings and factories. - Air is delivered through ducts at desired points.

3) BALANCED VENTILATION-: This is a combination of the exhaust and plenum systems of ventilation. - The blowing fan must balance the exhaust fan.

4) AIR CONDITIONING -: Air conditioning is defined as "the simultaneous control of all( i.e.-temperature, humidity, air movement, distribution, dust, bacteria, odours and toxic gases, most of which affect in greater or lesser degree the human 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. - Large institutions or hospitals often install central air conditioning system for entire building - Where the temperature difference is large between outside atmosphere and air conditioned room, "transition room" is sometimes provided.