ALL INDIA INSTITUTE OF LOCAL SELF GOVERNMENT DELHI

“ Ventilation Concepts for Paramedical”

ByDr. P.P.SINGH

Faculty AIILSGDEx Medical Superintendent Cum Consultant pathologist HRH Delhi

Ex. Director India Population Project 8 Delhi..SOURCE BOOKS OF AIILSGD.

VENTILATION VENTILATION IS SCIENCE OF

MAINTAINING THE ATMOSPHERIC CONDITIONS WHICH ARE COMFORTABLE AND HEALTHY. IT CONTROLS TEMPERATURE , HUMIDITY AND PURITY OF AIR

OBJECTIVES OF VENTILATION:1) TO ENSURE SUPPLY OF

OXYGEN IN THE ATMOSPHERE.

2) TO REMOVE TOXIC POISONS IF PRESENT.

3) TO REMOVE FOUL ODOURS IN THE AIR.

4) TO REMOVE HEAT & EXCESS MOISTURE AND TO COOL THE SURROUNDINGS.

METHODS OF VENTILATION:A. NATURAL.

I) INTERNAL VENTILATION.II) EXTERNAL VENTILATION.

B. ARTIFICIAL OR MECHANICAL (FOUR TYPES)

I) EXHAUST SYSTEM.II) PLENUM SYSTEM.III) COMBINED SYSTEM.VI) AIR-CONDITIONING.

NATURAL VENTILATION; -

Providing sufficient inlet and outlet for allowing fresh air into a room and escape out of it.

It is has advantage of being simple and least expensive but has disadvantage that it cannot be control and depend upon the out side temperature ,humidity and movement of air.

INTERNAL VENTILATION:

i. Minimum area of the room should be 3Mts X 3Mts.

ii. Minimum height of room should be 3 metres.

iii. The total area of door 7 window shall be at least 1/4th of floor area.

iv. The cross ventilation must be ensured .v. Several types of inlet and outlets ventilation

should be provided.vi.Electric fans to be installed for movement of

air.

EXTERNAL VENTILATION;- INDIRECT TYPE OF NATURAL VENTILATION MEANS

VENTILATION AROUND THE HOUSE EXTERNALLY.IT IS AS THE MAIN PART OF TOWN PLANNING, HAS TO

BE CONSIDERED BY ALL LOCAL OR STATE GOVERNMENTS.

Following measures should be taken by all LSGD.Constructing wider streets.Providing parks, more open spaces and playgrounds.Restricting the height of houses.Regular removal of street refuge.Planting trees in open space around buildings and both side of roads.Factories and offensive trades should be allowed away from residential area.

ARTIFICIAL OR MECHANICAL VENTILATION;

(A) EXHAUST SYSTEM;- INSTALLATION OF

EXHAUST FANS AT THE OUTLETS NEAR CEILINGS OR ROOF. SO THAT THE INSIDE PRESSURE IS LOWER THAN THAT OF OUTSIDE , AND FRESH AIR IS ALLOWED TO ENTER AUTOMATICALLY TO REPLACE INSIDE.

SUCH AS IN CINEMA HALLS, FACTORIES AND KITCHEN OF EATING HOUSE OR RESTAURANTS.

(B) PLENUM SYSTEM;- PROPULSION FANS ARE USED TO THROW FRESH

AIR FROM OUT SIDE IN THE HALL. THESE ARTE USED MAINLY IN THE FACTORIES .MAY BE CARRIED BY DUCTS .

PLENUM SYSTEM MAY BE EITHER UPWARD OR DOWNWARD.

UPWARD TYPE ;- THE AIR IS THROWN FROM FLOOR LEVEL AND VITIATED AIR IS ALLOWED TO ESCAPE THROUGH VENTS PROVIDED AT THE CEILING LEVEL.

DOWNWARD TYPE ;- THE AIR IS FORCED IN ROOM FROM CEILING LEVEL AND VITIATED AIR IS ALLOWED TO ESCAPE THROUGH VENTS PROVIDED AT THE FLOOR LEVEL OR SLIGHTLY ABOVE IT. THIS RATHER UNNATURAL SINCE THE COLD AIR IS INTRODUCED AT HIGHER LEVEL AGAINST THE LAWS OF NATURE.

© COMBINED OR BALANCED SYSTEM;-

AIR IS FORCED AT THE FLOOR LEVEL AND VITIATED AIR IS EXTRACTED THROUGH OPENINGS NEAR CEILING BY EXHAUST FANS.

THE EXHAUST ARE OF SMALLER CAPACITY THAN PLENUM SO THAT THE GREATER VOLUME OF OUT SIDE AIR IS PUMPED INTO THE ROOM.

THIS SYSTEM IS MORE EFFICIENT BUT ALSO MORE COSTLY.

(D)AIR CONDITIONING ;-

-THE AIR IS CONDITIONED REGARDING THE TEMPERATURE AND HUMIDITY. THE DUST IS ALSO FILTERED.

-THE TEMPERATURE IS INCREASED OR DECREASED BY COOLING OR HEATING PROCESS.

-THE HUMIDITY IS INCREASED OR DECREASED BY ADDING MOISTURE OR COOLING & REMOVING THE WATER.

-THE DIFFERENCE OF 10 -15 DEGREE F IS MAINTAINED FOR COMFORTABLE ATMOSPHERE

COMFORTABLE ATMOSPHERE IF ;-

1.TEMPERATURE IS 75 DEGREE F.

2.RELATIVE HUMIDITY IS 70%.

3. THERE IS NO DUST.

4. THERE IS MOVEMENT OF AIR OF THE ROOM AT LEAST 10 TIMES PER HOUR.

ACTION OF WIND :

THE WIND AFFECTS THE VENTILATION IN TWO DIFFERENT WAYS;-

1.DIRECTLY BY PERFLATION .DIRECT FLOW OF AIR IS CALLED

PERFLATION .

2. INDIRECTLY BY ASPIRATION .THE SUCKED IN AIR FROM OUT SIDE

INDIRECTLY DUE TO LOW PRESSURE IN THE ROOM

S

PLANLow pressure pocket

R

P

Q

Inlet OutletAspiration