VENTILATION :It is a process of introducing and circulating fresh air in a room in order to get rid of undesirable gases and replace fresh air.
Reasons for sufficient ventilation in the room
- to prevent humidity that on high concentration of moisture in the air that causes a stuffy feeling that causes drowsiness,
- to remove excess/surplus heat from people and machinery that makes working atmosphere uncomfortable.
- to allow free circulation of air hence reduce bacteria and viruses concentration and prevent spread of airborne diseases e.g influenza (common cold) and T.B.,
- to remove odours that develop when people are crowded,
- to get rid of pollution in a room e.g smoke, aerosol, sprays, dust, gases e.g CO2, Co and starch from decayed matter.
Dangers of poor ventilation in a room
- Suffocation and fainting
Occurs when people are overcrowded in a room. They use up all fresh air. May also be as a result of burning fuels e.g charcoal/coal in a poorly ventilated room. Overcrowded people uses up all the air in the room then released carbon dioxide gas that causes fainting, suffocation and death.
It is as a result of much humidity in the air/ O2 not being enough for breathing Discomfort
Occurs because of a room being excessively not due to heat from people and machinery.
It can also be due to bad smells on excessive humidity that make it feel stuffy and uncomfortable.
Easy transmission of communicable diseases
The room that has poor ventilation has a high bacteria and virus concentration that can be passed from one person to another.
Ways of ventilating a room
- natural means
- mechanical means
e.g (i) use of windows
Using windows to ventilate the room They may be wooden, glass and metal.
The design of windows used include:
- Louver windows
They open simultaneously. They let in fresh air and prevent raindrops from entering.
- Fanlight windows:
- Are small windows normally fixed high up on walls of toilets, bathrooms and stores,
- Thy open towards outside,
- Are supported by a catch at centre
- May be left open at night if fitted with burglar proof bars.
- Vertically pivotal windows
- they open vertically,
- half of window open towards the inside the other half towards outside, – can be modified to open towards outside only,
- horizontally pivoted windows
- they open horizontally
- half of it opens towards outside
- the other half towards inside
- Gliding windows
Open by gliding from side-side
Using doors to ventilate a room
- may be from wood, glass/metal
- they are of various types
e.g – single shuttered
- double shuttered
- gliding or sliding doors
How windows and doors are used for ventilation
- Adjacent method
- Two/more windows are placed on adjacent walls,
- They allow fresh air to move in slowly to replace stale one so refreshen the room,
- Cross method
– ventilation devices e.g windows and doors are placed opposite;
NB:- they should not be directly opposite because they allow a lot of air to rush in and out, that causes of doors and windows,
e.g (i) fans
(ii) air conditioners
The two supplement the natural means of ventilation
- they are normally fitted with rotary blades,
- operated by electricity
- when set into rotation they set air inside the room into current,
- they keep air in the room in motion therefore achieving ventilation,
- free standing
- table top
- wall mounted
they only keep air in a room in motion so never remove stale air and replace it with fresh one; so they should always be used with other natural methods of ventilation.
- Are used in large building that have poor position for natural ventilation,
- This device absorb stale air form inside of a room and replace it with fresh cooled air, NB:
- They are fitted through a wall for part it can be inside and the other out,
- They are more expensive to install and run than fans so not commonly used in homes.
ALL HOMESCIENCE NOTES FORM 1-4 WITH TOPICAL QUESTIONS & ANSWERS