Integrated Science M4 Ventilation methods

VENTILATIONModule 4 Unit 1 Lesson 4
Integrated Science
BEGIN

REVIEW QUIZREVIEW QUIZ
INTRODUCTIONINTRODUCTION
OBJECTIVESOBJECTIVES
Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
Ventilation features
of our houses
of our houses
OVERVIEWOVERVIEW
 Ventilation is the final topic in this unit which has
looked at: methods of heat transfer, appliances
that use heat transfer to work; the effect of
temperature on our body and the process of
evaporation of heat from the body by sweating.
 This slide presentation reviews sources of air
pollution, including indoor thermal pollution
which affects the indoor air quality, thus
necessitating various methods of ventilation.
 You can access various subtopics in the Menu on
the LEFT of the first slide.
2
NOTE: For some activities, you will be asked to type your responses
in boxes. To do so, you must be in Slide Show View. You can insert
and delete text in the box in Slide Show View.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
 In Term 1, you learned about various sources of
air pollutants, whose effects make ventilation
of buildings necessary.
 This is a teaching slide set that will give you all
of the content on types of mechanical and
natural ventilation equipment and strategies. The
activities will help you to better understand how
the use of the various ventilation methods can
prevent air pollutants, heat and moisture, from
remaining indoors because they affect the indoor
air quality, and can cause ill health and
discomfort.
3

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
On completing this slide presentation, you should
be able to:
recall and identify sources of indoor air pollution.
define ventilation and state its importance.
describe mechanisms to ensure proper passive
ventilation in buildings.
virtually observe and assess good/bad ventilation
features in Jamaican houses.
begin to appreciate the good structures of the
habitats in which they reside.
search for information and share ideas.
4

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
1:1: Causes/Effects of air pollution –Causes/Effects of air pollution –
Activity 1.1 : Pollutants inside our housesActivity 1.1 : Pollutants inside our houses
5
Question 1. Examine the diagram below and discuss within your
group the likely effects of the pollutants shown, on the comfort
within a house and on the health of people who might inhabit the
house.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Activity 1.1 : Pollutants inside our housesActivity 1.1 : Pollutants inside our houses
Question 2. What might be other sources of air
pollutants in our houses that are not shown in the
diagram on the previous slide?
6
CHECK

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Activity 1 .1– Pollutants in housesActivity 1 .1– Pollutants in houses
Feedback to Question 2:



7
When you sneeze or cough into the
air, viruses that cause, colds, ‘flu
etc. are spread through the air as
droplets and pollute the indoor air
spaces.
In some households
in Jamaica, air
pollution is
generated by
cooking with solid
fuels in poorly
ventilated places.
Constantly burning
rubbish pollutes
both the outdoor
and indoor air.
(World Health Organization, 2006)
7

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Recalling the effects of humidityRecalling the effects of humidity
 Think back to what was discussed in a previous
lesson about humidity and relative humidity.
 How hot and sweaty we feel, especially within
buildings, is a function of heat, humidity and air
movement.
 Remember …. Humidity is defined as the amount
of moisture in the air. Relative humidity of the air
affects how comfortable we feel. It is “ a
percentage showing how much water vapour is
currently trapped in the air relative to/compared
to the maximum amount of water vapour the air
can hold at a given temperature.”
 Listen to this song ‘Humidity’ to remind yourself
> http://www.youtube.com/watch?v=-vFg8l3aLe8
8

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
 As the relative humidity of air in a space –
especially an indoor space - gets higher, it’s
moisture-absorbing/holding capacity decreases.
 This slows down or stops further evaporation of
sweat from our skin into the air. So, the cooling
effect that evaporation would normally produce
for our bodies also decreases or ceases all
together.
 In short, higher humidity indoors causes us to feel
hotter as we lose our ability to cool ourselves
since no sweat evaporates from our skin. The air
is humid and stagnant and we feel sweaty and
uncomfortable.
9

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
 In contrast to that …. Low relative humidity
means the air is dry and could hold a lot more
moisture at that temperature. So, sweating
occurs.
 Because of its drying effects, low humidity in a
building:
 Can cause dry and itchy skin and mucous
membranes, dry nostrils and sinuses, cracked or
chapped lips, bloody noses, dry coughs and a dry
sore throat, other cold symptoms and respiratory
discomforts.
 Makes it seem colder than it actually is.
 Increases static electricity.
10

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
What is air pollution?What is air pollution?
 “Air pollution occurs when the air contains gases,
dust, fumes or odour in harmful amounts” – i.e.,
amounts which “when present in sufficient
concentration, for a sufficient time, and under
certain conditions, tend to interfere with human
comfort,” and which “could be harmful to the
health or comfort of humans and animals or
which could cause damage to plants and
materials.”
 The main reason for needing unpolluted air is: To
get ‘fresh air’ into our lungs for respiration, in
order to release energy needed for metabolism.
 The main reason for a lack of ‘fresh air’ that
causes indoor air pollution is poor ventilation.
11

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
2: What is ventilation?2: What is ventilation?
 The 'fresh air' that we need to inhale regularly
should have little or no pathogens, the normal
atmospheric O2 and CO2 concentration, suitable
humidity, little or no pollutants.
 When there is poor ventilation, air becomes
stagnant with CO2, pollutants settle in the space,
and heat and water vapour accumulate causing
thermal discomfort and giving poor indoor air
quality (IAQ). Read the content at >
http://www.betterairnow.com/impofcleanair.aspx
 So -- proper ventilation is needed always!
12
Ventilation is the process of helping ‘fresh’ air to
circulate throughout a building and removing
stagnant and polluted air at the same time.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
2: What is ventilation?2: What is ventilation?
13
Moist
air
We need good ventilation to…
Speed up evaporation of
sweat from the body surface
by moving the moist air away
from the person.
Remove moisture to outside
of the room.
Transfer heat to the outside.
Ventilation is carried out by:
a.mechanical devices and
b.using natural methods.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical Ventilation3: Mechanical Ventilation
 Mechanical ventilation utilizes equipment such as air
conditioners, de/humidifiers, fans and hoods. These
extract heat and moisture, thus changing the humidity,
and they also circulate air through the building.
 We refer to their use as ‘active ventilation’.
14
Most often, their use is
in kitchens and bath-
rooms where a lot of
moisture or vapour is
generated; they have to
be vented or opened to
the outside.
Hood (over stove) used
to vent air from a
kitchen

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical Ventilation - Fans3: Mechanical Ventilation - Fans
The most common mechanical ventilation device
that people use is an electric fan. Why are fans so
commonly used?? Well, a fan can be quite easily
installed and used when natural ventilation is
inadequate, or when rapid removal of odours, other
air pollutants or of moisture to lower the humidity,
is required.
15
1. Now, think about what
you’ve already learned
about what conditions make
us feel so hot, sweaty and
uncomfortable.
Write what a fan does to
help with ventilation and to
lesson our discomfort, then
check it as you continue
reading the next slides.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
 For effective room ventilation, a box fan can be
placed into/in front of an open window with the
fan blowing air into the room, to pull cooler air
from outside into the room.
 Watch up to 0.32 from >
http://www.youtube.com/watch?v=BELOgxbuJyA
 Interior doors should be opened, to enable the
incoming, cooler air to flow through from one
room to other rooms in the house.
 See the diagram on the next slide.
16

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical Ventilation – Fans moving air3: Mechanical Ventilation – Fans moving air
17
A second fan should be placed in/in front of another
window, to blow hot air out of the house.
Fan
#2
Fan
#1
This creates natural siphoning off of hot air throughout
the house and it exits through high wall vents.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical Ventilation – Ceiling Fans3: Mechanical Ventilation – Ceiling Fans
Because the temperature in a room varies in layers,
with the warmest air near the ceiling and the
coldest air near the floor, a ceiling fan is useful for
room ventilation purposes. As the fan blades turn,
(Green arrow) they push air (Blue arrows)
downward, towards the floor creating a downdraft,
keeping the air circulating throughout the room and
making the room feel much cooler. They create a
kind of ‘artificial breeze’ that makes you cooler.
Look at the path of air shown in this diagram.
18

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
 You’ve learned that, as humidity decreases, air
density increases. The greater the air density, the
more air will be moved by a fan spinning at a
constant rate. So, as the humidity goes down,
fans are more effective!
 And, as you also learned, the more air moving
across our skin, the easier it is for our sweat to
evaporate and cool us. So, a room cooling via a
reduction in humidity will feel extra cool because
of increased air flow which improves our body’s
cooling ability.
19

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical ventilation - Dehumidifiers3: Mechanical ventilation - Dehumidifiers
 Earlier, we recalled that high humidity stops the
evaporation of sweat making us uncomfortable.
 A dehumidifier reduces the level of humidity in
the air, especially in enclosed spaces.
 It does this by using a fan to pull in warm air,
running it over cold coils so it condenses into
a liquid; the condensation that forms on the coil
inside the dehumidifier is removed via a drain
pipe or collected in a special reservoir, which can
be emptied periodically. The dry air is reheated
as it passes over a warm coil, and then warm air
is discharged back into the room.
 Watch >
http://www.youtube.com/watch?v=_A87ys-eFV0
20

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical ventilation – What is a humidifier?3: Mechanical ventilation – What is a humidifier?
 Especially in cold, dry weather, the drying effects
of low humidity can cause skin and respiratory
discomforts. A humidifier can prevent such
effects.
 Humidifiers are devices that emit water vapour
or steam to increase the amount of water
vapour/moisture levels, i.e. humidity, in the air
The air moistened by a humidifier is more
comfortable to breathe.
 Read >
http://www.healthline.com/health/humidifiers-and-heal
 And, look at the video at >
http://home.howstuffworks.com/36090-gimme-shelter-h
21

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
3: Mechanical ventilation - Air conditioners3: Mechanical ventilation - Air conditioners
 Air conditioners are used especially during the
summer, in offices, cinema houses and large
buildings occupied by many persons.
 Air conditioners (ACs) both cool the air and also
remove moisture so you feel less hot and sticky.
By removing moisture, ACs essentially act like
dehumidifiers.
 Watch these videos and make notes from >
http://www.youtube.com/watch?v=1MiQCBIx1mM
 Also
http://www.youtube.com/watch?v=_lFUlA1PZ8U
22

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/Passive Ventilation4: Natural/Passive Ventilation
 Natural ventilation methods are said to
be passive, because the strategies use
various building features and air temper-
ature and pressure differences inside and
outside to move hot and cold air, rather
than relying on equipment or machinery
to manipulate the sun’s heat and the
wind for ventilation.
 Natural ventilation strategies involve:
 the intentional inflow of air through the
use of windows, vents, doors and other
openings in buildings;
 the outflow of air from indoor spaces to
the outdoors.
23

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural Ventilation – Features/Devices used4: Natural Ventilation – Features/Devices used
 So the placement and orientation of the building and
the use of vegetation outside form one important set
of strategies.
 Use of windows, doors and other types of openings
and vents are the most commonly used strategies,
because they allow both cross ventilation and stack
effect ventilation to remove heat and moisture. The
right placement of these openings as well as their
size is an important consideration to ensure they work
well.
 These strategies are often not as effective at removing
moisture, so a combination of the mechanical and
natural ventilation methods is frequently used.
 Watch/listen to this video, pausing it when necessary,
to note the range of passive ventilation methods the
narrator identifies >
ttp://www.youtube.com/watch?v=IvCI3Q_5A8Y
24

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/Passive ventilation – Activity 4.14: Natural/Passive ventilation – Activity 4.1
25
1. Look at the old Barbadian
chattel house (right), raised
high off the ground. What other
natural ventilation features
can you identify on it?
Click for possible answers
Buildings can be raised
on ‘stilts’ – so cool air
can circulate all around
it. It is a feature of older
houses!

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Feedback to Activity Question 1Feedback to Activity Question 1
Feedback to Question 1: What other natural ventilation features
can you identify in this old Barbadian chattel house?
26
26
From long ago, natural ventilation features were being built
into houses, such as raising them high off the ground for air
circulation.
How many of these ventilation features did you actually notice
in the Barbadian chattel house?
• Gabled roof and gable end vents high up under the eaves.
• Several windows, each with a sun-shade over it.
• Both sides of the door that can be opened for passage of air.
• Vegetation around house.
Have you ever seen similar features in old Jamaican houses?
Chattel houses were not built on solid foundations. They were just placed on
stilts – large stones, bricks or wood - so that they could be easily
disassembled and moved if the owners had to go to work on other sugar
estates. But, being high up off the ground also served the function of
ventilation – allowing air to circulate all around the house.
DID YOU KNOW?DID YOU KNOW?

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
27
2. What natural ventilation features can you identify in
this house photograph?
Click for possible answers

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Feedback to Activity Question 2Feedback to Activity Question 2
Feedback to Question 2: What natural ventilation features
can you identify in this house photograph?
28
How many of these did you actually identify?
•Several large/wide and high windows and also several
doors.
• Many windows on several sides of the house.
• Gabled roof (See diagram – shown).
• Gable end vents high up under the eaves.
• Roof overhanging windows/doors.
• Windows have shades over them.
• Light-coloured exterior walls.
• Vegetation around the house.
Now, go through the next slides to learn why these features provide good, natural ventilation.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/Passive ventilation - Methods used4: Natural/Passive ventilation - Methods used
 The most commonly used passive ventilation
methods are openings – windows, doors, vents,
transoms. This is because they allow us to control
and manipulate the passage of heat and wind
into, through and out of our buildings, by their
number, size, placement in the building and
structure.
 Especially when they are used with a well
designed house, they can provide all the
ventilation that might be needed.
29
1. Look at the house designs and placements of the
openings on the next set of slides. Note the arrows
that show air movement.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation methods –4: Natural/passive ventilation methods –
Activity 4.2: Room designs and windowsActivity 4.2: Room designs and windows
30
2. Discuss these two
diagrams. Why do
you think the top
house has a better
ventilation design
than the lower one?
Click for possible answers.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Activity 4.2: Room designs and windowsActivity 4.2: Room designs and windows
Feedback to question: 2. Why do you think the top
house has a better ventilation design than the lower
one?
Note that in the house in the top (Blue) diagram,
that design of single room depths provide “optimal
cross-ventilation because each room has opposite
exit and entry points (windows/openings) for the
breezes to pass through.”
The lower diagram (Pink) shows that “a poorly
designed home with internal walls and barriers to
cross-ventilation will have stagnant, stuffy hot-spots
that may need exhaust fans.”
31

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation methods – Activity4: Natural/passive ventilation methods – Activity
4.2: Room designs and openings4.2: Room designs and openings
32
3. In which room would you infer there is good air circulation
and ventilation? Left or Right?
Feedback to Question 3: The left room has poor ventilation
because there is no outlet for air, which stagnates in the room.
The right room has good ventilation. Why? Because hot air can
rise and exit via the roof vent and cause cool air to be pulled in
via lower window/s. Note also that the house is close to a tree
which provides shade and air movement.
Click here for possible answers.
Left Right

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation methods - Window4: Natural/passive ventilation methods - Window
placementplacement
When windows are being used…
Make the area of the windows as tall and as wide
as possible.
Use, ideally, both sliding glass and fine mesh
screen panels, to maximize air flow when windows
are fully open, yet at the same time preventing
insects (e.g. especially house flies, cockroaches and
mosquitoes) from entering.
Place few/no windows on East and West -- this
prevent rays of the rising/setting sun entering room
as earth rotates.
33

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Placing windows for breeze & to reduce sunlightPlacing windows for breeze & to reduce sunlight
 Place most windows on North and South walls or
on as many opposite walls as possible, so breezes
can blow through and the slightest breeze or air
movement will facilitate cross ventilation – i.e.
the breeze can go in one wall and out of the
opposite wall.
 Assign rooms for daytime/nighttime activities to
take advantage of the path of sunlight across the
house, from sunrise to sunset.
 Check the next slide!
34

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation methods - Position4: Natural/passive ventilation methods - Position
of windows for cross ventilationof windows for cross ventilation
35
Arrows show direction of air movement for cross ventilation

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Position of windowsPosition of windows
36
Arrows show direction of air movement for cross ventilation
Gable roof Gable end vent

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation methods4: Natural/passive ventilation methods
 High gabled roofs are good for getting rid of hot,
stale and possibly polluted air, as hot air is less
dense and lighter so tends to rise, and….
 Gable end vents below a gabled roof, placed
high above the windows under the protection of
the eaves - so the stale air, which is hot and
light, can rise then exit the room through gable
vents. See picture on next slide, 39.
 Placing small, fixed louvers and transoms above
windows/doors - serve the same function of
removing heat and stale air.
 Look at some of these on the next slide, #41.
37

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Openings for natural ventilationOpenings for natural ventilation
38
A transom, is a small,
detail window over a door
or, sometimes, above
another window. It is
called a ‘fanlight’ if it has
a semi-elliptical shape like
a flared- open hand-fan,
A gable end
vent helps
heat to
escape and
helps keep
condensation
from forming
on surfaces.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural ventilation methods –4: Natural ventilation methods –
Stack effect ventilationStack effect ventilation
 In tall/high spaces, placement of openings at
varying heights allow vertical stack effect
ventilation, especially when there is a
temperature difference between the inside space
(warmer) and the outdoors (colder).
 Windows must be lower so that the heavier
cool/cold air from outside enters the building,
then, as it heats up, from people’s activities, air
becomes lighter and rises, moving on convection
currents.
 The other openings higher up – e.g. vents,
transoms, air towers – are the exit points for
this hot, light air which is now hotter than the
outside air. So the heated air exits the building.
39

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural ventilation methods – Position of4: Natural ventilation methods – Position of
openingsopenings
40
Arrows show direction of air movement for stack effect ventilation
in tall buildings

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
4: Natural/passive ventilation - – Manipulating4: Natural/passive ventilation - – Manipulating
heatheat
41
A central courtyard allows hot air to be channeled up and
away from the building while, at the same time, cool air
enters to replace hot air.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
5: Ventilation features of our houses –5: Ventilation features of our houses –
Career FocusCareer Focus
 Who are the persons that either design, construct or install
ventilation devices in our buildings? First, of course, are
architects who design the buildings!
 Get a brief introduction to Jamaican architect – Michael
Lorde, at >
http://www.csa-utech.com/faculty_details.php?Lorde-16
 Another person is the contractor and his/her team of masons,
plumbers, carpenters, who construct the buildings according
to the blue print plan, making sure that all the natural
ventilation structures/devices are correctly built and/or
installed.
 Technicians/ electricians install mechanical ventilation
devices e.g. extractor fans, AC units, hoods etc.
 There’s a whole range of jobs from which you could have a
satisfying, rewarding career, including being a Researcher
who develops and tests new flooring, roofing, wall materials
and types of window glass for buildings.
42

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
REVIEW and QUIZREVIEW and QUIZ
 Are you ready to test yourself?
 There are Short-answer questions and
TRUE/FALSE questions that you are required to
do.
 For each of the latter questions, click on the
word ‘TRUE’ or ‘FALSE’, check the Feedback,
then click the button ‘NEXT QUESTION’ to
continue.
 Click the BEGIN QUIZ button to start the quiz.
43
BEGIN QUIZ

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
Short-answer QuestionsShort-answer Questions
1. 1. What are natural methods of ventilation?
44
Feedback -1 : Natural ventilation methods utilize
placement/size of windows, doors, vents and other
openings; location and size of the building; landscaping;
type and structure of roof; building design.
2. Name the usual mechanical ventilation devices used in large
buildings.
Feedback - 2: Air conditioners, humidifiers, fans, hoods in
kitchens, extractor fans in bathrooms, kitchens and damp
areas.
Click here for check your answer to Question 1
Click here for check your answer to Question 2

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
TRUE/FALSE QuestionsTRUE/FALSE Questions
Click True or False.
1. In ventilating a dwelling, these two elements
are manipulated for natural cooling.
45
TRUE
FALSE
The SUN’s
HEAT
The WIND

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
2. Providing openings for breeze to flow through
and move away vapour, creates drier air within
an enclosed building (up to a point) and that
improves the comfort level of occupants.
46
3. These windows are placed for cross ventilation.
TRUE FALSE
TRUE FALSE

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
47
5. In warm or humid months, in tropical
climates, maintaining thermal comfort can
only be done by using humidifiers.
4. All of these pictures show structures used for
mechanical ventilation.
L – R = extractor fan, window, stove hood
FALSETRUE
FALSETRUE

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
48
6. Thermal comfort is effected by heat conduction,
convection and radiation and also evaporative
heat loss.
TRUE FALSE
TRUE FALSE
5. Maintaining thermal comfort for occupants of houses
or other enclosed buildings is one of the important
goals of ventilation.

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
End of ActivityEnd of Activity
 You have reached the end of the content and the
activities.
 If you wish to review any concepts in this lesson,
go to the first slide and click the subtopic on the
left.
 If you have finished viewing the slides, click the
Close (X) button.
 Return to the ‘Closure’ section in your SIM.
49
49

Causes/Effects of
air pollution
Causes/Effects of
air pollution
What is
Ventilation?
What is
Ventilation?
Mechanical
Ventilation
Mechanical
Ventilation
Natural/Passive
ventilation
Natural/Passive
ventilation
of our houses
of our houses
CREDITSCREDITS
http://www.thedailygreen.com/environmental-news/latest/indoor-air-
quality-47020101#ixzz1sNSe359g
http://www.getasthmahelp.org/indoor-air-quality.aspx
http://www.builderbill-diy-help.com/tropical-building.html
http://www.sunstoneyoga.com/about/heat-humidity-
youhttp://www.panoramio.com/photo/41246932
http://www.aedhotep.com/index.php?
option=com_morfeoshow&task=view&gallery=7&Itemid=74
http://www.aedhotep.com/
http://en.wikipedia.org/wiki/File:Air_conditioning_unit-en.svg
http://janderson99.hubpages.com/hub/Cross-Ventilation-in-House-
designs-for-Natural-Passive-Air-Flow
http://janderson99.hubpages.com/hub/Cross-Ventilation-in-House-
designs-for-Natural-Passive-Air-Flow
http://home.howstuffworks.com/humidifier1.htm
http://www.youtube.com/watch?v=IvCI3Q_5A8Y
http://www.youtube.com/watch?v=1MiQCBIx1mM
http://www.youtube.com/watch?v=OphiN2y5w_A&feature=related
http://home.howstuffworks.com/humidifier.htm
http://home.howstuffworks.com/humidifier3.htm
http://www.youtube.com/watch?v=IvCI3Q_5A8Y
http://www.youtube.com/watch?v=VLwCqZmQpOg 50

Integrated Science M4 Ventilation methods

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Integrated Science M4 Ventilation methods

Similar to Integrated Science M4 Ventilation methods (20)

More from eLearningJa

More from eLearningJa (20)

Recently uploaded

Recently uploaded (20)

Integrated Science M4 Ventilation methods

Editor's Notes