Methods Of Ventilation - Fujitsu UTZ-BD035B Technical Manual

4-3. METHODS OF VENTILATION

Ventilation can be divided into natural ventilation based
on natural conditions and mechanical ventilation based on
mechanical power.
 NATURAL VENTILATION
Natural air
Air exhaust
(Natural
exhaust
Air supply
ventilation) Natural air
supply
Warehouses, gymnasiums, factories
where hot air is generated
Fig. 3-1
 MECHANICAL VENTILATION

Methods of mechanical ventilation
Class 1 Ventilation Method Class 1 Ventilation Method Class 1 Ventilation Method
Mechanical air Mechanical air
Mechanical Mechanical Mechanical Air Air Air Mechanical air
Exhaust
Exhaust Exhaust
supply supply supply
exhaust exhaust exhaust supply supply supply
Indoor Indoor Indoor Ventilating Ventilating
Ventilating
fan fan
Exter- fan
Exter- Exter-
nal air
nal air nal air
Ventilating fan Ventilating fan
Ventilating fan
To be applied for buildings, indoor parking
To be applied for buildings, indoor parking To be applied for buildings, indoor parking
lots, boiler rooms, electric rooms, machine lots, boiler rooms, electric rooms, machine lots, boiler rooms, electric rooms, machine
rooms, kitchens, and warehouses, etc. rooms, kitchens, and warehouses, etc. rooms, kitchens, and warehouses, etc.
Fig. 3-2
Fig. 3-2 Fig. 3-2
Class 2 Ventilation Method Class 2 Ventilation Method Class 2 Ventilation Method
Mechanical Air Mechanical air Mechanical air Mechanical air
Mechanical Mechanical Air Air
Exhaust Exhaust
Exhaust
supply
supply supply
exhaust exhaust exhaust supply supply supply
Positive
Positive Positive
pressure pressure
pressure
Exhaust
Exhaust Exhaust
Indoor Indoor Indoor
outlet outlet outlet
Exter-
Exter- Exter-
nal air
nal air nal air
Ventilating fan Ventilating fan Ventilating fan
To be applied for clean rooms and cooling
To be applied for clean rooms and cooling To be applied for clean rooms and cooling
machinery, etc. machinery, etc.
machinery, etc.
Fig. 3-3
Fig. 3-3 Fig. 3-3
Class 3 Ventilation Method Class 3 Ventilation Method Class 3 Ventilation Method
Mechanical Mechanical Mechanical
Air Mechanical air Mechanical air Mechanical air
Air Air
Exhaust Exhaust Exhaust
exhaust exhaust exhaust
supply
supply supply supply
supply supply
Negative Negative Negative
pressure pressure pressure
Ventilating Ventilating Ventilating
Indoor
Indoor Indoor
fan fan fan
Exter-
Exter- Exter-
nal air
nal air nal air
Air supply
Air supply Air supply
inlet inlet inlet
To be applied for kitchens, toilets, rooms where hot-water To be applied for kitchens, toilets, rooms where hot-water To be applied for kitchens, toilets, rooms where hot-water
heaters can be utilized in residences, and copying heaters can be utilized in residences, and copying heaters can be utilized in residences, and copying
rooms, etc. rooms, etc.
rooms, etc.
Fig. 3-4 Fig. 3-4 Fig. 3-4

Total ventilation and local ventilation
 Total ventilation
Air
supply
Contami-
nated air
Ex-
haust
Fig. 3-5
The total (general) ventilation can be categorized into the
following three types.
a) Individualized ventilation system
The amount of ventilation required for each room can be
satisfied by installing ventilation facilities at each room.
..........
b) Total ventilation system
The total amount of ventilation for the entire building
can be satisfied by utilizing local exhaust facilities and
installing natural air-supply inlet at each room. E.g., local
exhaust facilities + natural air-supply inlets, etc.
c) Central ventilation system
A single ventilation unit can satisfy the amount of
ventilation required for multiple rooms and the entire
building. ............
This ventilation is based on pressure
derived from external winds and
the outdoor and indoor temperature
differences. However, as natural
ventilation is weaker than mechanical
ventilation and may be greatly
affected by natural conditions,
significant results cannot be expected
As this method is based on enforced
ventilation with ventilating fans and air
blowers, etc., it is capable of generating
stable amounts of ventilation at
required timing, compared with natural
ventilation.
*
Highly contaminated rooms should
remain in negative pressure to prevent
contaminated air from leaking into
adjacent rooms and corridors (Class 1 or
Class 3 Ventilation). On the other hand,
for rooms that need to be kept clean,
positive pressure should be maintained
to prevent intrusion of contaminated air
(Class 2 Ventilation).
This ventilation is designed for an
entire house and for exchanging
the entire air in the house (Fig.
3-5).
 Local ventilation
This type of ventilation is performed for particular spots in a
house (rooms or parts).
a) Local exhaust
Local exhaust is performed for particular places in which
contaminants (combustion gases, humidity, smoke, and
smell, etc.) may be generated (Fig. 3-6).
Cooking o ven
hood fan
Oven
a) Room ventilation
Individualized ventilation designed for single rooms, etc.
(When individualized ventilation systems are installed
in all rooms, the entire setup can be referred to as total
ventilation.)
- (01-21) -
(Ohmsha, Ltd., Ventilation, the
Society of Heating, Air-Conditioning
and Sanitary Engineers of Japan)
This kind of ventilation is applied
Exhaust
specifically for kitchens, bathrooms,
and toilets, etc.
Fig. 3-6