Necessity Of Ventilation - Mitsubishi Electric Lossnay LGH-15RX3 Technical Manual

CHAPTER 1 G Ventilation for Healthy Living
Fresh outdoor air must be introduced constantly at a set ratio in an air conditioning system. This fresh air is introduced to be
mixed with the return air from the room, to adjust the temperature and humidity, supply oxygen, reduce body and other odors,
remove tobacco smoke and to increase the cleanness of the air.
The standard ventilation (outdoor air intake) volume is determined according to the type of application, estimated number of
persons in the room, room area, and relevant regulations. Systems which accurately facilitate these requirements are
increasingly being required to be installed in buildings.

1. Necessity of Ventilation

The purpose of ventilation is basically divided into "oxygen supply", "cleaning of air", "temperature control" and "humidity
control". Cleaning of the air includes the elimination of "odors", "gases", "dust" and "bacteria". The needs of ventilation are
divided into "personal comfort", "assurance of environment for animals and plants", and "assurance of environments for
machinery and constructed materials".
In Japan legal regulations regarding ventilation are set in the Building Srandard Law Enforcement Ordinance and the "Building
Management Law" for securing a sanitary environment in buildings. These are in general agreeance with similar regulations in
other countries.
1.1 Room air environment in buildings
In Japan, the Building Management Law, a law concerning the sanitary environment of buildings, designates eleven
applications including offices, shops, and schools with a total floor area of 3,000 m
law maintenance and management of the ventilation and water supply and discharge according to the Environmental
Sanitation Management Standards is obligatory.
The following table gives a specific account of buildings in Tokyo.
(Tokyo Food and Environment Guidance Center Report)
Specific Account of Buildings in Tokyo (March, 1993)
Offices
Shops
Department Stores
Schools
Inns
Theaters
Libraries
Museums
Assembly Halls
Art Museums
Amusement Centers
Total
Note: Excludes buildings with an expanded floor space of 3,000 to 5,000 m
The ratio of results of the air quality measurement public
inspection and the standard values that were not met (percentage
of unsuitability) for the approximately 500 buildings examined in
1980 is shown in the chart at the right.
There was a large decrease in unsuitable percentages of floating
particles, but there was almost no change in temperature and
carbon dioxide. Values for temperature, ventilation, and carbon
monoxide almost entirely cleared the standard values, and are
excluded. The study from 1989 shows the item with the highest
percentage of unsuitability as temperature with 37%, followed by
carbon dioxide at 15%.
2
2
or more, as buildings. According to this
Number of buildings
2,346
344
73
388
164
84
30
15
95
7
42
3,588
2
in particular areas.
Percentage of unsiutability of air quality by year
70
60
50
40
30
20
10
0
71 72 73 74 75 76 77 78 79 80 81
(according to the Tokyo Food and Environment Guidance Center)
%
65.4
9.6
2.0
10.8
4.6
2.3
0.8
0.4
2.6
0.2
1.2
100.0
relative humidity temperature ventilation
carbon dioxide carbon monoxide floating particles
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99