ii
Outdoor unit
0002_M_I
Refrigerant tubing
Indoor unit
Check of Density Limit
Do not install the indoor unit
to the place, such as a
basement, etc. where
refrigerant can stay, since
refrigerant is heavier than air.
The room in which the air conditioner is to be
installed requires a design that in the event of
refrigerant gas leaking out, its density will not exceed
a set limit.
The refrigerant (R22/R407C) which is used in the air
conditioner is safe, without the toxicity or combustibility of
ammonia, and is not restricted by laws to be imposed
which protect the ozone layer. However, since it contains
more than air, it poses the risk of suffocation if its density
should rise excessively. Suffocation from leakage of
refrigerant is almost non-existent. With the recent
increase in the number of high density buildings, how-
ever, the installation of multi air conditioner systems is on
the increase because of the need for effective use of floor
space, individual control, energy conservation by
curtailing heat and carrying power etc.
Most importantly, the multi air conditioner system is able
to replenish a large amount of refrigerant compared with
conventional individual air conditioners. If a single unit of
the multi air conditioner system is to be installed in a
small room, select a suitable model and installation
procedure so that if the refrigerant accidentally leaks out,
its density does not reach the limit (and in the event of an
emergency, measures can be made before injury can
occur).
In a room where the density may exceed the limit, create
an opening with adjacent rooms, or install mechanical
ventilation combined with a gas leak detection device.
The density is as given below.
Total amount of refrigerant (kg)
Min. volume of the indoor unit installed room (m
3
)
Density limit (kg/m
3
)
The density limit of refrigerant which is used in multi air
conditioners is 0.3 kg/m
3
(ISO 5149).
2 : The standards for minimum room
volume are as follows.
(1) No partition (shaded portion)
(2) When there is an effective opening with the
adjacent room for ventilation of leaking
refrigerant gas (opening without a door, or an
opening 0.15% or larger than the respective
floor spaces at the top or bottom of the door).
(3)
If an indoor unit is installed in each partitioned
room and the refrigerant tubing is interconnected,
the smallest room of course becomes the object.
But when a mechanical ventilation is installed
interlocked with a gas leakage detector in the
smallest room where the density limit is
exceeded, the volume of the next smallest room
becomes the object.
40
35
30
25
20
15
10
5
0
10 20 30
Total amount of refrigerant
Min. indoor floor space
m
2
kg
1170_M_
The minimum indoor floor space compared with the
amount of refrigerant is roughly as follows:
(When the ceiling is 2.7 m high)
>
For the amount of charge in this example:
The possible amount of leaked refrigerant gas in
rooms A, B and C is 10 kg.
The possible amount of leaked refrigerant gas in
rooms D, E and F is 15 kg.
1 : If there are 2 or more refrigerating systems
in a single refrigerating device, the amount
of refrigerant should be as charged in each
independent device.
0803_M_I
e.g., charged
amount (10 kg)
Outdoor unit
Indoor unit
Room A Room B Room C Room D Room E Room F
e.g.,
charged amount (15 kg)
NOTE
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