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Check of Density Limit
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 (R410A), which is used in the air
conditioner, is safe, without the toxicity or combustibility
of ammonia, and is not restricted by laws imposed to
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,
however, 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 to 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
≤ Density limit (kg/m
The density limit of refrigerant which is used in multi air
conditioners is 0.3 kg/m
3
(ISO 5149).
NOTE
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.
For the amount of charge in this example:
e.g., charged
amount (10 kg)
Indoor unit
Room A Room B Room C Room D Room E Room F
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.
RoHS
3
)
Outdoor unit
e.g., charged
amount (15 kg)
· This product does not contain any hazardous substances prohibited by the RoHS Directive.
WARNING
· You are requested to use RoHS compliant parts for maintenance or repair.
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 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.
3
)
Very
small
room
Small
room
Mechanical ventilation device – Gas leak detector
3. The minimum indoor floor space compared with the
amount of refrigerant is roughly as follows: (When
the ceiling is 2.7 m high)
40
35
m
2
30
25
20
15
10
5
0
ii
Outdoor unit
Refrigerant tubing
Refrigerant tubing
Medium
Large room
room
Range below
the density limit
of 0.3 kg/m
3
(countermeasures
not needed)
Range above
the density limit
of 0.3 kg/m
(countermeasures
needed)
10
20
Total amount of refrigerant
Indoor unit
Outdoor unit
Indoor unit
3
30
kg
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