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. Suffoca-
tion 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 oor
space, individual control, and energy conservation by curtail-
ing heat and carrying power, etc.
Most importantly, the multi air conditioner system is able to
replenish a large amount of refrigerant compared to conven-
tional individual air conditioners. If a single unit of the multi
air conditioner system is to be installed in a small room, se-
lect 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 ventila-
tion combined with a gas leak detection device. The density
is as given below.
The density limit of refrigerant which is used in multi air con-
ditioners is 0.3 kg/m
3
(ISO 5149).
1. If there are 2 or more refrigerating systems in a single re-
frigerating device, the amount of refrigerant should be as
charged in each independent device.
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.
Total amount of refrigerant (kg)
Min. volume of the indoor unit installed room (m
3
)
≤ Density limit (kg/m
3
)
e.g., charged
amount (10 kg)
Outdoor unit
Indoor unit
e.g., charged
amount (15 kg)
NOTE
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 oor 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. The minimum indoor floor space compared with the
amount of refrigerant is roughly as follows (for room with
2.7 m high)
Outdoor unit
Refrigerant tubing
Indoor unit
Refrigerant tubing
Outdoor unit
Indoor unit
Mechanical ventilation device – Gas leak detector
RoHS
∙ This product does not contain any hazardous substances prohibited by the RoHS Directive.
WARNING
∙ You are requested to use RoHS compliant for maintenance or repair.
Min. indoor oor space
Total amount of refrigerant
Room A Room B Room C Room D Room E Room F
Medium
room
small
room
Large
room
Very
small
room
Range below the den-
sity limit of 0.3 kg/m
3
(countermeasures not
needed)
Range above the density
limit of 0.3 kg/m
3
(counter-
measures needed)
SM830160-03ClassicPAC-iA4.ind33SM830160-03ClassicPAC-iA4.ind33 2010/02/1610:28:432010/02/1610:28:43
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