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Warnings on refrigerant leakage
Check of Concentration 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 concentration 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 to be imposed which protect
the ozone layer. However, since it contains more than air, it
poses the risk of suffocation if its concentration should rise
excessively.
Suffocation from leakage of R410A is almost non-existent.
With the recent increase in the number of high concentration
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 with
conventional individual air conditioners. If a single unit of the
multi 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 concentration 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 concentration may exceed the limit,
create an opening with adjacent rooms, or install
mechanical ventilation combined with a gas leak detection
device.
The concentration is as given below.
Total amount of refrigerant (lbs (kg))
Min. volume of the indoor unit installed room (ft³ (m³))
Concentration limit (lbs/ft³ (kg/m³))
The concentration limit of R410A which is used in multi air
conditioners is 0.019 lbs/ft³ (0.3 kg/m³).
NOTE 1 :
If there are 2 or more refrigerating systems in a single
refrigerating device, the amounts of refrigerant should be
as charged in each independent device.
Outdoor unit
e.g.,
charged amount
e.g.,
(22 lbs (10 kg))
charged amount
(33 lbs (15 kg))
Room A Room B Room C Room D Room E Room F
Indoor unit
For the amount of charge in this example:
The possible amount of leaked refrigerant gas in rooms
A, B and C is 22 lbs (10 kg).
The possible amount of leaked refrigerant gas in rooms
D, E and F is 33 lbs (15 kg).
61-EN
Important
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 floor spaces at the top or
bottom of the door).
Outdoor unit
Refrigerant piping
Indoor unit
(3) If an indoor unit is installed in each partitioned
room and the refrigerant piping 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.
Refrigerant piping
Outdoor unit
Very
small
Indoor unit
room
Small
Medium
Large room
room
room
Mechanical ventilation device - Gas leak detector
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62-EN
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