Toshiba RAV-SM2244AT8-A Service Manual page 113

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 concentra-
tion buildings, however, the installation of multi air condi-
tioner 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 mechani-
cal ventilation combined with a gas leak detection device.
The concentration is as given below.
Total amount of refrigerant (kg)
Min. volume of the indoor unit installed room (m³)
≤ Concentration limit (kg/m³)
The concentration limit of R410A which is used in multi air
conditioners is 0.3kg/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.
e.g., charged
amount (10kg)
Room A Room B Room C Room D Room E Room F
For the amount of charge in this example:
The possible amount of leaked refrigerant gas
in rooms A, B and C is 10kg.
The possible amount of leaked refrigerant gas
in rooms D, E and F is 15kg.
Outdoor unit
e.g.,
charged amount (15kg)
Indoor unit
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).
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 inter-
locked 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.
Very
small
room
Small Medium
room room
Mechanical ventilation device - Gas leak detector
NOTE 3:
The minimum indoor floor area compared with the amount
of refrigerant is roughly as follows:
(When the ceiling is 2.7m high)
40
Range below the
35
m²
density limit
of 0.3 kg/m³
30
(countermeasures
not needed)
25
20
15
10
5
0
10
Total amount of refrigerant
Outdoor unit
Refrigerant piping
Indoor unit
Refrigerant piping
Outdoor unit
Indoor unit
Large room
Range above
the density limit
of 0.3 kg/m³
(countermeasures
needed)
20 30
kg