Toshiba MMK-AP0073HP1-E1 Service Manual page 58

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 (kg)
Min. volume of the indoor unit installed room (m³)
Concentration limit (kg/m)
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
58
▼ 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
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.
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
m²
35
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