Safety Caution - Toshiba MMU-AP0072H2UL Engineering Data Book

Safety caution

Safety caution
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 (ft
≤ Concentration limit (lbs/ft
Concentration limit
Compliance to the local applicable regulations and
standards for the concentration limit is required.
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
((22 lbs) 10 kg)
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 22 lbs (10 kg).
The possible amount of leaked refrigerant gas in
rooms D, E and F is 33 lbs (15 kg).
3 3
(m ))
3 3
(kg/m ))
Outdoor unit
e.g.,charged amount
(33 lbs (15 kg))
Indoor unit
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
room
Mechanical ventilation device - Gas leak detector
2
Important
Outdoor unit
Refrigerant piping
Indoor unit
Refrigerant piping
Medium Large
room room
Outdoor unit
Indoor unit