Table of Contents
Advertisement
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.
Suffocation from leakage of refrigerant is almost non-exis-
tent. 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 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 to
conventional individual air conditioners. If a single unit of
the multi air 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 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
ventilation combined with a gas leak detection device.
The density is as given below.
Total amount of refrigerant (oz)
Min. volume of the indoor unit installed room (ft.
<
Density limit (oz/ft.
The density limit of refrigerant which is used in multi air condi-
3
tioners is 0.3 oz/ft.
(ISO 5149).
NOTE
1. If there are 2 or more refrigerating systems in a single
refrigerating device, the amount of refrigerant should be
as charged in each independent device.
For the amount of charge in this example:
e.g., charged
amount (353 oz)
Indoor unit
Room A Room B Room C Room D Room E Room F
The possible amount of leaked refrigerant gas in rooms A, B
and C is 353 oz.
The possible amount of leaked refrigerant gas in rooms D, E
and F is 529 oz.
2. The standards for minimum room volume are as fol-
(1) No partition (shaded portion)
(2) When there is an effective opening with the adjacent
(3) If an indoor unit is installed in each partitioned room
3
)
3
)
3. The minimum indoor floor space compared with the
Outdoor unit
e.g., charged
amount (529 oz)
3
lows.
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).
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.
Very
small
room
Small
Medium
room
room
Mechanical ventilation device – Gas leak detector
amount of refrigerant is roughly as follows (when the
ceiling is 8.8 ft. high):
3
ft.
4000
Range below
3500
the density limit of
3000
0.3 oz/ft.
3
(countermeasures
2500
not needed)
2000
1500
Range above
the density limit of
1000
0.3 oz/ft.
500
(countermeasures
needed)
0
0
200
400
600
Total amount of refrigerant
Outdoor unit
Refrigerant tubing
Indoor unit
Refrigerant tubing
Outdoor unit
Indoor unit
Large room
2
ft.
454
398
341
284
227
170
114
3
57
0
800 1000 1200
oz
Hide quick links:
Advertisement
Table of Contents
