127
OCH634C
10-2. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE
Indoor unit
The smallest
room
The second
smallest room
Outdoor unit
Ventilation apparatus
Branch header
Indoor unit
Branch header
Opening
Wall
Outdoor unit
(Situation in which there
are no door openings or
in which there are open-
ings above and below
doors that occupy at
least 0.15% of the floor
area)
Indoor unit
Branch header
Outdoor unit
10-2-1. Introduction
R410A refrigerant of this air conditioner is non-toxic and non-flam-
mable but leaking of large amount from an indoor unit into the room
where the unit is installed may be deleterious.
To prevent possible injury, the rooms should be large enough to
keep the R410A concentration specified by ISO 5149-1 as follows.
Note:
When single refrigeration system consists of several independent refrigeration circuit, figure out the total refrigerant
amount by each independent refrigerant circuit.
Follow (1) to (3) to confirm the R410A concentration and take appropriate treatment, if necessary.
(1) Calculate total refrigerant amount by each refrigerant system.
Total refrigerant amount is precharged refrigerant at ex-factory plus additional charged amount at field installation.
(3) Use the results of calculations (1) and (2) to calculate the refrigerant concentration:
If the calculation results do not exceed the maximum concentration, perform the same calculations for the larger second and
third room, etc., until it has been determined that nowhere the maximum concentration will be exceed.
Indoor unit
All refrigerant of this system will leak out to this
room if there is leakage at this indoor unit.
Direction
of refrigerant flow
Outdoor unit
Branch header
Maximum concentration
Maximum refrigerant concentration of R410A of a room is 0.44kg/
K
accordance with ISO 5149-1.
To facilitate calculation, the maximum concentration is expressed
in units of
O
/
K
( kg of R410A per
K
)
(ISO 5149-1)
Maximum concentration of R410A: 0.44
O
/
K
10-2-2. Confirming procedure of R410A concentration
(b) There are partitions, but there are openings that allow
the effective mixing of air.
(c) If the smallest room has mechanical ventilation apparatus
that is linked to a household gas detection and alarm device,
the calculations should be performed for the second smallest
room.
Total refrigerant in the refrigerating unit (
O
)
[
Maximum concentration(
O
/
K
)
The smallest room in which an indoor
unit has been installed (
K
)
Maximum concentration of R410A:0.44
O
/
K
(2) Calculate room volumes (m
3
) and find the room with the smallest volume
The part with represents the room with the smallest volume.
(a) Situation in which there are no partitions
