35
ENGLISH
Calculate minimum room capacity
Calculate room capacity by regarding a portion as one room or the
smaller room.
- With partition and with opening
which serve as passage of air to
adjoining room
- Without partition
Limiting concentration is the limit of Freon gas concentration
where immediate measures can be taken without hurting human
body when refrigerant leaks in the air. The limiting concentration
shall be described in the unit of Kg/m
3
(lbs/ft
3
) (Freon gas weight
per unit air volume) for facilitating calculation.
Limiting concentration: 0.44kg/m
3
(0.028lbs/ft
3
)(R410A)
Amount of additional
replenished refrigerant
Total amount of replenished 
refrigerant in refrigerant 
facility [kg(lbs)]
+
=
Note : In case one refrigerant facility is 
divided into 2 or more refrigerant 
systems and each system is 
independent, amount of replenished 
refrigerant of each system shall be 
adopted.
Amount of replenished 
refrigerant per one outdoor 
unit system
Amount of replenished 
refrigerant at factory shipment
Amount of additionally 
replenished refrigerant 
depending on piping 
length or piping 
diameter at customer
Outdoor unit
Indoor unit
Outdoor unit
Indoor unit
Opening
Partition
In the case of opening 
without door , or 0.15 
% or more openings 
(to floor space) both 
above and below door)
HR unit
HR unit
Outdoor unit
(No.1 system)
Flow of 
refrigerant
Indoor unit
Room where refrigerant leaks
(Refrigerant of the whole No.1 
system flows out.)
HR unit
- With partition and without opening which serve as passage of air to
adjoining room
Calculate refrigerant concentration 
Total amount of replenishedrefrigerant  
in refrigerant facility [kg(lbs)]
Capacity of smallest room 
whereindoor unit is installed [m
3
(ft
3
)]
- In case the result of calculation exceeds the limiting concentration, perform
the same calculations by shifting to the second smallest, and the third small-
est rooms until at last the result is below the limiting concentration.
=  Refrigerant concentration[Kg/m
3
(lbs/ft
3
)]
(R410A)
In case the concentration exceeds the limit
When the concentration exceeds the limit, change original plan or take
one of the countermeasures shown below:
• Countermeasure 1
Provide opening for ventilation.
Provide 0.15% or more opening to floor space both above and below
door, or provide opening without door.
• Countermeasure 2
Provide gas leak alarm linked with mechanical ventilator.
Reducing the outdoor refrigerant qty. 
Outdoor unit
Indoor unit
Smallest
room
HR unit
Countermeasure 2
Gas leak alarm
Mechanical ventilator
Countermeasure 1
Opening effective to ventilation
Indoor unit
Pay a special attention to the place, such as a basement, etc.
where refrigerant can stay, since refrigerant is heavier than air.
Checking procedure of limiting concentration
Check limiting concentration along following steps and take appropri-
ate measure depending on the situation.
Calculate amount of all the replenished refrigerant (kg) per each refrig-
erant  system.
The installer and system specialist shall secure safety against leakage
according to local regulations or standards. 
The following standards may be applicable if local regulations are not
available.
Introduction
Though the R410A refrigerant is harmless and incombustible itself ,
the room to equip the air conditioner should be large to such an extent
that the refrigerant gas will not exceed the limiting concentration even
if the refrigerant gas leaks in the room.
Limiting concentration
CAUTION FOR REFRIGERANT LEAK
1,MFL69717904,영영  18. 8. 29.  영영 2:50  Page 35