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CAUTION FOR REFRIGERANT LEAK
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 Concentration limit even if
the refrigerant gas leaks in the room.
Concentration limit
Concentration limit is the limit of Freon gas concentration where
immediate measures can be taken without hurting human body
when refrigerant leaks in the air. The Concentration limit shall be
3
described in the unit of [kg/m
air volume) for facilitating calculation.
Concentration limit: 0.44 kg/m
Outdoor unit
Flow of
(No.1 system)
refrigerant
Indoor unit
Checking procedure of limiting concentration
Check Concentration limit along following steps and take appropriate
measure depending on the situation.
Calculate amount of all the replenished refrigerant [kg (lbs)] per each
refrigerant system.
Amount of pre charged
Amount of additional
refrigerant per single unit
+
replenished refrigerant
system
Amount of replenished
Amount of additionally
refrigerant at factory shipment
replenished refrigerant
depending on piping
length or piping
diameter by customer
Calculate refrigerant concentration level
Calculate the volume of the room where indoor unit is installed as
single room or the smallest room.
- Without partition
Outdoor unit
Indoor unit
- With partition and without opening which serve as passage of air to
adjoining room
Smallest
room
3
(lbs/ft
)] (Freon gas weight per unit
3
3
(0.028 lbs/ft
) (R410A)
Room where refrigerant leaks
(Refrigerant of the whole No.1
system flows out.)
Total amount of
=
refrigerant in the system
[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.
- With partition but opened which
serve passage of air to adjoining
room
Outdoor unit
In the case of opening
Indoor unit
without door , or 0.15
Opening
% or more openings
(to floor space) both
Partition
above and below door)
Outdoor unit
Indoor unit
Calculate refrigerant concentration
Total amount of refrigerant
system [kg(lbs)]
Volume of smallest room
whereindoor unit is installed
3
3
[m
(ft
)]
- In case the result of calculation exceeds the Concentration limit, perform the
same calculations by shifting to the second smallest, and the third smallest
rooms until at last the result is below the Concentration limit.
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 size of opening to floor space both above
and below door, or provide opening without door.
• Countermeasure 2
Provide gas leak alarm linked with mechanical ventilator.
• Countermeasure 3
Reducing the system`s refrigerant quantity by deviding into smaller
separate system.
Gas leak alarm
Countermeasure 2
Mechanical ventilator
Indoor unit
Pay a special attention to the place, such as a basement, etc.
where refrigerant can stay, since refrigerant is heavier than air.
= Maximum concentration limit
3
3
[kg/m
(lbs/ft
)]
(R410A)
Countermeasure 1 Opening effective to ventilation
39
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