9 Piping work and
refrigerant charge
TCGB0070 rev.3 - 04/2012
115
9
9.4 Precautions in the event of gas refrigerant leaks
The installers and those responsible for drafting the specifications are obliged to comply with local safety codes and regu
-
lations in the case of refrigerant leakage.
9.4.1 Maximum permitted concentration of HFCs
The refrigerant R410A, charged in the RASC series system, is an incombustible and non-toxic gas. However, if leakage
occurs and gas fills a room, it may cause suffocation.
The maximum permissible concentration of HFC gas, R410A in air is 0.44 kg/m³, according to EN378-1.
Therefore, some effective measure must be taken to lower the R410A concentration in air below 0.44 kg/ m³, in case of
leakage.
9.4.2 Calculation of refrigerant concentration
1
Calculate the total quantity of refrigerant R (kg) charged in the system by connecting all the indoor units in the rooms
to be air-conditioned.
2
Calculate the room volume V (m³) of each room.
3
Calculate the refrigerant concentration C (kg/m³) of the room according to the following equation:
R
— = C
V
R: Total quantity of refrigerant charged (kg)
V: Room volume (m³)
C: Refrigerant concentration (=0.44* kg/m³ for R410A)
Outdoor unit (RAS-5HVRNME-AF)
Refrigerant: 3.6 kg
Gas leak
detector (*)
Fan m
3
/min (*)
Height 2.5 m
Floor
10 m2
Opening: 0.06 m
2
(*)
Indoor unit
(RWM-5.0FSN3E)
Room
R (kg)
V (m³)
C (kg/m³)
Countermeasure
A
3,6
25
0,144
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