12 Maintenace notes
468
SMGB0064 rev.0 - 08/2011
12.7 Caution with the refrigerant leakage
The designers and the installers have the responsibility to follow the local codes and the local regulations that specify the
safety requirement against the refrigerant leakage.
12.7.1 Maximum permissible concentration of the HCFC gas
The refrigerant R410A which is charged in the UTOPIA IVX/ES system is an incombustible non-toxic gas. However if the
leakage occurs and the gas lls a room the gas may cause suffocation.
The maximum permissible concentration of the HCFC gas and the R410A in the air is 0.44 kg/m
³
according to the refrige-
ration and air conditioning system standard (KHK S 0010) by the KHK (high-pressure gas protection association) of Japan.
Therefore you must take some effective measures in order to lower the R410A concentration in the air below 0.44 kg/m
3
if there is a leakage.
12.7.2 Calculation of the refrigerant concentration
1 Calculate the total quantity of refrigerant R (kg) that is charged in the system that connects all the indoor units of the
rooms that need air conditioning systems.
2 Calculate the room volume V (m
³
) of each room.
3 Calculate the refrigerant concentration C (kg/m
³
) of the room according to the following equation:
C = R/V
R: Total quantity of charged refrigerant (kg)
V: Room volume (m
³
)
C: Refrigerant concentration (≤0.44* kg/m
3
for the R410A)
* Use this value only for reference because this value is not xed yet.
12.7.3 Countermeasure for the refrigerant leakage according to the KHK standard
According to the KHK standards you should arrange the facility as follows so that the refrigerant concentration will be
bellow 0.3 kg/m
3
.
1 Provide a shutterless opening that will allow the fresh air to circulate into the room.
2 Provide a doorless opening with a size of 0.15 or more to the oor area.
3 Provide a ventilator which must be linked with a gas leak detector with a ventilating capacity of 0.5 m
3
/min or more per
Japanese refrigeration ton (=compressor displacement 8.5 m
3
/h of the air conditioning system which uses the refrige-
rant).
• IVX
O.U. model Ton
RAS-8HRNM 2.49
RAS-10HRNM 3.32
RAS-12HRNM 4.15
• ES
O.U. model Ton
RAS-(2-2.5)HVRN2) 0.88
RAS-3HVRNS2 1.14
RAS-4HVRNS2E 1.67
RAS-(5-6)HVRNS2E 2.27
RAS-8HRNSE 2.49
RAS-10HRNSE 3.32
4 Pay a special attention to the place such as a basement and others where the refrigerant may stay because the refri-
gerant is heavier than the air.
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