Caution With The Refrigerant Leakage; Maximum Permissible Concentration Of The Hcfc Gas; Calculation Of The Refrigerant Concentration; Countermeasure For The Refrigerant Leakage According To The Khk Standard - Hitachi RAS-5HVRNM1E Service Manual

12 Maintenace notes

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 fills 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
refrigeration 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
3
kg/m , 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 Calculate the refrigerant concentration C (kg/m
C = R/V
* Use this value only for reference because this value is not fixed 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
3
0.3 kg/m .
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 floor area.
3 Provide a ventilator, which must be linked with a gas leak detector, with a ventilating capacity of 0.5 m
Japanese refrigeration ton (=compressor displacement 8.5 m
refrigerant).
• IVX
O.U. model
RAS-8HRNM
RAS-10HRNM
RAS-12HRNM
• ES
O.U. model
RAS-(2-2.5)HVRN1(E)
RAS-3HVRNS
RAS-4HVRNS1E
RAS-(5-6)HVRNS1E
RAS-8HRNSE
RAS-10HRNSE
4 Pay a special attention to the place, such as a basement and others, where the refrigerant may stay, because the
refrigerant is heavier than the air.
464
SMGB0060 rev. 1- 12/2010
³
) of each room.
³
) of the room according to the following equation:
R: Total quantity of charged refrigerant (kg)
V: Room volume (m
C: Refrigerant concentration (≤0.44* kg/m
³
)
3
for the R410A)
3
/h of the air conditioning system which uses the
Ton
2.49
3.32
4.15
Ton
0.88
1.14
1.67
2.27
2.49
3.32
³
, according to the
3
/min or more per