Caution In Case Of Refrigerant Leakage; Maximum Permitted Concentration Of Hydrofluorocarbon (Hfc); Calculation Of Refrigerant Concentration - Hitachi RAS-(3-6)HVNC1(E) Service Manual

3 Piping work and
refrigerant charge
3.5 Caution in case of refrigerant leakage
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.
3.5.1 Maximum permitted concentration of hydrofluorocarbon (HFC)
The refrigerant R410A, charged in the UTOPIA 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/m , according to EN378-1.
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Therefore, some effective measure must be taken to lower the R410A concentration in air below 0.44 kg/m
suffocation in case of leakage.
3.5.2 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 (m
3 Calculate the refrigerant concentration C (kg/m
R: Total quantity of refrigerant charged (kg).
V: Room volume (m ).
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C: Refrigerant concentration (≤ 0.44 kg/m
3.5.3 Countermeasure for refrigerant leakage
The room must have the following features to prevent suffocation in case a refrigerant leakage occurs:
1 Provide a shutterless opening which will allow fresh air to circulate into the room.
2 Provide a doorless opening of 0.15% or more size to the floor area.
3 There must be a ventilator fan connected to a gas leak detector, with a ventilator capacity of 0.4 m³/min or higher per
Japanese refrigeration ton (= compressor displacement volume / 5.7 m³/h) of the air conditioning system using the
refrigerant.
IVX Premium series
Model
RAS-2HVNP1
RAS-2.5HVNP1
RAS-3HVNP1E
RAS-(4-6)H(V)NP1E
RAS-8HNPE
RAS-10HNPE / RAS-12HNP
IVX Standard series
Model
RAS-3HVNC1
RAS-4H(V)NC1E
RAS-(5/6)H(V)NC1E
RAS-8HNCE
RAS-10HNCE / RAS-12HNC
4 Pay a special attention to the place, such as a basement, etc., where refrigerant can stay, since refrigerant is heavier
than air.
89
SMGB0087 rev.0 - 12/2013
) of each room (including false ceiling).
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) of the room according to the following equation:
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C = R / V
for R410A).
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to prevent
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Tonnes
0.88
0.88
1.17
2.27
3.16
4.11
Tonnes
1.17
1.64
2.27
3.16
4.11
3