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Check the threshold concentration
The refrigerant (R410A) used in a multi-unit air conditioning installation is in itself a safe refrigerant that
is neither
fl
ammable nor poisonous, but just in case a leak in a small room should occur, steps need to
be taken to prevent gas from exceeding the permissible concentration and causing asphyxiation. The
Japan Refrigeration and Air Conditioning Association have stipulated a threshold concentration for
refrigerants in its publication “Guidelines for Ensuring Safety in the Event of a Refrigerant Leak from a
Multi-Unit Air Conditioning System” (JRA GL-13:2010).
Apart from the lowest level underground, the threshold concentration for the charge in a system has
been set to
total refrigerant/living space capacity
≤
0.42 kg/m
3
(R410A models).
If this condition is not met, the system must either be equipped with two of the countermeasures (alarm,
ventilation or safety shut-off valve) or be redesigned.
Please note, when the system is in the lowest level underground, depending on the type of refrigerant,
the threshold concentration and number of countermeasures required may vary.
For further details, either refer to the technical document JRA-GL-13 or consult with your dealer.
Fig. 9 Permissible Refrigerant Charge for Speci
fi
c Systems and their Required Countermeasures
(R410A Refrigerant)
<Not Including Lowest Level Underground>
Total Refrigerant Charge (kg) of a Multi-Unit Package Air Conditioning System
Threshold concentration
Living Space (m
3
)
If the concentration of the refrigerant is within this
range, the system must either be equipped with two
of the countermeasures (alarm, ventilation or safety
shut-off valve) or be redesigned.
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2012/09/07 9:32:40
2012/09/07 9:32:40
