Refrigeration Concentration Countermeasures - Fujitsu Airstage J-II Series Design & Technical Manual

1-3. REFRIGERATION CONCENTRATION
COUNTERMEASURES
When the concentration limit is exceeded, the designer will need to change the original design
or use one of the countermeasures below to reduce potential exposure to refrigerant. Always
consult local codes to ensure proper design.
● Countermeasure 1
Provide opening for ventilation.
Provide 0.15% or more opening to floor space both above and below or provide opening without
door. (0.15% floor opening based on standard ceiling height of 8.8 ft. (2.7m))
● Countermeasure 2
Reduce the total refrigerant charging amount of the refrigerant equipment
(1) Shorten the length of the refrigerant pipes
Move the location of the outdoor unit closer to the indoor unit, and reduce the total refrigerant
charging amount by shortening the length of the refrigerant pipes.
(2) Lower the capacity of the outdoor unit.
Separate the outdoor unit into multiple units to lower the outdoor unit capacity for each
refrigerant system and reduce the refrigerant charging amount.
For example, by changing a 12Ton × 1 unit system to a 6Ton × 2 units system,
the refrigerant amount for each refrigerant system can be reduced by about half.
● Countermeasure 3
Provide gas leak alarm linked with mechanical ventilator. If using the mechanical ventilator, The
back up power supply is required.
Countermeasure 3
Mechanical ventilator
Gas leak alarm
Pay special attention to areas where refrigerant can accumulate (like a basement), since refrigerant
is heavier than air.
Refrigerant pipe
Indoor unit
(Floor)
Countermeasure 1 Opening effective to ventilation
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