Fujitsu AIRSTAGE J-II Design & Technical Manual page 738

When concentration limit is exceeded
When the concentration limit is exceeded,change the original plan or take one of the
countermeasures shown below.
● Countermeasure 1
Provide opening for ventilation.
Provide 0.15% or more opening to floor space both above and below or provide opening without
door.
● 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 20HP × 1 unit system to a 10HP × 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.
Countermeasure 3
Mechanical ventilator
Gas leak alarm
Pay special attention to the place, such as a basement, etc. When refrigerant can accummalate,
since refrigerant is heavier than air.
Refrigerant pipe
Indoor unit
(Floor)
Countermeasure 1 Opening effective to ventilation
- (09 - 03) -