Refrigerant Concentration Countermeasures - Fujitsu AIRSTAGE J-IIIL Design & Technical Manual

1-3. Refrigerant 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.
NOTE: 0.15% floor opening based on standard ceiling height of 8.8 ft (2.7 m)
• Countermeasure 2
Reduce the total refrigerant charging amount of the refrigerant equipment.
– 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.
– Lower the capacity of the outdoor unit.
Separate the outdoor unit into multiple units to lower the outdoor unit capacity for each refriger-
ant system and reduce the refrigerant charging amount.
For example, by changing a 12 ton × 1 unit system to a 6 ton × 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
backup power supply is required.
Countermeasure 3
Pay special attention to the place, such as a basement, etc. Since refrigerant is heavier than air,
refrigerant may accumulate.
1-3. Refrigerant concentration countermeasures
Refrigerant pipe
Indoor unit
Mechanical ventilator
Gas leak alarm
(Floor)
Countermeasure 1 Opening effective to ventilation
- (09-4) -
1. Refrigerant leakage caution