Design and Technical Manual

6. SYSTEM DESIGN
REFRIGERATION CONCENTRATION 11-3.
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 oor space both above and below or provide opening without
door. (0.15% oor 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.
Countermeasure 3 ●
Provide gas leak alarm linked with mechanical ventilator. If using the mechanical ventilator, The
back up power supply is required.
Pay special attention to areas where refrigerant can accumulate (like a basement), since refrigerant is
heavier than air.
Countermeasure 3
Countermeasure 1 Opening effective to ventilation
Indoor unit
Refrigerant pipe
Mechanical ventilator
Gas leak alarm
(Floor)
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SYSTEM DESIGN SYSTEM DESIGN