Refrigerant Concentration Precautions; Introduction - Fujitsu Airstage J-II Series Design & Technical Manual

1. REFRIGERANT CONCENTRATION PRECAUTIONS

The system designer and installer are to ensure that the system adheres to all local regulations
regarding refrigerant leakage.

1-1. INTRODUCTION

Designing VRF systems requires special attention to codes and standards relating to Refrigeration
Concentration Limit (RCL). The RCL is intended to "reduce the risks of acute toxicity, asphyxiation
and flammability hazards in normally occupied, enclosed spaces".
Because R-410A in neither toxic nor flammable; the primary safety concern is asphyxiation due to
oxygen deprivation.
z Concentration limit
z
The purpose of the concentration limit is to protect occupants in the unlikely event that the
entire refrigerant system leaks into the smallest room served by the system. To calculate the
potential refrigerant concentration, divide the total refrigerant in the system by the volume of
the smallest space served by the system.
The Concentration Limit for R-410A : 25lbs./1,000 ft³ (0.40kg/m³)*.
*Based on ASHRAE 34-2007 and IMC-2009
Outdoor units
Flow of
refrigerant
Indoor units
- (09-01) -
Entire refrigerant charge in the
system leaks into the smallest
room.