Chiller rooms are the most common ASHRAE-15 requirement for a refrigerant monitor. Defined as an unoccupied space by ASHRAE-15, the chiller room must have a refrigerant monitor that activates audible and visual alarms inside and outside the room, activates a refrigerant exhaust fan and shuts off any combustion in the room.
Chiller room applications are the most common requirement for a refrigerant monitor.
The typical system will consist of a monitor sized with a sample point near each chiller, 4-20 mA analog output option, a combination horn strobe alarm inside the room, a combination horn strobe alarm outside each entrance to the room and a roll of tubing.
Multiple adjacent spaces can be monitored with one system by adding Individual Zone Alarm output option. This consists of up to eight additional DPDT relays that can be mapped to each sample area and mapped to different alarm levels.
Spaces with stairwells or tunnels adjacent to the machine room might require additional sample areas. Refrigerant is heavier than air and may fall into lower spaces, requiring detection in the lower area.
To date, there is no ASHRAE-15 safety requirement for a refrigerant monitor for a VRF or VRV system. Further, use of a refrigerant monitor for a system designed with a large amount of refrigerant will not meet the requirements of ASHRAE-15.
Though there is not an ASHRAE-15 safety requirement for a refrigerant monitor in AVRF-VRV applications, some engineers have added a monitor in certain locations as a maintenance aid.
We have also seen some specifying engineers specify a refrigerant monitor for spaces that are too small for the amount of refrigerant in the system - thinking that this will meet code. It will not.
ASHRAE-15 clearly defines two applications requiring a refrigerant monitor:
Unoccupied Spaces - Chiller Rooms
Industrial Occupancy - Cooled spaces where workers are present, and the amount of refrigerant cannot be reduced sufficiently, such as those found in food processing facilities and refrigerated warehouses.
We know of no VRF/VRV system that qualifies for either of these definitions.
Care must be taken when designing, quoting or installing a refrigerant monitor in a VRF or VRV application. While a refrigerant monitor can be useful to detect leaks and provide early warning of refrigerant loss, it must be clear to the owner that the monitor has been installed as a maintenance tool, and is not a safety device in this application.