What monitoring equipment belongs in a machine room that houses a large low-pressure chiller?
Correct Answer
B) A refrigerant vapor and oxygen level monitor with an audible alarm
The hazard in a chiller room is a refrigerant release that displaces the oxygen a worker needs to breathe. Because refrigerant vapor is colorless and gives little warning, the room is fitted with a monitor that senses refrigerant concentration and oxygen level and sounds an alarm loud enough to drive people out. Carbon monoxide detectors, smoke detectors and humidity sensors all watch for entirely different hazards and would not respond to a refrigerant release.
Why This Is the Correct Answer
A refrigerant and oxygen monitor watches for exactly the condition that kills people in machine rooms: refrigerant vapor accumulating and pushing breathable air out of the space. The alarm gives occupants a chance to leave and warns anyone approaching not to enter without proper respiratory protection.
Why the Other Options Are Wrong
Option A: A carbon monoxide detector mounted near the ceiling above the machine
A carbon monoxide detector responds to combustion products and will not react to a refrigerant release at any concentration. A room can reach a lethal level with that detector reading normal.
Option C: A smoke detector positioned directly above the compressor itself
A smoke detector responds to products of combustion. Refrigerant vapor released into the machine room produces no smoke for it to sense, however large the release turns out to be.
Option D: A humidity sensor near the water boxes and the pump skid
A humidity sensor tracks moisture in the air and says nothing about refrigerant concentration or oxygen level. It reads the same whether the machine is full or has dumped its whole charge.
Memory Technique
The room watches for what you cannot see or smell: too much refrigerant, too little oxygen.
Reference Hint
Machine rooms with large refrigerant charges require refrigerant and oxygen monitoring with alarms, tied to emergency ventilation.
More epa-608-type-3 Questions
Some jobs on a chiller count as a major repair under the refrigerant rules, which changes what a technician is allowed to do with a badly leaking machine. Which job falls into that category?
An owner asks how many pounds of refrigerant the rules allow to be left inside a chiller once the recovery has been signed off. What is the correct answer to give him?
The motor of a hermetic centrifugal chiller sits inside the pressure boundary rather than outside it on a shaft. What follows from that construction?
An oxygen monitor is used to decide whether a chiller machine room is safe to enter after a refrigerant release. Below what oxygen reading is the atmosphere treated as oxygen deficient?
A low-pressure chiller's rupture disc has a discharge line running from it. Where does that line have to terminate?
A refrigerant vapor detector in a chiller machine room reaches its alarm level. Besides sounding, what is that alarm expected to do?
Which piece of equipment requires a technician to hold Type III certification before it may be serviced?
What property of the refrigerant is what actually places an appliance into the low-pressure category?
During normal operation, what condition exists inside the evaporator of a running low-pressure centrifugal chiller?
In what unit is the required final recovery vacuum for a low-pressure appliance normally expressed?
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