Why is a cartridge style air purifying respirator the wrong protection for entering a machine room after a chiller has released its charge?
Correct Answer
D) It filters contaminants from the air but supplies no oxygen, and the room may be oxygen deficient
An air purifying respirator works by passing room air through a filter or sorbent, which means it depends entirely on there being enough breathable oxygen in that air to begin with. A large refrigerant release displaces oxygen, so the air is not merely contaminated, it is deficient. Filtering it changes nothing. Entry into that space requires supplied air, which is why a self contained breathing apparatus is the equipment specified for this situation.
Why This Is the Correct Answer
The failure is fundamental to how the respirator works: it cleans air but cannot create oxygen. In an oxygen deficient atmosphere the wearer suffocates while wearing what looks like protection, which is more dangerous than having no respirator at all because it invites entry into a space that should not be entered.
Why the Other Options Are Wrong
Option A: It cannot be sealed to the face while safety glasses and a hard hat are being worn
Respirators are routinely worn with glasses and a hard hat, and fit problems are solved with different equipment. The failure here is in what the respirator can supply, not in how it sits with other gear.
Option B: Its cartridges are rated only for high-pressure refrigerants and not for the low-pressure type in this machine
Cartridge ratings are not divided by refrigerant pressure class, and no cartridge of any rating puts oxygen back into the air. Matching a cartridge to the refrigerant misses the actual hazard.
Option C: It is too heavy to be worn safely while climbing around the machine on a ladder
Weight and ladder work are ordinary ergonomic concerns that apply to any respirator. They have nothing to do with why this one fails in an atmosphere that may be short of oxygen.
Memory Technique
Filters clean air, they do not make it. No oxygen in means no oxygen out.
Reference Hint
Air purifying respirators cannot be used in oxygen deficient atmospheres; a large refrigerant release requires self contained breathing apparatus.
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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