A large quantity of refrigerant has leaked into a basement equipment room where no ventilation has been running. What is the hazard facing the first person who opens that door?
Correct Answer
B) The vapor is heavier than air and settles low in the room, displacing the oxygen a person needs to breathe
Refrigerant vapors are heavier than air, so they collect in basements, pits, walk-in boxes and any low enclosed space. They do not smell like much and they give no warning, but they push the air out of the space, and a person walking into that room can lose consciousness before realizing anything is wrong. The correct response is to ventilate the space from outside it, use monitoring if available, and never send anyone in alone. Rescuers walking in unprepared are a large share of the casualties in these events.
Why This Is the Correct Answer
These vapors are denser than air and accumulate at the lowest point in a space. Because they simply take the place of air, the danger is a lack of oxygen rather than any toxic effect, and it develops without a strong odor or any other warning to the person entering.
Why the Other Options Are Wrong
Option A: The refrigerant will have turned to an acid mist while it pooled, and that mist burns exposed skin on contact
Acid forms when refrigerant decomposes at high temperature, over a torch flame or a hot surface. Refrigerant pooling in a cool basement has nothing to break it down, so no acid mist is waiting at the door.
Option C: The vapor will ignite from any spark thrown by the electrical equipment running in the room
The common refrigerants in this equipment are not readily ignited under these conditions, and framing the hazard as fire sends the responder looking for ignition sources while the danger is the air itself.
Option D: The vapor raises the pressure inside the closed room enough to cause ear injury on the way in
A leak does not pressurize a room in any measurable way. The room stays at atmospheric pressure with the wrong gas filling the lower part of it, so nothing about entering threatens the ears.
Memory Technique
Refrigerant sinks. It fills the basement from the floor up and takes the air with it.
Reference Hint
Refrigerant vapors are heavier than air and accumulate in low areas, displacing oxygen. Ventilation is required before entry.
More epa-608-type-2 Questions
A walk-in cooler condensing unit holds a full charge of twenty-five pounds of R-404A, which is below the fifty pound threshold that brings an appliance under the leak repair provisions. What still applies to this unit?
An office building has thirty water source heat pumps on a common water loop, and each one left the factory assembled, hermetically sealed and charged with four pounds of R-410A. How is one of those units classified?
A data sheet for an unfamiliar refrigerant lists a boiling point of about fifty-five degrees Fahrenheit at atmospheric pressure. What does that tell a technician holding Core and Type II certification?
A technician holds Core, Type I and Type III certification and is sent to recover the charge from a twenty ton rooftop unit charged with R-410A. What does that combination of sections allow on this job?
A fleet garage technician holds only the vehicle air conditioning certification issued under Section 609 and is asked to recover the charge from the shop's own rooftop air conditioner. What does that credential allow?
A split system's outdoor unit, indoor coil and the line set the installer ran and brazed between them are being considered. For the purposes of the refrigerant rules, what makes up the appliance here?
On a new installation the line set is brazed to a factory charged outdoor unit and an indoor coil shipped under a nitrogen holding charge, with the outdoor unit's service valves still closed. What does the recovery requirement call for before that brazing?
A rooftop unit's data plate has weathered until the charge figure cannot be read, and the technician needs the full charge to place the appliance under the evacuation and leak provisions. Where should that figure come from?
A computer room air conditioning unit holds forty pounds of R-407C and connects to a remote air cooled condenser through refrigerant piping run and brazed by the installer. How is that unit classified?
A shop's office manager, who holds no technician certification, is sent to a supply house to pick up a new recovery machine for the commercial crew. What does the sales restriction require at that counter?
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