- ATo allow filling from the vapor port
- To prevent overpressurization due to heat or overfilling
- CTo make recovery faster
- DTo mix different refrigerants
Correct answer
To prevent overpressurization due to heat or overfilling
Why
Pressure relief devices vent refrigerant if pressure gets dangerously high from overfilling or exposure to heat, preventing cylinder rupture.
The concept behind this question
Once refrigerant is in a cylinder and leaving the site, it is a hazardous material shipment and Department of Transportation rules apply on top of EPA's. Recovered refrigerant goes in a DOT-approved recovery cylinder — grey body with a yellow top — never in a disposable cylinder the refrigerant did not come in. Cylinders must be labelled with their contents, kept within the 80% fill limit, and accompanied by shipping papers. Mixing different refrigerants in one cylinder makes the contents unreclaimable and turns a recoverable asset into disposal cost.
More questions on this topic
Exam-style practice question. Not an official EPA exam question.