Flammable Refrigerant Leak in a Basement Suite
An apartment tenant reports that a refrigerator is warm and has been running continuously for two days. The nameplate identifies R-600a (isobutane) refrigerant with a factory charge of 52 g. You arrive at a basement suite measuring about 3 m by 4 m. There is no exterior window, and a gas water heater with a standing pilot is located 2 m from the refrigerator. The tenant has placed a box fan on the floor blowing toward the appliance. There is no distinct odor. While walking the area with a flammable-refrigerant detector, the meter alarms near the compressor access panel. The refrigerator is still plugged in and running. Your tool bag contains a standard vacuum pump, a brazing torch, and a recovery machine rated for HFC refrigerants only. The tenant asks whether the appliance can be repaired today because the suite is rented and food is spoiling.
1. What are your immediate actions and hazard controls before any diagnosis or repair? Explain why each action matters.
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Treat the detector alarm as a flammable atmosphere. Do not operate the box fan, light switches, the refrigerator plug, or any other device that can produce a spark, because R-600a is heavier than air and can accumulate at floor level. Isolate the refrigerator circuit at the panel only if the panel is outside the affected area. Evacuate the suite and ventilate from a safe location; do not place the tenant's fan in the gas cloud. Have the gas water heater pilot shut off by a qualified gas fitter or emergency responder, since a standing pilot is an ignition source. Notify the landlord and keep people out. Use only an intrinsically safe or flammable-refrigerant-rated detector. Do not start recovery or brazing until the reading is below the action level and the area is ventilated. The key judgement is that the leak has created a life-safety hazard, not just a cooling complaint.
2. Outline the safe recovery and repair sequence, including equipment restrictions and how you would confirm the area is safe for hot work.
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Recover the remaining charge with a recovery machine rated for A3 flammable refrigerants and an approved recovery cylinder; standard HFC equipment may have relays or brushes that spark. Ground and bond equipment, use spark-free tools, and keep a dry-powder extinguisher nearby. After recovery, purge the system with nitrogen before opening it. Locate the leak with an intrinsically safe detector or soap bubbles, not a torch. Replace the leaking component or line, install a new filter drier, pressure-test with nitrogen, and evacuate with a vacuum pump rated for flammable refrigerants. Charge by weight to the 52 g nameplate. Before hot work, verify the area is below the action level with the detector and continue ventilation. If the repair cannot be completed safely, cap the system and tag it.
3. What will you tell the tenant and record before leaving?
Read the worked answer
Tell the tenant the refrigerator cannot be repaired today because the refrigerant is flammable and the leak has created a measurable flammable atmosphere. Advise them not to plug it in, not to use the fan, and not to store food in it. Explain that the water heater pilot must be checked and relit by a qualified person. Record meter readings and locations, the actions taken, the circuit isolation, the referral to the landlord and gas fitter, and the customer's instructions. Leave a dated tag and a written notice; note that the food loss is a consequential issue and that the appliance must not be re-energized until repaired and leak-tested. This protects the next person and documents that you recognized the hazard.