Recovering R-13 from a Cascade System
A research laboratory is decommissioning a cascade refrigeration system that uses R-13 in its very-high-pressure circuit. The R-13 circuit holds 12 lb. R-13 is a CFC with a boiling point of about -114°F, and at room temperature it exerts a very high pressure. The technician has a standard recovery machine rated for R-410A and a recovery cylinder rated for 400 psig. The lab manager asks if the technician can simply vent the R-13 because it is a small amount and the lab is being demolished. The technician knows that R-13 is not a small-appliance refrigerant and that the system is not a small appliance because the charge exceeds 5 lb. The technician must recover the R-13 before dismantling the system. The recovery cylinder is at ambient temperature. The technician must decide whether the standard equipment is safe and what special precautions are needed. The technician is Type II certified.
1. Can the technician use the standard R-410A recovery machine and 400-psig recovery cylinder for R-13? Explain.
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Not necessarily. R-13 is a very-high-pressure refrigerant, and its pressure at ambient temperature can exceed the working pressure of standard R-410A equipment and a 400-psig cylinder. The technician must verify that the recovery machine, hoses, gauges, and cylinder are rated for the refrigerant’s pressure at the expected temperature. If they are not, the technician must use equipment rated for very-high-pressure refrigerants or reduce the pressure by chilling the recovery cylinder, for example with dry ice, and using a pressure-reducing valve. Using underrated equipment could cause a hose burst or cylinder failure.
2. What legal and safety steps must be taken before recovering the R-13?
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R-13 is a CFC, so venting is prohibited under Section 608. The technician must recover the refrigerant and must not vent it, even though the lab is being demolished. The technician should wear appropriate PPE, ensure adequate ventilation, and follow safe handling practices. The recovery cylinder must be DOT-approved, not overfilled under the 80% fill rule, and clearly labeled. The technician should record the amount recovered and the final destination of the refrigerant. The lab manager cannot authorize venting.
3. What certification is required, and what would you tell the lab manager?
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The technician must hold Type II certification because this is a high-pressure or very-high-pressure appliance that is not a small appliance or MVAC. The technician should tell the lab manager that venting R-13 is illegal and unsafe, and that the refrigerant must be recovered by a certified technician using properly rated equipment. The manager should also know that improper venting can result in penalties and that the recovered refrigerant must be reclaimed or destroyed by an appropriate facility. The technician should provide a recovery record and coordinate with the demolition contractor to ensure the system is empty before dismantling.