Why does 40 CFR 82.156(a)(1)(ii) let an R-113 machine finish pressurizing with nitrogen before a non-major…

Recovery requirements · EPA 608 Type III. The correct answer, and the reasoning behind it.

Evacuation levels for low-pressure appliances, and major versus non-major repairs.

The question

Why does 40 CFR 82.156(a)(1)(ii) let an R-113 machine finish pressurizing with nitrogen before a non-major repair, but bar nitrogen for the same job on R-11 and R-123 machines?

• AR-113 is not an ozone-depleting refrigerant
• BR-113 boils above 85 °F at atmospheric pressure; R-11 and R-123 do notCorrect answer
• CR-113 machines always hold less than 200 pounds, so less refrigerant is at risk
• DNitrogen reacts chemically with R-11 and R-123

Why “R-113 boils above 85 °F at atmospheric pressure; R-11 and R-123 do not” is correct

The rule draws its line at a boiling point of 85 °F at 29.9 inches of mercury. Refrigerants that boil at or below that temperature, like R-11 and R-123, can be warmed to atmospheric pressure fairly easily, so no purging method is allowed. R-113 boils well above 85 °F, so heat is used as far as it will go and nitrogen may make up the rest to atmospheric pressure.

Source: 40 CFR 82.156(a)(1)(ii)

Why the other answers are wrong

• R-113 is not an ozone-depleting refrigerant — R-113 is a CFC and is ozone-depleting; the distinction is its boiling point.
• R-113 machines always hold less than 200 pounds, so less refrigerant is at risk — Charge size plays no part in this rule.
• Nitrogen reacts chemically with R-11 and R-123 — Nitrogen is inert; the rule is about the purging that nitrogen would require afterward.

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