Refrigerant Leak Rate and the EPA Repair Threshold

ScopeThe rule is simple arithmetic with real teeth: for an appliance containing 50 pounds or more of an ozone-depleting refrigerant (40 CFR 82 Subpart F) -- or, from January 1, 2026, 15 pounds or more of an HFC (any GWP) or of a substitute with a GWP above 53 (EPA's AIM Act rule, 40 CFR 84.106), which takes in commercial and industrial refrigeration such as R-404A and R-448A systems but expressly excludes residential and light commercial air conditioning and heat pumps, where most R-410A and R-454B equipment sits -- the owner or operator tracks refrigerant added, annualizes it against the FULL CHARGE -- the amount the system is designed to hold, not what happens to be in it -- and compares the result against the threshold for that appliance type, which differs by category, with commercial and industrial process refrigeration at higher percentages than comfort cooling. Two details cause most of the errors. Full charge must be established and documented, and a system whose full charge has never been recorded cannot compute a compliant leak rate at all. And there are two permitted methods, and a facility must use one for all its appliances (40 CFR 82.152). The ANNUALIZING method takes the pounds of one addition over the time since the previous addition and scales it to a year, so a top-off three months after the last one is magnified four times. The ROLLING-AVERAGE method sums everything added over the previous 365 days and does not scale a shorter window up. A 200 lb system with 34 lb added over twelve months is at 17.0%: over a 10% threshold by 14 lb, and comfortably under a 20% one. The same 34 pounds is a violation on one appliance type and unremarkable on another, which is why identifying the category correctly is the first step and not a formality -- and if those 34 pounds went in as one addition six months after the previous one, the annualizing method reads 34% and the system is over even the higher threshold, with nothing about the leak having changed (the rolling average would still read 17%). Exceeding the threshold starts a clock: repairs within a set number of days, verification tests, and a retrofit or retirement plan if the leak cannot be repaired. A compliance screen; 40 CFR Part 82 Subpart F in full, the appliance's own category and threshold, and the service records govern.

Formula or tableannualizing: leak_rate_pct = pounds of one addition / full_charge_lb x (12 / months since the previous addition) x 100; rolling average: leak_rate_pct = pounds added over the previous 365 days / full_charge_lb x 100 (no scaling); allowed_lb = the threshold's pounds for the same window; exceeded when the rate is above the threshold.

Source and editionThe annualized leak-rate calculation of 40 CFR Part 82 Subpart F (ozone-depleting refrigerants, 50 lb and up) and, from January 1, 2026, 40 CFR 84.106 (HFCs at any GWP and substitutes with GWP above 53, 15 lb and up, excluding residential and light commercial AC and heat pumps) -- pounds added divided by the FULL CHARGE, by the 82.152 annualizing or rolling-average method, against the threshold for the appliance type -- cited by part and not reproduced. The thresholds differ by appliance category and are entered rather than bundled. 40 CFR Part 82 in full, the appliance's category, and the service records govern.

Free accessThe calculation is public federal regulation stated as a relation and cited by part; the full charge, pounds added, period, and applicable threshold are the owner's own records.

What governsEstimate. AHJ and licensed professional govern.

API field namesfull_charge_lb, pounds_added_lb, period_months, threshold_pct, method, leak_rate_pct, allowed_lb, pounds_over_lb

• Full charge the design charge, documented; without it no compliant leak rate can be computed40 CFR Part 82 Subpart F
• Two methods annualizing scales one addition by 12 / months since the previous one; rolling average sums 365 days and does not scale; one method for every appliance at a facility40 CFR 82.152 (leak rate)
• HFC scope from 2026, 15 lb or more of an HFC (any GWP) or a substitute over GWP 53; residential and light commercial AC and heat pumps are excluded40 CFR 84.106(a)
• Threshold by category differs by appliance type and is entered, not bundled; the same pounds can be a violation on one and not another40 CFR Part 82 Subpart F