7.1 Leak-Rate Thresholds & Repair Duty

Refrigerant leaks aren't just a maintenance headache — they're the primary way ozone-depleting substances (ODS) escape into the atmosphere from stationary equipment, and EPA's Section 608 program treats them as a compliance matter, not a suggestion. Subpart F of 40 CFR Part 82 imposes a specific legal duty: once a leak crosses a defined threshold, you must fix it or plan to retire the equipment. This section covers the trigger rates, the repair clock, and the verification testing every Type II technician needs to know cold.

Who the Rule Applies To

The leak repair requirements apply to any appliance that normally holds a full charge of 50 pounds or more of an ozone-depleting refrigerant — think CFC-12, HCFC-22, and similar ODS blends. Smaller systems (under 50 lb) are still subject to the general prohibition on knowingly venting refrigerant, but they are not subject to the leak-rate calculation, repair, and reporting machinery described here. If you service a 30 lb package unit, evacuation and reclaim rules still apply, but Subpart F's leak-repair duty does not kick in.

The Four Trigger Rates

EPA sets a different annual leak-rate threshold depending on what kind of appliance you're working on:

Notice the pattern: comfort cooling and the catch-all "all other appliances" category share the strictest threshold (10%), commercial refrigeration gets a slightly more forgiving 20%, and industrial process refrigeration — often massive systems with miles of welded piping — gets the most tolerance at 30%. The exam commonly asks you to match an appliance description to its correct percentage, so memorize the pairing, not just the numbers.

Calculating the Leak Rate

You must calculate the leak rate every time you add refrigerant to a covered appliance (≥50 lb full charge). The calculation compares how much refrigerant you added, the appliance's total full charge, and the number of days since the last time refrigerant was added (or since initial installation), annualized to a 365-day basis. In practice: if a 400 lb chiller needed 30 lb of refrigerant added after 90 days of operation, that addition is extrapolated out to what it would represent over a full year — and the resulting annualized percentage is compared against the appliance's applicable threshold from the table above.

The 30-Day Repair Clock

Once a calculation shows the leak rate meets or exceeds the applicable threshold, the owner has two options, not one:

1. Repair the leak(s) within 30 days of the date the leak rate was determined, or
2. Develop a one-year retrofit or retirement plan — committing, in writing, to either convert the appliance to a non-ODS refrigerant or retire it within 365 days.

There is no third option of simply doing nothing. An owner who neither repairs nor commits to retrofit/retirement within the required windows is out of compliance, and repeated failures to act are treated as ongoing violations, not a single lapse.

Verification Testing: Two Separate Checks

A repair isn't "done" just because the technician tightened a fitting and walked away. Subpart F requires two distinct verification steps:

• Initial verification test — performed after the repair is completed but before the appliance is returned to normal operating charge and conditions. This confirms the identified leak points are actually sealed before refrigerant is committed back into the system.
• Follow-up verification test — performed within 30 days after the appliance has returned to normal operating characteristics and conditions (full charge, normal pressures and temperatures). This step confirms the repair holds up once the system is running under real load, since some leaks only reappear under normal operating pressure and thermal cycling.

Skipping either step, or treating them as the same test performed once, is a common point of confusion the exam likes to probe.

Chronic Leakers and the 125% Benchmark

Some appliances leak so persistently that a single repair cycle isn't enough. EPA's chronically-leaking provisions target a separate and much larger threshold than the 10/20/30% repair trigger rates above: a covered appliance (one holding 50 lb or more of an ODS refrigerant) is a chronically leaking appliance if it loses 125% or more of its full charge in a single calendar year — not 125% of the 10/20/30% trigger rate. On a 350 lb commercial rack, that means losing 437.5 lb of refrigerant (125% × 350 lb) over 12 months. When an appliance crosses that line, the owner must report it to the EPA by March 1 of the following year, describing the efforts made to identify leaks and repair the appliance. On the exam, the key distinction is that the 125% figure is a fraction of the appliance's full charge, not a fraction of the trigger-rate threshold.

Periodic Leak Inspections After a Trigger Event

Once an appliance has exceeded its threshold, the owner doesn't just fix the leak and forget about it — the appliance is placed on a periodic leak inspection schedule (commonly quarterly) until it demonstrates leak rates below the threshold for enough consecutive inspection periods to be released from the heightened inspection schedule. This periodic inspection duty is separate from, and in addition to, the repair and verification-testing obligations already covered.

The 2020 Divide: ODS vs. HFCs

Here's a nuance that trips up technicians who learned the rules years ago: as of April 10, 2020, Subpart F's leak-rate, repair, and verification-testing requirements apply only to ODS refrigerants (CFCs and HCFCs like R-22) — they no longer apply to non-exempt substitute refrigerants such as HFCs (R-404A, R-134a, and similar). Leak-related obligations for those substitutes now live under a separate framework: the 2024 AIM Act Emissions Reduction and Reclamation (ER&R) program codified in 40 CFR Part 84. For Type II exam purposes, though, the classic 10/20/30% ODS thresholds covered in this section remain the core tested material — know them cold, and treat the HFC/AIM Act distinction as important context rather than a replacement for these numbers.

Scenario: Putting It Together

A grocery store's commercial refrigeration rack holds a 350 lb full charge of R-22. During a service call, a technician adds 80 lb of refrigerant, and records show the last refrigerant addition was exactly 146 days earlier. Annualized, that works out to a leak rate comfortably above the 20% commercial refrigeration threshold. The owner now has 30 days to complete repairs — or must commit, in writing, to a one-year retrofit-or-retire plan. Once repairs are made, the technician performs an initial verification test before recharging the rack to full capacity, then returns within 30 days of normal operation resuming to perform the follow-up verification test. If this same 350 lb rack goes on to lose 437.5 lb of refrigerant over a calendar year (125% of its full charge), it crosses into chronically-leaking territory — and the owner must report it to the EPA by March 1 of the following year.