LeakLedgerPart 84 guide
Part 84 vs Section 608: What Changed for HFC Refrigeration Systems
For years, refrigerant leak repair meant Section 608 of the Clean Air Act and 40 CFR 82.157: appliances with 50 lb or more of refrigerant. Since January 1, 2026, HFC systems follow a separate rule under the AIM Act: 40 CFR Part 84, Subpart C. Much of what ranks online still describes the old rule. Here's what changed for contractors.
Why there are two rules
Section 608's leak repair provisions cover ozone-depleting refrigerants such as R-22. EPA had extended them to HFC substitutes in 2016, then removed that extension in 2020. The AIM Act gave EPA new authority over HFCs, and Part 84 Subpart C — finalized in 2024 and effective for leak repair on January 1, 2026 — is the result. An appliance with only an ODS refrigerant stays under Section 608 and is excluded from Part 84 (§84.106(a)(3)(i)).
Side by side
| Section 608 (40 CFR 82.157) | Part 84 Subpart C | |
|---|---|---|
| Refrigerants | Ozone-depleting substances (e.g. R-22) | HFCs and substitutes with GWP > 53 (e.g. R-404A, R-448A, R-410A) |
| Size threshold | 50 lb or more | 15 lb or more |
| Leak rate thresholds | 20% commercial refrigeration, 30% IPR, 10% comfort cooling | 20% commercial refrigeration, 30% IPR, 10% comfort cooling, refrigerated transport and other |
| Leak rate methods | Annualizing or rolling average | Annualizing or rolling average, one method per facility (§84.102) |
| Repair window | 30 days (120 with an industrial process shutdown) | 30 days (120), with initial and follow-up verification tests (§84.106(d)–(e)) |
| Chronic leakers | Report at 125% of full charge in a calendar year | Report at 125% in a calendar year by March 1, from 15 lb (§84.106(j)) |
| Automatic leak detection | Not required | Required for commercial and IPR appliances of 1,500 lb or more (§84.108) |
| Residential / light commercial A/C | — | Excluded (§84.106(a)(3)(ii)) |
Section 608 summary based on 40 CFR 82.157 as amended in 2016 and 2020; check the current text for ODS appliances.
What it means in the field
- Many more appliances. Dropping the floor from 50 lb to 15 lb brings in walk-ins and smaller systems that were never tracked before.
- More customers asking for records. Owners need a leak rate at every addition; that data starts on your service tickets.
- Mixed fleets. A store with an R-22 system and an R-448A rack has one appliance under each rule — keep the refrigerant on every appliance record.
- New big-system obligations. 1,500 lb+ racks need automatic leak detection — for systems installed 2017–2025, by January 1, 2027.
Start with the complete Part 84 guide or check an appliance with the calculator.
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This guide summarizes 40 CFR 84.102, 84.106 and 84.108 as published in the eCFR. It is not legal advice; where the rule is unclear we say so. Read the rule: 40 CFR Part 84, Subpart C.