LeakLedgerPart 84 guide
Automatic Leak Detection for 1,500 lb Systems: The January 1, 2027 Deadline
Part 84 requires automatic leak detection (ALD) on the largest systems: commercial refrigeration and industrial process refrigeration appliances with a full charge of 1,500 lb or more of an HFC or a substitute with GWP above 53 (40 CFR 84.108(a)). For many existing supermarket and cold-storage racks, the deadline is January 1, 2027.
Which systems, which dates
| Appliance installed | ALD required |
|---|---|
| On or after January 1, 2026 | At installation, or within 30 days (§84.108(b)(1)) |
| January 1, 2017 – December 31, 2025 | By January 1, 2027 (§84.108(b)(2)) |
| Before January 1, 2017 | Not required by §84.108(b) |
Comfort cooling and other appliances aren't subject to §84.108, whatever their size.
What the system must do
- Be installed per the manufacturer's instructions and audited and calibrated annually (§84.108(c)–(d)).
- Monitor components located inside an enclosed building or structure (§84.108(e)).
- Direct detection (sensing refrigerant in air): sensors or intakes near the compressor, evaporator, condenser and other high-risk areas; detect 10 ppm of the refrigerant; alert at 100 ppm (§84.108(f)).
- Indirect detection (monitoring the system's conditions): alert when measurements indicate a loss of 50 lb or 10% of the full charge, whichever is less (§84.108(g)).
When it alerts
After an alert, the owner or operator either calculates the leak rate within 30 days (120 with an industrial process shutdown) and, if it's over the threshold, follows the full leak repair requirements — or repairs the leak first, before adding refrigerant, and then calculates the leak rate within the same window (§84.108(h)). If ALD covers only part of an appliance, the rest still needs the regular leak inspections (§84.108(h)(3)).
ALD and leak inspections
Parts of an appliance continuously monitored by an ALD system that is audited or calibrated annually don't need the quarterly or annual leak inspections that otherwise follow an exceedance (§84.106(g)(4)).
Records
Owners keep records of the ALD installation and annual audit and calibration, each date the system identified a leak, and the location of leaks — for at least three years (§84.106(l)(6), §84.108(i)).
For contractors
If you service 1,500 lb+ racks, now is the time to inventory install dates and full charges: every system installed from 2017 through 2025 needs ALD in place by January 1, 2027. LeakLedger doesn't track ALD deadlines today — use it to keep each rack's full charge and leak history straight, and see the complete Part 84 guide for the rest of the rule.
Do this math for every appliance automatically
LeakLedger reads the service records you already keep, calculates every leak rate with the arithmetic shown, tracks each Part 84 deadline, and builds a branded report for each customer. $149/month, 14-day free trial.
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.