7.3 Leak-Rate Calculation, Recordkeeping, and Reporting

What "Leak Rate" Actually Means

The legal definition (40 CFR 82.152 and, for HFCs, 40 CFR 84.102) is precise: the leak rate is the percentage of an appliance's full charge that would be lost over a 12-month period if the current rate of loss continued for that period. Two ideas are baked in:

1. It is always expressed per year, even if you only measured the loss over a few weeks.
2. It is measured between charges — the trigger event is adding refrigerant, which is the only moment you know how much was lost.

Because of point 2, the rule requires owners/operators to recalculate the leak rate every time refrigerant is added to a covered appliance. You cannot wait for an annual review; the math happens at each top-off.

The Two Approved Calculation Methods

EPA allows exactly two methods, and an owner must use one consistently (switching is allowed only under defined conditions):

1. Annualizing Method

This projects a single recent top-off out to a full year:

Leak rate (% / yr) = (lbs added ÷ full charge) ÷ (shorter of [days since last add] or 365 ÷ 365) × 100

In plain steps: divide pounds added by the full charge; divide that by the fraction of a year that elapsed since the last addition (capped at one year); multiply by 100. A small loss over a short interval annualizes into a large percentage — which is exactly the point, because a system bleeding 5% in one month is on pace for far more than 5% per year.

2. Rolling-Average Method

This smooths repeated small top-offs across a year:

Leak rate (% / yr) = (total lbs added over the past 365 days ÷ full charge) × 100

(or since the last successful follow-up verification test, if that is less than a year). Add up everything you have charged into the system over the trailing 12 months, divide by full charge, multiply by 100. It is more forgiving of one odd top-off but reacts more slowly.

Worked Calculation (Annualizing)

Example: A 100-lb R-410A comfort-cooling system (10% threshold) received 8 lb of refrigerant, and the last top-off was 90 days ago. Annualize:

1. 8 ÷ 100 = 0.08
2. Time fraction = 90 ÷ 365 = 0.2466
3. 0.08 ÷ 0.2466 = 0.3245
4. × 100 = 32.4% per year Because 32.4% far exceeds the 10% comfort-cooling threshold, the 30-day repair clock starts immediately.

Notice how the same 8 lb gives a very different answer depending on the interval: over a full 365 days the annualized rate would be just 8%, below threshold. The interval is everything.

Required Records (Covered Appliances)

Owners or operators of covered appliances must keep documentation and retain it for three years:

These records are how a technician (and EPA) reconstruct whether a system tripped a threshold and whether the repair-and-verify steps actually happened.

Chronically Leaking Appliances and Reporting

A distinct, higher bar triggers reporting to EPA (not just repair). An appliance is chronically leaking when it leaks 125% or more of its full charge in a single calendar year. When that happens:

• The owner/operator must submit a report to EPA by March 1 of the following year describing the appliance and the leak.
• This is separate from — and on top of — the ordinary 30-day repair duty; a system can be repeatedly repaired and still cross 125% for the year.

One refinement worth knowing: purged refrigerant that is destroyed at a verified destruction efficiency of 98% or greater does NOT count toward the leak rate, since it was reclaimed/destroyed rather than released.

Putting It Together

The flow is: add refrigerant → calculate leak rate (annualizing or rolling average) → compare to the 10/20/30% threshold → if over, repair in 30 days and verify → log every step for 3 years → and if the year's total loss hits 125% of charge, file the chronic-leak report by March 1. The arithmetic in 6.3 is what starts every obligation you studied in 6.2.