When the rule applies

§82.157 (the Leak Repair Rule, revised in 2024) applies to appliances that contain 50 pounds or more of an ozone-depleting refrigerant (Class I or Class II) or 50 pounds or more of an HFC refrigerant with a GWP of 150 or greater. The threshold catches most commercial refrigeration, large chillers, industrial process refrigeration, and supermarket rack systems.

If you service an appliance below the 50-pound threshold, the rule does not apply, but recordkeeping under §82.162 still does. The Universal exam makes this distinction explicit.

The leak rate formula

The EPA defines leak rate as a percentage of charge lost per year, calculated as:

Leak rate (%) = (Refrigerant added during the period / Total charge of the appliance) × 100

Where:

• Refrigerant added during the period is the total mass of refrigerant added to the appliance over the calculation period (12 months, or the period since the last successful leak verification).
• Total charge is the full nameplate charge of the appliance as listed on the equipment or in the manufacturer's documentation.

The calculation uses pounds, kilograms, or ounces consistently. The most common field form is:

Leak rate (%) = (Pounds added × 100) / Full charge in pounds

For example: a supermarket rack with 1,200 pounds of R-448A that has been topped up with 90 pounds over the past year has a leak rate of (90 × 100) / 1,200 = 7.5 percent.

The thresholds

The 2024 rule tightened the leak-rate thresholds for HFCs. Current thresholds:

• Commercial refrigeration: 10 percent leak rate triggers repair obligations.
• Comfort cooling (and IP units primarily providing cooling for human comfort): 15 percent leak rate.
• Industrial process refrigeration: 20 percent leak rate.
• Federal equipment (military, federal buildings): 5 percent leak rate.

If your calculated leak rate meets or exceeds the threshold for the appliance type, you must:

1. Identify and repair the leak within 30 days (or 120 days if an industrial process shutdown is required to make the repair).
2. Verify the repair by a follow-up leak inspection within 30 days of the repair.
3. Keep records of the leak rate calculation, the repair, and the verification for at least three years.
4. Continue to calculate leak rates annually even after a successful repair, until two consecutive calculations are below the threshold.

The leak inspection that triggers verification

The verification step is its own audit. You must inspect the appliance using a leak detection method that is at least as sensitive as the technology that detected the original leak. In practice:

• If you found the leak with an electronic detector rated for 0.1 oz/year, verify with an equivalent or better detector.
• If you found it with soap bubbles, verify with electronic detection or another approved method.
• The verification must be documented, with the date, the method, the technician's name, and the certifying organization.

Common exam traps

1. Confusing leak rate with total refrigerant added. Leak rate is a percentage of the full charge, not a pounds-per-year absolute number. A 5-pound top-off on a 200-pound residential-style commercial system is 2.5 percent — well below any threshold — but the same 5 pounds on a 30-pound unit (which wouldn't trigger §82.157 at all) is a higher percentage.

2. Forgetting the calculation period. Leak rate is annualized. If you added 50 pounds in six months, the annual rate is 100 pounds. The exam will sometimes present a six-month figure and expect you to annualize.

3. Believing the rule applies to all equipment. It applies to appliances with 50 pounds or more of qualifying refrigerant. A 30-pound rooftop unit is exempt from §82.157 but still subject to §82.162 recordkeeping.

4. Confusing the trigger for repair with the trigger for recordkeeping. Recordkeeping applies whenever refrigerant is added or removed, regardless of the leak rate. The repair timeline applies only when the calculated rate exceeds the threshold.

The annual calculation

If your leak rate calculation is below the threshold, you have two paths:

• Continue with regular service and annual calculations.
• If the calculation is below the threshold for two consecutive years, you can request an extension on the annual calculation from EPA — but in practice, most technicians just keep calculating annually because the math is fast.

If the calculation is above the threshold, the cycle becomes repair-and-verify until you achieve two consecutive below-threshold readings.

What the records must include

For each leak rate calculation, the operator's log must contain:

• The refrigerant added during the calculation period (in pounds or kilograms)
• The full charge of the appliance
• The resulting leak rate (as a percentage)
• The dates of the calculation period
• The name of the technician who performed the calculation
• The method used to verify any repairs

These records can be inspected by EPA at any time. Many states (notably California, New York, and Massachusetts) have additional recordkeeping or reporting rules layered on top of §82.157.

A practical closing note

The leak rate calculation is one of the few Section 608 tasks that combines a regulatory threshold with field math. Practicing the calculation on real system nameplate data — your own service base, your last service call, your last retrofit — is the single best preparation for the Universal exam's leak-rate questions. The formula is simple; the threshold depends on the equipment type; the timeline depends on the calculation. Master all three.