One of the hardest parts of EPA 608 Universal preparation is not learning a number. It is keeping the number attached to the correct rule.
The book calls this the Number Collision Matrix problem.
A useful study rule is:
Say the number together with its object and condition, not by itself.
Charge-size numbers
| Number | Attach it to |
|---|---|
| 5 lb or less | Part of the small-appliance definition, together with the factory-made, factory-charged, hermetically sealed conditions |
| More than 5 and less than 50 lb | A disposal-recordkeeping range described in the book |
| 50 lb or more | The current ozone-depleting-refrigerant leak-repair trigger framework discussed in the book and certain service records |
| More than 15 lb | The general system-dependent-recovery limit described for Type II, with a permanently attached pump-out exception |
| 200 lb | The dividing point that changes several high- and medium-pressure evacuation-table rows |
Do not let the repeated appearance of 5, 15, 50, and 200 pounds turn them into interchangeable thresholds.
Small-appliance recovery
| Number | Attach it to |
|---|---|
| 80% | Small-appliance recovery when the compressor is inoperative or recovery equipment is pre-November 15, 1993 |
| 90% | Small-appliance recovery with post-November 15, 1993 equipment and a functional compressor |
| 4 in Hg vacuum | Alternative small-appliance recovery endpoint |
The 80% figure also appears in recovery-cylinder fill safety, which is exactly why the object matters.
Evacuation values
For the current service-practice table summarized in the book:
| Appliance class | Pre-1993 equipment | Post-1993 equipment |
|---|---|---|
| High pressure, under 200 lb | 0 in Hg | 0 in Hg |
| High pressure, 200 lb or more | 4 in Hg | 10 in Hg |
| Medium pressure, under 200 lb | 4 in Hg | 10 in Hg |
| Medium pressure, 200 lb or more | 4 in Hg | 15 in Hg |
| Very high pressure | 0 in Hg | 0 in Hg |
| Low pressure | 25 mm Hg absolute | 25 mm Hg absolute |
The low-pressure row is the unit trap: 25 mm Hg absolute is not the same thing as 25 inches Hg vacuum.
Leak-repair percentages and timelines
The book identifies the current annual trigger pattern for covered 50+ lb appliances containing ozone-depleting refrigerant as:
- 30% — industrial process refrigeration;
- 20% — commercial refrigeration;
- 10% — comfort cooling;
- 10% — all other covered appliances.
It also identifies:
- 30 days as the normal repair period after a covered appliance exceeds its trigger;
- 120 days when an industrial process shutdown is required.
The book explicitly warns that older materials may show legacy percentages such as 35% and 15%.
Type III numbers
Keep these attached to low-pressure chiller concepts:
- 25 mm Hg absolute — recovery endpoint;
- 10 psig — a commonly taught provider convention for field leak testing of typical low-pressure chillers when a lower manufacturer limit does not control;
- 130 F — heat chiller oil before removal to help recover dissolved refrigerant.
The 10 psig figure is presented in the book as a provider/training convention, not as a universal standalone EPA regulatory threshold. The equipment nameplate and manufacturer limit control in the field if they require a lower value.
Dates
| Date | Attach it to |
|---|---|
| November 15, 1993 | Key dividing date for recovery-equipment requirements and evacuation-table history |
| January 1, 1996 | U.S. production/import phaseout milestone for most Class I ODS including CFCs, subject to limited exemptions |
| January 1, 2020 | Virgin HCFC-22 production/import phaseout milestone for servicing existing equipment, with the distinctions described in the book |
A better flashcard format
Avoid:
10 in Hg
Use:
High-pressure 200+ lb, post-1993 recovery equipment = 10 in Hg vacuum.
Avoid:
30%
Use:
Current annual trigger in the book for covered industrial process refrigeration using ozone-depleting refrigerant = 30%.
That longer flashcard is harder to write but much harder to misapply.
For the equipment-category side of the same problem, see Type I vs Type II vs Type III.