1. Ozone Depletion and Refrigerant Classes
Chlorine is what damages the stratospheric ozone layer. CFCs (such as R-12 and R-11) contain the most chlorine and have the highest ozone depletion potential (ODP). HCFCs (such as R-22 and R-123) contain chlorine too but break down sooner, so their ODP is lower. HFCs (R-134a, R-410A, R-32) and HFOs (R-1234yf) contain no chlorine and have zero ODP. Less ozone means more UV radiation reaches the ground, which raises skin cancer and cataract risk and harms crops.
The guide to refrigerant types, classes and A2L safety covers each class and the new flammable refrigerants in more detail.
2. The Clean Air Act and the Montreal Protocol
The Montreal Protocol is the international treaty that phases out production of ozone-depleting substances. In the U.S., Title VI of the Clean Air Act puts it into effect, and Section 608 is the part that governs refrigerant handling. The rules are in 40 CFR Part 82, Subpart F.
3. The Venting Prohibition
No one maintaining, servicing, repairing or disposing of an appliance may knowingly vent refrigerant (40 CFR 82.154(a)). This covers CFCs, HCFCs and non-exempt substitutes such as HFCs and HFOs. A few substitutes are exempt in listed uses only, for example CO2, nitrogen and water in any use, and isobutane in household refrigerators. "De minimis" releases during good-faith recovery using certified equipment are not violations. Releasing refrigerant after you have recovered it is.
4. Recover, Recycle, Reclaim
| Term | Meaning under 40 CFR 82.152 |
|---|---|
| Recover | Remove refrigerant in any condition and store it in an external container, without necessarily testing or processing it. |
| Recycle | Clean refrigerant for reuse (oil separation, filter-driers) without meeting full reclaim specs. |
| Reclaim | Reprocess to the appendix A specs (based on AHRI 700-2016) and verify by lab analysis. Only reclaimed refrigerant may be sold to a new owner. |
Refrigerant may go back into the appliance it came from, or another appliance with the same owner, without reclamation (82.156(h)). Never mix refrigerants in one recovery cylinder, because a mixture usually can't be reclaimed.
5. Who Needs Certification, and the Sales Restriction
Anyone who could reasonably be expected to open the refrigerant circuit while maintaining, servicing, repairing or disposing of an appliance must be certified (82.161). Apprentices are exempt while closely and continually supervised by a certified technician. Refrigerant that is not exempt may be sold only to certified technicians and the other buyers the rule lists (82.154(c)). Certification does not expire. You must keep a copy of your certificate until three years after you stop working as a technician.
6. Recovery Equipment and Evacuation
Recovery equipment must be certified by an EPA-approved testing organization (82.158). Self-contained equipment has its own compressor. System-dependent (passive) equipment relies on the appliance and may not be used on systems holding more than 15 lb. Long, narrow hoses and low temperatures slow recovery. After service, evacuate with a vacuum pump to remove air and moisture. The required vacuum levels are listed in our EPA 608 recovery and evacuation requirements.
7. Safety, Cylinders and Shipping
Fill recovery cylinders to no more than 80% liquid. Recovery cylinders have a gray body and yellow top. Never refill disposable cylinders. Leak-test with dry nitrogen through a regulator and relief valve, never oxygen or compressed air. Refrigerant vapour displaces oxygen. Read the refrigerant safety and cylinder handling guide for details.
8. Test Format
9. Key Dates to Remember
- 1 July 1992: the venting prohibition for CFC and HCFC refrigerants took effect.
- 15 November 1993: the date that separates older and newer recovery equipment for evacuation levels and certification.
- 15 November 1995: the venting prohibition was extended to substitutes such as HFCs.
- 1 January 2018: the sales restriction was extended to non-exempt substitutes such as HFCs.
- 1 January 2019: the lower leak repair triggers (10%, 20% and 30%) took effect.
10. Penalties
The Clean Air Act allows EPA to impose civil penalties for each day of each violation, and the maximum amount is adjusted for inflation each year. Knowingly venting refrigerant, selling refrigerant to unqualified buyers and failing to keep required records can all lead to enforcement. The exam may ask that violations can bring fines and that EPA can pay rewards to people who report illegal venting.
11. How to Use This Guide
Read each section once, then take a Core practice test. Note every question you miss and return to the matching section here. Repeat until you score well above 70% on fresh tests. Then move on to the type you need. Because Core questions also come up in the type sections, a strong Core foundation helps everywhere.
12. Common Core Traps
- "De minimis" releases are allowed only during good-faith recovery with certified equipment.
- Recycled refrigerant can't be sold to a new owner. Only reclaimed refrigerant can.
- HFCs have zero ODP but are still covered by the venting ban.
- Apprentices are exempt only while closely supervised.
- Certification doesn't expire.
13. Dehydration and Non-Condensables
Air and moisture in a system are called non-condensables and contaminants. They raise head pressure, reduce efficiency and can form acids that damage the compressor. Evacuate a system with a vacuum pump after repairs, and use a micron gauge to measure the vacuum. Moisture boils off more easily at lower pressure, so a deep vacuum removes it, and warming the system helps.
14. Leak Detection Basics
Leaks can be found with electronic detectors, bubble solutions, ultrasonic detectors and fluorescent dyes, where the maker approves dye. Signs of a leak include oily residue at fittings and a system that keeps needing refrigerant. Always find and fix the leak rather than topping up the charge.
15. Shipping and Disposal
Ship recovered refrigerant in DOT-approved cylinders labelled with the refrigerant and its hazard class. When an appliance is disposed of, the refrigerant must be recovered first, either by the technician or by the final processor, who may instead get a signed statement that recovery was done.
16. Key Terms
- Appliance: any device that contains and uses refrigerant, including air conditioners and refrigerators.
- Technician: anyone who could reasonably be expected to open the refrigerant circuit during service, maintenance, repair or disposal.
- Substitute: a non-ozone-depleting refrigerant that replaces a CFC or HCFC.
- De minimis release: a small, unavoidable release during good-faith recovery.
- Reclaimer: a certified company that reprocesses refrigerant to purity standards.
17. Final Check Before the Exam
Be able to explain from memory why chlorine harms the ozone layer, what the venting ban covers, the difference between recover, recycle and reclaim, who may buy refrigerant, the 80% cylinder fill rule and the 70% pass mark. If you can do that, you are well prepared for Core.
Quick Questions
How long does it take to study for Core?
Many people need a few days to a week of focused study. Use timed practice tests to see when you are scoring well above 70%.
Do I need to memorise the regulation section numbers?
No. The exam tests the rules, not the citation numbers. Knowing them helps you look things up while you study.
Which Core topic is most often missed?
Many learners struggle with the exact definitions of recover, recycle and reclaim, and with the details of the sales restriction. Review these until you can explain them without notes.
Are the dates on the exam?
Some questions use key dates, such as 15 November 1993 for recovery equipment. Learn the dates listed in this guide.
Each section has 25 questions, and you need 70% (18 of 25) to pass the closed-book test (Appendix D). Practise with the EPA 608 Core practice test.