Core plus a type, 70 percent to pass, and a credential that never expires. Straight from the regulation.

Core is 25 of the items on whichever Section 608 test you sit, and 25 of the 100 on Universal. Appendix D fixes its three areas: the environmental impact of CFCs, HCFCs and substitute refrigerants; laws and regulations; and the changing industry outlook. EPA's own topic list adds refrigerant identification, the three R definitions, recovery technique, dehydration evacuation, safety and cylinder handling, and shipping labels.

Type I certifies you to maintain, service or repair small appliances — units manufactured, charged and hermetically sealed in a factory with five pounds of refrigerant or less. Its 25 items concentrate on recovery: the 80 and 90 percent thresholds, the four inches of mercury alternative, passive recovery from a unit whose compressor has failed, and access valves. It is the only type that may be offered as a mail-in test.

Type II certifies work on medium-, high- and very high-pressure appliances other than small appliances, MVACs and MVAC-like appliances. Its 25 items are the densest on the exam: the Table 1 evacuation levels, which change with charge size and with whether the recovery machine predates 15 November 1993, the leak rate thresholds, major versus non-major repairs, and the prohibition on system-dependent equipment above 15 pounds.

Type III certifies work on low-pressure appliances — those using a refrigerant with a liquid-phase saturation pressure below 45 psia at 104 °F, such as R-11, R-123 and R-245fa. Low-pressure centrifugal chillers run under a vacuum, which inverts most of what Type II teaches: leaks draw air and moisture in rather than pushing refrigerant out, recovery is to 25 mm Hg absolute, and pressurising for a leak test is done with controlled heat first, with nitrogen only as the fallback.

Type I, II, III or Universal is decided by the equipment you work on and what you do to it, not by your job title. This walks the rule at 40 CFR 82.161(a)(1) and gives you the type, with the citation.