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EPA regulations require the test to be a "closed book" proctored exam. The only outside materials allowed are a temperature / pressure chart, scratch paper and a calculator. The certification exam contains 4 sections: Core, Type I, Type II, and Type III. Each section contains 25 multiple choice questions.
Originally, Section 612 was limited by ozone-depleting chemicals. However, after passing regulations to phase-out R134a, an HFC refrigerant with no ozone-depleting potential, this phase-out was defended by a subsidiary of DuPont siding with the EPA as it was challenged by a major manufacturer of R134a, and was struck down in 2017.
In open atmosphere however, HFO-1234ze actually forms HFC-23 as one of its secondary atmospheric breakdown products. HFC-23 is a very potent greenhouse gas with a GWP100 of 14,800. This makes the secondary GWP of R-1234ze in the range of 1,400±700 considering the amount of HFC-23 which may form from HFO-1234ze in the atmosphere.
R-410A is a refrigerant fluid used in air conditioning and heat pump applications. It is a zeotropic but near-azeotropic mixture of difluoromethane (CH 2 F 2, called R-32) and pentafluoroethane (CHF 2 CF 3, called R-125). R-410A is sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A.
A refrigerant needs to have: a boiling point that is somewhat below the target temperature (although boiling point can be adjusted by adjusting the pressure appropriately), a high heat of vaporization, a moderate density in liquid form, a relatively high density in gaseous form (which can also be adjusted by setting pressure appropriately), and ...
1,1-Difluoroethane, or DFE, is an organofluorine compound with the chemical formula C 2 H 4 F 2.This colorless gas is used as a refrigerant, where it is often listed as R-152a (refrigerant-152a) or HFC-152a (hydrofluorocarbon-152a).
1,1,1,2-Tetrafluoroethane is a non-flammable gas used primarily as a "high-temperature" refrigerant for domestic refrigeration and automobile air conditioners. These devices began using 1,1,1,2-tetrafluoroethane in the early 1990s as a replacement for the more environmentally harmful R-12. Retrofit kits are available to convert units that were ...
Trichlorofluoromethane was first widely used as a refrigerant.Because of its high boiling point compared to most refrigerants, it can be used in systems with a low operating pressure, making the mechanical design of such systems less demanding than that of higher-pressure refrigerants R-12 or R-22.