R32 is not a new refrigerant. HFO refrigerants contain at least one double bond (C=C), which is different from the traditional saturated halohydrocarbon refrigerants such as the chlorofluorocarbons (CFCs), hydrochlorofluorocarbon (HCFCs), and hydrofluorocarbons . of some hydrocarbon (A3) refrigerants, such as propane and isobutane. c. They have high Ozone Depletion Potential (ODP) Thus, Edition 7.0 of this standard should facilitate the use of A3 refrigerants with respect to Edition 6.0. Systems with less than 150 g flammable refrigerant charge. Why are some of the hydrofluoroolefins classified as A2L? The ozone layer ozone layer The region of the stratosphere containing the bulk of atmospheric ozone. Students and technicians will require additional train-ing for the safe handling and transportation of these refrigerants. a. These refrigerants are created by nature, not a chemical company, and are often referred to as natural refrigerants. You will be required to provide your certificate number or declare the item will be resold to an EPA certified technician on certain types of Refrigerant. Which of the following refrigerants has the lowest global warming potential? c. Measurement of HCFCs in air samples from the stratosphere. David Boswell Reid was a pioneer of post occupancy evaluations, allowing MPs to feed back on their comfort levels during the development of the Palace of Westminster's Victorian ventilation system Hydrofluoroolefin indicates that the refrigerant is comprised of hydrogen, fluorine, and carbon. a. Retrofitting CFC-12 MVAC systems is also regulated under the SNAP program. What synthetic lubricant is presently used with ternary blends containing HCFCs? Contact your local rep. On Demand In this webinar, we go through the recent updates on R-290 natural refrigerant, and the impact it will have on the HVACR industry. d. Avoid violating the warranty on equipment. a. industrial melanism. Plant and animal life, agriculture, and materials like plastics and paints are also affected. Official websites use .gov Well, its just a little bit different with the new HFOs. d. Remain at least 5 feet away from the operating equipment. The rise in the amount of chlorine measured in the stratosphere matches the rise in the amount of fluorine, which has different natural sources than chlorine, over the same period. HFO refrigerants, or Hydrofluro-Olefins, are a new class of refrigerants that have a much lessened global warming potential than its HFC alternatives. What is the strongest evidence that HCFCs are in the stratosphere? Describe the mechanism of a heartbeat, mentioning all the factors that account for this repetitive process. Like the ozone-depleting substances they replace, most HFCs are potent greenhouse gases with very high global warming potentials (GWPs). Please note that Environmental Protection Agency law requires certain individuals to be licensed before purchasing some refrigerants. H2 Mod 4 03205-13 Leak Detection, Evacuation,, Zoning, Ductless, and variable refrigerant fl, Adv Adm - Part 2: Objects and Applications. A test for energy efficiency adopted by the Canadian government.C. Adopting natural refrigerant-based cooling in India: The road ahead Summary Despite this, incremental progress has been made through two important actions that have India's third refrigerant transition, the phasedown contributed to favourable conditions for alternative of high global warming potential (GWP) cooling technologies. Creating a new air conditioner using dry-charge components.B. Continue Reading. It provides . Frequent questions. Automobile manufacturers began to transition to the non-ozone depleting refrigerant, HFC-134a, with 1992 model year vehicles. Honeywell is one of the three big refrigerant manufactures in the world and are the ones to watch for new industry trends. After the phase-out of a refrigerant, where will supplies of that refrigerant for equipment servicing come from? d. Higher natural background radioactivity, c. Increased rates of skin cancer in humans. Low GWP but flammable. b. solvent conversion c. R-22 What are the characteristics of hydrofluoroolefins (HFOs)?A. We also want you to know that Refrigerant HQ is a participant in the Amazon Services LLC Associates Program and The E-Bay Partner Program. HFC-134a will no longer be approved for use in new light-duty vehicles manufactured or sold in the United States as of model year 2021 as a result of EPAs. At the time of this writing (in early November 2014), only R-600a (isobutane), R-290 (propane), and R-441A (HC blend) had been approved by the EPAs SNAP program for use in the U.S. They can have very high global warming potentials. The Significant New Alternatives Policy (SNAP) Program. Top 5 Reasons Why You Should Buy Refrigerant in Bulk. Is R32 refrigerant a blend? They are prohibited for use in the u.s. D. They have ozone depleting potentials, and have low global warming potentials. What would be the benefit of using a semipermeable membrane for a chemist studying diffusion? Freezer equipment can use propane (R-290) as long as the refrigerant charge does not exceed 5.3 ounces (150 grams); and new domestic refrigerators and freezers or combination refrigerator/freezer can use isobutane (R-600a) or R-441A as long as the refrigerant charge size does not exceed 2.0 ounces (57 grams). b. Rewiring an external electrical circuit. admin 6 mins ago 1 min read. Which of the following is a high-pressure refrigerantunder EPA's section 608 regulations? Resulting design criteria. ** d. Remain at least 5 feet away from the operating equipment. These effects include increases in cataracts, skin cancer, and weakened immune systems. How many ozone molecules can each chlorine atom in the stratosphere destroy? An international treaty that addresses ozone-depleting substances and their alternatives, Recovery equipment that relies on the compressor in the appliance and/or the pressure of therefrigerant in the appliance would be considered:A. System-dependentB. a. What is unique about an azeotropic refrigerant mixture? What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes? HFOs are distinguished from HFCs by being derivatives of olefins rather than alkanes (paraffins). Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Julian Smith, Peter Harriott, Warren McCabe. At uneven rates due to different vapor pressures. b. An HFO refrigerant is a type of hydrofluoroolefin (HFO) that replaces some of the traditional halogenated refrigerant molecules used in cooling systems with oxygen or nitrogen atoms formed through chemical reactions between different substances like methane, ethylene oxide etc., leading to gases which are far less dangerous than conventional . What characteristics of HFC refrigerants make them damaging to the environment? Whenever these gases accidentally leaked due to equipment failure, poor maintenance, or human error, it always results in big accidents like a huge fire or an explosion. In other words, they are "artificial.". They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable. b. R-113 Olefins have carbon atoms linked by a double bond where alkanes have single bonds between carbon atoms. b. Get started for free! Hydrofluoroolefin (HFO) refrigerants are also composed of hydrogen, fluorine, and carbon atoms, but contain at least one double bond between the carbon atoms. b. Rewiring an external electrical circuit. What characteristics of CFCs and HCFCs make them more likely to reach the stratosphere than most other compounds containing chlorine? HFO refrigerants fall under the 'slightly flammable' category (A2L). Which of the following refrigerants is an HFO? HC refrigerants are classified by ASHRAE in the A3 safety group. Similar tests of the current R134a refrigerant did not result in ignition. Source. They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable. b. Radon Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs), have which of the following in common? By visiting this website, certain cookies have already been set, which you may delete and block. A printable brochure is available for new climate-friendly motor vehicle air conditioning refrigerants. One example being the 134a alternative, 1234YF, which is 335 times lower on the global warming potential scale and only four times higher than standard carbon dioxide. a. The date when the production and import of new R-22 in the U.S. ends is; As of 2017, how much can a technician be fined for violating the Clean Air Act, including knowingly releasing non-exempt refrigerant from appliances. HFOs have a higher minimum ignition energy, and a slower burning velocity compared to hydrocarbons. Even though it protects us when it is in the stratosphere, ozone at ground level can be harmful to breathe and is a prime ingredient in smog. Servicing a system that uses CFC's or HCFC's after the phaseout date. c. HFCs Release of mixtures of nitrogen and refrigerant that result from adding nitrogen to a fully charged appliance to leak check the appliance. Browse over 1 million classes created by top students, professors, publishers, and experts. I say for now because weve been through this before. Benefits of using this refrigerant: With a GWP of 292, Solstice N15 is 80% lower than R-134a and 50% lower than R-124. Please click here to see any active alerts. Acceptable, subject to use conditions, for new vehicles only (June 6, 2012, 77 FR 33315), Operates at 5 to 10 times higher pressure than other MVAC systems, Under development by several foreign automobile manufacturers, Exempt from the Section 608 venting prohibition, meaning it is legal to knowingly release this refrigerant to the environment; however, CO. Engineering strategies and/or mitigation devices shall be incorporated such that in the event of refrigerant leaks the resulting CO2 concentrations do not exceed the STEL of 30,000 ppm averaged over 15 minutes in the passenger free space and the ceiling limit of 40,000 ppm in the passenger breathing zone. Why Are Hfo Refrigerants Less Flammable Than Hydrocarbon Refrigerants. Design, CMS, Hosting & Web Development :: ePublishing. It is being the common refrigerant for automotive manufacturers to switch to. Common applications include commercial refrigerators and bottle coolers, split air conditioning units, and domestic refrigerators and freezers. Which of the following is TRUE if a system WILL NOT hold a vacuum after it has been evacuated?A. What are the characteristics of hydrofluoroolefins (HFOs)? To date, the use of HFO refrigerants and blowing agents has helped avoid the release of 170 million metric tons of CO2e into the atmosphere so far, equivalent to emissions from more than 35 million cars, almost all licensed cars in the UK. For additional information, visit Choosing and Using a Retrofit Refrigerants for a CFC-12 Motor Vehicle Air Conditioner. What should a technician do if they lose their Section 608 certification card? Why are some hydrofluoroolefin (HFO) refrigerants classified as A. Which type of refrigerant is the most harmful to stratospheric ozone? What is one of the most serious results of damage to the stratospheric ozone layer? What is the state of refrigerant entering the compressor of a refrigeration system? Refrigerants emitted when connecting or disconnecting low loss hoses to charge or service anappliance. How does the global warming potential of R-410A compare to carbon dioxide? Lets keep everyone on their toes. The three new HFOs from DuPont are as follows: It seems like they just got there but HFCs are already being phased out across the world. They have high ozone See Details 4.The Professor's Lesson on HFO, HC Refrigerants - ACHR News Author: www.achrnews.com Post date: 30 yesterday Rating: 4 (827 reviews) Highest rating: 3 Low rated: 2 Summary: If you are in the EU youve already been dealing with them for years and if you are in the states get ready! a. c. Prevent stratospheric ozone depletion. Refrigerants are controlled substances due to 1) High Pressures (100-145 psi), 2) Extreme temperatures (-50C to 145C), 3) Flammability A1 class non-flammable, A2/A2L class flammable & A3 class extremely flammable/explosive and 4) Toxicity B1-low, B2-medium & B3-high, as classified by ISO 817 & ASHRAE 34. c. Hydrogen, Chlorine, Fluorine, &Carbon Distributors must verify which of the following before they can sell HFC or HCFC refrigerant? Refrigerants emitted when cutting a line without properly evacuating the appliance. R32 has a flammable range of around 15 points so it meets the definition of the GHS for a Category 2.1 gas. b. R-123 (Table 2 lists some known CFC, HCFC, HFC, HFO, HC, and natural refrigerants with their safety classifications and boiling points at atmospheric pressure for comparison purposes.). These are affiliate advertising programs designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com or E-Bay.com. What would the period of the pendulum in Problem 60 be if the pendulum were on the moon, where the acceleration due to gravity is one-sixth that on Earth? Non-ozone depleting and have low globalwarming potentials. In what state should a system be to measure a final system vacuum?A. Measurement of HCFCs in air samples from the stratosphere. R-1234yf What characteristics of HFC refrigerants make them damaging to the environment? HFO refrigerants are categorised as having zero ODP (Ozone Depletion Potential) and low GWP (Global Warming Potential) and so offer a more environmentally friendly alternative to CFCs, HCFCs and HFCs. They are "synthetic chemicals," not "natural.". What temperature does this indicate? Secondly, the majority of all the patents on HFOs, including 1234YF, are held by two companies DuPont and HoneyWell. d. be secure All Rights Reserved BNP Media. What other factors are involved in blood flow? Other applications include vending machines, fridges, beverage dispensers, air dryers, and carbon dioxide cascade systems in commercial refrigeration. Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), and Hydrofluorocarbons (HFCs) have what in common. Which of the following refrigerants damages stratospheric ozone? b. HCFCs When transporting cylinders containing used refrigerant, DOT requires that you: How does the global warming potential of R-410A compare to that of carbon dioxide. Why are HFO refrigerants less flammable than hydrocarbon refrigerants? It is hoped that this paper will initiate a dialog among stakeholders, and increase the likelihood that the more widespread use of flammable refrigerants does not result in a decline in safety. begin the trip with 22300kg22300 \mathrm{~kg}22300kg of fuel. d. Infrared radiation from the sun. Servicing existing R-22 systems. Now in Russian Federation and other countries large-scale oil terminals (volume of one tank exceeds 100 000 m 3, total volume of tanks exceeds 300 000 m 3) are designed and constructed.Therefore fire safety of such objects becomes a very important task, solution of which is hardly possible without detail fire risk assessment.This study is aimed to a solution of this problem. d. All refrigerant lubricants. What does ozone in the stratosphere above the earth consist of? The EU Regulation 517/2014 has recently been approved in a further attempt to curb the effects of Global Warming. Throughout your physics course, your Identify several substances found in blood plasma. In Lack's study, the effect of weather on the size of the finchs beak is an example of Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the ACHR News audience. 100,000 molecules Just as Honeywell has begun producing new HFO refrigerants DuPont is doing the same. Why are some hydrofluoroolefin (HFO) refrigerants classified as A. So, the CFCs were phased out and replaced with the HFCs which had a substantially lower amount of Chlorine compared to its predecessors. Given int[] list = {1, 2, -1}, can you invoke sort(list) using the sort method in Listing 19.4? This is because the HC refrigerant constitutes only a small percentage (less than 3 percent) of the total refrigerant blend. At present, the price of most HFO refrigerants in Europe is lower than that of HFCs and higher than that of naturals. Non-ozone depleting, and have high global warming potentials.B. How do the global warming potentials of isobutane(R-600a), propane (R-290), and R-441A compare to the GWPs of HFC-134a, R404A, and R-410A? Substitutes for R404A/R507A and R410A. a. a. R-410A What is the Montreal Protocol? Which of the following refrigerants is an HFO? D. With the system isolated and the vacuum pump turned off. These refrigerants include HCs, ammonia, air, water, and carbon dioxide. Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), and Hydrofluorocarbons (HFCs) have what in common. in production of insulation foams, food industry . a. HFOs In your answer, be sure to: identify two factors that could influence the nutrients that can pass from the mother to the fetus, identify the group of hormones that alter cell membrane receptors and explain how this alteration can affect cell function, state the role of the uterus in the development of the fetus and the placenta. c. Measurement of HCFCs in air samples from the stratosphere. They are less flammable 4.The Professor's Lesson on HFO, HC Refrigerants - ACHR News Author: www.achrnews.com Post date: 12 yesterday Rating: 5 (1222 reviews) Highest rating: 4 Low rated: 1 Summary: 5. Which of the following refrigerants contains chlorine? Maybe HFOs are the perfect refrigerant, but I have a feeling well be going through this again and sooner rather than later. They contain chlorine. d. The purchaser is or employs a Section 608 certified technician. Aspects on the development of HFO and HFO/HFC refrigerants. They knew that amount Which gas is used as the baseline measurement for global warming potential? The world switches away from the harmful HFCs and over the HFOs and then DuPont/HoneyWell get to charge a arm and a leg and nobody can say a damn thing because everybody needs it. c. They contain fluorine. Two popular HFO refrigerants are HFO-1234yf and HFO-1234ze (See table 1 here). They must be recovered before opening or disposing of appliances. d. They can have very high global warming potentials. They contain chlorine which damages the ozone layer. . Which factor does NOT affect the speed of evacuation? C. They are prohibited for use in the u.s.D. a. EPAsSignificant New Alternatives Policy (SNAP) program reviews substitutes within a comparative risk framework in a variety of industrial sectors that historically used ozone-depleting substances. Helium, Carbon, Fluorine, & Chlorine c. Ultraviolet radiation from the sun. 3. A large cylindrical bucket of base area A is filled with water. Which gas(es) would cause the LEAST damage to the environment? c. 100,000,000 molecules They are no different than HFCs. HFO-1234ze also offers excellent energy efficiency, is cost-effective, and can be used in existing equipment design with minimal changes. After the phase-out of a refrigerant, where will supplies of that refrigerant for equipment servicing come from? What does ozone depletion potential (or ODP) measure? b. Why are HFO refrigerants less flammable than hydrocarbon refrigerants? The environmentally harmful effect of HFO refrigerants due to the trifluoroacetic acid that is formed as one of their atmospheric decay products will very likely lead to banning HFO refrigerants in a future European F-gas regulation. They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable. c. Stratospheric Ozone As we mentioned above, flammability is the main risk when working with hydrocarbon refrigerants. In the event of a large release of CFC, HCFC, or HFC refrigerant in a contained area which of the following is true? Why are HFO refrigerants less flammable than hydrocarbon refrigerants? Uses for these three HC refrigerants include new stand-alone retail refrigerators. even considering that mildly flammable refrigerants are difficult to ignite and propagate the combustion, it is important to understand that, when combusted, the released products of combustion can be . a. Want more HVAC industry news and information? They must be recovered before opening or disposing of appliances. We do not directly sell any products or refrigerants, but rather provide information, knowledge, and explanations to the consumer. A refillable cylinder must not be filled above what percent of its capacity by weight: Under what conditions may you use a disposable cylinder to recover refrigerant? xcos2(x2)dx\int x \cos ^ { 2 } \left( x ^ { 2 } \right) d xxcos2(x2)dx. An international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion. a. R-134a d. R-32 Class A rating on toxicity signifies refrigerants for which toxicity has not been identified at concentrations of less than or equal to four-hundred parts per million. What is the affected end-use? a. The miscibility of HFOs with POE lubricants is comparable to that of R-134a. Under EPA regulations, what standard must reclaimed refrigerant meet before it can be resold? HFCs are intentionally-made fluorinated greenhouse gases used in the same applications where ozone-depleting substances have been used, including motor vehicle air conditioning. Low flammable HFCs tends to break down relatively fast in the atmosphere. They are significantly higher They have toxicity characteristics. b. In the new real-life test scenario, the refrigerant is dynamically dispersed at high pressure near to hot components of the test vehicles exhaust system. The use of CO2 in MVAC systems must adhere to the standard conditions identified in SAE Standard J639 (EPA 2012b). At uneven rates due to different vapor pressures. What range is displayed on a high pressure gauge on a service manifold? Since 1994, the most common refrigerant used in MVAC systems has been hydrofluorocarbon (HFC)-134a. The ability of a substance to destroy ozone in the stratosphere. Under SNAP, all flammable refrigerants, except HFC-152a and HFO-1234yf, are listed as unacceptable for use in new and retrofit MVAC systems. previously fuel had been measured in pounds. Servicing of existing vehicles using HFC-134a with HFC-134a will not be impacted and will continue to be allowed. c. be labeled Individual CFC molecules are labeled with a unique numbering system. How do refrigerant blends leak from a system? Hydrofluoroolefins (HFOs) The last round of changes took place Manufacturers have addressed the safety issues around using A2L refrigerants in air conditioning However, it is likely that in some air conditioner somewhere, at some point in time, refrigerant will be They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable Why are some A2L and B2L are low-flammability refrigerants with a maximum burning velocity equal to or smaller than 10 centimeter per second (cm/s) or 3.9 inches per second (in./s). New A2L listings for AC applications. Manufacture's often color code the exterior of gauges. The 6-kg cylinder is released from rest and falls on the spring, which has been initially precompressed 50 mm by the light strap and restraining wires. What does a Section 608 certification allow a technician to do? The purchaser is or employs a Section 608 certified technician. B. Acceptable, subject to use conditions, for new passenger cars and light-duty trucks only (March 29, 2011, 76 FR 17488; March 26, 2012, 77 FR 17344), Mildly flammable (ASHRAE A2L), but can be used safely, Models using HFO-1234yf include: Cadillac XTS, Chevrolet Spark EV, BMW i3 and i8, Chrysler 200, Chrysler 300, Dodge Challenger, Dodge Charger, Dodge Dart, Dodge Durango, Jeep Cherokee, Jeep Wrangler, Ram 1500, Fiat 500 and 500L, Alfa Romeo 4C, Honda Fit EV, Tesla Model S, Range Rover, and Range Rover Sport. Servicing a system that uses CFCs or HCFCs after the phaseout of those refrigerants. Which refrigerant does not contain chlorine? They contain fluorine. a. R-600a and R-441A R134a alternatives. admin. All three are HFOs a. R-1234yf a. Many automobile manufacturers have already begun to switch to the new HFO alternative 1234YF refrigerant. They have ozone depleting potentials, and have low global warming potentials. Request a replacement from their certifying organization. HFOs are the refrigerant of the future for now. Fluorine makes HFO refrigerants less flammable than hydrocarbon refrigerants, which are highly flammable. Which element of CFC or HCFC molecule causes ozone depletion? Please click here to continue without javascript.. Technology Can Help Solve the HVAC Labor Issue, Moving Forward with R-290 Natural Refrigerant, Decarbonization with Heat Pump Technology, BNI Mechanical/Electrical Square Foot Costbook, 2023 Edition. Which of the following is not a violation of the refrigerant management regulations under the Clean Air Act? Under the Section 608 "safe disposal requirements", who is responsible for ensuring that CFC, HCFC, and HFC refrigerant has been removed from household refrigerators before they are dispose of? Which of the following factors affect the speed of system dehydration? Refrigerants emitted when connecting or disconnecting low loss hoses to charge or service anappliance. Ammonia, carbon dioxide and hydrocarbons, sold as refrigerants, are manufactured in large chemical plants. 1234YFs main opponent is Daimler out of Germany. Notice the EPAs SNAP program only allows HC use in the U.S. in limited applications and in new equipment only. With the vacuum pump operating.C. They are no different than HFCs.B. Non-ozone depleting, and have a low global warming potential. ** b. filled to 95% of capacity. Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer. What type of synthetic oils are commonly used in new HFC systems and for retrofitting HCFC equipment to HFC refrigerants? There have been many tests across the world from various agencies and they have not been able to replicate this test that Daimler did. Why are some hydrofluoroolefin (HFO) refrigerants classified as A. What are the characteristics of hydrofluoroolefins (HFOs)? a. Which of the following statements is true? a. R-22 d. They are attracted to Ultraviolet radiation. Copyright 2023. The system is ready to be charged.B. This website requires certain cookies to work and uses other cookies to help you have the best experience. Ozone depleting, and have high global warming potentials.D. Ammonia has the ability to use less than 0.5 lbs . Blowing off units. Both HFO-1234yf and HFO-1234ze have a zero ozone depletion potential (ODP) with extremely low global warming potentials (GWP). Under EPA's regulations, what standard must reclaimed refrigerant meet before it can resold? This corresponds to a serious head-on collision in which the refrigerant line is severed and the reproducible results demonstrate that refrigerant which is otherwise difficult to ignite under laboratory conditions can indeed prove to be flammable in a hot engine compartment. ** d. All of the listed are correct. With the system heated.D. What process applies to cleaning refrigerant for immediate reuse by oil separation and single or multiple passes through devices, like replaceable core filter driers, which reduce moisture and acidity? Under EPA's regulations, what standard must reclaimed refrigerant meet before it can be resold? In fact the GWP scale is based off of carbon dioxide, or R-744. The first being that since these are new refrigerants the supply is very low and the demand will be increasing so obviously the price point is going to be high until the market balances out. By closing this message or continuing to use our site, you agree to the use of cookies. d. Satellite measurements of light passing through the atmosphere. This will still make an impact, but it will be minimal to the 134a switch. You have to leak-check a unit which has a lost complete charge. Which of the following is a lawful use of HCFC-22? d. The purchaser is or employs a Section 608 certified technician. By visiting this website, certain cookies have already been set, which you may delete and block. What is the index of refraction of the substance and its likely identity? The Significant New Alternatives Policy (SNAP) Program. a. What is the name of the EPA's program that identifies refrigerants with lower overall risks to human health and the environment? Also, oil changes may be needed with R-32.