HVAC CFC Exam with complete solutions

Absolute pressure - Answer- Atmospheric pressure + gauge pressure; PSIA= PSI+14.7 Boiling Point - Answer- The temperature at which a liquid changes to a gas Condensing point - Answer- The temperature at which a substance changes from a gas to a liquid. Chillers - Answer- Is a piece of refrigeration equipment that removes heat from water that circulates through a building for cooling purposes. Basic types of chillers - Answer- High pressure chillers, low pressure chillers and absorption chilled-water systems. Chlorofluorocarbons (CFCs) - Answer- Refrigerants consisting of chlorine, fluorine and carbon. CFC are stable, nonflammable, low in toxicity and inexpensive to produce. Classified as Class I substances. Class I substances - Answer- Is a refrigerant that poses the highest danger to the environment. Hydrochlorofluorocarbons (HCFCs) - Answer- Refrigerants consisting of hydrogen, chlorine, fluorine and carbon. HCFC are less harmful to the environment. Classified as Class 2 substances. Class II substances - Answer- Is a refrigerant that is considered to present a medium danger to the environment. Hydrofluorocarbons (HFCS) - Answer- Refrigerants consisting of hydrogen and carbon. HFCS have no chlorine molecules and create no threat to the ozone layer. Present low danger or no danger to the environment. Perfluorocarbons (PFCs) - Answer- Consisting of Carbon and fluorine. PFC refrigerant do not deplete stratospheric ozone. However, PFCs have extremely high global warming potentials (GWs) and very long lifetimes. High pressure refrigerants - Answer- R-12; R-22; R-114; R-500, R-502. Very high pressure: R-13 and R-503 Low pressure refrigerants - Answer- R-11 and R-123 Viscosity - Answer- a liquid's resistance to flow. Is the measurement of a fluid's internal resistance to flow. Flash Point - Answer- Is the temperature at which a fluid's vapor will ignite without the fluid igniting. Cleaveland cup is the test used to measure the flash point temperature of a fluid. Fire Point - Answer- Is the temperature (higher than flash point) at which a fluid will burn for at least 5 seconds. Pour Point - Answer- Is the lowest temperature a fluid can be at and still flow. Arctic cup is the test used to measure the pour point temperature of a liquid. Troposphere - Answer- The region that covers the surface of the earth to about 6 to 7 miles up. Stratosphere - Answer- Region above the troposphere; is approximately 8 to 30 miles above the surface of the earth Ozone Layer - Answer- Is located in the stratosphere at approximately 28 miles above the earth's surface. The ozone layer plays the vital role of absorbing harmful ultraviolet (UV) radiation from the sun. Ionoshere - Answer- Region above the stratosphere; approximately 31 to 300 miles above the surface of the earth. CFC And HCFC - Answer- CFC and HCFC gases are mixed throughout the atmosphere by large scale winds and survive the several year journey up to the stratosphere where CFCs are eventually broken down by ultraviolet radiation. The substances produced by breaking down the CFC molecules deplete the ozone layer. The decreased amount of ozone may let an increased amount of UV radiation penetrate the stratosphere and troposphere and reach the surface of the planet. Also, oxygen present in the stratosphere decreases the amount of UV radiation that the ozone layer is able to absorb. Ozone Destruction - Answer- Ozone is destroyed when ultraviolet radiation attacks a CFC molecule and break away chlorine atoms from the CFC molecule. The free chlorine atoms destroy ozone molecules, oxygen and chlorine monoxide molecules are formed in the stratosphere when chlorine atoms break down ozone molecules. The chlorine monoxide molecule is so unstable that the chlorine and oxygen atoms separate, allowing the chlorine atom to be free to attack other ozone molecules and continuing the cycle. Ultraviolet Radiation - Answer- Ultraviolet radiation is the portion of the light spectrum that is damaging to living organisms. the greater the ozone depletion, the greater the amount of UV radiation reaching the surface of the planet. The harmful effects of UV increases as a result of ozone depletion. Ultraviolet radiation has been linked to skin cancer, cataracts, damage to materials like plastics, and harm to crops and marine organisms. Evidence of ozone depletion - Answer- Rain effectively scrubs the lower atmosphere clean, removing the natural forms of chlorine. Measurements show that concentration of natural chlorine vanish very rapidly as altitude increases. Neither sea salt from ocean evaporation or atmospheric-level volcanic eruptions contribute significantly to stratospheric chlorine levels. It is the stability of CFC molecules that allows the threat to the ozone layer to occur. Chlorine monoxide found in the upper stratosphere is another indication that the ozone layer is being destroyed. The strongest evidence that CFCs are in the stratosphere is a measurement of CFCs in air samples from the stratosphere. It is presently accepted that CFCs and other substances such as Halon used in human activities are the primary source of chlorine molecules in the stratosphere. Accumulation (Level Ozone) - Answer- there are human environmental effects of ozone depletion. Ozone depletion contributes to or can cause skin cancer (which is now one of the fastest growing forms of cancer), cataracts, and damage to the human immune system. Ozone depletion affects marine and plant life by reducing growth. At present, ozone depletion is limited to certain regions, but is considered a global problem. The effects of ground level 1 ozone - Answer- Ozone are experienced in hot weather. According to the EPA, millions of people live in areas where ozone health standards are exceeded. Low-level ozone damages and vegetación and eco systems. Global Warming - Answer- Global warming is also known as the greenhouse effect. Global warming occurs when heat is trapped in the troposphere. The higher temperatures can have consequences such as drought, disease, floods and lost ecosystems. Montreal Protocol (September 16 1987) - Answer- The United States and 22 other countries signed the Montreal Protocol on substances that deplete the ozone layer. The Montreal Protocol is an international environmental agreement that establishes requirements to phase out ozone-depleting CFC substances worldwide. Advance Notice of Proposed Rulemaking (ANPRM) - Answer- On May 1, 1990, the EPA published an advance notice of proposed rulemaking (ANPRHL, 55 FR 18256) that address issues related to the development of a national CFC recycling program. The ANPRM notice emphasized the importance of recycling CFC refrigerants and allowed the continued use of equipment requiring CFC refrigerants. London Amendments to the Protocol (June 29, 1990) - Answer- At the second membership meeting of the Montreal Protocol parties, held in London on June 29, 1990, the parties to the Protocol passed amendments and adjustments which called for a full phase out of already regulated CFC refrigerants and Halons by the year 1996. The parties also voted to phase our HCFCs by the year 2020, but with the possibility of allowing use until the year 2040. Copenhagen Revisions to the Montreal Protocol (November 25, 1992) - Answer- on November 25 1992, the fourth meeting of the Montreal Protocol parties was convened in Copenhagen. The attending parties took a number of actions, including acceleration of the phase out of CFC refrigerants and Halons. HCFC refrigerants were also added to the list of chemicals tho be controlled under the Montreal Protocol. The new schedule stopped to production of Halons after 1993 and CFCs after 1995. HCFC refrigerants can be produced until 2030. Talks may accelerate the schedule to the year 2020. The Montreal Protocol is a global policy and the Clean Air Act (CAA) is a federal law of the United States. Clean Air Act Amendments (CAA) - Answer- The Clean Air Act Amendments (CAA) of 1990, signed November 15 1990, included requirements for controlling ozone-depleting substances. Section 608 (CAA) - Answer- Promotes minimizing emissions and maximizing recycling of ozone depleting substances. President George H. Bush announced on February 11 1992, that the U.S. would unilaterally accelerate the phase out schedule for ozone depleting substances, and called upon other nations to do so as well. President Bush also asked CFC, HCFC and Halon producing countries to voluntarily reduce production of ozone depleting substances. Section 608 (CAA) regulations: - Answer- 1-) Require service practices that maximize recycling of ozone depleting substances such as CFC and HCFCs. 2-) Set certification requirements for recycling and recovery equipment, technicians, and reclaimers. 3-)Restrict the sale of refrigerants only to certified technicians. 4-)Require persons or technicians servicing or disposing of air conditioning and refrigeration equipment to prove to the EPA that recycling and recovery equipment being used is in compliance with EPA rules. Require the immediate repair of substantial leaks in air conditioning and refrigeration equipment with a charge greater than 50 lb. 5-)Establish safe disposal requirements to ensure the removal of refrigerants from goods such as motor vehicle air conditioners, home refrigerators, and room air conditioners and prevent them from entering the waste stream with the refrigerant charge intact. The Prohibition on Venting - Answer- Effective July 1 1992, section 608 of the CAA prohibits individuals from knowingly venting CFC and HCFC ozone depleting substance into the atmosphere while maintaining, servicing, repairing, or disposing of air conditioning or refrigeration equipment (appliances). Only for types of releases are permitted under the prohibition: 1-) "De mínimis" (minimal) quantities of refrigerant released in the course of making good faith attempts to recover, recycle, or safely dispose of refrigerant. 2-) Refrigerant releases during the normal operation of air conditioning and refrigeration equipment, such as from mechanical purging and/or leaks. However, the EPA does require the repair of leaks above a specific size in large equipments. 3-) Release of CFCs or HCFCs that are not used as refrigerants. Any heat transfer fluids are considered refrigerants. For example, mixture of nitrogen and R-22 that are used as holding charges or as leak test gases may be released, because the ozone depleting compound is not used as refrigerant. 4-) Small releases of refrigerant that result from purging hoses or from connecting or disconnecting hoses to charge or service appliances d not be considered violations of the prohibition on venting. However, recovery and recycling equipment manufactured after November 15 1993 must be equipped with low loss fittings. Venting Prohibition for refrigerant substitutes - Answer- An amendment was added in November 1995 to section 608 CAA that prohibits the venting of substitute refrigerants during the maintenance, service, repair and disposal of air conditioning and refrigeration equipment. Exceptions to Evacuation Requirements - Answer- The EPA has established limited exceptions to the evacuation requirement for repairs to leaky equipment such as repairs that are not considered major and when evacuation of the equipment to the environment is not required. Technician Certification - Answer- The EPA has established a technician certification program for technicians who perform maintenance, service, or repair, or who dispose of equipment that could be reasonably expected to release refrigerants into the atmosphere. Section 608 of the CAA allows work that would not be expected to release refrigerant into the atmosphere to be performed on equipment by non certified personnel. Apprentices are except of certification requirement as long as supervised by a certified technician. Leak rate for appliances with more than 50lb - Answer- Commercial refrigeration 35% Industrial refrigeration 35% Comfort cooling 15% All others appliances 15% Safe Disposal Requirements - Answer- Under the rules of the EPA, equipment that is typically dismantled onsite before disposal, such as retail food freezers, residential central air conditioners, chillers, and industrial process refrigeration systems, must have the refrigerant recovered for disposal in accordance with the requirements of the EPA. However, equipment that typically enters the waste stream with the charge intact, such as motor vehicle air conditioners and household refrigerators, freezers, and room air conditioners, are subject to special safe disposal requirements. Under thee safe disposal requirements, the final person in the disposal chain (scrap metal recycler or landfill owner) is responsible for ensuring that refrigerant is recovered from equipment before the final disposal of the equipment occurs. Refrigerant Sales Restrictions - Answer- Under EPA regulations, only certified technicians are allowed to purchase CFC or HCFC refrigerants. Technicians who have completed an EPA-approved certification program under either section 608 or section 609 are issued a certification card and are eligible to purchase refrigerants containing CFCs or HCFCs. Recordkeeping - Answer- Section 608 of the CAA requires that any person who sell CFC and HCFC refrigerant retain invoices that indicate the name of the purchaser, the date of the sale and the quantity of the refrigerant purchased. The records kept by sellers must be maintained for a minimum of three years. Wholesalers who sell refrigerants to companies that employ certified technicians must keep proof of buyer certifications (copies of certification cards) and a list of authorized personnel or job titles/classifications who may purchase refrigerants to be used by the certified technician employed at the same company. CFC Recovery, Recycling and Reclaiming - Answer- CFC substance have not been manufactured since 1995. After 1995, supplies of CFC refrigerants for equipment servicing have come from recovery and recycling efforts. As time passes, CFC refrigerants will become harder to obtain. As CFC refrigerants become less available, CFC refrigerant will become too expensive to use. Recovery - Answer- Refrigerant recovery is the removal of refrigerant in any condition from a system without testing or processing the refrigerant and storing the refrigerant in an external container. The recovery of refrigerants is necessary to ensure adequate supplies of refrigerants for present and future service use after production bans are in effect. Recovering refrigerants also prevents the venting of refrigerants to the atmosphere and ozone depletion. Recovery can be achieved by using passive or active methods. Passive Recovery (refrigerant) - Answer- Is a refrigerant recovery process achieved with the assistance of system components to remove the refrigerant from the system (pump-down). The passive recovery method can only be used with appliances designed to use 15lb or less refrigerant. Active Recovery (refrigerant) - Answer- Is a refrigerant recovery process using a self contained recovery unit (machine). the active recovery method is the most popular method. The recovery unit removes the refrigerant with no assistance from system components. Recycling (refrigerant) - Answer- Refrigerant recycling is the removal of refrigerant from a system and the cleaning of the refrigerant for reuse. Recycled refrigerant is refrigerant that has been processed using oil separators and single or multiple pass filter/dryers to separate moisture, acidity, and particulate matter from the refrigerant. Reclaiming (refrigerant) - Answer- Refrigerant reclaiming is the reprocessing of used refrigerant to meet new refrigerant standards and includes chemical analysis to verify purity. Refrigerants that are seriously contaminated cannot be reclaimed. Refrigerants with serious contaminants, such as acid contaminants created from burnouts, are the most difficult for a reclaiming facility to handle successfully. When recovering refrigerant, it is important not to mix different refrigerants in the same container because most refrigerant mixtures are impossible to reclaim. Refrigerants that cannot be separated must be destroyed. Refrigerants should never be mixed. Low-Loss Fittings - Answer- Are special fittings that prevent the release of refrigerant from a system to the atmosphere and prevent air from entering the system. Low loss fittings automatically trap refrigerant in a hose when disconnected and are required on all recovery, recycling and reclaiming equipment. Equipment Certification - Answer- The EPA requires that recovery and recycling equipment manufactured on or after November 15 1993, be tested by an EPA approved testing organization. Recovery and recycling equipment intended for use with air conditioning and refrigeration equipment must be tested under the ARI 740-1993 test Protocol. The recovery and recycling equipment intended for use with air conditioning and refrigeration systems must be able to recover a specific percentage of refrigerant or create a specific level of vacuum on the system. Small appliances refrigerant recovery - Answer- 1-) 80% recovery required: Technician uses equipment manufactured before November 15, 1993; compressor of the appliance is not operation 2-) 90% Recovery required: Technician uses equipment manufactured on and after November 15 1993; Compressor it the appliance is operations.