Quiz_ The Fernie Arena Loss incident - Graded_ Attempt review

5/14/23, 11:31 AM Quiz: The Fernie Arena Loss incident - Graded: Attempt review https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=12943138&cmid=7028686 1/4 Dashboard / My courses / ENGG 404A (LEC X01 Spring 2023) / Week 2 - Online Study: / Quiz: The Fernie Arena Loss incident - Graded Started on Sunday, 14 May 2023, 11:15 AM State Finished Completed on Sunday, 14 May 2023, 11:27 AM Time taken 11 mins 55 secs Marks 9.00/9.00 Grade 100.00 out of 100.00 Question 1 Correct Mark 2.00 out of 2.00 The refrigeration system at the Fernie Memorial Arena uses two hazardous substances, ammonia and brine. Match two hazardous properties for each of ammonia and brine. Ammonia, physical property relating to flammability  Ammonia, physical property relating to a breathing hazard  Brine, physical property relating to skin contact  Brine, physical property relating to corrosion  flammable and explosive gas toxic gas, noxious gas skin irritant at neutral pH corrosive to ferrous metals Your answer is correct. Ammonia, the refrigerant, in its pure form is a gas at standard temperature and pressure, and is both a flammable material and a toxic material that attacks the respiratory tract of a person. Ammonia solution, what one would find in an ammonia household cleanser, is a solution of ammonia gas in water. Brine, the heat transfer fluid, is a saturated solution of a salt, typically NaCl, that is corrosive to most metals, especially ferrous metals, and is an irritant to the skin of a person. Additives in the brine may significantly reduce or increase the pH, thus increasing the corrosivity of the brine. Technically, the word "flammable" is really not a word. The correct word that indicates a gas can burn is "inflammable"; however, through everyday usage, "flammable" has taken on the same meaning as "inflammable", much to the chagrin of grammar teachers. The correct answer is: Ammonia, physical property relating to flammability → flammable and explosive gas, Ammonia, physical property relating to a breathing hazard → toxic gas, noxious gas, Brine, physical property relating to skin contact → skin irritant at neutral pH, Brine, physical property relating to corrosion → corrosive to ferrous metals

5/14/23, 11:31 AM Quiz: The Fernie Arena Loss incident - Graded: Attempt review https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=12943138&cmid=7028686 2/4 Question 2 Correct Mark 2.00 out of 2.00 According to The Energy Wheel , what source of energy was released at the Fernie Arena? As a helpful hint, the loss of control was: The brine corroded the chiller tubes over the life of the heat exchanger, and caused a pin-hole leak. The ammonia leaked from the higher-pressure side into the lower-pressure brine side of the heat exchanger (chiller) though the pinhole leak. The ammonia increased the pressure in the brine-side of the refrigeration system. This over-pressure caused the mechanical component to fail on the brine-side piping components. This failure caused a release of a mixture of ammonia gas and brine solution. Note: There are three correct responses, you only need select one. Select one: a. Chemical - Ammonia Toxicity  Ammonia gas was released and impacted the workers. b. Electrical - Exposed electrical conductors on the motor c. Mechanical - The compressor disintegrated d. Gravitational - Worker tripped on grade-level piping e. Pressure - Ammonia Leak f. Chemical - Brine Reaction g. Chemical - Ammonia Reaction Your answer is correct. There are many sources of energy in an ammonia refrigeration system such as operated at the Fernie Arena. Process description: Ammonia and brine are process fluids used in the refrigeration system at the Fernie arena. Ammonia is used as a refrigerant, and brine is used as the heat transfer fluid between the refrigerant and the ice surfaces. The ammonia cools or chills the brine, and the brine freezes the water on the arena surface. Some refrigerant systems use propylene, but not in this facility. Some heat transfer systems use ethylene glycol solutions (an antifreeze fluid), but not in this facility. Chemical energy: Ammonia is an inflammable (look it up) explosive gas and could be ignited and burn or explode, is corrosive to some metals and substances, and reacts readily with some chlorinated substances. Although there are no chemical reactions, there is a phase-change of ammonia from liquid (in the higher pressure ammonia piping system) to gas (in the lower pressure brine piping system). Brine is a water solution with an high concentration of salt (NaCl) and trace quantities of corrosion inhibitors;. Chemical reaction energy: In an ammonia refrigeration system, there are no intended chemical reactions by design. However, these could happen: ammonia corrodes unprotected components or attacks soft tissues of humans; ammonia could react with other substances especially any containing chlorine such as bleach, a common cleaning substance in arenas. (Never MIX ammonia and bleach.) Brine with reduced corrosion inhibitors can corrode metal components in heat exchanger systems. Pressure energy: The ammonia gas is compressed and liquefied in the refrigeration process, thus building pressure within the ammonia piping system. The ammonia pressure typically runs higher than the pressure in the brine system. Electrical and Mechanical: The electrical energy powering the power that drives the compressor, and the mechanical energy in the spinning motor and compressor. There are three correct choices: Depending on how it is defined and context, three sources of energy can be named: ammonia chemical energy (but NOT chemical reaction energy), pressure (pressurised) energy, and brine reaction energy as explained in the feedback for each of the choices. Mechanical potential is the set or assembly of moving parts of the rotating equipment. The correct answers are: Chemical - Ammonia Toxicity, Pressure - Ammonia Leak, Chemical - Brine Reaction cross out cross out cross out cross out cross out cross out cross out

5/14/23, 11:31 AM Quiz: The Fernie Arena Loss incident - Graded: Attempt review https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=12943138&cmid=7028686 4/4 ammonia in the brine system caused a pipe coupling to fail., The workers were not wearing self-contained breathing apparatus, ... → which could have protected the workers from the toxic ammonia gas. ◄ Quiz: Safety Metrics - Graded: Jump to... Week 2 Lecture Slides ►