| 1. |
On August 23, 2010, at the Millard Refrigerated Services facility in Theodore, Alabama, hydraulic shock caused a roof-mounted 12-inch suction pipe to catastrophically fail leading to the release of more than _____________of anhydrous ammonia. |
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2,000 pounds |
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10,000 pounds |
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25,000 pounds |
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32,000 pounds |
| 2. |
In low-temperature systems, the combination of high-pressure hot gas (commonly used for defrost) and cold liquid ammonia can result in __________ with the potential for ammonia-containing equipment to suddenly and catastrophically fail. |
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Hydraulic shock |
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Condensation |
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Evaporation of Ammonia |
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Varies by situation |
| 3. |
The MFD conducted air monitoring after arriving on scene. According to the MFD report on the incident response, colorimetric gas detection tubes used to sample ammonia on the dock detected ammonia concentrations between ______________ ppm. |
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25 and 45 |
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250 and 450 |
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550 and 850 |
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1250 and 1450 |
| 4. |
The purpose of the ACE survey was to determine the severity of the health effects from the ammonia release and make public health recommendations. |
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True |
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False |
| 5. |
Hydraulic shock is a sudden localized _____________ that can occur in piping or equipment when there is a rapid change in the velocity of a flowing liquid. Often referred to as “water hammer,” hydraulic shock is a well-understood phenomenon that has occurred in water and steam systems found in both domestic and industrial settings. |
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Drop in pressure |
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Spike in pressure |
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Drop in temperature |
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None of the above |
| 6. |
The use of the emergency stop button (e-stop), located in the _______________, would have shut down the compressors and pumps, and de-energized valves. Shutting down these components would have stopped the circulation of ammonia into the other evaporators and decreased the quantity of ammonia that flowed out to the failed suction line located on the roof. |
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Millard ground floor |
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Millard control room |
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Millard maintenance room |
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None of the above |
| 7. |
"____________" is the first step in the defrost cycle. It is intended to remove residual liquid ammonia in the evaporator by using heat from the room air to vaporize, or boil off the liquid ammonia resident in the coil prior to the introduction of hot gas. |
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Pump-in |
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Pump-out |
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Liquid-out |
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None of the above |
| 8. |
___________________ – Hydraulic shock is caused by the rapid closing of a valve in a pipe carrying flowing liquid. When the flow of liquid stops suddenly, a spike in pressure within the valve body and connected piping occurs. |
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Sudden Liquid Deceleration or Water Hammer |
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Vapor-Propelled Liquid Slug |
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Condensation-Induced Shock |
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None of the above |
| 9. |
Anhydrous ammonia refrigeration systems are susceptible to hydraulic shock mechanisms during the transition between hot gas defrost and normal cooling in the refrigeration process. |
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True |
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False |
| 10. |
The risk of hydraulic shock failure during hot gas defrost increases as coil volume ____________and temperature decreases.
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Decreases |
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Increases |
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Doesn’t affect at all |
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None of the above |
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