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21 Cards in this Set
- Front
- Back
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List 3 sewer line hydraulic cleaning methods |
- Balling - Kiting - High velocity cleaning |
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High velocity cleaning machine are used to do all of the following except:
A) Remove roots B) Remove grease C) Open stoppages D) Clean lines of silt and sand |
A) Remove roots B) Remove grease C) Open stoppages D) Clean lines of silt and sand |
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True or False:
Sewer balls use the principle of hydraulic head to develop high-velocity flow around the ball |
True |
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The most common method of cleaning sewer force mains is:
A) Scooters B) Power rodding C) High velocity cleaning D) Poly pigs |
A) Scooters B) Power rodding C) High velocity cleaning D) Poly pigs |
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List 2 sewer line mechanical cleaning methods |
- Bucket machines - Power Rodding |
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Which chemical is not used for the control of hydrogen sulfide?
A) Sulfuric acid B) Chlorine C) Lime D) Hydrogen peroxide |
A) Sulfuric acid B) Chlorine C) Lime D) Hydrogen peroxide |
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Chemicals are used to control what types of problems in sewers?
A) Grit B) Roots C) Viscosity D) Blockage |
A) Grit B) Roots C) Viscosity D) Blockage |
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What technique would be used to remove large amounts of debris in larger sewer lines?
A) Flushing B) High velocity cleaning C) Rodding D) Power bucket |
A) Flushing B) High velocity cleaning C) Rodding D) Power bucket |
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What factors contribute to the production of hydrogen sulfide in a collection system? |
- Low pH - Anaerobic conditions - High temperatures |
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True or False:
Power rodders are most effective in lines greater than 25 inches in diameter |
False |
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Why are inside drop lines installed in manholes? |
To prevent splashing |
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True or False:
When performing internal repairs of piping with a grout sealing system, the camera is generally located upstream of the sleeve packer |
False
(It is located downstream so water build-up doesn't obstruct view) |
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What is the purpose of a mandrel test? |
To make sure a pipeline is clear; a mandrel is 5% less than the inside diameter of the pipe, it is pulled through to make sure the pipe isn't flattened or offset when backfilling |
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What is the purpose of sewer pipe bedding? |
To cushion and protect the pipe |
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Name 3 different methods of locating a paved-over manhole |
- CCTV - Referencing as-built plans - Metal detectors |
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A mixture of sand and cement applied pneumatically that forms a high density, resistant concrete
A) Epoxy B) Plaster C) Caulking D) Gunite |
A) Epoxy B) Plaster C) Caulking D) Gunite |
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Name 3 desirable properties of chemical grout sealants |
- Non toxic - Remains flexible - Non corrosive |
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A pipe leaks 3 gallons in 90 minutes. What is the rate of loss in gallons/day? |
3gal/90min = 2gal/hr x 24hr/day = 48gal/day
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Calculate the force against a one foot diameter plug when the test pressure is 5 PSI.
Force(lbs) = Head(PSI) x Area(square inches) |
1 foot = 12 inches Area = (12")(12")(0.785) = 113.04 square inches 113.04 square inches x 5 psi = 565.2lbs |
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What is the elevation of the pipe invert at each station if the desired slope is 0.006?
Station Elevation of invert 0+00 160.00 0+50 _______ 1+00 _______ |
Station Elevation of invert 0+00 160.00 0+50 160.30 1+00 160.60 |
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What is the volume of water required to fill an 18 inch pipe that is 500 feet long? Give answer in gallons.
Volume = Area x Length |
18 inches = 1.5 feet Area = (1.5ft)(1.5ft)(0.785) = 1.77square feet Volume = (1.77 square feet)(500ft) = 885 cubic ft (885 cubic feet)(7.48) = 6619.8gallons |
