Distro quick cards

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Distro quick cards
2014-09-19 19:41:02
water distribution

water d2 test
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  1. has a rotten egg smell and is considered the most hazardous in a confined space
    Hydrogen Sulfide (H2S)
  2. is NOT a primary confined space concern although it displaces oxygen
    Carbon Dioxide (CO2)
  3. Type C fire extinguishers
    are used on electrical fires
  4. The Lower Explosive Level (LEL) is
    the point where a Confined Space explosive atmosphere exists
  5. The OSHA standard for minimum oxygen content of any working atmosphere is
  6. The three major design configurations are
    Arterial Loop, Grid, and Tree
  7. A public water system provides drinking water to at least
    15 service connectionsor serves at least 25 persons 60 days or more each year
  8. The Zone of Saturation (Aquifers)
    is a layer of soil, gravel, or rock in which the spaces or pores are completely filled with water
  9. The Water Table is the line dividing the
    Zone of Aeration and the Zone of Saturation
  10. A Perennial surface stream flows
    throughout the year
  11. flows typically only immediately following a rainstorm
    Ephemeral stream
  12. The primary components of hard water
    dissolved Calcium (Ca+2) and Magnesium (Mg+2)
  13. 100 – 200 gpcd
    is the national average consumption
  14. the uncombined chlorine remaining after application
    “Free” Chlorine residual
  15. A sudden drop in the distribution system chlorine residual signifies
    the presence of chlorine consuming contaminants
  16. A PH sample may be held for a maximum time of
    6 hours
  17. The first course of action required when following a positive total coliform result is to
    initiate a repeat sampling
  18. The primary concern regarding turbidity is that
    it can inhibit disinfection
  19. When collecting bacteriological samples
    3 minutes or 3 volumes of the sample line should be flushed
  20. the maximum hold time for a bacteriological sample if not properly chilled
    1 Hour   (24 hours if refrigerated)
  21. The primary responsibility of any sampler is to
    prevent contamination of the sample
  22. “Routine” bacteriological samples should be taken
    at locations that represent customer water quality
  23. 40 pounds is the recommended daily maximum withdrawal for a
    150 lb. cylinder (400 for a 1-ton
  24. Chlorine cylinder fusible plugs melt at
    158-162 degrees F
  25. The painted line on a pipe indicates when the pipe is
    fully inserted into the bell
  26. AWWA recommends that system storage reservoirs be inspected every
    3-5 years
  27. the most reliable backflow device
    Air gap
  28. A main break could be a cause of
  29. Besides after being installed or repaired, backflow devices must be tested
    annually and records must be maintained for 3 years
  30. The degree of hazard is the primary determining factor for selecting
    the proper backflow device
  31. Galvanic corrosion is due to dissimilar
    metals (Magnesium and Zinc are highest)
  32. Iron corrosion is normally associated with
    red water complaints
  33. Sodium Hydroxide (Caustic Soda) is commonly used to reduce the corrosive nature of water by
    increasing the PH
  34. convert AC power to DC
  35. are placed at the low points along a water main
    Blow-off valves
  36. Butterfly valves (disc on a rotating shaft) are classified as
    rotary valves
  37. A Globe valve (most commonly used is household residential applications) has a
    flat or tapered disc that raises and sets into a seat – used for throttling
  38. The primary function of thrust restraints is to
    prevent separation of joints
  39. Water mains should be
    10 ft away and 12 inches above wastewater lines and never in the same trench
  40. It is recommended to backfill
    to the springline on both sides of the pipe prior to initial compaction
  41. The angle of repose for a trench in average soils is
  42. The recommended minimum velocity for a system flush is
    2.5 fps
  43. Pipeline in areas of significant vibration should be installed
    in a case pipe 2-8 inches greater in diameter
  44. During normal conditions, water main velocities should
    never exceed 5fps
  45. Hydrants should only be placed on mains
    s 6 inches or larger and have a minimum residual pressure of 20 psi during fire flow demand
  46. Hydrants should be installed
    24 inches from the curb
  47. AWWA recommends that residential service meters be calibrated
    every 5-10 years
  48. The Doppler effect is the principle
    the sonic meter is based upon
  49. are accurate at high flows and have no moving parts (flow stays the same and velocity increases through the throat – pressure relates inversely to velocity)
    Venturi meter
  50. Expected accuracy is 98.5 – 101.5%
    (Turbulence is a major cause of inaccuracy)
  51. Positive Displacement meters should be one size smaller than the service line
    when there is an accuracy issue
  52. Direct Current (DC)
    has a constant polarity
  53. Water pressure is typically expressed in “
    “Feet of Head”
  54. Maximum Contaminant Level for Nitrate
    45 mg/l
  55. Under normal condition a system should be at
    35 psi/
  56. under a state of duress (fire, etc.) the system should not drop below
    20 psi
  57. AWWA recommends normal pressure span to be between
    50-75 psi
  58. MCL for THMs
    is 80 ppm
  59. Chlorine residual minimum is
    0.2 ppm or mg/l and maximum is 4.0 mg/l