4b051 Bioenvironmental Engineering Journeyman CDC Ure Questions Vol. 5

100 Questions | Total Attempts: 628

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CDC Quizzes & Trivia

Questions and Answers
  • 1. 
    In ventilation work, what pressure is exerted outward against the interior surface of an enclosure?
    • A. 

      Positive static.

    • B. 

      Negative static.

    • C. 

      Positive velocity.

    • D. 

      Negative velocity.

  • 2. 
    The value for velocity pressure in a ventilation system is
    • A. 

      Always positive.

    • B. 

      Always negative.

    • C. 

      Negative on the blowing side.

    • D. 

      Negative on the exhausting side.

  • 3. 
    Less resistance and better contaminant capture in a ventilation system can be realized by using
    • A. 

      An air cleaner.

    • B. 

      Higher velocities.

    • C. 

      Elbows in the ducting

    • D. 

      A flange or tapered hood.

  • 4. 
    How can friction losses in a ventilation system be reduced?
    • A. 

      Decrease the hood size.

    • B. 

      Increase the duct length.

    • C. 

      Increase the duct velocity.

    • D. 

      Increase the duct diameter.

  • 5. 
    A density factor of one means that the air you are dealing with is at
    • A. 

      A high altitude.

    • B. 

      Elevated temperature.

    • C. 

      High barometric pressure.

    • D. 

      Standard temperature and pressure conditions.

  • 6. 
    Which type of velocity refers to the speed of air at a point in front of a hood that is needed to pull contaminants into the hood?
    • A. 

      Face velocity.

    • B. 

      Duct velocity.

    • C. 

      Capture velocity.

    • D. 

      Transport velocity.

  • 7. 
    What are two parameters at a given point in ventilation systems that are needed to calculate the air flow volume?
    • A. 

      Area and pressure.

    • B. 

      Area and velocity.

    • C. 

      Velocity and pressure.

    • D. 

      Diameter and velocity.

  • 8. 
    Areas of ducts and hoods must be expressed in
    • A. 

      Inches.

    • B. 

      Linear feet.

    • C. 

      Square feet.

    • D. 

      Cubic feet per minute.

  • 9. 
    What circumstance would result in a high K factor?
    • A. 

      Adequate mixing of air.

    • B. 

      Higher contaminant toxicities.

    • C. 

      An even evolution of contaminant.

    • D. 

      A high occupational exposure limit.

  • 10. 
    What is the maximum amount of a certain chemical vapor that air can hold at a given temperature?
    • A. 

      Vapor pressure.

    • B. 

      Explosive limit.

    • C. 

      Saturation concentration

    • D. 

      Required air flow volume.

  • 11. 
    A minimum K factor of four is used in dilution ventilation for fire and explosion control because
    • A. 

      Very toxic chemicals are involved.

    • B. 

      Good air distribution cannot be achieved.

    • C. 

      Concentrations must be kept at or below 25% of the lower explosive limit (LEL).

    • D. 

      Concentrations must be kept at or below 25% of the upper explosive limit(UEL).

  • 12. 
    Other than good contaminant control, what is the biggest advantage of local exhaust over dilution ventilation?
    • A. 

      Less noise.

    • B. 

      Lower operating costs.

    • C. 

      Better protection for equipment.

    • D. 

      Easier worker access to the process.

  • 13. 
    Two major advantages of local exhaust enclosures are that they provide
    • A. 

      Better protection for the equipment and less noise.

    • B. 

      The best contaminant control with the lowest air volume.

    • C. 

      Better air distribution with the elimination of disturbances.

    • D. 

      Easier worker access to the process and lower operating costs.

  • 14. 
    The purpose of using splitter vanes, multiple takeoffs, or baffles inside of a local exhaust hood is to provide
    • A. 

      A reduction in system resistance.

    • B. 

      An increase in hood static pressure.

    • C. 

      Proper discharge of air away from inlets.

    • D. 

      Uniform air distribution across the hood face.

  • 15. 
    Increasing the velocity of air through a slot hood without increasing the air flow volume most often results in
    • A. 

      An increase in contaminant control.

    • B. 

      A decrease in contaminant control.

    • C. 

      An increase in system resistance.

    • D. 

      A decrease in system resistance.

  • 16. 
    What type of ventilation system survey would Bioenvironmental Engineering (BE) perform on a new ventilation system to verify it is operating properly before putting it into service?
    • A. 

      Routine survey.

    • B. 

      Baseline survey.

    • C. 

      Initial acceptance survey

    • D. 

      Contaminant source survey.

  • 17. 
    In a routine survey, ventilation system data collected during the routine assessment should be compared to
    • A. 

      Key parameters.

    • B. 

      Factory findings.

    • C. 

      Previous routine survey data.

    • D. 

      Data collected during the baseline survey.

  • 18. 
    When performing face velocity measurements, what must you do just before measuring the air flow of a ventilation system?
    • A. 

      Calibrate the survey meter.

    • B. 

      Take static pressure measurements.

    • C. 

      Identify the key parameter for the system.

    • D. 

      Measure out or mentally form a grid over the duct opening.

  • 19. 
    What important procedure must you follow to obtain accurate readings with a velometer?
    • A. 

      Hold the probe parallel to the air flow.

    • B. 

      Always make two traverses at right angles to one another.

    • C. 

      Choose a section of the duct with smooth flow for measurement.

    • D. 

      Hold tube so that the mark aligns with the side of the duct and point tube directly into the air stream.

  • 20. 
    What may be indicated by a very strong flow coming in an open door of a room containing a local exhaust system?
    • A. 

      Adequate makeup air.

    • B. 

      Excessive cross drafts.

    • C. 

      Inadequate makeup air.

    • D. 

      Proper discharge of air away from inlets.

  • 21. 
    What is the purpose of the inner tube that makes up a pitot tube?
    • A. 

      Detect total pressure.

    • B. 

      Detect static pressure.

    • C. 

      Determine the duct diameter.

    • D. 

      Determine the density factor.

  • 22. 
    What can be said of velocity pressure when measured across the duct?
    • A. 

      It is constant across the duct.

    • B. 

      It is weak along the sides and becomes weaker as you near the center.

    • C. 

      It is weaker along the sides and becomes stronger as you near the center.

    • D. 

      It is stronger along the sides and becomes weaker as you near the center.

  • 23. 
    When evaluating ventilation systems using the pitot traverse method, what step is performed after balancing the system?
    • A. 

      Prepare the equipment for use.

    • B. 

      Find a suitable measurement point.

    • C. 

      Take velocity pressure measurements.

    • D. 

      Identify the key parameter for the system.

  • 24. 
    The range of acceptable values for the air flow volume on routine tests is within what percentage of the baseline value?
    • A. 

      25%.

    • B. 

      20%.

    • C. 

      15%.

    • D. 

      10%.

  • 25. 
    Two sources of indoor air contamination are interior air and
    • A. 

      Volatile organic compounds (VOC).

    • B. 

      Exterior air.

    • C. 

      Inadequate ventilation.

    • D. 

      Combustion contaminants.

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