Third Class Stationary Engineer

Examination Review.

Public Safety Department State of Massachusetts.

By: Thang Duc Le

Institution: Massachusetts Maritime Academy

101 Academy Drive, Cape Code, Massachusetts.

What is the definition of a boiler?

    Boiler is closed vessel in which water, under pressure is transformed into steam by the application of heat.

  1. What is the definition of a pressure vessel?

    A pressure vessel is a close vessel in which the source of pressure in external to its self, any pressure vessel not identified as a boiler.

  2. How often must boilers be inspected?

    Boiler have to be inspection once of each year internal and external.

  3. How much note is require to prepare a boiler for inspection?

    Boiler need to be inspection have to noted to customer in 14 days.

  4. Which air tank require an inspection?

    Air tank above 50 psi have to be inspection every 2 years.

  5. How chapter 146 determine boiler horsepower?

    There are 4 way in chapter 146 determine boiler horse power

    A) boiler data tag.

    B) 1 boiler horse power equal 33475 BTU output

    C) 1 boiler horse power equal 41840 BTU input.

    D) 1 boiler horsepower equal 34.5 lbs/hr

    Detail the calculation:

      a) 1 boiler hp equal 34.5 lbs steam/hr.

      b) BTU to heat 1 lbs water to 212F steam is 970.3 BTU X 34.5 lbs/hr= 33780 BTU output.

      c) Boiler most case efficiency is 80% then BTU input will be 33780X 1.2= 41840 BTU input.

  6. How does chapter 146 determine engine horsepower?

    Engine horsepower calculation P.L.A.N/33,000 = engine horsepower.

    Where: P = pressure apply in PSI

        L= length in FEET

        A= area of the piston Ft2.

        N= number of stroke.

  7. How does chapter 146 determine turbine horsepower?

    Base on Outside diameter of steam supply line

    1 ¾ in or less = 9 horsepower.

    1 ¾ in to 3 ½ in or less = 50 horsepower THIRD CLASS PLANT.

    3 ½ in to 5 in or less = 150 horsepower SECOND CLASS PLANT.

    5 in or more than 150 horsepower FIRST CLASS PLANT.

  8. What can you do with third class engineer license?

  1. What information on Certificate of Inspection.

    -Name of boiler owner/user

    -Location of the boiler.

    - Manufacturer and year of built.

    -Size and number of the boiler.

    -Date of inspection.

    - Signature of inspector.

    - MAWP.

  2. Where is the operator license kept?

    In the boiler room, engine room, control room, where it can be easily read.

  3. What boiler horsepower require “periodic attendance”

    Periodic attendance 9-250 BHP ( it mean maintenance daily as the department 's maintenance log book, the engineer remain in same building, boiler shall equipped with automatic shut down devices)

  4. What boiler horsepower”noncontinuous attendance”?

    Noncontinuous attendance 251-500 BHP. ( meaning monitoring station shall be ability to shut down boiler and boilers, shall be inspected between 4 to 6 times per shift)

  5. What boiler horsepower require “continuous attendance”?

    - continuous attendance 501 BHP.( manned attendance all time during boiler operating)

  6. What is ton of refrigeration?

    The BTU to melting 1 ton of ice into water state.

    As known 144 BTU( latent heat of fusion) needed to melt 1 lb of ice into water state at 32F

    1 ton = 2,000 lbs X 144 BTU/day = 288,000 BTU/day.

    288,000BTU/day/ 24 hr/day = 12,000BTU/hr.

    It means 1ton of refrigeration equal 12,000 BTU/hr.

  7. How often refrigeration equipment require of inspection?

    Over 20 ton needed to be inspection every year.

  8. How perform hydrostatic test?

    Secured all valve and cap removed and cap pressure safety valve.

    Filled boiler with water from 70F to 120F to top of the boiler,

    increased pressure to 1.5 MAWP stay for 15 minus,

    dropped pressure down to MAWP make around check for leaking.

  9. Entering in side the boiler?

    Check all log out and tag out.

    Check O2 level in side the boiler.

    Out side guy always standby.

  10. How to prepare for air tank inspection?

    Isolated all valves and open all hand hole and man hole.

  11. List 4 methods used to classify boiler type?

    1. Water tube boiler

    2. Fire tube boiler.

    3. Direction of Axis Horizontal.

    4. Direction of Axis Vertical.

  12. What is fire tube boilers?

    Fire tube boiler is firing inside boiler tubes and water out side boiler tube.

  13. What is water tube boiler?

    Water tube boiler is firing out side boiler tube and water inside water tube.

  14. What is the different between a dry top vertical boiler and wet top vertical boilers?

    Dry top vertical boiler: there are short distance boiler tubes above water level than boiler can generated super heat steam.

    Wet top vertical boiler: water level is on top boiler tube than boiler can be only generated saturated steam.

  15. What does H R T stand for?

    HRT are stand for horizontal return tubular.

  16. Why HRT boiler sloped to the rear head?

    HRT boiler sloped to the rear head to help scale, slug and settlement toward blow down pipe and clean up when boiler blow down is performed.

  17. Name 2 method support HRT boiler?

    1. lug and roller

    2. overhead expansion.

  18. Name 2 type Scotch Marine boiler.

    1. Dry back ( rear boiler door insulated by refractory)

    2. Wet back ( rear boiler cover by section of water)

  19. What is the primary different between HRT and a Scotch Marine boiler?

    HRT boiler is external firing.

    Scotch Marine boiler is internal firing.

  20. Name five advantages of a fire tube package boiler?

    1. boiler is fully automatic operation.

    2. low cost to operation the boiler.

    3. turnkey operation.

    4 limited space requirement.

    5. no setting.

  21. Dis-advantage of fire tube package boiler?

    1. Limited steam and pressure.

    2. high cost to prepare for boiler inspection and repaire.

    3. slow steamer.

    4 restricted on fuel source ( could not burn solid fuel )

  22. When blow off pipe moved to front HRT boiler?

    When convert HRT from coal to oil fire to prevent bag at bottom of the boiler.

  23. Why reinforcement plat add to boiler?

    Reinforcement plat add to the boiler to provide addiction thickness for thread penetration on blow off pipe.

  24. How much slop on HRT boiler toward to rear end boiler?

    Slop should be around 1 to 3 inches.

  25. What limitation of HRT boiler?

    Maximum pressure is 250 psi and steam capacities 25,000 lbs/hr.

  26. What cause the stack temperature rise?

    1. soot deposited.

    2. scale built inside boiler tube( water side).

    3. too much excess air ( combustion process).

  27. How are water tube boilers classified?

    D type, A type and O type,

  28. Why water tube boiler used in electric-generating plant?

    Because the water tube boiler can generating high pressure and supper heater dry steam before entering turbine

  29. Name 5 different type of water tube boiler?

    O type, D type, A type,

  30. How many pressure gauge require on a boiler?

    Minimum require 1 pressure gauge for a boiler

  31. How many safety valves are require on a boilers?

    Minimum 1 safety valve for each boiler and boiler 500 ft2 over heating surface need at least 2 or more

  32. What is the purpose a handhole and a manhole?

    For entering into the boiler for cleaning, inspection and repair.

  33. Name 3 special purpose boilers?

    Generating steam to run turbine for electricity. Heat and processing production.

  34. What does HRSG stand for?

  35. What is a longitudinal join? A circumferential joint?

    A longitudinal join is along side the boiler welding or riveting.

    A circumferential join to attach boiler shell to the boiler body

  36. What water column use for?

    To indicated water level in the boiler.

  37. Describe a gate valve?

    Gate valve has a wedge sharped disc that is raised to open and lowed to close the valve, It is used fully open or totally closed and is not designed for throttling.

  38. Describe a glove valve?

    Glove valve uses a round disc or tapered plug type disc that seats against a port to close the valve. Glove valve are used where throttling and / or when frequent operation.

  39. What is the purpose of the main steam stop valve?

    The purpose the main steam stop valve to isolated the boiler for service.

  40. What is purpose of the non-return valve?

    The purpose of the non-return valve that do not allow steam from other back feed into the boiler.

  41. Explain how you would “cut -in” a boiler equipped with a non-return valve.

    The boiler equipped with a non-return valve, when steam pressure from other boiler will pressure on the disc of non-return again the seat to close the valve that will not allow steam enter the boiler,

    and when the pressure at the boiler increase will push the disc away from the seat to allow steam leaving the boiler.

  42. When two blow down valve requirement?
    Two approved blow down valve required when boiler operation at 100 psi and above.

  43. What is slow opening and quick opening valve?

    Slow opening valve is when the valve start open water slow flow full flow when valve fully open.

    Quick open valve is the valve act fast fully close or fully open in short period time.

  44. Explain how you would blow down a boiler.

    Performance bottom blow down a boiler open quick opening valve and slow open slow opening valve. After will closed slow opening valve and closed quick opening valve last.

  45. Explain the principal of operation bourdon tube pressure gauge?

    When pressure push into the bourdon tube and will move and the linkage will move the indicator that show pressure inside the boiler.

  46. What is siphon? What is snubber?

    Siphon is designed for containing condensate (water) to pressure gauge from live steam.


  47. what is purpose of the water column?

    Purpose water column to slow down the turbulence of boiler water so an accurate reading of the water level in the gauge glass can be obtained.

  48. How to blow down a water column? And gauge glass?

    1 slowly open water column drain/ full open/ close

    2 open drain on water gauge glass.

    3 close top gauge glass valve

    4 close bottom gauge glass valve.

    5 open top gauge glass valve

    6 open bottom gauge glass valve.

    7 close gauge glass drain valve.

    8 check level with try-cocks.

  49. Explain how you would test low water cut out.

    When the boiler on line open quick open valve and slow open drain water column which low water cut out piped, the boiler will shut down due to low water.

  50. When flat gauge glass should be used?

    When boiler pressure over 250 psi, flat gauge glass shall be used.

  51. What is a closed feed water heater?

    A closed is the heater that steam and water do not come in direct contact,

    example economizer or heat exchanger.

  52. What is check valve?

    Check valve is a valve that only allow water or liquid go one direction.

  53. Where in the plant are you likely to find a check valve?

    Check valve normally see on feed water line between feed pump and boiler.

    Cold water supply to DA tanks.

  54. What is cyclone separator? Where would it be located?

    Cyclone separator is devices that to help steam dry before steam leaving the boiler.

    Cyclone separator is located inside steam drum.

  55. What purpose flash tank?

    Purpose flash tank is flash steam to dropped pressure and cool water before water entering into sewer system.

  56. What is purpose DA tank?

    1 removed oxygen and non-condensible gases.

    2 heat up feed water.

    3 act as storage capacity for the system.

  57. Start up boiler?

    1 prepare for fuel to burn.

    2 check boiler water level.

    3 check all boiler access doors and panel should be secured.

    4 open all steam drain.

    5 check feed line all valve should be open to the boiler.

    7 open superheater drain.

    8 check all blow down valve should be secured.

    9 start the boiler purge boiler for air throughout boiler.

    10 start flame on low fire to warm up the boiler. And ramp up as recommend boiler manufacturer.

    11 at 25 psi close steam drum valve.

    12 open bypass valve to warm up steam line.

    13 when pressure equalized open main steam stop valve.

    14 at 75% working pressure test pressure safety valve.

    15 at 80% working pressure open non return valve.

    16 allow steam flow 20% and close superheater drain valve.

    17 check combustion and all maxillaries equipment.

  58. Performance boiler shut down.

    1 blow soot if apply

    2 shut down fuel burners.

    3 when non-return valve close, open superheater drain valves.

    4 shut down blower fans.

    5 maintain water level.

    6 when steam pressure below 25 psi open all steam drains.

    7 when boiler cool maintain water level, shut down feed pumps and auxiliaries equipment that boiler is not needed.

  59. What is Potential Energy? Kinetic Energy?

    Potential energy is energy processed by reason of position or deformation

    Kinetic energy is energy processed by reason of motion.

  60. What is the First Law of Thermodynamics? The Second Law?

    1st law of thermodynamics: Energy can not be created or destroyed but may be converted from one form to another.

    2nd law of thermodynamics: No machine actual or ideal can both continuously and completed transform heat into mechanical energy.

  61. Name three ways that heat is transferred.

    Radiation: heat transfer by light waves without material carries.

    Convection: heat transfer by current in a fluid.

    Conduction: heat transfer by molecule to molecule.

  62. What is a British Thermal Unit?

    BTU is amount of heat to increased 1 lb of water to 1 degree Fahrenheit atmospheric.

  63. Convert 220 Celsius to 0 Fahrenheit.

    º F = (ºCx1.8) + 32= (220X1.8) + 32 = 396 º F

  64. Convert 105° F to ° Celsius.

    º C = (º F – 32) / 1.8 = (105 – 32) / 1.8 = 40.55 º C

  65. How many BTU 's are required to raise one pound of water from 50 0 F to 210 0 F ?

    210º F – 50º F = 160º F

  66. How many BTU 's are required to raise the temperature of 500 gallons of water from 70 of to 160 OF?

    500 gls* 8.33 lb/gls * ( 160º F- 70º F) = 374850 BTU

  67. You have a 2,000 gallon tank filled with water. How much does the water weigh?

    2000 gls * 8.33 lb/gls = 16660 lbs of water

  68. The pressure gauge reads 130 PSI. What is the absolute pressure?

    At atmospheric as same 14.7 absolute pressure

    130 pisg + 14.7 = 144.7 pisa

  69. What is the Latent Heat of Fusion?

    Latent heat fusion is amount of heat apply to 1 lb solid to change state to 1lb liquid at 32º F equal 144 BTU's ( ice to water)

  70. What is the Latent Heat of Evaporation?

    Latent heat of evaporation is amount of heat apply to 1lb liquid to change state to 1 lb gas/vapor equal 970.3 BTU's ( 1 lb water at 212º F to 1lb steam when 970.3 BTU's are added)

  71. How many Btu's in a pound of steam at 212 OF?

    970.3 btu + (212 – 32) = 1150.3 BTU's

  72. What is sensible heat? Latent heat?

    Sensible heat is mount of heat is added into substance that cause a change in temperature can be measure with a thermometer.

  73. What is the critical pressure of steam?

    Critical steam is 3206.2 psia

  74. What is the critical temperature of steam?

    Critical temperature of steam is 705.4º F

  75. What happens to the boiling point of water as the pressure increases?

    When pressure increase boiling point is increase.

  76. What happens to the Enthalpy of Evaporation as the pressure increases?

    When pressure increase enthalpy of evaporation is decrease.

  77. What are the three states of matter?

    Solid, liquid and gas (vapor)

  78. What is the definition of specific heat?

    Specific heat is amount of heat required to raise 1lb of any substance into 1º F.

  79. relation ship between heat and mechanical power/

    1 kw = 1.34 horsepower.

    1 hp = 2545 BTU's

  80. What is saturated steam?

    Saturated steam is dry steam (no moisture) at a temperature corresponding to its pressure

  81. What is superheated steam?

    Superheated steam is steam at temperature higher than that temperature corresponding to its pressure.

  82. What is Enthalpy?

    Enthalpy indicated the total heat content of substance.

  83. A boiler equipped with one safety valve, where will it be set top blow?
    A boiler equipped with one safety valve pressure set to blow should be lower or at MAWP.

  84. A boiler equipped with 3 safety valve, where can they be set at?

    A boiler equipped with 3 safety valve, 1st should be at superheater at 10% below MAWP. 2nd will set at MAWP, 3rd will set at 3% above MAWP.

  85. Where is the superheater safety valve set?

    Superheater safety valve set at 10% below MAWP, to make sure that steam flow through superheater to prevent superheater damage.

  86. Why does a safety valve pop open?
    a) load stop certainly.

    b) over firing more than load needed.

    c) boiler over filled that cause water hammer.

  87. What type of valve (s) permitted between boiler and safety valve?
    Not any valve allow between boiler and safety valve.

  88. How soot blower classified?
    a) Retractable ( that should be set up for high heat area)

    b) Stationary ( that set up for lower heated area)

  89. what precaution should be taken period to soot blowing?

    - do not blow soot if load is under 50% firing rate.

    - do not blow soot if load is 100% firing rate.

  90. How are opacity excursion handled during soot blowing?

    If opacity wired to shut down the boiler the circuit should be de-energy.

    Noted on recorder on period soot blowing.

  91. If you fail a written test, when you can apply again?

    90 days.

  92. What is purpose of a steam trap?

    The purpose of a steam trap removed air and condensation out of steam line without steam lost.

  93. Name 4 types steam trap?

    a) Thermodynamics.

    b) Thermostatic and float.

    c) Thermostatic.

    d) inverter bucket trap.

  94. Describe the operation of bucket trap?

    When steam apply into the cup push up the cup and condensate vent will be close, when steam condensate plus weigh of the cup will be heavy will lower cup open condensate valve and release condensation and air.

  95. Describe the operation of thermostatic and float ( F&T) trap?

    Steam enter into the trap body and heat up close thermostatic port and close condensate vent. When steam condensate water level will rise float open condensation vent port and also cold down thermostatic section to release air.

  96. How would you know a steam trap was not working?.

    a) condensate receiver will flash out steam.

    b) temperature on inlet side and out let side of condensation as same temperature.

    c) steam unit will not be proper working due to low temperature or not functional as designed.

  97. Define combustion.

    Combustion is chemical process which a combustible united with oxygen producing heat and open light.

  98. What is perfect combustion?

    Perfect combustion is processing fuel completely burn with theory amount of air required.

  99. What is Complete Combustion? Incomplete Combustion?

    -Complete combustion is process burning fuel fuel complete using minimum amount of access air.

    -Incomplete combustion is process not burn complete fuel.

  100. What is spontaneous combustion?

    Spontaneous combustion is gas relief from coal and get ignition temperature and ignited.

  101. What three conditions are necessary for complete combustion?

    Time , temperature and turbulence.

  102. What are the combustibles in fuel?

    Carbon, hydrogen and sulphur.

  103. What is Primary Air? Secondary Air?

    Primary air is the air supply to the burner with the fuel that control the rate of combustion as well as the amount of fuel to be burned.

    Secondary air is air supply to combustion process that control efficiency,( how to completely the fuel burned)

  104. What is excess air?

    Excess air is amount of air supply for complete combustion process that greater the theoretical amount required.

  105. What is viscosity?

    Viscosity is internal resistance of the fuel oil to flow.

  106. What is pour point, flash point and fire point?

    Pour point is the point that lowest temperature the fuel oil can flow.

    Flash point is the temperature of fuel oil ignited as pop but not continuing to burn.

    Fire point is the temperature of fuel oil ignited and continuing burn.

  107. Name three ways to atomize #6 oil.

    - pressurized.

    - air or steam atomized.

    - rotary cup.

  108. Give five (5) reasons a boiler burning #6 oil would smoke.

    - improper mount of air and fuel in combustion processing.

    - poor atomizing air for fuel oil.

    - water in fuel oil.

    - boiler plugged.

    - diffuser dirty.

  109. Name the necessary components of a #6 fuel oil system.

    - oil heater.

    - fuel oil pump.

    - fuel oil strainer.

  110. Name the types of draft found in power plants.

    - Force draft.

    - Induce draft.

    - Balance draft.

  111. How is draft measured?

    Inches water column.

  112. What is the greatest heat loss in a boiler?

    The greatest heat loss in a boiler is out the stack.

  113. How many BTU's in a gallon of #6 oil?

    150000 BTU/GAL #6

  114. How many gallons in a barrel of fuel oil?

    42 gls

  115. What do you do if the flame is lost while burning #6 oil?

    I will check several components.

      - fuel oil pressure.

      - flame scanner.

      - atomizing pressure source.

      - all fan motor ( FD.ID or balance draft fans)

  116. What is an opacity violation?

    - 20% more than 6 minutes during any 1 hr.

    -40% more than 2 minutes during any 1 hr.

    - 40% anytime

    are will be violated.

  117. What are the three (3) primary contaminants in raw water?

    -dissolved solid.

    - suspended solid.

    - dissolved gases

  118. What are the two (2) sources of water used in power plants?

    Surface water and ground water.

  119. What are the two forms of water treatment used in power plants?

    Internal or external

  120. Why do we treat boiler feed water? (Four reasons)

    - prevent corrosion.

    - scale

    - slug.

    - carry over.

  121. What are Cations? What are Anions?

    Cations is carry positive charge ions.

    Anion is carry negative charge ions.

  122. How are suspended solids removed from raw water?

    Suspended solid can be removed by filtration.

  123. How are minerals removed from raw water?

    Water softener or Demineralization. There devices used to removed Mg+ Magnesium and Ca+ Sodium.

  124. How are dissolved gases removed from make-up water/feedwater?


  125. Define PH.

    A measure of the water's acidity or alkalinity.

  126. Is 7.0 on the PH scale acidic or alkaline?

    7.0 on the PH is neutral none acidity or alkalinity.

  127. How are chemicals added to the boiler?

    Chemical and added into boiler through deaerator or pump into a can and open the feed water to force chemical into the boiler.

  128. What is meant by the term "cycles of concentration"?

    Cycle concentration is the concentration of dissolve solid in the water boiler divided by dissolve solid in water make up.

  129. What PH level do we try to maintain in boilers?

    10 to 11.

  130. What is foaming? What is priming?

    Foaming is layer of foaming (bubble) on the boiler water surface that created surface tension making difficult for steam bubble breaking through cause water surging.

    Priming is the carryover large slugs of water with the steam

  131. Name some conditions in a boiler that could cause carryover.

    High conductivities, high water level or foaming.

  132. What chemicals are used to adjust boiler PH?

    The chemical use to adjust boiler HP is caustic soda or Sodium hydroxide NaOH.

  133. What are the two (2) major categories of pumps?

    Dynamic pump and Displacement pump.

  134. Name four (4) general classifications of pumps.

    Injector pump.

Duplex pump.

Power pump.

Centrifugal pump.

  1. Explain the operation of a feedwater injector.

    High pressure stream of fluid is direct through nozzle design high velocity. The resulting high velocity fluid created a low pressure area in mixing chamber causing the suction fluid to flow into chamber.

  2. What is the maximum feedwater temperature when using injectors?

  1. What are the operating mediums for duplex pumps?

  2. How do you set the valves on a duplex pump?

    a) center the piston.

b) plumb rocket arm.

c) square the valve over the top

d) equalized lost motion.

e) off center the piston.

  1. What is meant by the term "lost motion"?

    Lost motion is time allow water valve to closed tightly before start of the next stroke.

  2. What is the effect of too much lost motion? Not enough lost motion?

    Too much lost motion will cause piston strike the head.

    Not enough lost motion will cause the pump short stroke and worn out linkage part.

  3. What is a cushioned valve?

    Cushion valve that device to feed small amount of steam to piston head to prevent piston striking into the steam chest.

  4. What is the area of a piston 6" in diameter?

    28.26 in2

  5. Does a duplex pump displace an equal amount of water on the forward and reverse stroke? Why?

    No, because when reverse stroke will lost for volume piston sharp.

  6. What type of pump is a metering pump? A vacuum pump.

    Gear pump.

  7. What type of service would you expect to see a rotary pump? A gear pump?

    Oil pump.

  8. Define cavitation.

    Cavitation the term said that pump will not delivery liquid, cause by lost suction head or low suction pressure.

  9. Explain what you would do if your pump began to cavitate.

    If the pump cavitation, will check water temperature and water level on feed tanks.

  10. What is the best way to avoid pump cavitation?

    Created net positive pressure for suction, adjusted proper temperature at feed tank that allow the pump to operate. Sized the pump above maximum requirement for the boiler.

  11. Explain the operation of a centrifugal pump.

    Water enter the center impeller and is thrown outward by centrifugal force, water leaving in impeller at high velocity and convert into pressure through volute.

  12. Name three advantages and disadvantages of centrifugal pumps.


    Easy to installed and operation.

    Less maintenance.

    Reasonable price.


    Need power to run motor.

    Easy cavitation.

    Could not operation high temperature.

  13. Define the following: static pressure head, NPSH and Velocity Head.

    NPSH: net positive suction head that minimum suction condition to prevent cavitation in a pump.

    Velocity head: the kinetic energy per pound or the vertical distance a liquid would have to fall to acquire the stated velocity.

    Static pressure head: the energy per pound due to pressure, the height to which liquid can be raise by a given pressure.

  14. What do the numbers 8 X 6 X 12 refer to in a duplex pump.

    8 = Steam piston diameter.

    6 = water piston diameter.

    12 = length of the pump stroke.

  15. Calculation for duplex pump.

    Gals = L*A*N*E/ 231

    where L: length of stroke.

      A: area water piston.

      N: number stroke.

      E: efficiency (slip)