Engineering License Exam Solutions: Grade 3 Stationary Engineering, Exams of Engineering

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UPSTATIONARY GRADE 3 ENGINEERING LICENSE

EXAM SOLUTIONS Questions with 100% Answers

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1. how can you loose your license?: 1) drinking on the job

2. sleeping on the job
3. negligence
4. unsafe work
5. signing a falsified license application for someone
6. failing to renew your license annually

2. what must you do if you change jobs?: notify city hall if you change jobs, address or retire
3. why should you do rounds?: Find and correct problems to prevent break- downs. keeping permanent records will make it easy to forecast most breakdowns because you will get to know equipment
4. what is a steam boiler?: closed vessel, PARTIALLY FILLED WITH WATER, under pressure that transforms water to steam with the application of heat.
5. what are the requirements of a good boiler?: 1) simple

2. designed to accommodate expansion and contraction
3. adequate steam and water space
4. efficient
5. responsive to demands
6. accessible for cleaning and repairs
7. safe

6. Name and describe 3 types of heat transfer used in boiler operation: 1) RADIANT HEAT - transmitted from hot body to a cold body by means of direct radiation (heat from sun reaches us by radiation)

2. CONDUCTION - physical contact (coffee cup is heated by conduction when hot coffee touches the cup)
3. CONVECTION - carried along by a moving part such as air or water (your living room is heated by warm air from your furnace in another location

7. what is a combustion chamber?: the area of the boiler where COMPLETE burning of the fuel occurs

**8. what is an internally fired boiler?

name 4 types:** those in which the grate and combustion chamber are enclosed within the boiler shell.

1. Scotch marine

**14. what is a longitudinal joint?

what is a circumferential joint?:** LONGITUDINAL JOINT = seam running the length of the shell and is butt strap construction or fusion welded. it is above the fireline to avoid overheating. CIRCUMFERENTIAL JOINT = lap joint running the circumference of the drum

15. what is the difference between a flue and a tube?: 1) Flue - 4" or more in diameter measured internally

2. Tube - 4" or less in diameter measured externally

16. what is a drypipe and where is it located?: a steam separator located within the boiler shell and connected to the steam outlet. its upper surface is perforated. steam enters the perforations rapidly changing its direction of flow causing droplets and impurities to separate from the steam before entering the steam outlet. **17. describe a Scotch Marine Boiler?

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how it is fired:** it is an internally fired self contained horizontal return firetube boiler. it is a cylindrical shell containing the combustion chamber and tubes that are surrounded by water.

18. how is a Stirling Boiler suspended?: lugs on the ends of the upper drums rest on the beams of its structure. the lower (MUD) drum is suspended from the tubes and is free to move by expansion.
19. describe the circulation of water within the Stirling Boiler: feed water enters the top rear drum, passes down the rear tubes to the mud drum. steam and boiler water go up the front and center tubes to the front and center drums. CIRCULATING TUBES allow boiler water to pass between the drums. what does not go out as steam, goes back down the rear tubes.
20. what provisions are made for tube removal on water boilers?: 1) some tubes are left out

2. the tubes are staggered
3. sometimes, every other row is omitted **21. What is a water tube boiler?

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list 5 advantages

list 5 disadvantages**

name 4 types: in a water tube boiler, products of combustion pass around tubes containing boiler water ADVANTAGES:

1. rapid steamers
2. use less water
3. less chance of explosion
4. no flat surfaces
5. smaller tube sizes DISADVANTAGES:
6. elaborate settings
7. field assembled
8. initial cost per pound of steam is higher
9. greater number of openings thus more air infiltration
10. require more floor space TYPES:
11. B.&W.
12. Stirling
13. Heine
14. "D" type

**22. what is a fire tube boiler?

list 5 advantages

list 5 disadvantages

name 4 types:** in a fire tube boiler, products of combustion pass through tubes or flues surrounded by water. ADVANTAGES:

1. very little setting required
2. factory assembled for fast installation
3. low initial cost
4. can be made portable
5. compact

**27. what is an economizer?

what is a air pre-heater?:** an economizer is a heat exchanger designed to recover waste heat from the products of combustion by pre-heating the feedwater. It's located in the breaching between the boiler and stack. NOTE: there is great economy in heating feedwater. the air pre-heater consists of a series of tubes or plates that have hot gasses on one side and incoming air on the other. heat in the hot gasses leaving the boiler is recovering by the incoming air. (both reduce stack temperatures and increase boiler efficiency)

28. what is a water wall?: a set of tubes containing boiler water set in the refractory. they absorb heat that would otherwise be lost to the refractory and they increase the capacity of the boiler **29. what is A.S.M.E. and its purpose?

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what code of information is stamped on the boiler?

what is an A.S.M.E. symbol stamp?

where are the code markings found on a boiler?:** American Society of Mechan- ical Engineers has written a set of minimum standards for the safe construction of pressure vessels. stamped on the boiler shell or a plate attached to the shell will be:

1. model and serial numbers
2. safe working pressure
3. date of manufacture
4. horsepower rating
5. square feet of heating surface
6. steam generation in pounds per hour
7. fuel designed for
8. ASME stamp the ASME symbol stamp will identify the boiler or accessory type. fire tube boiler - it may be located by the water column near the front right side water tube boiler - it will be located next to the manhole on the steam drum

30. what is the cross section of a 1" bolt?: DxDx.7854(1/4pi) 1x1x.7854=.7854 sq.in. show your work and label everything! **31. what is an alloy?

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name 5:** a mixture of two or more metals.

1. brass
2. bronze
3. steel
4. stainless steel
5. cast iron

32. at what pressure is the use of cast iron fittings permitted?: 15 psi. or 250*F. Not to exceed either one
33. what is meant by "Factor of Safety"?: the bursting pressure divided by the working pressure or the comparison of the tensile strength to the actual working stress
34. what is the Factor of Safety for Boilers, Flywheels and Pipe?: New boilers is 4 Pre-owned boilers constructed to ASME code is 5 Flywheels is 4 Pipe is 8 **35. what is a lap joint?

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what is a butt joint?

what is a butt-strap joint?:** LAP JOINT = when one plate overlaps the other and is joined BUTT JOINT = when two ends of the plate meet end to end and are joined BUTT-STRAP JOINT = when two ends of the plate meet end to end and are joined by a plate. (one plate is a single butt strap joint / two plates are a double butt strap joint)

36. is the longitudinal joint the strongest part of the boiler: NO! it is the strongest type joint, but any joint is the weakest part of a boiler

2. stay bolt
3. diagonal stay
4. gusset stay

**43. describe a through stay

why are hollow through bolts used on water legs?:** a through stay is a rod threaded on both ends, held in place with nuts on the inside tightened against nuts on the outside of the plates. it runs from one tube sheet or flat surface to the other. a small hole is drilled into the stay bolt so if it failed a leak will develop and be detected at once **44. describe a diagonal stay

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describe a gusset stay

where would each be used?:** DIAGONAL STAY = made of flat materials similar to the boiler shell and is attached directly to the boiler shell and head or tube sheet GUSSET STAY = made of boilerplate riveted to the shell and head or tube sheet by means of angle iron. MORE RIGID both are used to brace right angle surfaces **45. why are hand-holes and man-holes made oval instead of round?

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what are the minimum sizes for man-hole and hand-hole openings?:** so they can be inserted into and removed from their respective openings in the boiler man-hole = 10x16 or 11x hand-hole = 2-3/4 x 3-1/ **46. what is thermal efficiency?

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what is considered a good percentage?:** the ratio of heat absorbed by the water (TO) the heat provided by the fuel a good percentage is 85%, some boilers made today can reach 95% **47. how do you determine boiler capacity?

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what is boiler heating surface?:** BOILER CAPACITY = total heating surface

BOILER HEATING SURFACE = any area that has hot gases on one side - boiler water on the other. MEASURED FROM THE FIRE SIDE.

**48. what is furnace volume?

is furnace volume measured in square feet or cubic feet?:** FURNACE VOL- UME = the space available for complete combustion of the fuel before the products of combustion enter the heat absorbing sections of the boiler. varies with the type of fuel used cubic feet **49. what is superheated steam?

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does its temperature rise?:** SUPERHEATED STEAM = steam that has been heated to a higher temperature, but its pressure remains the same YES **50. define flash point

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define ignition point

define pour point:** FLASH POINT = the lowest temperature at which vapors of a substance will make a flash of flame but not continue to burn when exposed to open flame IGNITION POINT = the lowest temperature at which vapors of a substance will ignite and burn continuously when exposed to open flame POUR POINT = the lowest temperature at which liquid will flow

51. define combustion: a CHEMICAL REACTION between oxygen and com- bustibles. it is the process of rapid OXIDATION by which the heat stored in fuel is released **52. what is rate of combustion?

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does air and fuel have any relationship in figuring the rate of combustion?- :** the rate at which the heat stored in fuel is released

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

**58. define perfect combustion

define complete combustion

define incomplete combustion:** PERFECT COMBUSTION - burning all the fuel using only the theoretical amount of air COMPLETE COMBUSTION - burning all the fuel using more than the theoretical amount of air INCOMPLETE COMBUSTION - when a portion of the fuel remains unburned because of insufficient amounts of air

59. in a flue gas analysis, what do you consider a good percent of CO2?: good = 12% to 15% ideal = 20% (mostly unattainable) **60. how is density of smoke measured?

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how do you use a Ringlemann Chart?:** With an opacimeter or Ringlemann chart.

1. hold at arms length looking through the hole in the chart
2. observers line of sight should be a right angle to the direction of smoke travel
3. observer should be no less than 100ft or no more than 1/4 mile from the stack
4. observer should not look toward bright sunlight
5. the background immediately behind the top of the stack should be free of buildings or other dark objects
6. compare the shade or density of the smoke seen through the hole to the corresponding shade on the chart 61. what grades of smoke are allowed in the City of Omaha boiler operation?- : no darker than grade 1 for more than 5 minutes/hour and no more than 3 times in a 24 hour period

62. what are seven heat losses in a boiler?: 1) moisture in the air

2. moisture in the fuel
3. moisture formed in the burning of hydrogen
4. incomplete combustion
5. unburned carbon in the ash
6. heat carried away in dry flue gasses
7. radiation
8. blowdowns

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

63. what is the heat content of one pound of a good coal and of one pound of carbon?: Coal = 13,000-14,000 BTUs Carbon = 14,540 BTUs **64. what is an Orsat Apparatus?

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where is it used?

why is it used?:** a flue gas analyzer detecting amounts of CO, CO2 and O2 in flue gasses combustion gasses are sampled from the last pass or the breeching to determine combustion efficiency and excess air **65. what is a Fyrite analyzer?

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where is it used?

why is it used?:** a flue gas analyzer to determine the amounts of CO2 and O2 in flue gasses combustion gasses are sampled from the last pass or the breeching to determine combustion efficiency **66. what is a pyrometer?

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where would it be located on a boiler?:** thermometer for measuring tempera- tures above the range of mercury in the hot gas passages and in the refractory

67. what are tuyeres (tweyars)?: air-admitting grates on stokers
68. what is a waterback?: a water wall that is behind the grate on a stoker and its purpose is to cool the wall to prevent clinkers from sticking to the back wall **69. define purging

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name two types:** purging = the forced removal of combustibles from the firebox.

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

3. sludge
4. low oil pressure
5. low oil temperature
6. oil too heavy to flow
7. vapor in the pump
8. air in the suction line
9. improper venting of the tanks
10. faulty atomization
11. worn burner tip
12. carbon formation on the burner tip 1st two things to look for:
13. pump failure
14. plugged strainers you would valve over to a clean strainer if the delta-P was excessive

**74. name three types of nozzles used in oil burners.

explain where secondary air is admitted.:** nozzles:

1. rotary atomizing
2. steam atomizing
3. air atomizing
4. pressure atomizing secondary air is admitted around the tip. **75. under what conditions must fuel oil be heated?

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how is it heated?

how hot is it heated?:** #4/5/6 oils need to be heated steam and electricity can be used to heat oil oil should not be heated to more than 10F below its flash point. (rule of thumb is) #4 - 135F #5 - 185F #6 - 220F

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

**76. what is a gun type burner?

name its parts:** gun type burner = an assembly found on package boilers parts:

1. blower
2. igniter
3. transformer
4. nozzles
5. dampers
6. PRV
7. oil pump
8. metering valve
9. oil or gas solenoid
10. fire eye

77. you are operating on gas and the gas company calls and tells you to go to oil right away. your oil type is #6 and it's ice cold. what will you do and how will you heat the oil to operating temperature so you can fire the boiler?: 1) call your gas company and plead for more time

2. call your boss to get help
3. try to heat the lines with steam hoses or any way you can conceive
4. maybe call your oil company to bring in a tanker with heated oil, etc...
5. use your imagination (think outside the box)
6. DON'T GET CAUGHT IN THIS SITUATION!

78. draw a picture of low pressure gas piping to a burner: must include:

1. main gas shut off
2. valve
3. a tee to the pilot w/shut-off valve and pilot solenoid
4. manual reset valve
5. gas pressure switch
6. PRV with vent
7. main gas solenoid
8. mixing chamber
9. blower pushing through the venturi
10. into the burner

79. the gas meter for your boiler malfunctions and you have to shut off all gas. how can you keep your boiler on line?: if you have an alternate fuel, hook up a propane bottle with a regulator to the pilot

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

1. INDUCED DRAFT = a fan in the breeching between the boiler and the stack pulling air through the furnace. the boiler operates below atmospheric pressure
2. FORCED DRAFT = a fan at the point of air entry pushing air through the furnace. the boiler operates above atmospheric pressure.
3. BALANCED DRAFT = the addition of both forced and induced fans, and the boiler operates slightly below atmospheric pressure, about .05 to .10 inches water column.

**87. what is a pressurized furnace?

why is it not desirable on large boilers?:** PRESSURIZED FURNACE = has a fan placed at the point of air entry to maintain the furnace above atmospheric pressure pushing the products of combustion through the furnace and out the stack. flue gasses can leak into the operating areas and become a health hazard 88. how do you control the dampers on a large fan from a remote location?- : the control panel sends a signal to electric or pneumatic actuators that move the damper linkages

89. if maintenance was done on your boiler, put back in operation, and the stack temperature was higher than normal, what would you look for as thecause?: water tube boiler = most likely defective or missing baffles fire tube boiler = could be missing turbulators or blocked tubes
90. where are turbulators used and what is their purpose?: used in the tubes of a fire tube boiler to increase heat transfer to the tubes
91. how often should you test the low water cutoffs and fully describe 3 ways of safely doing this.: 1) at least once a shift furiously blow down the water column and insure that the water returns rapidly and smoothly into the glass

2. EVAPORATION METHOD = once a month done by securing the feed pump and allowing the water to evaporate from the boiler on low fire only. DO THIS WITH SUPERVISION AND REMAIN ALERT DURING THE TEST.
3. SLOW DRAIN METHOD = once a month done by securing the feed pump and slowly blow down the boiler on low fire only. DO THIS WITH SUPERVISION AND REMAIN ALERT DURING THE TEST.

UPSTATIONARY GRADE 3 ENGINEERING

LICENSE EXAM Q&A

**92. how often should you blow down your sight glass?

what would you do if the glass broke while the boiler was operating?:** the start of each shift

1. put on safety equipment
2. operate gauge glass shut-off valves
3. use tri-cocks to check water level during the repair
4. open blow-down for the gauge glass
5. remove all the broken glass
6. install the new glass with new washers
7. very slowly, open the top shut-off to warm the glass
8. close the blow-down
9. slowly open the bottom shut-off

93. what would cause a false level in the sight glass?: 1) sight glass closed

2. sediment accumulation
3. tilted boiler
4. foaming because of over firing or high TDS
5. improperly installed water column
6. leaking top sight-glass washer

94. if it were - 35F and you had no water showing in the boiler sight glass, your supervisor told you to keep firing, what would you do?:* TURN IT OFF !!! under no circumstances can you fire an unsafe boiler! **95. what is the smallest pipe allowed for a water column?

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what style fittings are used to pipe a water column and why?:** 1" made of brass, extra heavy iron or steel crosses and tees for cleaning and inspection

96. describe how to pipe a water column on an H.R.T. boiler: 1) the top of the column is connected to the top of the steam shell

2. the bottom is connected to a point 6" below the center of the drum
3. the bottom of the sight glass is 3" above the top row of tubes and at least 2" above the fusible plug
4. the gauge glass must be 1/2" in diameter
5. blow off not less than 3/4"
6. crosses and tees are used instead of elbows for cleaning and inspection