MA 2nd Class Fireman's Practice Exam
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Questions and Answers

What happens if the feedwater regulator is stuck open?

  • The water temperature decreases
  • Too much feedwater enters the boiler
  • Both A and B (correct)
  • The boiler may overflow

    • What is the purpose of a bowl at the bottom of the water column?

  • Serve as a condenser
  • Serve as a sediment chamber (correct)
  • Serve as a siphon
  • None of the above

    • When checking a safety valve with the hand-lifting gear, the pressure should be no lower than ___% of the safety valve set pressure.

    75

    If valves are located between the boiler and water column, they must be:

    <p>Locked or sealed open</p> Signup and view all the answers

    When a hydrostatic test is put on a boiler, each safety valve should be:

    <p>Held to its seat by means of a testing clamp</p> Signup and view all the answers

    After installing a new gauge glass, the proper procedure for returning the glass to service is:

    <p>Open the drain and crack open the top valve</p> Signup and view all the answers

    The steam pressure gauge is graduated in:

    <p>Pounds per square inch</p> Signup and view all the answers

    One of the purposes of the water column is to:

    <p>Dampen the oscillation of the water in the gauge glass</p> Signup and view all the answers

    The gauge glass should be blown down:

    <p>Daily</p> Signup and view all the answers

    The flame failure control is tested by:

    <p>Securing the fuel supply to the burner</p> Signup and view all the answers

    Which of the following controls operates due to changes in temperature?

    <p>Aquastat</p> Signup and view all the answers

    The pressure-sensitive device attached to the fan housing of a fully automatic burner starts operating when there is:

    <p>Fan failure</p> Signup and view all the answers

    If the pressuretrol starts the burner and ignition failed to take place, the control that protects the boiler is the:

    <p>Flame failure cutoff</p> Signup and view all the answers

    The pressure-sensitive device in Question 91 is sometimes called a(n):

    <p>Vaporstat</p> Signup and view all the answers

    Draft is measured in:

    <p>Inches of water</p> Signup and view all the answers

    Which of the following is used to measure temperature?

    <p>Pyrometer</p> Signup and view all the answers

    The main stop valve is located on the:

    <p>Steam line</p> Signup and view all the answers

    OS&Y stands for:

    <p>Outside screw and yoke</p> Signup and view all the answers

    An interlock control is a(n):

    <p>Device that prevents attempts to fire unless safe</p> Signup and view all the answers

    Trial for ignition refers to the:

    <p>The flame scanner detecting the pilot flame</p> Signup and view all the answers

    More than one safety valve is required on boilers that have over:

    <p>500 ft^2 of heating surface</p> Signup and view all the answers

    At 0 PSIG, how many BTU are necessary to change 1 lb of water at 212 degrees Fahrenheit into 1 lb of steam?

    <p>970</p> Signup and view all the answers

    Radiation is

    <p>a form of heat transfer by waves.</p> Signup and view all the answers

    Steam at 100 PSI and 400 degrees Fahrenheit is

    <p>superheated.</p> Signup and view all the answers

    Which of the following most closely defines sensible heat?

    <p>Heat quantity that can be felt or measured by a thermometer.</p> Signup and view all the answers

    What is required to raise the temperature of 1 lb of water from 32 degrees to 212 degrees Fahrenheit?

    <p>180 Btu</p> Signup and view all the answers

    Increasing the pressure has what effect on the boiling point of water?

    <p>Temperature will be raised</p> Signup and view all the answers

    Heat absorbed by water when it changes from liquid to steam at the boiling point is called

    <p>latent heat.</p> Signup and view all the answers

    Heat may be transferred in how many ways?

    <p>Three</p> Signup and view all the answers

    A boiler horsepower is defined as

    <p>Evaporation of 34.5 lb of water from and at 212 degrees Fahrenheit per hour</p> Signup and view all the answers

    A boiler's steam pressure gauge reads 150. What is the absolute pressure?

    <p>164.7</p> Signup and view all the answers

    What does 212 degrees F equal on the Celsius scale?

    <p>100</p> Signup and view all the answers

    One boiler horsepower is equal to how many Btu?

    <p>33,472</p> Signup and view all the answers

    A British thermal unit is

    <p>The amount of heat needed to raise one pound of water one degree F</p> Signup and view all the answers

    Hydronic heat is

    <p>Hot water heat</p> Signup and view all the answers

    Superheated steam is

    <p>Reheated steam</p> Signup and view all the answers

    2,545 Btu represents

    <p>1 horsepower-hour</p> Signup and view all the answers

    A throttling calorimeter is used to measure the quality of

    <p>Saturated steam</p> Signup and view all the answers

    The amount of heat in one pound of saturated steam is approximately equal to

    <p>1,150 Btu</p> Signup and view all the answers

    A boiler operating at 100 PSI has a dry saturated steam temperature of 338 degrees F. What is the boiler's water temperature?

    <p>338 degrees F</p> Signup and view all the answers

    A dry pipe is used to

    <p>Separate moisture from steam as it leaves the drum.</p> Signup and view all the answers

    The purpose of a staybolt is to

    <p>Strengthen and support flat plates of a fire-tube boiler.</p> Signup and view all the answers

    The boiler vent valve is located on the

    <p>Top of the steam drum.</p> Signup and view all the answers

    The purpose of the hole in the end of the staybolt is to

    <p>Indicate that a staybolt is cracked or broken.</p> Signup and view all the answers

    A fusible plug melts at

    <p>450 degrees F</p> Signup and view all the answers

    As the firing rate increases in a boiler equipped with a convection superheater, the steam temperature

    <p>Increases</p> Signup and view all the answers

    When boilers are connected to a common header, it is required that an ample free blowing drain be provided between the stop valves if either or both boilers have

    <p>Manholes</p> Signup and view all the answers

    It is permissible to have only one bottom blowdown valve on a boiler when the

    <p>MAWP does not exceed 100 PSI</p> Signup and view all the answers

    When the boiler pressure exceeds ______ PSI, it is required that extra-heavy pipe be used on the blowoff system.

    <p>125</p> Signup and view all the answers

    Baffles are placed between the tubes of a boiler for the purpose of

    <p>Directing the travel of flue gases.</p> Signup and view all the answers

    A boiler has a steaming capacity of 35,500 lb of steam per hour. The evaporation rate is 10 lb/ft² of heating surface per hour. What is the horsepower rating of this boiler?

    <p>1,000</p> Signup and view all the answers

    Boiler tube sizes are specified by

    <p>Outside diameter.</p> Signup and view all the answers

    The maximum size of boiler blowdown lines, valves, and fittings shall not exceed

    <p>2.5 inches</p> Signup and view all the answers

    The purpose of an expansion tank in a hot water heating system is to provide for the expansion of

    <p>Water</p> Signup and view all the answers

    Heavy accumulation of soot in a boiler will result in

    <p>Loss of boiler efficiency</p> Signup and view all the answers

    How are the tubes secured in a fire-tube boiler?

    <p>Rolled and beaded over</p> Signup and view all the answers

    A tube in a fire-tube boiler is surrounded by

    <p>Water</p> Signup and view all the answers

    Atmospheric pressure is considered to be

    <p>14.7 psia.</p> Signup and view all the answers

    In a water tube boiler,

    <p>Flue gas surrounds the tube.</p> Signup and view all the answers

    Diagonal stays are found in

    <p>Fire-tube boilers</p> Signup and view all the answers

    Handholes and manholes are oval

    <p>For removal from a pressure vessel</p> Signup and view all the answers

    To check the water level in the gauge glass of a steam boiler

    <p>Use the trycocks</p> Signup and view all the answers

    The vent valve

    <p>Both A and B</p> Signup and view all the answers

    A high-pressure boiler has its safety valve set above

    <p>15 PSI</p> Signup and view all the answers

    Which of the following is an advantage of fire-tube boilers over water tube boilers?

    <p>Low initial cost</p> Signup and view all the answers

    Water walls are found

    <p>In water-tube boiler furnaces</p> Signup and view all the answers

    The best time to bottom blow a boiler is at

    <p>Low load under full pressure</p> Signup and view all the answers

    A telltale hole is found in a

    <p>Stay bolt</p> Signup and view all the answers

    A 2-inch boiler tube has a wall thickness of 3/16 inch. What is its inside diameter (ID)?

    <p>1-5/8 inches</p> Signup and view all the answers

    At what temperature does steel start to rapidly lose its strength?

    <p>700 degrees F</p> Signup and view all the answers

    A hot-water heating system is about to be started. How full of water should the expansion tank gauge glass be?

    <p>1/3</p> Signup and view all the answers

    What is the relationship between longitudinal stress and circumferential stress?

    <p>Longitudinal stress is twice circumferential stress</p> Signup and view all the answers

    A therm is equal to how many Btu?

    <p>100,000</p> Signup and view all the answers

    The factor of evaporation is

    <p>Heat added to the boiler divided by 970.3</p> Signup and view all the answers

    The purpose of a bottom blowdown is to

    <p>Remove sludge and sediment</p> Signup and view all the answers

    Damage by spalling refers to the

    <p>Refractory</p> Signup and view all the answers

    Superheaters raise the temperature of

    <p>Steam</p> Signup and view all the answers

    The steam space is

    <p>The area above the operating water level</p> Signup and view all the answers

    The heating surface of a boiler is the area

    <p>Exposed to the flame and flue gases</p> Signup and view all the answers

    The purpose of a superheater is to

    <p>Heat steam above its saturation temperature</p> Signup and view all the answers

    What is the formula for the factor of evaporation?

    <p>H-b/970.3 Btu</p> Signup and view all the answers

    What can cause a superheater tube to overheat?

    <p>Dirty tube</p> Signup and view all the answers

    A boiler has a steaming capacity of 34,500 lb of steam per hour. The evaporation rate is 10 lb/ft² of heating surface per hour. What is the boiler heating surface?

    <p>3,450</p> Signup and view all the answers

    How many square feet of heating surface does a 3-inch fire-tube, 20 ft long with a 3/16-inch wall have?

    <p>13.7</p> Signup and view all the answers

    In a high-temperature hot water boiler, what would cause a tube to overheat?

    <p>Poor circulation (plugged tube)</p> Signup and view all the answers

    A downcomer is

    <p>Found in a water-tube boiler</p> Signup and view all the answers

    Extreme firebox temperature changes cause

    <p>Spalling</p> Signup and view all the answers

    The low-water cutoff

    <p>Shuts off the burner when the boiler is low on water</p> Signup and view all the answers

    Steam coming from the bottom try cock would indicate

    <p>Low water level</p> Signup and view all the answers

    What type of valve has the most resistance to flow?

    <p>Globe</p> Signup and view all the answers

    When checking the water level of a boiler,

    <p>Blow down the gauge glass and water column</p> Signup and view all the answers

    A siphon or pigtail is used to protect a steam pressure gauge

    <p>From steam temperature</p> Signup and view all the answers

    The feedwater regulator is located

    <p>At the normal operating water level</p> Signup and view all the answers

    An automatic feedwater regulator

    <p>Ensures the proper water level in the boiler</p> Signup and view all the answers

    To test the low-water cutoff,

    <p>The burner must be firing</p> Signup and view all the answers

    The purpose of testing a safety valve by hand is to

    <p>Make sure the valve can lift</p> Signup and view all the answers

    The automatic control that protects a boiler from being dry fired is the

    <p>Low-water cutoff</p> Signup and view all the answers

    To check the water level in the gauge glass of a steam boiler,

    <p>Blow down the gauge glass and water column</p> Signup and view all the answers

    On a steam boiler, testing the operation of the safety valve by hand with the boiler under pressure should be done

    <p>Monthly</p> Signup and view all the answers

    What type of valve has the least resistance to flow?

    <p>Gate</p> Signup and view all the answers

    Study Notes

    Boiler Basics

    • At 0 PSIG, it takes 970 BTU to convert 1 lb of water at 212°F into steam.
    • Radiation transfers heat via waves, differing from conduction (direct contact) and convection (movement of liquids/gases).
    • Superheated steam is identified at 100 PSI and 400°F, indicating heat beyond saturation.

    Heat and Energy

    • Sensible heat is measurable and can be felt by a thermometer.
    • To heat 1 lb of water from 32°F to 212°F, 180 BTU is required.
    • Raising water's boiling point requires increased pressure; the temperature will rise.

    Heat Transfer Terms

    • Latent heat refers to heat absorbed during the phase change from liquid to steam.
    • Heat can be transferred in three ways: conduction, convection, and radiation.

    Boiler Operations

    • Boiler horsepower equates to the evaporation of 34.5 lb of water at 212°F per hour.
    • The absolute pressure from a 150 PSIG reading is 164.7 PSIA (adding atmospheric pressure).

    Measurement Conversions

    • 212°F equals 100°C; one boiler horsepower equals 33,472 BTU.
    • A British thermal unit (BTU) raises 1 lb of water by 1°F.
    • A therm is an energy measurement equal to 100,000 BTU.

    Boiler Components and Calculations

    • Hydronic heat utilizes hot water; superheated steam is reheated steam.
    • A throttling calorimeter measures the quality of saturated steam.
    • Approximate heat in 1 lb of saturated steam is 1,150 BTU.
    • A boiler's heating surface area can be calculated based on evaporation rates and steam capacity.

    Safety and Maintenance

    • Fusible plugs melt at 450°F, providing a safety mechanism to prevent overheating.
    • Boiler vent valves are located on the top of the steam drum to release excess pressure.
    • A dry pipe separates moisture from steam as it exits the boiler drum.

    Structural Elements

    • Staybolts strengthen fire-tube boilers by supporting flat plates.
    • Baffles direct flue gas travel and improve efficiency.
    • A high-pressure boiler's safety valve operates above 15 PSI.

    Operating Conditions

    • Bottom blowdown removes sludge; testing low-water cutoff ensures safe operation.
    • Gauge glass indicates the water level; issues could arise from blocked connections.

    Valve Operations

    • Globe valves provide high resistance to flow, while gate valves offer the least resistance.
    • Siphon protects steam pressure gauges from high-temperature steam.

    Testing and Regulation

    • Monthly testing of safety valves under pressure confirms they can lift correctly.
    • Automatic feedwater regulators maintain proper water levels in the boiler system.

    Troubleshooting

    • Low-water level indications are checked by try cocks on the boiler.
    • Issues with boiler efficiency can stem from soot accumulation or inadequate maintenance.

    Safety Features

    • The automatic control that prevents dry firing in boilers is the low-water cutoff.
    • Steam temperature rapidly decreases boiler efficiency if not managed properly due to spalling.

    Additional Information

    • Diagonal stays are typically found in fire-tube boilers, contributing to structural integrity.
    • The heating surface must be exposed to flame to maximize efficiency in boiler operation.### Valves and Safety Measures
    • Safety valves must be locked or sealed open if located between the boiler and water column.
    • During hydrostatic testing, safety valves should be held to their seat by a testing clamp.

    Gauge Glass Procedures

    • After installing a new gauge glass, open the drain and crack open the top valve for proper service return.
    • The gauge glass should be blown down daily to ensure accuracy and safety.

    Pressure Gauges and Measurements

    • Steam pressure gauges are typically graduated in pounds per square inch (PSI).
    • Draft is measured in inches of water, which indicates airflow in system applications.

    Monitoring and Control Devices

    • One purpose of a water column is to dampen the oscillation of water in the gauge glass, providing stable readings.
    • An Aquastat operates based on temperature changes, ensuring boiler function within safe limits.
    • Vaporstats are pressure-sensitive devices that indicate fan failure, triggering protective measures.

    Ignition and Flame Failure Controls

    • The flame failure cutoff protects the boiler if ignition fails after burner activation.
    • Trial for ignition involves the flame scanner detecting the pilot flame, ensuring a safe ignition process.

    Boiler Surface Area Regulations

    • A boiler must have more than one safety valve if it has over 500 ft² of heating surface to meet safety standards.

    Measurement Tools and Their Functions

    • A pyrometer is used to measure temperature accurately, critical for maintaining proper operating conditions.
    • OS&Y stands for "outside screw and yoke," a type of valve used for controlling steam flow.

    Safety and Interlock Systems

    • Interlock controls are devices preventing firing attempts unless deemed safe, enhancing operational safety.
    • The main stop valve is located on the steam line, crucial for regulating flow in the system.

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    Test your knowledge with this flashcard quiz designed for the MA 2nd Class Fireman's exam. The quiz covers essential topics such as heat transfer and energy requirements, providing an excellent review for aspiring firemen. Enhance your understanding and preparation effectively.

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