MA 2nd Class Fireman's Practice Exam

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.

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

Locked or sealed open Signup and view all the answers

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

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

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

Open the drain and crack open the top valve Signup and view all the answers

The steam pressure gauge is graduated in:

Pounds per square inch Signup and view all the answers

One of the purposes of the water column is to:

Dampen the oscillation of the water in the gauge glass Signup and view all the answers

The gauge glass should be blown down:

Daily Signup and view all the answers

The flame failure control is tested by:

Securing the fuel supply to the burner Signup and view all the answers

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

Aquastat 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:

Fan failure 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:

Flame failure cutoff Signup and view all the answers

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

Vaporstat Signup and view all the answers

Draft is measured in:

Inches of water Signup and view all the answers

Which of the following is used to measure temperature?

Pyrometer Signup and view all the answers

The main stop valve is located on the:

Steam line Signup and view all the answers

OS&Y stands for:

Outside screw and yoke Signup and view all the answers

An interlock control is a(n):

Device that prevents attempts to fire unless safe Signup and view all the answers

Trial for ignition refers to the:

The flame scanner detecting the pilot flame Signup and view all the answers

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

500 ft^2 of heating surface 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?

970 Signup and view all the answers

Radiation is

a form of heat transfer by waves. Signup and view all the answers

Steam at 100 PSI and 400 degrees Fahrenheit is

superheated. Signup and view all the answers

Which of the following most closely defines sensible heat?

Heat quantity that can be felt or measured by a thermometer. 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?

180 Btu Signup and view all the answers

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

Temperature will be raised Signup and view all the answers

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

latent heat. Signup and view all the answers

Heat may be transferred in how many ways?

Three Signup and view all the answers

A boiler horsepower is defined as

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

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

164.7 Signup and view all the answers

What does 212 degrees F equal on the Celsius scale?

100 Signup and view all the answers

One boiler horsepower is equal to how many Btu?

33,472 Signup and view all the answers

A British thermal unit is

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

Hydronic heat is

Hot water heat Signup and view all the answers

Superheated steam is

Reheated steam Signup and view all the answers

2,545 Btu represents

1 horsepower-hour Signup and view all the answers

A throttling calorimeter is used to measure the quality of

Saturated steam Signup and view all the answers

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

1,150 Btu 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?

338 degrees F Signup and view all the answers

A dry pipe is used to

Separate moisture from steam as it leaves the drum. Signup and view all the answers

The purpose of a staybolt is to

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

The boiler vent valve is located on the

Top of the steam drum. Signup and view all the answers

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

Indicate that a staybolt is cracked or broken. Signup and view all the answers

A fusible plug melts at

450 degrees F Signup and view all the answers

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

Increases 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

Manholes Signup and view all the answers

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

MAWP does not exceed 100 PSI 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.

125 Signup and view all the answers

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

Directing the travel of flue gases. 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?

1,000 Signup and view all the answers

Boiler tube sizes are specified by

Outside diameter. Signup and view all the answers

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

2.5 inches 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

Water Signup and view all the answers

Heavy accumulation of soot in a boiler will result in

Loss of boiler efficiency Signup and view all the answers

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

Rolled and beaded over Signup and view all the answers

A tube in a fire-tube boiler is surrounded by

Water Signup and view all the answers

Atmospheric pressure is considered to be

14.7 psia. Signup and view all the answers

In a water tube boiler,

Flue gas surrounds the tube. Signup and view all the answers

Diagonal stays are found in

Fire-tube boilers Signup and view all the answers

Handholes and manholes are oval

For removal from a pressure vessel Signup and view all the answers

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

Use the trycocks Signup and view all the answers

The vent valve

Both A and B Signup and view all the answers

A high-pressure boiler has its safety valve set above

15 PSI Signup and view all the answers

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

Low initial cost Signup and view all the answers

Water walls are found

In water-tube boiler furnaces Signup and view all the answers

The best time to bottom blow a boiler is at

Low load under full pressure Signup and view all the answers

A telltale hole is found in a

Stay bolt 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)?

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

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

700 degrees F 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?

1/3 Signup and view all the answers

What is the relationship between longitudinal stress and circumferential stress?

Longitudinal stress is twice circumferential stress Signup and view all the answers

A therm is equal to how many Btu?

100,000 Signup and view all the answers

The factor of evaporation is

Heat added to the boiler divided by 970.3 Signup and view all the answers

The purpose of a bottom blowdown is to

Remove sludge and sediment Signup and view all the answers

Damage by spalling refers to the

Refractory Signup and view all the answers

Superheaters raise the temperature of

Steam Signup and view all the answers

The steam space is

The area above the operating water level Signup and view all the answers

The heating surface of a boiler is the area

Exposed to the flame and flue gases Signup and view all the answers

The purpose of a superheater is to

Heat steam above its saturation temperature Signup and view all the answers

What is the formula for the factor of evaporation?

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

What can cause a superheater tube to overheat?

Dirty tube 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?

3,450 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?

13.7 Signup and view all the answers

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

Poor circulation (plugged tube) Signup and view all the answers

A downcomer is

Found in a water-tube boiler Signup and view all the answers

Extreme firebox temperature changes cause

Spalling Signup and view all the answers

The low-water cutoff

Shuts off the burner when the boiler is low on water Signup and view all the answers

Steam coming from the bottom try cock would indicate

Low water level Signup and view all the answers

What type of valve has the most resistance to flow?

Globe Signup and view all the answers

When checking the water level of a boiler,

Blow down the gauge glass and water column Signup and view all the answers

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

From steam temperature Signup and view all the answers

The feedwater regulator is located

At the normal operating water level Signup and view all the answers

An automatic feedwater regulator

Ensures the proper water level in the boiler Signup and view all the answers

To test the low-water cutoff,

The burner must be firing Signup and view all the answers

The purpose of testing a safety valve by hand is to

Make sure the valve can lift Signup and view all the answers

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

Low-water cutoff Signup and view all the answers

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

Blow down the gauge glass and water column 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

Monthly Signup and view all the answers

What type of valve has the least resistance to flow?

Gate 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.