UP-STATIONARY Grade 3 Engineering License
Exam Questions and Answers
A+
Question>> 1
What type stays are used in wet back (Scotch Marine) type boilers?
ANS>>
stay bolts and through stays. these sometimes will have a telltale drilled in them
Question>> 2
what is a water wall?
ANS>>
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
Question>> 3
Why is a row of tubes sometimes left out of an HRT boiler?
Page 1 of 135
,ANS>>
to improve circulation reducing carryover
Question>> 4
what is a lap joint? what is a butt joint?
what is a butt-strap joint?
ANS>>
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)
Question>> 5
what are tube ligaments?
ANS>>
the area between the tube holes on the tube sheet
Question>> 6
two boilers are make of the same grade of steel, same thickness of plate and same
Page 2 of 135
,type of joints. one is 30" in diameter the other is 60" diameter. which will withstand the
greatest pressure and demonstrate your answer
ANS>>
the 30" boiler-it has less total pressure on the shell. DxDx.7854(1/4pi)xpsi
30x30x.7854x120 psi = 84,823 lbs. total pressure 60x60x.7854x120 psi = 339,292 lbs.
total pressure show your work on everything!
Question>> 7
what is a radiant type superheater? what is a convection type superheater? what is the
third type of superheater?
ANS>>
A radiant superheater is set over the fire to absorb radiant heat from the furnace by
direct radiation
a convection superheater is placed in the gas passage of the furnace, usually between
the first and second pass. little to no radiation will reach this type
the third type is a combination of radiant and convection
Question>> 8
what is a fire tube boiler? list 5 advantages
list 5 disadvantages
name 4 types
Page 3 of 135
, ANS>>
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
DISADVANTAGES:
1) slow steamers
2) limited in pressure and capacity
3) liable to disastrous explosions because drums and joints are set over the fire
4) inefficient
5) inaccessible for inspection
TYPES:
1) H.R.T.
2) locomotive
3) Scotch Marine
4) Vertical fire tube
Question>> 9
what is meant by "Factor of Safety"?
Page 4 of 135
Exam Questions and Answers
A+
Question>> 1
What type stays are used in wet back (Scotch Marine) type boilers?
ANS>>
stay bolts and through stays. these sometimes will have a telltale drilled in them
Question>> 2
what is a water wall?
ANS>>
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
Question>> 3
Why is a row of tubes sometimes left out of an HRT boiler?
Page 1 of 135
,ANS>>
to improve circulation reducing carryover
Question>> 4
what is a lap joint? what is a butt joint?
what is a butt-strap joint?
ANS>>
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)
Question>> 5
what are tube ligaments?
ANS>>
the area between the tube holes on the tube sheet
Question>> 6
two boilers are make of the same grade of steel, same thickness of plate and same
Page 2 of 135
,type of joints. one is 30" in diameter the other is 60" diameter. which will withstand the
greatest pressure and demonstrate your answer
ANS>>
the 30" boiler-it has less total pressure on the shell. DxDx.7854(1/4pi)xpsi
30x30x.7854x120 psi = 84,823 lbs. total pressure 60x60x.7854x120 psi = 339,292 lbs.
total pressure show your work on everything!
Question>> 7
what is a radiant type superheater? what is a convection type superheater? what is the
third type of superheater?
ANS>>
A radiant superheater is set over the fire to absorb radiant heat from the furnace by
direct radiation
a convection superheater is placed in the gas passage of the furnace, usually between
the first and second pass. little to no radiation will reach this type
the third type is a combination of radiant and convection
Question>> 8
what is a fire tube boiler? list 5 advantages
list 5 disadvantages
name 4 types
Page 3 of 135
, ANS>>
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
DISADVANTAGES:
1) slow steamers
2) limited in pressure and capacity
3) liable to disastrous explosions because drums and joints are set over the fire
4) inefficient
5) inaccessible for inspection
TYPES:
1) H.R.T.
2) locomotive
3) Scotch Marine
4) Vertical fire tube
Question>> 9
what is meant by "Factor of Safety"?
Page 4 of 135
