©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Power Plant Maintenance Exam
Questions and Answers 100% Solved
Piping - ✔✔is used in power plants to convey fluids to and from their
place of usage, and is integral to
plant operation.
It is important to understand the different piping requirements for the
various fluids used. This
includes selection of: - ✔✔a) The most suitable piping materials
b) The proper pipe sizes for the volumes transferred
c) The most appropriate methods of connection, and
d) The most appropriate fittings.
These codes will help to select material that is safe under anticipated
operating conditions of ____________ - ✔✔pressure, temperature, and
corrosion.
what is the most common material used for piping? - ✔✔steel
Steel pipe is manufactured in two main categories - ✔✔seamless and
welded
,©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Forged steel - ✔✔steel that has been heated and fored into shape used
for fittings.
Cast Iron - ✔✔has high resistance to corrosion and abrasion. It is used
for ash handling systems, sewage lines, and underground water lines
Malleable iron and ductile iron - ✔✔are commonly used for screwed
fittings, where the greater
strength of steel fittings is not required.
Brass and Copper - ✔✔(other copper alloys) are non-ferrous materials.
They are used in power plants in instrumentation and water services,
where extreme pressure and temperature are not prime considerations
Commercial pipe - ✔✔is manufactured in standard sizes, each having a
unique diameter and wall thickness. Tables for the various pipe sizes list
these dimensions.
The diameter of standard piping is - ✔✔loosely designated by its
Nominal Pipe Size.
what is meant by "nominal" pipe size? - ✔✔in name only
There are two systems used to designate nominal pipe size. - ✔✔1. The
Imperial System uses an "NPS" (Nominal Pipe Size) number, which
indicates inches.
,©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Table 1 lists NPS numbers in the first column, from NPS 1/2 to NPS 30
The equivalent metric system assigns a "DN" (diametre nominal) number,
which indicates millimeters. This is shown in the second column of Table 1.
Nominal pipe size - ✔✔is an approximate indication of pipe diameter.
nominal inside diameter of the pipe. - ✔✔Up to and including NPS 12
(DN 300) pipe,
the actual outside diameter of the pipe. - ✔✔For NPS 14 (DN 350) and
larger pipe, the number represents
how many systems used to designate the wall thickness of the different
sizes of pipe? - ✔✔two
older method - ✔✔pipe as Standard (S), Extra strong (XS), or Double
extra strong (XXS).
A newer method - ✔✔replaced the older method, uses Schedule
Numbers to designate wall thickness.
for any given nominal pipe size, the outside diameter stays the same.
Therefore, the inside diameter will get smaller as the wall thickness
increases. - ✔✔true
, ©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Since the outside diameter never changes, the actual inside diameter can
be determined by the formula: - ✔✔d = D - 2t
d = inside diameter
t = wall thickness (in the Tables, the upper number in the boxes below each
Schedule)
D = outside diameter (see column three)
There are three general methods used to join or connect lengths of
pressure piping. - ✔✔1. Threaded pipe and screwed connections
2. Flanges
3. Welded joints
Screwed Connections - ✔✔threads are cut into the pipe at each end,
and screwed fittings such as unions, couplings, and elbows are used to join
the lengths.
This method is generally used for pipe sizes
The advantage of screwed Connections? - ✔✔The advantage of this
method is that the piping can be easily assembled or disassembled.
Elbows - for making angle turns in piping. - ✔✔for making angle turns in
piping.
Nipples - ✔✔for making close connections. They are
Power Plant Maintenance Exam
Questions and Answers 100% Solved
Piping - ✔✔is used in power plants to convey fluids to and from their
place of usage, and is integral to
plant operation.
It is important to understand the different piping requirements for the
various fluids used. This
includes selection of: - ✔✔a) The most suitable piping materials
b) The proper pipe sizes for the volumes transferred
c) The most appropriate methods of connection, and
d) The most appropriate fittings.
These codes will help to select material that is safe under anticipated
operating conditions of ____________ - ✔✔pressure, temperature, and
corrosion.
what is the most common material used for piping? - ✔✔steel
Steel pipe is manufactured in two main categories - ✔✔seamless and
welded
,©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Forged steel - ✔✔steel that has been heated and fored into shape used
for fittings.
Cast Iron - ✔✔has high resistance to corrosion and abrasion. It is used
for ash handling systems, sewage lines, and underground water lines
Malleable iron and ductile iron - ✔✔are commonly used for screwed
fittings, where the greater
strength of steel fittings is not required.
Brass and Copper - ✔✔(other copper alloys) are non-ferrous materials.
They are used in power plants in instrumentation and water services,
where extreme pressure and temperature are not prime considerations
Commercial pipe - ✔✔is manufactured in standard sizes, each having a
unique diameter and wall thickness. Tables for the various pipe sizes list
these dimensions.
The diameter of standard piping is - ✔✔loosely designated by its
Nominal Pipe Size.
what is meant by "nominal" pipe size? - ✔✔in name only
There are two systems used to designate nominal pipe size. - ✔✔1. The
Imperial System uses an "NPS" (Nominal Pipe Size) number, which
indicates inches.
,©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Table 1 lists NPS numbers in the first column, from NPS 1/2 to NPS 30
The equivalent metric system assigns a "DN" (diametre nominal) number,
which indicates millimeters. This is shown in the second column of Table 1.
Nominal pipe size - ✔✔is an approximate indication of pipe diameter.
nominal inside diameter of the pipe. - ✔✔Up to and including NPS 12
(DN 300) pipe,
the actual outside diameter of the pipe. - ✔✔For NPS 14 (DN 350) and
larger pipe, the number represents
how many systems used to designate the wall thickness of the different
sizes of pipe? - ✔✔two
older method - ✔✔pipe as Standard (S), Extra strong (XS), or Double
extra strong (XXS).
A newer method - ✔✔replaced the older method, uses Schedule
Numbers to designate wall thickness.
for any given nominal pipe size, the outside diameter stays the same.
Therefore, the inside diameter will get smaller as the wall thickness
increases. - ✔✔true
, ©JOSHCLAY 2024/2025. YEAR PUBLISHED, 2024.
Since the outside diameter never changes, the actual inside diameter can
be determined by the formula: - ✔✔d = D - 2t
d = inside diameter
t = wall thickness (in the Tables, the upper number in the boxes below each
Schedule)
D = outside diameter (see column three)
There are three general methods used to join or connect lengths of
pressure piping. - ✔✔1. Threaded pipe and screwed connections
2. Flanges
3. Welded joints
Screwed Connections - ✔✔threads are cut into the pipe at each end,
and screwed fittings such as unions, couplings, and elbows are used to join
the lengths.
This method is generally used for pipe sizes
The advantage of screwed Connections? - ✔✔The advantage of this
method is that the piping can be easily assembled or disassembled.
Elbows - for making angle turns in piping. - ✔✔for making angle turns in
piping.
Nipples - ✔✔for making close connections. They are
