B9 Flashcards
What is the primary purpose of Portland cement mortar linings in pipelines?
a) To increase the structural strength of the pipeline
b) To prevent corrosion of ferrous materials
c) To improve water flow velocity
d) To reduce the weight of the pipeline
To prevent corrosion of ferrous materials
What does the term “passivation” mean in the context of cement linings?
a) The process of reinforcing concrete with steel
b) The formation of a chemical oxide film on metal surfaces
c) The application of mortar lining by hand
d) The reduction of water content in concrete
The formation of a chemical oxide film on metal surfaces
Which method is not used for placing concrete in pressure pipes?
a) Vertical casting
b) Centrifugal casting
c) Pneumatic placement
d) Radial compaction
Pneumatic placement
What is the minimum thickness of mortar lining required for fittings in concrete pressure pipes?
a) 0.25 inches (6 mm)
b) 0.375 inches (9 mm)
c) 0.50 inches (13 mm)
d) 0.75 inches (19 mm)
0.375 inches (9 mm)
Why might ductile iron pipes transporting raw sewage require linings other than cement mortar?
a) To reduce the weight of the pipe
b) To resist attack by sulfuric acid
c) To improve thermal insulation
d) To avoid cracking during handling
To resist attack by sulfuric acid
What is one precaution recommended during the shipping of mortar-lined pipes?
a) Use unpadded lifting devices for cost efficiency
b) Place wire rope cables through the pipe for stability
c) Avoid letting lifting cables bear directly against the lining
d) Rotate pipes regularly during transport
Avoid letting lifting cables bear directly against the lining
What are the three methods for placing concrete in concrete pressure pipes?
a) Hand layup, pneumatic placement, centrifugal casting
b) Vertical casting, centrifugal casting, radial compaction
c) Radial compaction, hand layup, pneumatic placement
d) Centrifugal casting, pneumatic placement, vertical casting
Vertical casting, centrifugal casting, radial compaction
What is a potential issue with concrete or mortar linings in low humidity conditions?
a) Scaling
b) Shrinkage cracking
c) Reduced flow characteristics
d) Tuberculation
Shrinkage cracking
What does Portland cement mortar primarily protect in pipelines?
a) Water quality
b) Ferrous materials from corrosion
c) Pipeline insulation
d) Pipe joints from external stress
Ferrous materials from corrosion
What is one benefit of concrete linings for ferrous material pipelines?
a) They enhance the tensile strength of the pipe
b) They reduce the internal diameter of the pipe
c) They protect against corrosion
d) They act as a heat insulator
They protect against corrosion
Which of the following is NOT a recommended method for placing concrete in pressure pipes?
a) Vertical casting
b) Centrifugal casting
c) Pneumatic spraying
d) Radial compaction
Pneumatic spraying
What does the term “tuberculation” refer to in the context of ferrous metal pipelines?
a) Water discoloration caused by chemicals
b) The growth of mineral deposits inside the pipe
c) The expansion of the metal pipe due to pressure
d) The loss of pipe strength due to corrosion
The growth of mineral deposits inside the pipe
What is the most effective way to prevent corrosion in pipelines transporting raw sewage?
a) Using ductile iron pipes
b) Lining pipes with cement mortar
c) Adding an extra layer of coating
d) Using high-strength concrete
Lining pipes with cement mortar
Which of the following conditions may require the use of linings other than cement mortar in pipelines?
a) High chlorine levels
b) Sulfuric acid in sewage
c) Excessive humidity
d) High pipe pressure
Sulfuric acid in sewage
In which condition should the manufacturer be consulted regarding the linings of a pipeline?
a) When shrinkage cracks are visible
b) When cracks appear due to handling
c) In case of severe damage or extensive cracks
d) For general maintenance queries
In case of severe damage or extensive cracks
What should be avoided when shipping mortar-lined pipes?
a) Using padded lifting devices
b) Exposing the pipes to direct sunlight
c) Using unpadded lifting cables that bear directly on the lining
d) Storing pipes on a flat surface
Using unpadded lifting cables that bear directly on the lining
