B12 Flashcards
Why is direct burial of unprotected plastic-lined steel pipes not recommended?
A) It could lead to corrosion and damage to the pipe.
B) The pipes may overheat.
C) It is difficult to install without machinery.
D) It is too expensive.
It could lead to corrosion and damage to the pipe.
What type of material should be used for backfilling around buried plastic-lined pipes?
A) Gravel and sand mixture
B) Clean sand with no rocks or foreign material
C) Any soil available
D) Concrete
Clean sand with no rocks or foreign material
What is the typical flow velocity limit for liquids in plastic-lined piping to minimize pressure drop?
A. Less than 6 ft/sec (1.8 m/sec)
B. Less than 12 ft/sec (3.7 m/sec)
C. Less than 24 ft/sec (7.3 m/sec)
D. Less than 35 ft/sec (10.7 m/sec)
Less than 12 ft/sec (3.7 m/sec)
What is the most commonly available size range for corrosion-resistant lined pipes?
A. NPS 1 to 8 (DN 25 to 200)
B. NPS 1 to 12 (DN 25 to 300)
C. NPS 6 to 24 (DN 150 to 600)
D. NPS 12 to 24 (DN 300 to 600)
NPS 1 to 12 (DN 25 to 300)
Why should plastic-lined piping not be used below its recommended minimum operating temperature?
A. The liners will melt and degrade.
B. The liners can swell and react with the chemical media.
C. The liners can become brittle and fail mechanically.
D. The liners will release harmful gases.
The liners can become brittle and fail mechanically.
What should the piping-design engineer consider first when selecting a liner material?
A. Manufacturer reputation
B. Chemical resistance charts
C. Service conditions, including chemicals, concentration, and temperature
D. Cost of the liner material
Service conditions, including chemicals, concentration, and temperature
What is the primary benefit of plastic-lined metallic piping compared to corrosion-resistant metal piping?
A. Lower installation complexity
B. Superior resistance to chemical attack in all cases
C. Lower installed cost for flanged systems
D. Easier fabrication at the job site
Lower installed cost for flanged systems
Why is a plastic-lined metallic piping system preferred over solid-plastic piping systems?
A. Wider range of line sizes and fittings
B. Lower material cost
C. Simpler installation techniques
D. Reduced chemical resistance
Wider range of line sizes and fittings
What is one limitation of evaluating materials solely based on material costs?
A. It ignores factors like liner thickness.
B. It overlooks in-place costs, including fabrication and installation.
C. It does not consider chemical resistance.
D. It assumes all materials have equal service capabilities.
It overlooks in-place costs, including fabrication and installation.
What property of fluorinated plastics provides outstanding resistance to chemical attack?
A. High abrasion resistance
B. Fluorine-carbon bonding
C. Cold weather impact strength
D. Low coefficients of friction
Fluorine-carbon bonding
Which of the following fluorinated plastics has the highest temperature-handling capability?
A. PTFE
B. FEP
C. PFA
D. ETFE
PTFE
Which liner type is known to be virtually inert to most chemicals and was originally developed by DuPont in 1938?
A. PFA
B. FEP
C. PTFE
D. PVDC
PTFE
Which fluorinated plastic was the first melt-processible resin with chemical resistance comparable to PTFE?
A. FEP
B. PFA
C. ETFE
D. PP
FEP
What is a general characteristic of nonfluorinated plastics like polypropylene (PP) and polyvinylidene chloride (PVDC)?
A. Higher temperature resistance than fluoropolymers
B. More expensive than fluoropolymers
C. Good overall chemical resistance but lower than fluoropolymers
D. Higher thermal stability compared to fluorinated plastics
Good overall chemical resistance but lower than fluoropolymers
What is the purpose of the electrostatic test conducted on plastic-lined pipes?
A. To check for the proper sealing surface of the liner
B. To ensure the liner does not contain any defects
C. To test the chemical compatibility of the liner
D. To verify the pipe size and liner type
To ensure the liner does not contain any defects
What indicates the presence of a defect in the liner during the electrostatic test?
A. A change in voltage
B. A visible or audible spark at the probe
C. A decrease in pressure
D. Discoloration of the liner
A visible or audible spark at the probe
Fluorinated plastic lining materials include which of the following?
A. Polypropylene (PP)
B. Polytetrafluoroethylene (PTFE)
C. Polyethylene (PE)
D. Nylon
Polytetrafluoroethylene (PTFE)
What is the primary purpose of thermoplastic spacers?
A. To provide additional flexibility to the pipe
B. To connect plastic-lined pipes to dissimilar materials while forming a seal
C. To act as a replacement for gaskets
D. To reduce the wall thickness of lined pipes
To connect plastic-lined pipes to dissimilar materials while forming a seal
Which of the following thermoplastics is NOT mentioned as a widely used liner material?
A. Polypropylene (PP)
B. Polyvinylidene fluoride (PVDF)
C. Polytetrafluoroethylene (PTFE)
D. Polyethylene (PE)
Polyethylene (PE)
What is the primary challenge addressed by pipe lining techniques?
A. Ensuring that the liner and metal housing expand and contract as one.
B. Preventing shrinkage during sintering.
C. Controlling the wall thickness of PTFE tubes.
D. Reducing void content in PTFE liners.
Ensuring that the liner and metal housing expand and contract as one.
What is the primary purpose of the sintering process in PTFE production?
A. To melt the PTFE resin completely for molding.
B. To compact the resin for easier handling.
C. To coalesce polymer particles into a strong homogeneous structure.
D. To cool the PTFE to achieve crystallinity development.
To coalesce polymer particles into a strong homogeneous structure.
What should be done with protective end covers on plastic-lined pipe and fittings?
A. They should be removed immediately upon delivery.
B. They should be left on until just before installation.
C. They should be discarded after inspection.
D. They should be reused for other materials.
They should be left on until just before installation.
What is the purpose of using a calibrated torque wrench during installation?
A. To ensure bolts are tightened to the maximum torque.
B. To avoid excess torque that can damage the plastic flare faces.
C. To speed up the installation process.
D. To measure the weight of the fittings.
To avoid excess torque that can damage the plastic flare faces.
How should bolts be tightened on a flange connection?
A. In a circular pattern.
B. In a star pattern.
C. Randomly to save time.
D. Only the top bolts should be tightened.
In a star pattern.