OQ-0001 Measure Structure To Electrolyte Potential Flashcards
(35 cards)
What are methods of corrosion control?
Cathartic protection
Protective coatings/wrap
What are the 2 types of cathodic protection (CP)?
Sacrificial Anodes
Impressed Current ( Rectifier)
What is the definition of an anode?
An electrically conductive material which discharges current into the ground to provide CP
Magnesium anodes are attached to blank
Steel pipe
CP rates will be taken when?
Steel pipe is exposed (except vacuum excavation)
Coating is removed
Coating show signs of deterioration
When is CP reading not required?
When the pipeline has been vacuum exposed
For steel risers when using the voltmeter what do you do with the voltmeter
You go over the pipe at the riser , approximately 12” away from the riser
For pipeline mains and isolated services what do you do when using the voltmeter ?
Go over the pipe from anode locations
What do you do when trying to take reads with the voltmeter in dry conditions?
Wet soil around the cell
Where do you connect the single lead from the voltmeter?
To the structure
When using the voltmeter you measure the pipe to blank blank
Soil potential
Where do you use the multimeter when there is a pipeline main and isolated steel services?
Over the pipe away from the anode locations
Where do you use the multimeter when there is an isolated steeel riser ?
Over the pipe at the riser , approximately 12” away from the riser
When using the multimeter in dry conditions what do you do?
Wet soil around the cell
Where do you connect the positive lead from the voltmeter to?
The structure
Where do you connect the negative lead from the voltmeter to?
Reference cell
When using the multimeter you measure the blank to blank potential
Pipe to soil
True or false - the pipe to soil read will be negative when connected as described for both types of meters
True
If the pipe to soil read is positive or no sign who do you contact?
Contact technical services ( corrosion control)
When you document/record the pipe to soil read what do you document/record?
Three (3) places to the right of the decimal point ( example -.095 V)
What is Adequate pipe to soil reads?
-0.850 volts to -2.500 volts
What does wrt mean ?
With respect to
What is inadequate pipe to soil reads?
-0.200 to -0.849 volts
When you measure p/s both sides of insulator with what?
1/2 cell in same position
