Chapter 6 Environmental Testing Flashcards
1
Q
- Identify some of the defects that can be caused by incorrect application temperatures.
A
- Blistering
- Pin holing
- Cratering
- Dry Spray
- Mud Cracking
2
Q
- Describe relative humidity.
A
Relative humidity is a measure of the amount of moisture in the air compared to saturation level.
3
Q
- What is the dew point temperature?
A
Dew Point is the temperature at which moisture begins to form on a steel surface.
4
Q
- Name some of the effects wind may have on a coating project.
A
- Blow abrasives past the boundaries of the abrasive-blast work area to an area where coating are being applied
- Cause excessive drift or overspray of sprayed coatings
- Accelerates solvent evaporation after application
- Contribute to the formation of dry spray
5
Q
- What are some of the common errors when using an electronic hygrometer?
A
Operator-based errors: the reading was taken in direct sunlight, the instrument was left in place too long, or removed before it stabilized
Equipment-based errors: calibration or equipment malfunctions
6
Q
- Explain the process for use of the sling psychrometer.
A
To use the sling psychrometer:
• Saturate the sock with clean water.
• Whirl the instrument rapidly for about 40 seconds.
• Read the wet-bulb temperature.
Repeat the process (spin and read without additional wetting) until the temperature stabilizes