If the oxygen content is greater than 21%, which of the following gases must be used to set the span point?
A. Oxygen
B. Dry air
C. Nitrogen
D. Hydrogen
Answer:A
If the oxygen content is greater than 21%, which of the following gases must be used to set the span point?
A. Oxygen B. Dry air C. Nitrogen D. Hydrogen
Explanation: If the oxygen content is greater than 21%, oxygen is used to set the span point. This is done for calibration purposes.