An evacuation procedure specifies an absolute pressure of 500 microns or lower and a rise of no more than 100 microns during its stated isolated hold test. A system starts at 400 microns and rises to 650. Which conclusion follows?
- AIt passes because the initial reading was below 500 microns.
- BIt passes because 650 is a smaller vacuum than atmospheric pressure.
- It fails the specified pressure-rise check.
- DThe rise is only 50 microns.
Where to look it up
Explicit exercise assumptions; not a universal code requirement.
Why C is correct
The rise is 650 − 400 = 250 microns, exceeding the specified 100-micron allowance. Investigate the failed test; do not confuse absolute microns with an unspecified inches-of-mercury gauge reading.