Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72°F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56

Illustration GS-RA-56: the U.S. Coast Guard has not released this illustration.

Question

Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72&deg;F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56

Illustration GS-RA-56: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option D: 29.99" Hg or 254 microns of Hg absolute. Deep vacuum evacuation to 29.99" Hg or 254 microns reduces water's boiling point sufficiently below ambient temperature to vaporize and extract all residual moisture. This satisfies marine HVAC standards to prevent acid formation and freeze-ups.