Certified Hyperbaric Technologist Practice Test

Disable ads (and more) with a membership for a one time $2.99 payment

Prepare for the Certified Hyperbaric Technologist Test with flashcards and multiple choice questions, each featuring hints and explanations. Equip yourself for success on your exam!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.


At a depth of 10 fsw, what are the equivalent pressure values in ATA, mmHg, and psi?

  1. 1.1 ATA, 888 mmHg, 3.5 psi

  2. 1.3 ATA, 988 mmHg, 4.4 psi

  3. 1.5 ATA, 1068 mmHg, 5.0 psi

  4. 1.2 ATA, 928 mmHg, 4.0 psi

The correct answer is: 1.3 ATA, 988 mmHg, 4.4 psi

To determine the equivalent pressure values at a depth of 10 feet of seawater (fsw), several conversions are needed. In hyperbaric medicine, it's important to know that the atmospheric pressure at sea level is approximately 1 ATA (atmosphere absolute), which equates to 760 mmHg and approximately 14.7 psi. As you descend underwater, pressure increases due to the weight of the water above you. For every 33 fsw, the pressure increases by one atmosphere. Therefore, at 10 fsw, the increase in atmospheric pressure is roughly 0.3 ATA above the 1 ATA at the surface. This results in a total pressure of about 1.3 ATA at 10 fsw. Next, to convert this to mmHg, the calculation is: 1.3 ATA * 760 mmHg/ATA, which results in approximately 988 mmHg. For psi, we use the conversion of 1 ATA being equal to 14.7 psi. Thus, at 1.3 ATA, the pressure would amount to 1.3 * 14.7 psi, which calculates to approximately 19.11 psi. However, since some psi values can be approximate or