Definition: atmosphere

A unit of pressure. One atmosphere (one ATM) is equivalent to approximately 15 pounds per square inch. The following table shows ATM ratings for water resistance:

   #      Depth
   of     Rating
  ATMs   (meters)  Water Usage

  1ATM      10    Splashes

  3ATM      30    Brief immersion

  5ATM      50    Shallow water swimming

  10ATM    100    Swimming, snorkeling

  15ATM    150    Scuba diving