SCBA
SCBA stands for self-contained breathing apparatus. On a ship, this protects the wearer from gasses, vapors, dust and oxygen deficiency. Most self-contained breathing apparatus used on vessels are the open circuit type in which air from the one or two pressurized cylinders is for inhalation while the exhaled air is released into the atmosphere. All vessels that have ammonia as a refrigerant onboard must be equipped with a minimum of two SCBAs.