The International Organization for Standardization (ISO) provides the following definitions for survival suits:
• Immersion suit — A suit designed to protect the user’s body from the cooling effects of unintended immersion in water. Cooling effects include cold shock and hypothermia.
• Constant-wear suit — An immersion suit designed to be routinely worn for activities on or near water in anticipation of accidental immersion, but permitting physical activity “to such an extent that actions can be undertaken without undue encumbrance and thus, head, hands and feet need not be covered.”
• Abandonment suit — An immersion suit including head, hand and feet protection designed to permit rapid donning in the event of an imminent immersion in water.