Exposure Protection Suits AKA Wetsuits

Form-fitting exposure suits are usually made of foam neoprene rubber (wetsuits) or spandex-like materials (skins), sometimes with a fleece lining.

What They Do - Exposure suits insulate you against the cooling effect of water, which can rob your body of heat 25 times faster than air. The thickness and type of exposure protection you need depends on dive conditions. Simple Lycra suits provide little thermal insulation, but do help protect against scrapes and stings.

What to Look For - Fit and comfort. Exposure suits should fit snugly without restricting movement or

breathing. Reject any suit that's too loose, however. Gaps at the arm, leg, crotch and neck allow water to circulate and defeat the suit's ability to prevent heat loss.

Cost - Wetsuits and skins range from $70 to $650. Dry suits can cost from $650 to $2,800.

Our Advice - As long as a wetsuit fits correctly, it will do the job. If you're going the budget route, your choices will usually be limited to basic models. Bright colors and graphics aren't necessary.

Exposure Suit Comfort Zones

Water Temp
75-85F - 1/16" (1.6mm) neoprene, Lycra, Polartec
70-85F - 1/8" (3mm) neoprene
65-75F - 3/16" (5mm) neoprene
50-70F - 1/4" (6.5mm) neoprene
35-65F - 3/8" (9.5mm) neoprene, dry suit

How A Wetsuit Works
A wetsuit keeps you warm in two ways:

Keeping Water Out. Any water that gets inside the suit is going to leak out again. When the water is inside, it absorbs some of your body heat. When it leaves, it takes that heat with it. So the first thing a wetsuit has to do is keep the cold ocean from flushing through it. A good fit, one that feels equally snug everywhere, is critical, so the space the ocean wants to use to flow along your skin is as small as possible.

Providing Insulation Against Heat Loss. A little science here: Solids and liquids conduct heat well; gases do not. Air, for example, is about 20 times less conductive than water. As a practical matter, good insulation—above or below water—is all about trapping air. That's why neoprene foam works so well. Gas bubbles are permanently trapped inside the "closed cells" of the wetsuit material.

Our tests have shown that other "innovations"—such as metal foils and fleece linings in suits—do nothing to enhance insulation. However, some features can help the suit do its job. They include: wrist, collar and ankle seals; sealing flaps behind zippers; pre-bent arms and legs; and smooth inner coatings to minimize water flow inside the suit.


Portions Reprinted with permission from Scuba Diving - The Magazine Divers Trust