Atmospheric suits, Hot water suits, Drysuits, Semi-dry suits,
Wetsuits, Dive skins, Shorties, hoodies, Combinations, Farmer Johns.
So many to choose, so much to lose.
Why is it called an Exposure Suit?
An Exposure Suit is a garment or other device designed to protect a diver from the underwater environment not just the cold as many people think. If you have ever dived as I have in an area invested with Box Jellies, you will understand exactly what I mean. To put it simply, an exposure suit prevents or helps you against exposure to hazards. There are many types of exposure suits The primary reason why a suit is necessary is the fact that water is a much better conductor of heat than air. On dry land, walking around at an air temperature of 25 °C or so feels nice. But swimming in 25 °C water quickly feels cold. That's because water removes heat from the human body about 20 times quicker than air. What happens is that the body heats up a thin layer of water surrounding it. That water then expands and moves up, to be replaced by cold water. That cycles continues until you feel cold. This happens even in what one might consider very warm water, say 30 °C. Water would have to be in the 90s in order for a human being to feel comfortable in it over an extended period of time. The underlying reason is that our average body temperature is about 37 °C. If the water is any cooler than that, heat loss occurs, and it happens the faster the greater the temperature differential between body and water temperature.
OK, so as you can see there are many types of exposure suits and I will give you a brief explanation of each.
OK, so as you can see there are many types of exposure suits and I will give you a brief explanation of each.
- An Atmospheric Diving Suit is a small one-man articulated submersible of anthropomorphic form which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. These can be used for very deep dives for long periods without the need for decompression, and eliminate the majority of physiological dangers associated with deep diving.
- Hot Water Suits are used in cold water commercial surface supplied diving. An insulated pipe in the umbilical cord, which links the diver to the surface support, carries hot water from a heater on the surface down to the suit.
- Drysuits are used typically where the water temperature is between -2 and 15 °C. Water is prevented from entering the suit by seals at the neck and wrists.
- Semi-Dry Suits are effectively a thick wetsuit with better-than-usual seals at wrist, neck and ankles. They are used typically where the water temperature is between 10 and 20 °C. The seals limit the volume of water entering and leaving the suit. The wearer gets wet in a semi-dry suit but the water that enters is soon warmed up and does not leave the suit readily, so the wearer remains warm.
- Wetsuits are relatively inexpensive, simple, Neoprene suits that are typically used where the water temperature is between 10 and 25 °C. The foamed neoprene of the suit thermally insulates the wearer. Although water can enter the suit, a close fitting suit prevents excessive heat loss because little of the water warmed inside the suit escapes from the suit to be replaced by cold water, a process referred to as "flushing".
- Dive skins are used when diving in water temperatures above 25 °C. They are made from spandex or Lycra and provide little thermal protection, but do protect the skin from jellyfish stings, abrasion and sunburn. This kind of suit is also known as a 'Stinger Suit'. Some divers wear a dive skin under a wetsuit, which allows easier donning and (for those who experience skin problems from neoprene) provides additional comfort.
The "Dive Skin" was originally invented to protect scuba divers in Queensland Australia against the "Box" jellyfish (Chironex Fleckeri) - Shorties, A wet suit with short arms and legs, hence the name 'Shorty'
- hoodies, A wet/SemiDry Suit with a hood.
- Farmer Johns. Otherwise known as a 'two piece', the "Farmer John" (or "Farmer Jane") nickname comes from one piece looking like an overall and the other like a jacket. That design provides a double layer of protection to the diver's midsection. 2-piece suits are usually made of thicker neoprene, generally up to 7 millimeters. 2-piece suits are easier to put on and take off. Add gloves and a hood, and a 2-piece suit can be worn in water temperatures down to about 10 °C. Personally I am not a big fan of Farmer John/Jane suits as they are uncomfortable, cumbersome and extremely buoyant. They seem on their way out as more and more people use 7 mm jumpsuits with hooded vests
- Combinations, Tend to be wet/semi-dry suits of different types worn with jackets.
So now you can talk the talk, but can you walk the walk?
It's time to go shopping for your new Exposure Suit.
Probably the single biggest mistake divers make when buying a new exposure suit is in sizing, too big or too small. Some may argue here the the biggest problem will be buoyancy but I beg to differ as buoyancy can easily, and often is, corrected with excess weight.
Zippers may also be an issue and you should take this into consideration when buying an exposure suit:
When selecting a wet suit, whatever style you pick, do make sure it fits well. There's nothing worse than an ill-fitting suit where the water sloshes around instead of generating the desired thin insulating film. And pick one that zips in the back rather than the front. Most importantly, allow a good amount of time when shopping for a wet suit! They don't go on easy, and you might find yourself working up a good sweat by the second or third suit. Don't plan on making other important purchases (like a regulator, BC, or dive computer) during the same trip to your dive shop; the wet suit selection will take up most of your time.
- Too Small and it will be restricting, it may look good in the shop as it squeezes in the midriff but try exercising in it and see if you can still breath. When an exposure suit is too small it can restrict chest movement preventing the diver from easily taking a full breath, add this to water pressure at depth and you have panic. Too tight around the neck and restricted blood flow can lead to blackout, too tight around the wrists and ankles can also lead to restricted blood flow and may lead to numbness and cold extremities.
- Too Large and your biggest problem with a wet/semidry suit is 'flushing' - A continuous flow of water through the suit taking away your valuable body heat.
Zippers may also be an issue and you should take this into consideration when buying an exposure suit:
- Front Zippers are great when putting on your wet suit but you have to be some kind of Houdini when taking it off, especially when wet and cold. It's easy in the store when you have an assistant standing there saying "one moment sir/madam, let me help you with that", but at the dive site when everyone else is doing their own thing, you will be left standing there waiting for someone to help pull it off your shoulders.
- Rear Zippers are sometimes not the easiest means of zipping up your suit but by far the easiest to get out of without assistance. Normally rear zippers have a long tail on the zip pull so you can bring it over your shoulder and pull the zip up without too much difficulty.
When selecting a wet suit, whatever style you pick, do make sure it fits well. There's nothing worse than an ill-fitting suit where the water sloshes around instead of generating the desired thin insulating film. And pick one that zips in the back rather than the front. Most importantly, allow a good amount of time when shopping for a wet suit! They don't go on easy, and you might find yourself working up a good sweat by the second or third suit. Don't plan on making other important purchases (like a regulator, BC, or dive computer) during the same trip to your dive shop; the wet suit selection will take up most of your time.