Andrea Zaferes
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Personal Protection Equipment: Choosing an exposure suit for water operations.
By Andrea Zaferes and Walt "Butch" Hendrick
Lifeguard Systems, www.teamlgs.com
Contaminated water diving course: bring your own wetsuit.
When we read advertisements like this we cringe and then realize its time to write another article.
The one mission that must be successfully completed one hundred percent of the time is when the operation is over you need to go home. Proper personal protection equipment (PPPE) is vitally important to the success of that mission, with exposure suits being one of the most important pieces of PPPE for water operation personnel.
When choosing an exposure suit the first question to ask is what kind of water do you need protection from? Is the water contaminated, cold, full of debris, moving, or a combination of these variables? The next decision has to be what do you need the suit for? Will it be for public safety diving, swiftwater operations, surf rescue, boat or personal watercraft operations, or surface ice rescue? Other questions to ask include, what are the budget constraints, how many technicians and operations personnel need to be outfitted with suits, what is the turnover rate for team members, and how often will the suits be used?
Contamination is an important consideration that is often overlooked when the districts water is not currently contaminated. Floods, run offs from heavy rains, biohazards from bodies, creosote from pilings, and petroleum products from submerged vehicles can turn clean water into a hazmat situation. Too often we hear technicians say that they do not need drysuits because they have warm water and they would overheat. Proper procedures can prevent heat exhaustion, but only hazmat tested drysuits can protect technicians from contamination related illnesses.
Cold can also be a misunderstood variable. Water conducts heat twenty-five times faster than air. We lose heat at the same rate in 42o F air as we do in 80o F water. Some divers consider a wetsuit effective protection for winter water operations because they do not become cold easily, but are they considering what happens when they have to first sit as a 90-percent ready diver and then as a back up diver, prior to serving as a primary diver? Even surface rescue personnel must be prepared for unusually long operations and atypical weather conditions.
Everyone reacts differently to cold exposure and should be dressed accordingly. What is good for one team member may be completely insufficient for another. A navy study of the effects of immersion found that a higher level of body fat reduced the rate of rectal temperature loss. A 110 lb person losing heat at the same rate as a 250 lb person will most likely have a lower core temperature than the larger person. A study of 8 Navy combat swimmers in 6o C water showed that each diver appears to have a particular core temperature decline profile with respect to cold water exposure.
For example one diver may be perfectly comfortable using wetsuit gloves, while another will feel pain in 15 minutes while wearing an insulated dry glove. A previous cold injury can increase susceptibility to cold problems, even if the original injury was many years earlier. Individual differences between ability to withstand cold can be great and should not be ignored, especially in the grin and bear it atmosphere of police and fire personnel. Technicians and surface support should be observant of individual cold stress susceptibility of themselves and of their teammates. This means that if the team captain has been ice diving in wetsuits for twenty years without becoming cold that does not mean that wetsuits are acceptable for other team members.
A large percentage of outdoor drownings occur in water not designated for swimming, which means that trees, rocks, garbage, and other debris can be a real concern. Divers often must search in low or zero visibility water, forcing them to be bottom dwellers searching by feel. Ice rescue technicians may come in contact with spider wire and fish hooks, while swift water technicians may be pushed into sharp rocks or branches from strainers.
Once enough information is gathered about environmental variables, the teams needs, and department budget constraints, the next decision is what kind of suit is necessary? Most noncommercial divers wear passive exposure suits, meaning that the suits do not provide a heat source to the wearer, rather they provide insulation between the wearer and the environment. Active exposure suits are more commonly found on commercial diving sites and typically involve hot water suits. Public safety personnel can manage with passive suits because their in-water times should be much shorter than those of commercial divers. Passive suits are self-contained and far less expensive than the actively-insulated suits that typically burden divers with an umbilical and the need for highly trained water and surface support personnel.
There are, however, battery powered heating units on the market that are designed to be worn under drysuits by divers who move very slowly looking for small search objects in low visibility water, for divers who stay in one place for periods of time conducting research, or for ice divers who sit through the 90-percent ready and back-up diver positions before acting as a primary diver. Active heaters can also be helpful for divers who feel the effects of cold quickly, such as some women and individuals with little body fat.
Passive suits fall into two main categories, wetsuits and drysuits. Wetsuits help keep divers warm by trapping and insulating a layer of water next to a wearers skin. That layer is warmed by the divers body heat. The wetsuit itself is a spongy material with thousands of gas bubbles inside, which are the insulation that traps body heat. Increased suit thickness will increase the degree of insulation. If the suit does not fit well then cold water will replace the warmed water and heat loss will occur.
for more articles see www.teamlgs.com
By Andrea Zaferes and Walt "Butch" Hendrick
Lifeguard Systems, www.teamlgs.com
Contaminated water diving course: bring your own wetsuit.
When we read advertisements like this we cringe and then realize its time to write another article.
The one mission that must be successfully completed one hundred percent of the time is when the operation is over you need to go home. Proper personal protection equipment (PPPE) is vitally important to the success of that mission, with exposure suits being one of the most important pieces of PPPE for water operation personnel.
When choosing an exposure suit the first question to ask is what kind of water do you need protection from? Is the water contaminated, cold, full of debris, moving, or a combination of these variables? The next decision has to be what do you need the suit for? Will it be for public safety diving, swiftwater operations, surf rescue, boat or personal watercraft operations, or surface ice rescue? Other questions to ask include, what are the budget constraints, how many technicians and operations personnel need to be outfitted with suits, what is the turnover rate for team members, and how often will the suits be used?
Contamination is an important consideration that is often overlooked when the districts water is not currently contaminated. Floods, run offs from heavy rains, biohazards from bodies, creosote from pilings, and petroleum products from submerged vehicles can turn clean water into a hazmat situation. Too often we hear technicians say that they do not need drysuits because they have warm water and they would overheat. Proper procedures can prevent heat exhaustion, but only hazmat tested drysuits can protect technicians from contamination related illnesses.
Cold can also be a misunderstood variable. Water conducts heat twenty-five times faster than air. We lose heat at the same rate in 42o F air as we do in 80o F water. Some divers consider a wetsuit effective protection for winter water operations because they do not become cold easily, but are they considering what happens when they have to first sit as a 90-percent ready diver and then as a back up diver, prior to serving as a primary diver? Even surface rescue personnel must be prepared for unusually long operations and atypical weather conditions.
Everyone reacts differently to cold exposure and should be dressed accordingly. What is good for one team member may be completely insufficient for another. A navy study of the effects of immersion found that a higher level of body fat reduced the rate of rectal temperature loss. A 110 lb person losing heat at the same rate as a 250 lb person will most likely have a lower core temperature than the larger person. A study of 8 Navy combat swimmers in 6o C water showed that each diver appears to have a particular core temperature decline profile with respect to cold water exposure.
For example one diver may be perfectly comfortable using wetsuit gloves, while another will feel pain in 15 minutes while wearing an insulated dry glove. A previous cold injury can increase susceptibility to cold problems, even if the original injury was many years earlier. Individual differences between ability to withstand cold can be great and should not be ignored, especially in the grin and bear it atmosphere of police and fire personnel. Technicians and surface support should be observant of individual cold stress susceptibility of themselves and of their teammates. This means that if the team captain has been ice diving in wetsuits for twenty years without becoming cold that does not mean that wetsuits are acceptable for other team members.
A large percentage of outdoor drownings occur in water not designated for swimming, which means that trees, rocks, garbage, and other debris can be a real concern. Divers often must search in low or zero visibility water, forcing them to be bottom dwellers searching by feel. Ice rescue technicians may come in contact with spider wire and fish hooks, while swift water technicians may be pushed into sharp rocks or branches from strainers.
Once enough information is gathered about environmental variables, the teams needs, and department budget constraints, the next decision is what kind of suit is necessary? Most noncommercial divers wear passive exposure suits, meaning that the suits do not provide a heat source to the wearer, rather they provide insulation between the wearer and the environment. Active exposure suits are more commonly found on commercial diving sites and typically involve hot water suits. Public safety personnel can manage with passive suits because their in-water times should be much shorter than those of commercial divers. Passive suits are self-contained and far less expensive than the actively-insulated suits that typically burden divers with an umbilical and the need for highly trained water and surface support personnel.
There are, however, battery powered heating units on the market that are designed to be worn under drysuits by divers who move very slowly looking for small search objects in low visibility water, for divers who stay in one place for periods of time conducting research, or for ice divers who sit through the 90-percent ready and back-up diver positions before acting as a primary diver. Active heaters can also be helpful for divers who feel the effects of cold quickly, such as some women and individuals with little body fat.
Passive suits fall into two main categories, wetsuits and drysuits. Wetsuits help keep divers warm by trapping and insulating a layer of water next to a wearers skin. That layer is warmed by the divers body heat. The wetsuit itself is a spongy material with thousands of gas bubbles inside, which are the insulation that traps body heat. Increased suit thickness will increase the degree of insulation. If the suit does not fit well then cold water will replace the warmed water and heat loss will occur.
for more articles see www.teamlgs.com