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Frequently Asked Questions
A-1 What should a Public Safety Diver look for in a buoyancy compensator? A-2 What type and size of line is best for ice and water operations? A-3 Can I use a rappelling harness for water/ice operations or diving? A-4 Do I want leg straps for my harness? A-5 Should I wear an octopus as a Public Safety Diver? A-6 Why do I need a contingency strap? A-10 What can I do if my AGA leaks?
B-1 Is there a table with the descent rates for different objects (i.e. rifles, pistols, etc.)? B-5 Can a team safely run a
dive operation with four people? B-6 What is the Valsalva
Maneuver B-7 What should you do if the
water is deeper than 60 feet? B-8 Could you clarify the NFPA
levels of duty? Awareness, Operations, Technician B-9 Are there any major differences in procedures between an urban and a small rural team?
A-1 What should a Public Safety Diver look for in a buoyancy compensator? Something with all or some of the following features:
The Lifeguard Systems BCD meets all these requirements and more! A-2 What type and size of line is best for ice and water operations? 3/8" (9mm) highly flexible, floating line with some stretch is best for ice/water rescue/recovery operations not requiring low or high angle rigging.
Line with 1500 lb. tensile strength will do the job well. A-3 Can I use a rappelling harness for water/ice operations or diving? No, not unless rappelling is part of the rescue operation. Rappelling harnesses have tether points low on the torso, putting the person in a vertical position. In the water or ice, we need to be in a horizontal position for a variety of reasons. Low tether points make extrication from an ice hole very difficult or impossible, can result in drowning, and are completely wrong for divers. A-4 Do I want leg straps for my harness? NO, we do not recommend them for most types of operation, and do not use them for diving.
A-5 Should I wear an octopus as a Public Safety Diver? NO! Octopuses are for shallow water, high visibility, buddy, sport diving. They are NOT a true alternate air source and do absolutely nothing for you if you use up your air. An octopus is only a second mouthpiece. It is strictly for a buddy, not for you. Public Safety Divers, deepdiver, ice divers, and low/no visibility divers belong in quick-release pony bottles, which supply a true alternate gas source and can be passed off to an entangled diver. An octopus not only does nothing for you, it actually becomes a safety hazard when it causes entanglements. In ice diving, an octopus significantly increases the chance of freeflowing, which is a definite hazard. A-6 Why do I need a contingency strap? The use of a contingency strap allows contingency divers to descend to the primary diver without pulling on the primary divers tether line. This is important because pulling on the line could increase the severity of an entanglement problem and could drive a fish hook deeper in. The contingency strap also allows the contingency diver to have two hands free without the possibility of losing the primary divers tether line. The strap should have enough length to allow some maneuverability around the primary diver, but not enough length to allow it to reach the primary divers throat if the contingency diver attempts to rise and reach behind the primary diver. The strap has a quick release buckle in its center that allows the contingency diver to disconnect from the primary divers tether line and work behind the primary diver. A-7 We use full face masks, pony bottles, and blocks and dive in
contaminated water. If our pony bottle runs out of air what can we do to access more air
without removing our full face masks and exposing ourselves to contaminated water? Butch designed the concept and functioning of the RSV-1 second breath block for that very purpose. The pony intermediate pressure hose is connected to the block with a quick-release connection such as a Scubapro Air II hose. If the pony runs dry a contingency bottle with the same hose on its regulator can be connected in. This does take practice though. Do not expect to do it without repetitive, stress-loaded training. A-8 Is there really a
difference in total air consumption when using an AGA as opposed to a conventional
regulator? Yes. We have found that divers using positive pressure AGA masks uses 10 to 20 percent more air. Demand AGA users can use about 10 percent more air. A-9 I need an opinion on
FFM comm systems. I initially thought to go with a hard wired rope system, due to needing
a rope anyway on search patterns, then thought maybe a wireless would be better, because
in a pinch, we could use any rope? That is a question many teams face. We recommend hardwire comms
for teams who dive tethered. Wireless comms can be a real annoyance sometimes. OTS makes
the best comm. Systems out there and even with their wireless comms we find more problems
than with their hardwire systems. When wireless comms work they are great, but they are
more of a headache more often. Hardwire if taken care of properly, and if it is an OTS
system, will almost never fail. It takes
seconds to set up. It is not another thing to worry about because it becomes the tether
line, and all the tender does it connect the batteries, don the headset and turn on the
box clipped to her belt or backpack. A-9 What can I do if my AGA leaks? You need to ensure the mask is donned correctly and must be sealed against the
skin or a latex hood. It will not seal (properly) against a neoprene hood. When donning
the mask, you must ensure all the straps start at their full length, then put your chin in
first or ensure your chin is seated in the chin pocket. Then Pull the straps BACK (towards
the back of the head) on the chin straps then the temple and then just lightly snug the
top. The mask will fit in this manner for about 85% of the people. If you have a very
narrow face or a very wide or large face you will need some modification. B-1 Is there a table with the descent rates for different objects (i.e. rifles, pistols, etc.)? What this question is referring to are drop rates of objects. Drop rates are used in conjunction with current and depth to calculate the most likely location a search object will be on the bottom. Use the drop rate and the depth to calculate how long it will take the object to drop. As long as it is in mid-water, the current will affect it. So for examples we have found that on average a human body will drop at about 2 feet per sec on fresh water and 1 to 1 ½ feet per second in salt water. We do not have a table for other items. We suggest that when a call comes in to search for a particular object, find a similar one and do a re-enactment. B-2 How do you decide how wide to make each sweep in arc, dock walk, or
other solo-tethered-tender-directed-diver patterns? The following is based on solo-tethered-tender-directed diving.
The distance between sweeps depends on the size of the search object, bottom composition
and visibility. Let us first look at visibility and bottom composition. Consider a silt
bottom lake with ten foot visibility when it is undisturbed. This last word is very
important. Few divers have been trained how to cruise a foot off the bottom without
kicking up any silt. Therefore, that ten foot visibility can become zero visibility in
matter of seconds as an over-weighted diver lands on the bottom. Now we can look at the search object size. If it is an adult
body then the sweeps can be ten feet wide. That allows the divers the ability to double
check each area between sweeps, which is a good idea because sometimes a 180 degree angle
change could make a difference. B-3 Other than attention
span, is there any reason to limit a zero-visibility search dive to 20-25 min. if
conditions are good? Attention span is a key issue when it comes to searching. For those of you not familiar with this concept, we know that for most divers on a zero-visibility dive, after about 15 minutes there is a little voice that says something to the effect of, why am I here?..., lets get this over with After 20 minutes the little voice has been known to say, Its not here, Im not going to find it here Once that happens, no matter how hard you search, your search quality has decreased. Divers need to have constant minds eye focus to visualize everything they touch. Most teams have a diver that we call a magnet. This magnet will find whatever you want as long as you put the magnet in the right area. Magnets have nonstop minds eye focus with a 100% belief that they will find the search objects. Most of us can keep this going for 20-25 minutes in blackwater. Yes, there are other reasons. How do you feel after doing an effective search dive that lasts 40 minutes? Whipped. Can we put you back in safely and effectively in an hour to do another search? No. If we keep searches to a max of 20-25 minutes then we can put the diver back in, in an hour after hydration, if the diver is warm enough. Therefore if a team has three divers and two tenders (primary, backup, and 905 diver, with a primary and backup tender), they can easily conduct 9 search dives in less than 5 hours which is one dive short of 30,000 square feet for an adult body in blackwater. Nitrogen absorption is another issue. If the team stays with the 50-60 feet depth and 20-25 minute dive maximums then decompression sickness is not a major concern. If you start allowing 30 minute, 40 minute dives, then dive tables become mandatory, and how many tenders can do dive tables?Air management is another issue. Most divers in no current dives can easily perform a 20-25 minute search dive in 30 or 40 feet of water and come back with more than the 1000 psi minimum to be back on deck with. Add the adrenaline of a real call in a rescue mode and air consumption can easily double. Then that 20-25 minute time is not that short. Or, add a current. A diver who normally breaths 20 psi/min SAC can easily go to 100 psi per minute in 15 feet of water in a 1.5 knot current. A depth air consumption rate of 100 psi /per minute means the diver should only have a 15 minute dive.If you go to 55 feet, then 20-25 minutes may be too long in regards to air since the diver will be breathing almost three times the amount of air as on the surface. Other factors such as exertion and cold can also greatly increase air consumption. Attention span also relates to the primary and backup tenders. Primary tenders have to keep all their visual and mental focus on their divers, and have to make sure the search pattern is accurate. Backup tenders have to have equal vigilance regarding search pattern accuracy, diver breathing rates, and diver search rates, and have to accurately record all this information on the search pattern profile map. In the hot sun, in the cold, even in average weather conditions, how long can tenders maintain safe and effective, continuous vigilance? We have found this to be 20-25 minutes. Then consider that backup and 90% divers are waiting their turn to be the next primary as they sit or float as contingency divers for the primary diver. If the primary diver has a 45 minute dive, then the backup has to wait 47 minutes to dive and the 90% diver has to wait over an hour and a half to dive. If it is too hot or cold, that could mean that one primary diver wipes out two contingency divers. What an unnecessary waste that will also cause frustration and future voluntary dehydration on the part of contingency divers who refuse to wear adult diapers. So yes, attention span and searching quality of the primary diver, attention span and vigilance on the part of tenders, air management, and nitrogen absorption are all important factors that make 20-25 minute max dive times for non-ice conditions. In ice conditions we use 15-20 minute max dive times. B-4 When doing an arc
pattern, what is the average goal of how long an arc sweep is? What is the angle of the
arc? Usually if you use a ¼ of a circle as your arc then you will have a decent size search area. Sometimes teams listen to a convincing witness and make a very narrow arc. Generally, thats not a good idea. Dont short cut. Also, if you make a ¼ of a circle arc pattern (the pie shaped piece of search pattern is a quarter of a pie) then you can easily figure out the length of each divers sweep by plugging in the divers distance out into the chart we have in our book Public Safety Diving (PennWell Publishing, 340 pages, 2000). Then you can add up each sweep and see if the divers search rate was good for the size of the search object. If the rate was too fast then the area may need to be re-searched. B-5 Can a team safely run a
dive operation with four people? Our standard requires three divers and two tenders: primary
diver, backup diver, 90%-ready diver, primary-tender, backup-tender. Butch came up with
the term 90%-ready diver more than 20 years ago, but he did not make it mandatory for our
standards until about seven years ago. The reason he made it mandatory was because he
observed a few occasions when a backup diver was not able to get to a primary diver in
less than two minutes either because the backup diver could not equalize or had an
equipment failure. We are constantly working a contingency plan
that has an extremely high chance of succeeding. If a call comes in for an officer down in
a law enforcement incident, or a firefighter down in a fire issue, is just one backup
person sent? Now there is a way of getting around only having 4 people. We did this with
the Paratroopers in B-6 What is the Valsalva
Maneuver An understanding of Boyles law is primary to understanding
the function of a valsalva maneuver. As ambient pressure increases the volume of a gas
correspondingly decreases. Imagine an upside down empty bucket with a ten pint volume.
Push it under the water with the open side down to 33 feet and the volume of the gas
inside the bucket will be 5 pints with the gas having twice the density as it had on the
surface. As we descend in the water the gas density in our ear increases with the
increasing pressure and the volume of the gas decreases. That is what causes discomfort
when we swim to the bottom of a pool or descend in an airplane. In diving the Valsalva
maneuver refers to holding the nose and mouth closed and gently blowing against these
closed airways. The result is increased pressure that forces air into the eustachian tubes
into the middle ear. This is done to equalize pressure in the middle ear when a person
descends to a greater ambient pressure such as when diving into a swimming pool or
descending form altitude in a car or plane. Gentle is key word because a too forceful
valsalva can result in a round window rupture and an oval window break both of
cause serious vertigo and potential damage/infection to the inner ear. B-7 What should you do if
the water is deeper than 60 feet? The LGS standard for low visibility searches is 50 feet with a
possible 10 foot extension for teams trained to the Phase 2 level. If your community has
water between 60 and 100 feet and wants your team to be capable of searching at those
depths then the community has to come up with the funding for the training and equipment
to do such dives. The training is not only for the team but for the local B-8 Could you clarify the
NFPA levels of duty? Awareness, Operations, Technician Awareness training is usually about 4 hours in duration and teaches students how not to do further harm. Anyone who would respond to a specific type of scene should have at minimum awareness level training for that type of incident. Examples included ice, ocean, and moving water. Awareness level personnel can secure the scene by designating hot, warm and cold zones. They can identify hazards, number of victims, begin interviewing witnesses, and can call for appropriate resources to the best of their ability. Operations personnel can perform all duties of the operation that do not involve direct contact with the hazardous atmosphere, which is defines as an atmosphere that does not sustain life. Water fits that definition. Technicians are at the highest level of training because they have direct exposure to the hazardous atmosphere. In surface ice incidents chief tenders, line handlers and other shore personnel would be at the operations level, while the rescuers who go on the ice are at the technician level. In diving incidents tenders are operations and divers are technicians. Ice diving operation tenders are in a gray zone between technicians and operations because in real incidents the ice is unsupportive. A real call means one victim already fell through, so there is a good chance that tenders will fall through and will have to perform their duties form in the water. Such tenders wear the same personal protection equipment as surface ice rescue technicians. Incident command should have at minimum awareness level training, and a technician level advisor should be consulted when making a plan of action. B-9 Are there any major
differences in procedures between an urban and a small rural team? There are many factors to consider. Number of available
personnel per shift is an example. FDNY Rescue Company dive teams were easily able to meet
the minimum 5 personnel necessary to run a dive call, while Game Wardens in B-10 Ive been in
lakes where the bottom is made up of feet of pulpy weed waste matter. Is it
recommended to descend into this pulp layer to find solid bottom while searching? That depends on what you are searching for. The average child weighs 4-6 lbs underwater and the average adult weighs 9-18 pounds. If you are looking for an adult, and you as a diver are weighted to be 2 lbs negatively buoyant then lay on top of the weeds, and exhale to see how far you sink in the weeds. Every pint of air is equal to about a pound of buoyancy. A normal tidal exhalation is less than a pint. A full exhalation can be more than six pints. If you exhale six pints for example, then you are 8 pounds negative. A child would not sink as far, an adult may sink further. If you are looking for evidence, use a similar object and perform a re-enactment to see where the search object is most likely to be. B-11 Once you rescue a
victim as a public safety diver are you required to start CPR as your tender is pulling
you to shore if there has only been a few minutes from arrival on scene to finding the
victim? CPR is not known to be effective in the water so that is not
something that is done. In the old days, for example in the 1970s LGS used to train
PSD divers to initiate mouth-to-mouth because back then EMS often called a long term
drowning victim dead. By initiating rescue breathing,
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Contact us at: LGS@TeamLGS.com Lifeguard Systems, Inc. Box 594 Shokan, NY 12481Phone: 845-657-5544Fax: 845-657-5549
Copyright © 1998 Lifeguard Systems, Inc.
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