Redundant Air Source Configuration

[BladesRobinson]

Indianapolis Fire Department has kicked the redundant air supply configuration question around a lot and has come up with a "keep it simple stupid" solution that I prefer over most others.

Their solution was based on the knowledge (fact) that there have been several "near miss" scenarios in recent years involving PSDs using "unnerving" redundant air supply systems.

Also, it is important to understand that Indianapolis Fire Department conducted their thorough research because they have paid the ULTIMATE price ... twice, with a line of duty death in 2000 and another in 2002. I assure you that today they have a well trained team and knowledgeable decision makers in place!!! They have done away with their recreational dive training and after exhaustive research they are now training with a legitimate public safety diving training agency and have adopted "real world" procedures. Today they think through every component of their system and have a committee that conducts thorough research before implementing a procedure.

Their solution is remarkably simple AND it is extremely safe AND effective!

The pony bottle is back mounted and is equipped with first stage and ONE single hose that attaches to a conventional second stage regulator which is secured to a neck strap. If one of their divers has an emergency, the diver doffs the full face mask and breathes off of the alternate second stage that is worn around the neck.

Some teams may debate the safety of this setup because of their perception of "diving in contaminated water." If the water is that bad that skin would melt from their face they would likely call in a commercial dive team.

Indianapolis conducted a risk/benefit analysis and determined that their frequent training and their systems approach for monitoring the diver's air consumption/supply would make using a redundant air supply unit a very unlikely event. Had they chosen to adopt an "unnerving" redundant air system, the danger would be present on every dive. Based on the number of real world "near misses" in the PSD community using the "unnerving" systems, they chose their KISS system.

The "exposure," if they had to resort to their redundant air supply is mitigated by time (it would only take 60 seconds or so to safely reach the surface), thorough decontamination procedures, and medical intervention if necessary (unlikely).

I will also mention that Indianapolis Fire Department has gone one step further in recent months and they are now using surface supplied air delivered through an Interspiro DP-3 system. This assures their divers with MAXIMUM safety. See: Interspiro DP1

 

[ditch-diver]

What "unnerving" redundant air supply systems? I know there are more than a couple out there. I don't have the knowledge(Facts) you speak about in the near misses, but am always looking for more facts.

What "legitimate public safety diving training agency" are they training with??? You are well known and respected here Blades, IMO I do not think anyone would object to you saying "this is what DRI does and such and such FD now trains with us and are very happy with the training and set up we provide."

What is DRI's and IARDS's stance on redundant systems, Blades?

When PADI came out with their PSD thing a little while back, everyone was up in arms because their line pull signals were different that the major training agencies for PSDs. Has any attempt been made in the training agencies to standardize PSD gear configuration? Wow.., that'd be a herculean task, but if possible, what a massive result!!!

Most of the PDS team I have spoken with in discussing redundant air systems, was the desire for a diver to go on bail-out without losing comms with topside and or his/her rescue diver coming in. A pretty nice feature for a diver to have, not to mention for a sup to be able to further monitor his diver and relay instructions/directions. Contamination wasn't even a factor

 

[BladesRobinson]

There are several teams that (IMO) have over thought the redundant system. The "unnerving" systems are ones where teams have added quick disconnects so back-up divers can plug additional air sources into the system, back feed air through the first stages, connected air lines to nipples & quick disconnects using hose clamps, etc.

The RSV is another system that I have concerns about based on the following facts:
1) They were not designed with support from Interspiro. The Delrin second stage on the Interspiro mask was not designed to have forces applied at 90 degrees. This is the angle required to support the RSV and switch from the primary to secondary air supply.
2) There have been incidents where divers have begun their dive with the RSV in the wrong position and divers have not initially been aware of the error. After a short period of time they run out of air and when they perform their reflexive gross motor skills to activate the RSV, they still don't get air. In Idaho, this scenario resulted in a near fatal accident involving a PSD under ice and it was only because of the prompt rescue by the standby diver, and good ACLS skills of topside personnel that the diver was successfully resuscitated.
3) They are not approved by the U. S. Navy, likely for the reasons previously mentioned.

The Kirby Morgan valves offer (IMO) a better option but they too have challenges. During a visual gear inspection, one cannot determine if the valve is open or closed unless they place their hand on the valve and turn it to check. This is true of the tank valve too and one would think that we could trust divers to have their air supply valves in the proper configuration but we know better and that is why most conduct an equipment check before the diver gets into the water. In a rescue mode, sometimes this check is overlooked and problems occur.

In another instance a unit went out for service and when it was returned, the low pressure supply hoses were switched at the local dive store. A well trained public safety diver began his dive on the redundant air source and shortly into the dive, ran out of air. He then switched over to primary system and aborted the dive after making a safe ascent.

My concern is, when these "safety systems" are the cause of an out of air situation, we need to step back and re-think these systems.

Are they REALLY safe??? I realize that is sounds nice for a diver to go to a redundant system without loosing comms or removing the FFM but the reality (facts) are that most out of air situations I am aware of are the result of improperly configured "safety systems." If we eliminate the option for them to be configured improperly (as the Indianapolis Fire Department did) I think we have a safer system.

In the hands of a well trained diver the switch block "safety systems" are likely to be safe.

We know though that well trained divers don't typically run out of air underwater. Poorly trained divers are more apt to run out of air underwater and these poorly trained divers are less likely to use redundant switch block air supply systems safely ... and sometimes begin their dive with switch block configured improperly.

Over the past year I have been honored to speak around the country on the lessons learned from more than 60 line of duty deaths involving public safety divers. Many people who are designing their team's redundant air system are concerned about divers getting pinned under/inside vehicles ... the stuff of Hollywood fiction. I am not saying that it couldn't happen but in 50 years of public safety diving, it hasn't happened. Consequently, I and others draw the conclusion that the scenario is "unlikely." Should we anticipate unlikely scenarios? ... sure! ... But not at the expense of SAFETY!!! Again, when these "safety systems" are the cause of accidents, the PSD community should be concerned and take notice. What sounds good isn't always ... so we need to think hard and look to past history for guidance.

It is my opinion that divers should NOT run out of air.

We teach divers to monitor their air supply, we teach tenders to monitor the diver's air supply, we teach the safety diver to monitor the primary diver's air supply, we have a 90% diver that is also monitoring the primary diver's air supply and by the time we factor in safety officer, team leader, etc, we have redundant "systems" in place to prevent an out of air situation. Bottom times are limited (typically to 20 minutes or less) and the divers are being pulled from the water with 1,000 psi (>24 cf) in "reserve."

It is my opinion that DRI and the IADRS should provide public safety divers with good information so they can make good decisions. I believe the people we interact with are smart enough to make good risk/benefit decisions and good cost/benefit decisions.

I believe if divers are working an area where severe entanglement is likely or in environments that are "high risk" then I believe they should use commercial divers or at least commercial diving equipment that would include surface supplied air and consider the benefits of dive helmets.

For some teams the cost/benefit analysis would lean towards hiring a commercial contractor for the "once in one hundred years" scenario and for other teams, the cost/benefit may warrant the purchase ... until they conduct the risk/benefit analysis and determine that their training may also warrant the hiring of commercial divers.

These are team decisions that are made with good information. Dive Rescue International and the IADRS supplies this type of "real world" information to dive teams and allows educated PSDs to make these good decisions. We are not in the business of dictating to dive teams, and we only offer suggestions based on each team's unique circumstances. I believe many refer to this as a "common sense approach."

Ditch-diver draws a correct conclusion regarding my reference to a "legitimate public safety diving training agency" but I think it is improper for me to pat my back too hard. And I recognize our training partners like LGS, ERDI, PSDA, IANTD, NAPD and others in the alphabet soup for their programs. Nearly all of us know the benefit of "legitimate PSD training" and the lessons we know today come from the blood, sweat and tears of fellow PSDs that have gone before us.

I am grateful to those who have shared their lessons with me so we can pass them along to others. And today I pause ... to pay tribute to those who have died in the line of duty. May our brothers, and sister Alane, Rest In Eternal Peace.

Fraternally,

Blades

 

[BladesRobinson]

Ditch-diver also asked why the PSD training agencies couldn't come up with a standardized gear configuration.

I wish all of the training agencies could work together but the fact is, we can't. Many years ago, in an effort to standardize line signals I suggested to one agency that we both drop our current line pull signals and work on a common system. I went so far as to suggest that we pull out of a hat the messages we wanted to communicate. It was a sincere attempt to make PSD safer but the other agency refused.

I know that #### pictures a diver using a RSV in their program and ### strongly supports their use. Frankly, I cannot condone the use of the RSV based on information supplied by Interspiro (the manufacturer of the FFM they are commonly used on) and past history that includes "near miss" incidents.

Additionally, if every training agency agreed to do things identically, then each agency would also loose their identity, no one would be better and as a business, no one would stand out as being the best.

Selfishly (and I apologize for being selfish) I prefer having one training agency stand out.

The bottom line is, when training agencies cannot agree on something as simple as line signals, I am not optimistic that we will ever have a unified consensus on gear configuration. "Technical divers" debate the same issues as to the benefit of being streamlined and minimalist to carrying everything needed to survive a nuclear Holocaust and a tsunami.

Again, our goal at Dive Rescue International is to explain the pros and conns based on facts and real world scenarios and allow smart people to make good decisions. These decisions will vary based on a dive team's unique need, cost/benefit analysis, risk/benefit analysis, and education.