by Thomas Powell
In the public safety world, gas fills can become complicated. Fire stations must follow OSHA regulations, and fill station operators require training that is not required in standard dive shop environments. If a person were to speak to most current dive team leaders in the United States, they would insist that mixed gasses of any sort, and even basic nitrox, are not allowed in public safety diving programs. Extensive research will show that, in the majority of cases, there are no standing rules preventing the use of nitrox or mixed gas. The reality is that not every public safety dive team has easy access to a fill station. The difficulty acquiring basic air scares team leaders and oversight bodies away from the complications of obtaining gasses that may be even harder, and more expensive, to acquire.
Helitrox is a breathing gas made up of nitrogen, helium, and oxygen. The proper mixtures of these gasses can allow a diver to function and operate at depths beyond the range of standard air fills. In the modern world helitrox is often used by technical divers or commercial divers undergoing complex and often deeper dive activities. To perform technical dives using helitrox, a diver must understand the physiology associated with how the gas can affect the human body underwater, and how to plan for a dive that may involve soft or hard ceilings. To date, advanced mixed gasses have rarely been used in public safety dive training programs or operations. Despite this fact, roughly one year ago, the entire world saw a group of commercial divers, diving helitrox, recover a man who had been submerged in a trapped shipwreck for three days. The gas being used allowed divers to remain underwater and perform an unplanned recovery.
The United States is bordered by two major oceans and consists of a vast number of deep waterways within her interior. When looking at these bodies of water, operational dive teams must recognize that one day they may be called to perform a recovery, or even a rescue, at depth. Imagine that a diver has been trapped at depth while diving helitrox. If a rescue is possible, the team performing the operation must understand the physiology associated with the gas being inspired by the victim. This knowledge will allow the dive team involved to best plan a rescue and return to the surface that does not exacerbate already existing problems.
Similarly, certain bodies of water in the United States exist at altitude. This factor makes even recovery operations go off standard “table diving” scenarios. Essentially, a one hundred foot (deep) recovery dive may be converted to a deeper theoretical depth based on altitude. This factor suggests that divers at altitude may be safer if they have a good knowledge base and understanding of how to use mixed gasses. One of the most interesting things to do with a diver is to let them do comparison dives between helitrox and air. Essentially, let the diver do a dive on helitrox and then later do a dive on air. Then have the diver determine which dive is more memorable. The helitrox dive will be better remembered. This scenario shows that helitrox allows a diver to remain more “clear-headed.”
In the world of public safety diving, being clear-headed and cognizant of all operational activities could save a life. These divers already perform activities in near-zero visibility using a sense of touch. If a problem arises, a clear-headed diver may be more prepared to correct issues or solve problems. Similarly, a clear-headed diver may better remember dive-related details essential to a courtroom scenario.
There is no reason for a dive team to avoid gaining improved levels of knowledge. In many cases, leadership personnel will establish a goal for public safety dive teams. This goal may be the completion of a course such as ERD II. Once that goal is achieved, leadership often turns to team status maintenance. New divers get trained, and current divers do in-service training. This mindset often leads to a lack of focus and the establishment of a normal routine. Education requires a break from this routine and a focus on continued improvement. Even if a dive team does not dive mixed gasses on a regular basis, an understanding of the related dive theory will help dive team members better acknowledge how gas can affect the human body.
Mixed gas diving requires strong education and a focus on learning how to be safe at deeper depths. Despite this, helitrox can allow emergency response divers to perform activities for longer periods, with clearer minds, at deeper depths. A dive team must determine if mixed gas diving could play a role within its territory, and then consider if the team wishes to be available for extended range calls for help in an area exceeding local territory boundaries. At altitude, helitrox diving may be essential to remain safe. Closer to sea level, helitrox diving may be an activity that is beyond the skills set desired by a team. Team leaders must work to make the best decisions possible in regard to team capabilities and knowledge bases.
In North Carolina, the staff at Air Hogs Scuba is working with various dive teams to begin developing a better understanding (for team members) of how gas affects the human body. Three teams are currently working through the TDI Nitrox program as a starting point. The objective is to learn the math, and better understand how to draw personal conclusions regarding how to dive differing gas mixtures. This course is the entry-point for dive teams considering mixed-gas response capabilities. No dive team should turn down educational opportunities provided within reasonable parameters, and helitrox has its place in public safety diving. The reality is that teams have to make the move to become more educated and step outside normal training parameters. Actions of this type will give dive teams greater capabilities, and an improved potential for performing operational activities in expanded environments.
Owner/Instructor Trainer – Air Hogs Scuba