confined space

Diving Dangerous Waters – Hazards of Confined Spaces

by Benjamin-James R. Yates

There are times that arise in diving when things go wrong.  It is just a fact of life.  When these times come, people either know how to handle the situation or they do not. In the times when they do not, someone has to be called in to take care of the aftermath. Normally, this duty falls to public safety divers. Whether they are with a Police Department, Sheriff’s Department, Fire Department, or another agency, nobody enjoys these moments. But when called upon to perform the hardest tasks a diver has to deal with, we go. Knowing from the moment we are notified that it is already a hard and potentially dangerous situation.

Confined Space
During these times there are numerous levels of awareness and training that are taken into account in order to complete such a task. No matter how much training has taken place beforehand, there are always hazards that public safety divers can potentially encounter. One of the worst hazards to deal with is being in a confined space. Let’s address a fact of this situation now. As human beings we are land based, air breathing (21% oxygen, 79% nitrogen) mammals, that have a skeletal structure in order to facilitate our existence in our normal environment. We are warm blooded with unique skin layers to protect from the sun, not necessarily cold, wet environments. We are far from being an octopus that can squeeze itself into a bottle through an opening smaller than our thumb to get whatever it wants inside.

There is a list of additional hazards that can be added to the problem of diving into confined spaces. These include, but are not limited to, the amount and  type of gear involved (for starters: hazardous materials dry suits, breathing systems, additional weight systems, tools, full face masks with communication units, and the universally loved tender line); limited, to no, visibility (black water); and entanglements.  Altogether, the list can continue for as long as the imagination will allow.

Beginning the Dive
As with all dives, ours begins from either a shore or a platform of some type (a boat, a dock, or a pier). Here, the diver (you) and supporting team are going to prepare for the operation. You don gear, including thermal layers, a hazardous materials dry suit, buoyancy compensator (possibly with additional weight system), and full face mask. Each piece added has now made you bulkier than normal. Your air is turned on, communications are connected and checked, and the diver is assisted to the water by a tender.  After what feels like an eternity of preparation and safety checks, you are finally ready to enter into the unknown. At this point your heart is beating faster than a sprinting runner because you do not know what you are going to encounter. This is the time to attempt to remain as calm as possible. Unfortunately, that is easier said than done.

The faster your heart rate is, the faster your other bodily functions are going to be working. This includes your breathing. On average, a public safety diver will be entering the water with an Aluminum 80 cubic foot scuba cylinder. That cylinder is pressurized to 3000 pounds per square inch. The amount of time you can breathe off of that cylinder is going to be dependent on a number of factors, including the diver’s depth and workload. Most public safety divers are not allowed to exceed 30 minutes due to safety protocols that are put in place to protect the diver. The diver’s time is normally monitored by someone on the shore or dive platform and relayed to the diver, who in turn, relays current cylinder pressures back. If these are not closely monitored, an already bad situation can become far worse. Being in a confined or enclosed space makes this critical as there is possibly no direct route to the surface.

Visibility
As we make our descent the natural light that penetrates the water has already begun to fade. Depending on the type of body of water, temperature, sediment, and other factors, we may begin our dive in limited visibility. Now we have added another hazard from the start. It does not take long for limited visibility to become no visibility. The level of visibility can change almost instantly. This is why most operations of this type are conducted during daylight hours depending on the circumstance. During these situations flashlights can become a problem more than a benefit since there is the possibility that the high powered beam given off by the light can be reflected back in turbid water. Imagine being at a depth of 8 feet, with your visibility being 1-2 feet in front of you, and upon descending to 9 feet everything goes black. I do not have to imagine it because this happened to me during a recovery dive earlier this year.

Public safety divers typically conduct operations in one type of exposure protection. This would be a Hazardous Materials Dry Suit made of vulcanized rubber. The reasons this is the preferred type of suit are too numerous to list, but all have the potential to cause extreme health concerns to the diver. Unfortunately, if there is debris in the water, jagged edges on metal objects, or other snag and entanglement possibilities, there is a chance something could puncture or tear the suit as well as cut the diver. This also becomes an issue for other gear that is required for this type of operation. The buoyancy compensator, air hoses, and tender line are only a few. Crash sites, areas with sunken trees, and wrecks are likely places for a diver to become entangled. If these areas require the running of guide lines as well as tender lines, they present an extra element to this hazard.

Communication
Have you ever heard the expression, “Communication is key”? Being able to speak with someone else is a comfort to most people. In order for a public safety diver to do this underwater we must use a full face mask with a communications unit of some type. Some are wireless units that operate on batteries and radio frequencies, but now someone has to make sure the batteries are fresh or they could run out during the dive. Then who are you going to call? Nobody. The units that most agencies prefer integrate communication lines inside a woven rope which is now tethered to the diver. This also becomes a safety line for the diver in the event something happens and they need to be pulled out. Unfortunately, this also becomes another entanglement possibility.

All of the hazards previously mentioned apply to any situation. Cars or busses that become submerged have windows that may need to be broken in order to recover people from inside. Airplanes could have to perform either an emergency or crash landing in a body of water. It has happened before. When this occurs, all types of hazards are now present. Floating debris from luggage, jagged metal from broken apart pieces, and fuel from engines, not to mention what a diver may come across inside the cabin of the aircraft. Another situation no diver likes to discuss is the possibility of flooded service tunnels. These tunnels include sewer lines that workers may be working in or subway lines that trains have become trapped in at the time they became flooded. Hurricanes are a prime cause of such disasters in areas that support these types of services. These places and situations present great danger to any public safety diver. Everywhere around these scenes a diver may find entanglement and environmental hazards.

So now we are in an underwater confined space. It is cold and there is the chance we are diving in contaminated water. We are possibly in zero visibility so we cannot see how much air we have left. Eventually we are going to deal with our safety line becoming entangled or snagged. It could be as simple as being caught on a branch or as complex as being run through a flooded service tunnel. At this point we have four options: disconnect our communications and safety line, trace it back to the source of the problem, call for a safety diver, or wait for our air to run out. Which would you prefer?

We Will do the Job
These are a few of the things that any public safety diver might have to deal with if they go into a confined space. Keep in mind that a confined space can be any space that hinders movement. This could be a wrecked vehicle, a cave, even a piece of cement culvert tubing in a scuba park. Either way, you are confined. Please keep these things in mind if you think you want to attempt to dive beyond your training level and experience. We will do the job if we are called upon to do so, but that does not mean we will like it. To operate in confined spaces, a dive team must consider participating in true Confined Space Operations training. This type of program may at least prepare divers to remain calm, stay focused, and work to overcome possible problems.


Benjamin-James R. Yates – Public Safety Dive Professional – Air Hogs Scuba – Garner, NC

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