Many years ago, divers do not have much of an option to customize their dive gig. It is black or black. Came braided hoses, divers have been overwhelmed with choices of colors. And beside colors, braided hoses are also more flexible and easier for storage.
Like many other divers, Orpheus Dive likes to check out for new innovations in diving gear, and helping divers reduce bulk and weight while traveling is one of our main priority. A full set of dive equipment in a typical roller bag (which is already about 4 to 6kg on an empty bag) weights about 20 to 25kg. And this is excluding your DSLR underwater setup.
When the nylon-braided hoses became available, they piqued our interest for the potential benefit of being lighter and more compact.
On the technical side, braided hoses are extremely tough and durable. They are manufactured with an inner liner layer of polyester and polyurethane compound line, which makes them stronger and gives them a proven lifespan longer than traditional hoses. Their low-pressure regulator hoses are manufactured to a burst test pressure of 3600psi, which is twice that of traditional hoses. Braided hoses are approved to EN250 standards (European normative standard), and now have a 10-year track record on the market. During manufacturing, 30 individual safety tests are made during production on every hose. And on the practical side, the hoses are 30% lighter than traditional hoses and extremely flexible. Because of their flexibility, you can literally tie a braided hose into a knot and have uninterrupted airflow, with no kinking. While that won’t likely happen on a typical dive, their lighter weight and smaller profile do have several practical advantages.
But in the last few years, a new trend has emerged. Many divers are buying braided hoses from unknown sources and the issues are surfacing.
April, 2017 issue of Undercurrent.
While most of our subscribers are members of DAN, and therefore, receive their magazine, Alert Diver, we think it’s important to call attention to a recent story (winter 2017 edition) that points out a potential problem with the lightweight, flexible hoses that have replaced the old, standard, rubber-covered regulator hoses. They are so flexible, they can be tied in knots!
DAN has reported a regulator failure that was caused by this type of hose becoming restricted in such a way that for the diver, it seemed as if he was out of air; however, the tank was not empty. The inside of the braided hose had become blocked with a polymorphic crystallization related to the molecular structure of the internal tube — a phenomenon associated with cyclical heating and cooling.
It seems that the sun may heat up the hose, and when the tank valve is opened, the flow of depressurized air then cools it rapidly. This happens before every dive, causing tiny crystals to form and accumulate over time. As they grow, these crystals can either block the hose or migrate into the second-stage, resulting in a significant failure.
The incidence of failure is quite small. However, because this occurs internally, it is not visible to a diver looking at the hose, so the deteriorated internal surfaces go unnoticed. That means divers should periodically examine these hoses by squeezing them every inch or so along their length to assess whether they exhibit the same degree of flexibility. Any change in resistance would be a sign of an impending problem.
If you’re diving in hot tropical climates, you need to know that DAN believes these hoses have a limited functional life, because the internal surfaces appear to be prone to this crystallization in hot weather. If you notice any gas-flow restriction, cease using your regulator.
To better understand the phenomenon, DAN wants more information. If you observe this degradation in your regular hose, please contact DAN, preferably with pictures showing the condition of the hose. [email protected]
Scubapro has also issued a notice against swapping their high quality hoses for braided hoses. There has been more and more reports of third parties braided hoses failing in our tropical weather. Personally, we have encountered a few incidents as well.
For those divers who are already on braided hoses, it is highly recommended that you have to changed every 5 to 6 years. It is almost impossible to check the integrity of the hoses during your annual servicing and having them change every 5 to 6 years is highly recommended.