Technical diving is a type of diving that goes beyond the limits of recreational diving, usually deeper than 40 meters. Trimix is a breathing gas used in technical diving and consists of oxygen, helium and nitrogen.
Why use Trimix?
- Reduced nitrogen narcosis: Nitrogen narcosis, a state similar to intoxication, can occur at greater depths. Trimix reduces the amount of nitrogen in the breathing gas, reducing the effects of narcosis.
- Lower gas density: At greater depths, the gas pressure is higher, making breathing difficult. Helium, a less dense gas than nitrogen, improves the work of breathing at depth.
Composition of Trimix
Trimix gas is formulated depending on the depth of the dive and the desired properties. Consider these factors:
- Partial pressure of oxygen (PO2) the level must be kept within safe limits throughout the dive to avoid oxygen toxicity (convulsions). At greater depths, it is necessary to use a lower percentage of oxygen in the mixture.
- Equivalent narcotic depth (END) refers to the depth at which a diver would experience similar narcosis to breathing air at a given depth. The aim of the Trimix is to achieve the desired END (usually shallower than the actual dive depth) to manage narcosis.
Trimix examples
This example provides examples of Trimix gas mixtures for various diving depths:
- 60 meters for diving Trimix 20/40 (20% Oxygen, 40% Helium, 40% Nitrogen) can be used. This maintains a safe PO2 level and reduces the END to about 30 meters.
- 120 meters for diving Trimix 10/70 (10% oxygen, 70% helium, 20% nitrogen) can be used. It maintains safe PO2 levels and reduces END to 30 meters.
- 200 meters for diving Trimix 5/90 (5% oxygen, 90% helium, 5% nitrogen) can be used. However, even with this mixture, the gas density is still high. For such diving depths, rebreathers are often used to improve gas management and decompression control.
Important consideration
- Superficial security: Some Trimix mixtures are not safe to breathe on the surface due to low oxygen content. Divers must reach a certain depth before using gas.
- Decompression: High inert gas content (helium) in Trimix increases decompression duties compared to air or nitrox.
- Costs: Helium is expensive. Open circuit diving with Trimix at greater depths requires many cylinders, making rebreathers a more cost-effective option.
- Rebreathers: These closed-loop breathing systems offer advantages in Trimix diving, including maintaining a constant PO2 level, reducing gas consumption (cost), and reducing heat loss when breathing high-helium mixtures.
Table of Contents
Top 10 questions and answers about diving with Trimix
Trimix diving is an exciting but difficult form of diving that requires careful preparation and understanding. Here are the answers to the 10 most frequently asked questions about trimix diving:
1. What is Trimix and why is it used?
Trimix is a breathing gas consisting of oxygen, helium and nitrogen. It is used in technical diving to reduce the risk of nitrogen narcosis and improve breathing comfort at greater depths. Helium is less dense than nitrogen, thus reducing breathing resistance.
2. Why is Trimix safer than air or Nitrox at greater depths?
Trimix reduces the amount of nitrogen in the breathing gas, which is the main factor that causes nitrogen narcosis. Nitrogen narcosis can cause confusion, euphoria and even hallucinations, making safe diving difficult.
3. How is the optimal composition of Trimix calculated?
The optimal composition of Trimix is calculated based on several factors, including dive depth, desired equivalent narcotic depth (END) and partial pressure of oxygen (PO2). Special programs and tables are available to help divers calculate the optimal gas mixture.
4. What are the risks of Trimix diving?
Risks of Trimix diving include:
- Nitrogen narcosis: Although Trimix reduces this risk, it still exists.
- Oxygen toxicity: A partial pressure of oxygen that is too high can cause convulsions.
- Decompression sickness: Improper decompression can cause decompression sickness.
- Cold: Helium gives off heat quickly, so it's important to maintain body temperature.
- Gas density: Higher gas density can make breathing difficult.
5. What are the differences between Trimix and rebreathers?
Trimix is a breathing gas, while a rebreather is a closed-loop breathing system. A combination of the two can provide optimal performance in deep dives. Rebreathers allow precise control of oxygen partial pressure and reduce gas consumption.
6. What is the difference between Trimix and Nitrox?
Trimix contains helium, while Nitrox contains only oxygen and nitrogen. Trimix is suitable for greater depths where nitrogen narcosis is a greater risk. Nitrox is usually used for the shallowest dives.
7. Do I need special training to dive with Trimix?
Yes, trimix diving requires specialized training. There are several diving organizations that offer trimix courses.
8. What is the best way to learn to dive with Trimix?
The best way to learn to dive with Trimix is to find a qualified trimix instructor and take a specialized course.
9. What is the price of trimix diving?
The cost of a Trimix dive can vary greatly depending on a variety of factors, including location, training intensity and equipment used.
10. What are the future prospects for trimix diving?
Trimix diving continues to evolve, with new equipment and technology being developed to make it safer and more accessible.
Important: Using Trimix is difficult and can be dangerous if not done correctly. It is important to get proper training and experience before diving with Trimix.
Safety Disclaimer: This is a general overview of trimix diving. It is important to consult a qualified diving instructor before any diving.
Do you have any other questions about trimix diving?
The most popular Trimix calculation programs:
- Diveplan: One of the most widely used programs offering a wide range of features including gas planning, decompression calculations and profile analysis.
- Buhlmann: This program is based on the Buhlmann decompression models and is especially popular among technical divers.
- Mixed Gas: Another popular program that offers an intuitive interface and extensive customization options.
- Deep6: This program is specially designed for deep diving and offers detailed calculations and analysis.
What do programs calculate?
- Optimum gas mixture: The programs calculate the exact ratio of oxygen, helium and nitrogen to ensure a safe PO2 level and the desired END.
- Decompression profiles: The programs generate detailed decompression profiles based on dive depth, time and gas used.
- Gas consumption: Programs help to calculate the required amount of gas for diving.
- Risk analysis: Some programs offer risk analysis features that help you assess the danger of different diving scenarios.
Conclusion
Trimix allows technical divers to explore greater depths while managing risks such as narcosis and gas density. However, Trimix diving requires specialized training, equipment and careful gas planning due to its complexity.
