How Do You Breathe Onboard a Submarine?
How Do Submarines Breathe? Oxygen Generation and CO₂ Removal Explained
One of the most critical challenges submariners face is maintaining a safe, breathable atmosphere while operating deep beneath the ocean’s surface. Unlike surface vessels, submarines cannot rely on a constant supply of fresh air, everything must be generated, controlled, and monitored onboard.
Creating breathable air inside a submarine depends on two essential processes:
- Producing oxygen (O₂)
- Removing carbon dioxide (CO₂)
Both systems must operate continuously and reliably to ensure crew safety, performance, and mission effectiveness during extended underwater deployments.
Oxygen Generation on Submarines
1. Electrolysis: Producing Oxygen from Seawater
The primary method submarines use to generate oxygen is electrolysis, a process that extracts oxygen from water.
Before electrolysis can take place, seawater is purified through distillation to remove salts and other impurities. An electrical current is then passed through the purified water, splitting it into its constituent gases:
- Oxygen (O₂), which is released into the submarine atmosphere
- Hydrogen (H₂), which is safely managed or discharged from the vessel
Because submarines operate in an environment with access to seawater, electrolysis provides a continuous and reliable source of oxygen, making it well suited to extended underwater operations.
2. Oxygen Candles: Emergency Oxygen Supply
Submarines also carry oxygen candles, sometimes known as chemical oxygen generators, as an emergency backup source of breathable air.
These devices contain a mixture of chemicals, typically sodium chlorate and iron powder, which release oxygen through a controlled chemical reaction when activated. The result is a steady supply of oxygen without the need for an external power source.
Key Benefits
- Reliable backup oxygen supply during emergencies
- Operates without electrical power
- Long shelf life when stored correctly
Oxygen candles provide an important layer of redundancy, helping ensure a continued oxygen supply in the event of system failures or other onboard emergencies.
CO₂ Removal: Keeping Air Safe to Breathe
Producing oxygen is only half the challenge. As crew members breathe, they continuously exhale carbon dioxide (CO₂), which must be removed to prevent dangerous concentrations from building up inside the submarine.
CO₂ Scrubbing Systems
Submarines use CO₂ scrubbing systems to remove carbon dioxide from the atmosphere, typically through chemical absorption processes.
Common methods include:
- Soda Lime Scrubbers
These systems use a mixture of sodium hydroxide and calcium hydroxide, which chemically react with CO₂, trapping it and removing it from circulation. - Lithium Hydroxide Canisters
A passive CO₂ removal method that absorbs carbon dioxide without requiring electrical power. These systems are particularly valuable during emergencies when power may be limited.
Without effective CO₂ removal, carbon dioxide levels can rise quickly, creating a hazardous atmosphere even during normal day-to-day operations.
Why Atmospheric Monitoring Is Mission-Critical
Even with oxygen generation and CO₂ removal systems operating continuously, maintaining a safe atmosphere onboard a submarine requires constant monitoring.
Submarine environments are enclosed, complex, and high-risk. Atmospheric conditions can change due to:
- Equipment malfunctions
- Leaks or system failures
- Changes in operational conditions
Real-time atmospheric monitoring ensures that any unsafe changes are detected immediately, allowing corrective action to be taken before crew safety is affected.
Continuous monitoring of oxygen, carbon dioxide, and other atmospheric parameters is therefore a critical component of life support systems, helping to protect crew health, maintain operational effectiveness, and support mission success.
Central Atmospheric Monitoring Systems (CAMS)
A Central Atmospheric Monitoring System (CAMS) serves as the control hub for onboard air quality management.
These systems:
- Continuously monitor oxygen, carbon dioxide, and other atmospheric gases
- Provide real-time air quality data throughout the submarine
- Support rapid decision-making during critical situations
- Help identify and prevent hazardous atmospheric conditions before they escalate
CAMS units are considered mission-essential equipment, forming a core part of a submarine’s life-support and safety infrastructure. Their ability to provide continuous atmospheric awareness helps protect crew health, maintain operational effectiveness, and support extended underwater missions.
Supporting Submarine Safety with Advanced Gas Monitoring
With decades of experience supporting submarine and defense applications, Analox designs and manufactures robust gas monitoring systems engineered for the unique challenges of underwater operations.
From centralized atmospheric monitoring systems to specialized gas detection solutions, Analox helps support:
- Crew safety
- Mission continuity
- Compliance with stringent defense standards
Beyond supplying equipment, Analox also provides:
- Custom system design and integration
- Lifecycle support, from installation through to maintenance
- Specialist training, delivered either on-site or within simulation environments
By combining advanced monitoring technology with long-term technical support, Analox helps ensure submarines maintain safe, reliable atmospheric control throughout their operational life.
FAQs About Submarine Air Systems
How do submarines get oxygen?
Submarines primarily generate oxygen through electrolysis, extracting oxygen from purified seawater. Backup systems, such as oxygen candles, provide an additional source of breathable air during emergencies or system failures.
How is carbon dioxide removed on submarines?
CO₂ is removed using chemical scrubbing systems, typically soda lime or lithium hydroxide, which absorb carbon dioxide from the atmosphere and help maintain safe air quality onboard.
Can submarines run out of air?
Submarines primarily generate oxygen through electrolysis, extracting oxygen from purified seawater. Backup systems, such as oxygen candles, provide an additional source of breathable air during emergencies or if primary oxygen generation systems become unavailable.
To learn more about Analox solutions for submarine atmospheric monitoring, explore our dedicated submarines page.
Key Takeaway
Maintaining breathable air onboard a submarine is a complex balance of oxygen generation, carbon dioxide removal, and continuous atmospheric monitoring.
Without these systems working together, safe underwater operations simply would not be possible.
Advanced monitoring solutions, such as Central Atmospheric Monitoring Systems (CAMS), provide crews with continuous visibility of onboard air quality, helping ensure that any changes in atmospheric conditions are detected and addressed quickly.
By combining reliable life-support systems with real-time gas monitoring, submariners can operate with confidence, knowing their environment is being continuously managed and protected.