Submarine Atmosphere Monitoring


We understand the complexities of the submarine environment in terms of pressure, temperature and humidity variations. Requirements may vary between types of submarine and different solutions are offered for diesel electric, air-independent propulsion (AIP) and nuclear boats. The permissible level of gas on a submarine may also vary from nation to nation.

Distributed gas sensor network on a submarine                              Gas monitoring in submarines

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Centralised submarine atmosphere analyzer

A centralised atmosphere analyser (AA) monitors up to 30 gases from various locations—this is ideal for nuclear boats (and potentially AIP boats) which need to sample a large number of gases at low concentrations. An AA is typically installed in a central location and connected to sample lines which pull air samples from different compartments around the boat. 
Sampling occurs automatically but can be over-ridden to sample a specific compartment if needed.
Up to three AA units can be connected together to provide system redundancy. A centralised AA provides real-time continuous monitoring of life-support gases and trace gases including oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), hydrogen (H2) and refrigerant gases such as R134a. Non-standard gases are also continually monitored, but generally only displayed on request. These include methanol, hydrogen cyanide, hydrogen chloride, oxides of nitrogen, sulphur dioxide and specific hydrocarbons. Submarine pressure is also monitored.

Batteries on diesel-electric submarines release H2 into the atmosphere as a by-product of the charging process.

H2 can be removed from the atmosphere by the boat snorkelling, or alternatively, by burning the H2 - this turns it into carbon dioxide which can be scrubbed out of the atmosphere.

Small amounts of hydrogen can be explosive, which can be catastrophic in a confined space such as a submarine. This means H2 monitoring in a submarine is essential, and any sensors used need to be ATEX approved for use in a potentially explosive atmosphere.

Analox Military Systems offer stand-alone hydrogen sensors as well as a distributed sensor network which can be used to measure a range of gases around the submarine.

Distributed sensor network

distributed sensor network comprises a centrally located programmable logic controller (PLC) user interface linked to discrete gas sensors or sensor modules located around the boat. Typical gases monitored include O2, CO2, CO and H2, in addition to refrigerant gases and submarine pressure and humidity. This system is ideal for diesel boats (and potentially AIP boats) which need to monitor the life-support gases but which may have limited space. It is ideal for MPC60 and 24-hour limits.
The main benefits of the distributed sensor network are:
  • Flexible system architecture, providing adaptability throughout the boat's operational life
  • Sensors located in the area where the gas poses a direct risk, providing real-time alerts to hazards in the area they occur
  • Designed to be maintained in destination country, providing increased availability of the system


Carbon monoxide (CO) monitoring

CO monitoring in the submarine environment requires a different technology than that used in off-the-shelf carbon monoxide detectors. Standard electrochemical sensors are extremely cross-sensitive to hydrogen, making them unsuitable for use in the submarine environment. Analox Military System's solution for routine CO monitoring is the COSAMS which uses a selective infrared sensor which eliminates cross-sensitivity to other gases likely to be present within the submarine atmosphere.


Portable gas monitors

Portable monitors are typically used as an emergency backup to the primary atmosphere analyser or for confined space entry. In collaboration with our customers, Analox Military Systems has found the Sub Aspida (dual O2/CO2), HYP (partial pressure O2 monitor) and multi-gas monitoring ACG+ to be a cost-effective alternative to colorimetric tubes.
Contact us today to find out more about how we can help with your atmosphere monitoring requirements, or click on the links below