Life Support Systems Design Inside the Submarines

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Posted By: Tomas Baino 25-Jan-2019

INTRODUCTION

The atmospheric characteristics inside the submarine are importantly equal to the submarine’s major ship systems such as propulsions, navigations and sensors, weapons, auxiliaries, etc. A need to ensure an efficient and reliable health and safety of the submarine’s complements and ship machineries from atmospheric pollutants is definitely a must. To achieve and maintain this goal, an atmospheric control system to maintain good quality air while the submarine is operating submerged underwater is summarized in this article, and how submarine crew are able to live under hydrostatic pressure exerted by the water on all sides of the external surface of the submarine. A good life support system of quality air must be maintained and contain the following tabulated clean dry air composition. (Ref. Technical Manual for Nuclear Power Submarine Atmospheric Control Manual)

Humans need to breathe clean and dry air to sustain life. In similar manner, propulsion machineries and other auxiliaries that need to support proper combustion need to be naturally aspirated for efficient operational performance.

EFFECT TO HUMAN LIFE AND MEDICAL TOXICOLOGICAL ASPECTS

The air we breathe into our lungs is through the respiratory system, where air reaches a small dead-end space of the organ called alveoli. The alveoli provides a large surface area through which gasses press into the capillaries’ blood and into the blood stream. Gasses establish almost immediate equilibrium and balance with blood, causing oxygen to come in and carbon dioxide to leave. The red blood cells and oxygen unite chemically with hemoglobin to form a relatively weak chemical bond. When red blood cells have been consumed by the cell, the blood returning to the lungs carries CO2 and other waste products for expulsion. Fig. 1 shows a material balance for an average submarine crew member.

Under normal conditions, the human respiratory breath rate is 15 times/minute, which requires about 0.02 cubic feet of air intake at work. With each exertion of energy, it requires greater demand of greater interval of breathing to test whether the body absorbs oxygen for biochemical brain activity and other organs. When not at work, crewmembers of the submarine are required to lay down in the bunks to rest in order not to consume small amounts of oxygen when standing or sitting.

IMPROPER DESIGN OF ATMOSPHERIC CONDITIONS INSIDE THE PRESSURE HULL OF SUBMARINES CAN RESULT IN THE FOLLOWING:

  • Lack of Oxygen can result in impaired right vision, heavy breathing, dizziness, faulty judgment, slow thinking, weak muscular coordination, fainting, or death.
  • Sickness as a result of decompression causes the formation of bubbles in the blood due to nitrogen, and results into an excessive reduction of ambient pressures.
  • Lung injury due to oxygen poisoning.
  • Carbon Buildup and increased respiration with mild discomfort, dizziness, stupor, unconsciousness and death.
  • Carbon Monoxide can lead to deprivation of oxygen in the blood
  • Excess Refrigerants can cause simple asphyxiation causing dizziness at low concentration, and death at high concentrations.
  • Excess Hydrocarbon at high levels can impact liver function and can affect metabolism of various organs and irritate the skin and mucous metabolism.
  • Excess Ozone can cause eye irritation and may result in coma, etc.
  • Excess Hydrogen is highly inflammable and explosive. This is generated from battery charging and products of electrolytic oxygen generators.

PROPER DESIGN OF SUBMARINE ATMOSPHERIC CONTROL SYSTEMS

This necessitates the elimination of toxic contaminants and control of the source of origin; and the removal of contaminate and ample supply of oxygen to maintain proper atmospheric condition, with the following approach of design:

  • Installation of Electrochemical Oxygen Generators (EOG) – Replenishes consumed oxygen while the submarine is operating underwater. The EOG can supply in longer periods dependent on the storage capacity.
  • Installation of Solid Polymer Generator (SPG) – A new development of oxygen generators with a safe and reliable oxygen production unit that produce oxygen for breathing through water electrolysis by using a solid Polymer Electrolyte (SPE) cell.
  • Installation of Oxygen Candle Furnace – A mixture of sodium chlorate, iron, small amounts of barium peroxide, and fibrous binding materials that are screened and removed by burning the candle to decompose the chlorate by thermal means.
  • Installation of Carbon Dioxide Removal. There are 2 systems to remove the Carbon Dioxide (CO2) inside. These are:
    • LiOH Absorbers – A non-regenerate system called CO2 “scrubb filter to entrap droplets of the Mono-ethanolamine (MEA) Solution and the air returns to the submarine internal section atmosphere at about 750 to 100% Relative Humidity.
  • Air Purification Systems (Co-H2 Burner). The system is used to remove CO, H2 hydrogen and other contaminants by oxidizing the CO2, H2 (Carbon Dioxide and Water). In the final stage, air passes through activated charcoal as absorber.
  • Activated Carbon. Charcoals are activated and prepared from carbonaceous materials and activated by controlled heating steam. Heat removes noxious gases from the capillaries. Activated charcoal increases vapor absorption.
  • Emergency Supply of Compressed Air Supply
    • Oxygen Breathing Apparatus (OBA) is a self contained unit worn by each person/crew for a duration of at least 60 minutes. It removes exhaled CO2.
    • Emergency Air Breathing System (EABS) is typically used when there is fire. It simply allows for direct connection of full-face masks for each crew member to clean high pressure air storage banks. It consists of masks connected by hoses to the source.
    • Scott air Packs (SCBA) is also a self contained breathing apparatus which is similar to the SWBA but designed for air environment; a portable recharge breathing system can come as alternative equipment for OBA’s.
    • Atmospheric Monitor. In a closed submarine atmosphere inside the pressure hull of the submarine, frequent and routine monitoring is needed to ensure continuity of air quality. Said monitoring allows detection of potentially hazardous substances as well as adjustment of air composition.

HUMAN LIFE INSIDE THE SUBMARINE

On the surface of the sea, nature is very unforgiving, but underwater, nature can kill human life quickly. The submarine must be designed to have extremely reliable equipment and reliable crew. The life support system is the paramount important system in the submarine. If this fails while underwater, submarine crew will die instantly. Lives of the submarine officers and crew depend on the reliability of the submarine life support systems and their level of expertise as the first and foremost system to be concerned of by the submarine commanding officer. The submarine crew work in isolations for long periods of time, without family contacts, always in radio silence to avoid being detected, and many submarines have been lost to accidents. A submariner always depends on himself and knows what he is doing. The submariner’s actions must always be 100% correct at all times when operating in the submarine underwater.

RECOMMENDATIONS

A Navy dreaming of acquiring submarines for the first time must focus and concentrate at the forefront of the program on training on the physiology of human body proficiency, built-up and enhanced shipyard support system capabilities of how to preserve, operate, and respond to various levels of maintenance, logistic support systems, etc. to reach a level of expertise before deciding to sign the acquisition and delivery of a submarine. This cannot be achieved based on hasty preparations but rather through long years of training to reach maturity. The navy can start by acquiring a training laboratory and when the right time to acquire a shallow water attack submarine comes, it is recommended to begin with the affordable Italian Cosmos or Piranha Class. This approach is similar to the submarine strategy of the Pakistani Navy.

SOURCE/REFERENCES

  • How submarine work by Marshall Brain and Craig Freudenrich Ph.D.
  • Exide submarine Propulsion Batteries
  • Technical Manual for Nuclear Powered Submarine Atmosphere have Control Manual (1992) Naval Sea System Command S9510-AB-ATM-010(v),value 1 REV 2, 30 July.
  • Mary Harris, Chemistry Teacher, Robert E. Fitch High School How Submarine Breathing Underwater for 90 Days.
  • Sub-science, Weber Warship. CA

About the Researcher:

CAPT TOMAS D BAINO PN (Ret) completed his post-graduate studies in Submarine Design at the Department of Naval Architecture, University College of London, United Kingdom of Great Britain, under the sponsorship grant of the UK Ministry of Defense. Capt Baino is an associate editor of the Maritime Review, providing series of articles on Naval Ship Design and presently serving as Naval Architect Consultant with the Department of Transportation and the Philippine Coast Guard Project Management Office in ship acquisition program.