survivors transfer under pressure from the PRM to the DTL and then to the SDC, where they undergo saturation decompression to the surface. The PRM can transport a maximum of 16-seated DISSUB survivors per sortie and two attendants. Each SDC has a maximum capacity of 35 occupants; however, only 33 can be seated.

 

There is no known commercially available hyperbaric oxygen delivery and monitoring system capable of handling this many people at sea where compressed oxygen and air are limited. (1) Clinical hyperbaric systems support much fewer occupants. There is no known system for monitoring the oxygen status for 35 individuals in a hyperbaric chamber. (2) Shore-based hyperbaric oxygen is typically administered via open circuit because compressed oxygen is easily obtained. Compressed oxygen for submarine rescue is limited and may not be replenished during the successful rescue window of opportunity. (3) Certain methods for monitoring hyperbaric oxygen delivery do not appear to scale to these larger numbers. (4) The chamber pressure in the PRM cannot be reduced during transit.

Other properly functioning hyperbaric chambers can be vented to avoid unwanted pressurization.

 

The decompression of survivors is accomplished via the U.S. Navy SRS Decompression Plan and is currently administered using standard air decompression tables, which result in decompression timelines in excess of 57 hours for each able-bodied survivor from 5 Atmospheres Absolute (ATA). Biomedical research has identified that delivery of Oxygen (O2) in advance of decompression and decompression via O2/air significantly increases the successful decompression of saturated personnel and significantly decreases the amount of time required to decompress.

Implementation of O2/air decompression capabilities will reduce decompression time by as much as 25 hours, which will significantly reduce the amount of time DISSUB survivors must remain on the DISSUB awaiting rescue.

 

The program office desires an ODMS for use in the PRM, the SDCs, and on the surface. The system must be capable of performing under the following conditions: (1) Single-person closed circuit oxygen breathing apparatus capable of administering and monitoring oxygen delivery for 12 hours (Carbon dioxide scrubber changes are permitted) to 18 personnel in the PRM, 35 personnel in each SDC and up to 12 for surface use; (2) Apparatuses must also include Carbon Dioxide scrubbers with swappable container capabilities; (3) Oxygen delivery must be via oral-nasal masks to interface with each individual use; (4) The ODMS will be used in a dry normobaric or hyperbaric environment, [Ranges are: (1) PRM � max RH 99%, Temperature 34 � 97 deg F; (2) 50-80% RH, Temperature 70 � 85 deg F; (3) Surface � Ambient conditions, Temperature 0 � 110 deg F] although the ambient relative humidity may be high; (5) Due to space constraints in the PRM, the occupants will likely be seated elbow- to-elbow and knee-to-knee; (6) Apparatuses must provide interfaces as necessary with oxygen headers for oxygen re-supply, have a purge capability, and be capable of supporting a maximum of 13 sorties with minor disinfecting/cleaning or resupply.

 

In the PRM, mask leakage must be minimized to less than or equal to 3.5 % to prevent additional pressurization of the PRM compartment. The PRM cannot be ventilated underwater. In the SDC or on the surface, mask leakage less important while mask comfort becomes more important since the masks may be worn for longer periods of time.

The PRM mask may differ from the mask used in the SDC or on the surface.

 

Oxygen monitoring must be provided to alert users and attendants when the oxygen concentration is below predetermined levels necessary to provide accelerated decompression scenarios using partial pressures of oxygen up to 2.8 ATA. Monitoring status indications must be available at each oxygen breathing apparatus. Status indications should be updated at least once every five seconds for each oxygen apparatus. In addition, each unit must have telemetry capability to allow for remote monitoring and status indications (outside the SDC for example). Remote monitoring may be accomplished via wireless means, but there must also be hard wire transmission capability for redundancy. Wireless monitoring must be able to work with up to 16 units in the metal compartment of the PRM and up to 35 units in the metal compartments of each of the two SDCs. There should be no special software requirements and the system must be capable of obtaining a U.S. Navy Authority to Operate certification in accordance with NAVSEA TS500-AU-SPN-010, U.S. Navy General Specification for the Design, Construction, and Repair of Diving and Hyperbaric Equipment. Telemetry information must include temperature, depth, oxygen, and device identification information. Software must scale to allow the display of the status of all oxygen-breathing apparatuses in use in the PRM and/or in a single SDC.

 

Oxygen delivery threshold will be capable of being operated by an individual user or locally by internal attendants with an oxygen supply pressure of 120-150 pounds per square inch over bottom (psiob) to depths of 60 feet seawater (fsw). The apparatuses may be pressurized to depths of 165 fsw in the PRM or 85 fsw in a SDC, but will be used at a