ENGINEERING EVALUATION 333 



monitors, the fixtures for the interior lighting should be recessed overhead or constructed so 

 that no light is emitted from the sides. 



4. Redesign the exterior lighting system to provide two levels of lighting, one for photog- 

 raphy and one for normal use. Quartz-iodine type lamps should be used. The fixtures should 

 be mounted with universal swivel mounts on short booms extending from the hull. Power out- 

 lets which can be connected wet should be installed at each light location and each outlet con- 

 trolled by a dimmer switch located inside Sealab. Fixtures with wet -bulb changing capabilities 

 would be desirable. The use of mercury vapor lamps is not recominended, since they require 

 auxiliary equipment and operate at voltages up to 400 volts. 



Ventilation and Heating System — It seems desirable to retain the radiant-deck heating sys- 

 tem and some overhead radiant heating, which contributed much to the level of comfort in Sea- 

 lab II. Otherwise the ventilation system should be completely redesigned as an integrated 

 atmosphere-control or conditioning system. Ideally, this system should perform all 

 atmospheric-control functions including ventilation, distribution, filtering, dehumidification, 

 atmospheric replenishment, and temperature control (heating and cooling). This system must 

 include adequate sensing and control equipment and should be specifically designed for use in 

 the Sealab environment. The dehumidifiers must be capable of maintaining the required physi- 

 ological comfort levels in the Sealab environment. Means should be provided for more efficient 

 removal of carbon dioxide than in Sealab n. Means should also be provided for the removal of 

 carbon monoxide and other trace contaminants which were not absorbed by charcoal or LiOH in 

 Sealab II. 



Breathing-Gas System — As indicated above, the atmosphere-replenishment functions 

 should be incorporated into the atmosphere-control system. The gas systems need improve- 

 ments of control equipment, such as more reliable valves, more reliable regulators with 

 higher flow rates and bypass circuitry, improved sensing and control equipment, and leak-free 

 piping and storage systems. 



Since the emergency breathing (Bibb) system installed in Sealab n was considered mar- 

 ginal, it is recommended that the basic design be improved to provide adequate flow rates at 

 the required pressure and that adequate corrosion-resistant quick-connect fittings be provided. 

 Although the Bibb system was not required in Sealab II, it is felt that it provides a required 

 safety feature which should definitely be included in all future Sealab designs. 



Gas-Sampling System — The gas-sampling system performed its intended function and 

 certainly should be included in any future designs. However, every effort should be made to 

 obtain equipment for atmosphere analysis inside Sealab. It would also seem desirable to pro- 

 vide the capability of detecting and monitoring the long-term buildup of trace contaminants 

 which may create a safety hazard as test runs become longer in duration. 



Arawak System — It is recommended that sufficient lead time be allowed for satisfactory 

 development of future Arawak systems. More efficient compressors and vacuum pumps are 

 essential, but reduced noise levels are equally important. Hoses, vests, and regulators should 

 be evaluated and tested to assure compatibility with diver's requirements. The installation of 

 Arawak systems in Sealabs should also be designed to eliminate or reduce the noise level. 



Plumbing and Sanitary System — The discharge lines for the sanitary drains must be non- 

 buoyant when filled with air or gas to prevent "trapping." The salt-water intake for the water 

 closet should be extended downward to a point below the water level in the entrance trunk, to 

 prevent atmosphere loss. A water closet with a larger flushing pump should be installed. 



Since the shower tubs were not utilized, they should be removed, and one shower should 

 be eliminated to provide additional space in the entry. 



Provisions are necessary for increased water-supply capacity. The 50-gallon-per-man- 

 day supply used for Sealab II was adequate but probably should be doubled for colder runs, 

 where hot water may be used to restore or maintain the body heat of the divers. 



