44 DESIGN OF THE SEALAB II HABITAT 



Hookah Pumps 



Two hookah pumping units are suspended from the overhead, aft of the hatch in the entry- 

 way. Due to late delivery of these equipments, they were mounted at Long Beach Naval Ship- 

 yard. Four hull penetrations, one inch IPS by six inches long, threaded nipples, were installed 

 in the after semi-elliptic head. These penetrations are located approximately six inches above 

 deck level and spaced on four- inch centers horizontally about the longitudinal centerline. All 

 threads are protected with pipe caps. 



Refrigerator- Freezer 



A combination refrigerator-freezer of approximately 10 cu ft storage capacity (5 cu ft 

 refrigerator - 5 cu ft freezer) was installed in Sealab II. The refrigeration cycle is the con- 

 ventional Freon gas system. Since the helium-rich Sealab II atmosphere is approximately six 

 times as conductive as air, it is necessary to provide sufficient insulation to reduce heat gain, 

 or an increased cooling capacity is required to compensate for the increased heat gain of a 

 standard commercial insulation system. If mercury type temperature controls are utilized, 

 these should be adequately protected against rupture (see Chapter 9) . 



Plumbing and Sanitary Facilities 



The supply piping is of conventional design for 125 psi service. Fresh water was supplied 

 to Sealab from shore to provide a minimum flow of 10 gpm at a minimum pressure of 40 psi 

 above ambient. Maximum (static) pressure did not exceed 75 psi above ambient. Pressure- 

 relief valves for the supply system and water heater'were set at 100 psig. A 50-gallon water 

 heater is installed (see Chapter 9). An emergency fresh- water storage tank of 150 gallon ca- 

 pacity is installed for use in the event of failure of the shore water supply. This tank is pro- 

 vided with a hose bibb for filling and draining and is vented. The emergency water tank is not 

 connected to the Sealab water system, in order to prevent accidental usage of the emergency 

 supply. The emergency tank may be drained and refilled periodically in order to maintain 

 "fresh" tasting water. A hose bibb is installed in the supply system and located in the entry- 

 way for this purpose and also for general washdown purposes. A 25-ft length of "garden" hose 

 is provided. 



The sanitary system is of conventional design, gravity flow, overboard discharge. A 50-ft 

 length of hose is provided for attachment (external) to the overboard sanitary discharge. This 

 serves to keep the discharge opening below the water level in the entry trunk, thereby prevent- 

 ing gas loss from Sealab, and conveys the effluent away from Sealab. Since it is impossible to 

 vent the sanitary system externally, all vents are fitted with potassium permanganate or char- 

 coal filters to remove odors from the vent gases. 



Air- Conditioning System 



The air-conditioning system provides the following functions and capabilities: 



Dehumidification - 18 gallons per day 



Ventilation - 1200 cfm 



Heat - 25 kva (see Electrical Specifications) 



CO2 Scrubbers - 1 Ib/hr (approximately 4600 cu in. LiOH) 



Charcoal Filter - to remove hydrocarbons, odors, and aerosols 



(approximately 2300 cu in.) 

 Gas sampling and make-up - (see Breathing Gas Systems) 



It is desirable to obtain gas flow through the air-conditioning system with a single fan in 

 order to reduce the number of electrical motors in the system. It is further desirable to en- 

 close the one fan motor in a pressure- tight (5 psi over ambient) enclosure to reduce fire or 

 contamination hazard. The distribution and return system is arranged so as to provide com- 

 plete circulation of the Sealab atmosphere in order to eliminate any stagnant areas which might 



