Water Supply Problems in Alaska— Alter 



229 



of a single main distribution system and a Pitot type tap. Service 

 connections may be kept from freezing by use of electrical 

 resistance tape or by use of short house-to-street utilidors. 



Day, of the Arctic Health Research Center at Anchorage, 

 reports successful laboratory experimentation with the Pitot 

 type tap. Day states, "From the data obtained by observations 

 on model pipe main and double house service pipe system, it is 

 concluded that circulation of flow will occur in the house service 



Seasonally frozen ground 

 Permafrost 

 LEGEND: Penetrating frost 



Entrapped ground water 

 Lost heat 



E33 



GROUNO SURFACE 



;h^^^ h »t.u... i- *^i£t5£*«s«s 



DRAINAGE OF ENTRAPPED WATER INTO IMPROPERLY SEALED 



UTILIDOR 



Fig. 3. 



connection. The velocity of flow in the street main will appar- 

 ently have to be capable of being maintained at two to three 

 feet per second. Special orifices must be used in place of the 

 standard corporation cock. The total length of house service 

 pipe should probably not exceed 125 feet for dependable 

 operation" (1 1). 



At Fairbanks, means of protection for house service connec- 

 tions has presented the greatest problem of design and installa- 

 tion of a community water distribution system. Dual main 

 distribution systems and utilidors are much more costly than a 

 functionable single main recirculation system. 



