7-11. 7-12. 7-13. 7-14. 7-15. 7-16. 7-17. This valve is well suited for use when a regulated flow is required. 1.  A 2.  B 3.  C This valve must be operated in the fully open position. 1.  A 2.  B 3.  C This valve is backflow in a 1.  A 2.  B 3.  C used  to  prevent pipeline. On  water  mains,  thrust  blocks should  be  installed  for  what purpose? 1. To prevent pipe displacement caused  by  high  water  pressure 2. To prevent pipe ruptures caused by high water pressure 3. To prevent sagging due to the weight  of  the  piping  material 4. To prevent sagging due to the weight of the pipe and the water  contained  in  the  pipe Which  of  the  following  types  of piping is becoming increasingly popular for use in underground sanitary  sewage  systems? 1. Cast  iron 2. polyvinyl  chloride 3. Concrete 4. Wrought  iron To make a 22 l/2-degree change in pipe direction, what cast-iron fitting should you use? 1. Combination Y and 1/8 bend 2. 1/4 bend 3. Short  sweep  1/4  bend 4. 1/16  bend What  fittings  are  used  in  waste pipe systems to catch and hold water,    thereby forming a seal to prevent  sewer  gases  from  backing  up into a building? 1. Traps 2. Street  ells 3. Valves 7-18. 7-19. 7-20. In what way, if any, do waste stacks  differ  from  soil  stacks? 1. Waste  stacks  carry  human  waste, soil stacks do not 2. Soil stacks carry human waste, waste stacks do not 3. Waste stacks empty into building drains, soil stacks empty  into  building  sewers 4. None Under most local codes, what is the minimum distance that a building drain must extend beyond the building  wall? 1. 2 ft 2. 3 ft 3. 6 ft 4. 10 ft In a plumbing plan, which of the following  symols  should  be  used for a hot-water line? 1. 2. 3. 4. 7-21. What symbol should you use to show a screwed joint in a piping plan? 4. All of the above 44