|  |
		|  | <-- vent stack to roof - 	the vent stack connection the pipe is approximately 3/4" - 1" 
		\  \				LOWER than the connection to the soil stack forming a trap
	  _______\  \___________
	 /
	/  (A)__________________ <- drain connection for 3rd floor bathroom
	|  |
	|  |
	|  |
	|  |  <- soil pipe stack in race
	|  |
	|  |