PRACTICE QUESTION TOPIC: Plumbing: 'Pumped Upfeed" water distribution

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mabellebelle

April 29, 2024 20:42

Hi all,

Inside the PPD practice exam, a question on plumbing water distribution for a building qualifies (to me) Pumped upfeed the same as Upfeed.

Can someone please provide a difference between the two terms: Pumped upfeed and Upfeed? To me upfeed clearly needs a pump, same as pumped upfeed...! Although I answered correctly (curiously), wanted to bring this up in case someone else is thinking the same.

Found diagrams in this website describing upfeed, downfeed and upfeed booster variation (which has a tank in the basement and distributes to multiple floors in separate lines): https://opentextbc.ca/plumbing3b/chapter/describe-the-building-water-supply-system/

Question from PPD practice exam below:

Question 27 A low-rise building is designed to allow for a future addition that will result in a midrise building with a higher water demand. When the addition is complete, the majority of the building's rooftop will be dedicated to the mechanical system and individual floors will not be able to support a water tank. Which water supply system should be used? A. Upfeed distribution B. Downfeed distribution C. Pumped upfeed distribution Your answer: C Correct answer: C CORRECT RESPONSE Pumped upfeed distribution Pumped upfeed distribution uses multiple pumps to supply water directly to fixtures without using a water storage tank. Section: Building Systems, Materials, & Assemblies

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  Eugene O'Callaghan April 29, 2024 21:06

  An upfeed system uses just the mains water pressure, it works up to somewhere in the 40' to 60' range. If there's not enough mains water pressure (lower than typical pressure or a taller building) the pump will make up the difference. Although the question doesn't give exact height definitions, it's fair to assume mid-rise is likely to mean 6+ stories.

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  mabellebelle April 29, 2024 21:40 (Edited April 29, 2024 21:56)

  Update: 

  After digging in MEEB's water chapter, I now understand that:
  Upfeed: is intended for low or small buildings where water demand is low and connection to water main from the street can suffice for pressure demand. 
  Downfeed: mid to high rise, can have a water tank on the roof to distribute down by gravity. (requires pumps and meters).
  Pumped Upfeed: is for medium sized buildings that are too tall to support the street main pressure but not so tall to need a water storage on the roof. Water can be delivered at various rates and multiple lines for zones depending on the program intented to be used for.

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  mabellebelle April 29, 2024 21:42

  Thanks Eugene!

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  rajank74 October 01, 2024 20:22

  I found these diagrams in MEEB that provide a clearer explanation of each distribution system. I hope they make the concepts easier to understand.
  
  A. Upfeed distribution

  

  _{Source: Mechanical and Electrical Equipment for Buildings, Water and Waste, Water Supply, Water Distribution, p975}

  B. Downfeed distribution

  

  _{Source: Mechanical and Electrical Equipment for Buildings, Water and Waste, Water Supply, Water Distribution, p977}

  
  C. Pumped upfeed distribution
  

  _{Source: Mechanical and Electrical Equipment for Buildings, Water and Waste, Water Supply, Water Distribution, p982}

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  mabellebelle October 02, 2024 01:47

  Hi Rajan! Yes! These were the diagrams that helped me understand. The description I added though, helped me remember how to identify the system verbally in case no diagram is shown. Thanks for sharing!

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