Fixture Units to (gpm)
Fixture Units to (gpm)
(OP)
Hi all please help me with a question. I am vary much junior to the industry so please bare with me if I am annoying.
I am able to convert Fixture Units (Fu) to Gallons per mint (gpm) on a table.
What is or where can I find the simplest mathematical calculation to do the same conversion?
Sincerely
I am able to convert Fixture Units (Fu) to Gallons per mint (gpm) on a table.
What is or where can I find the simplest mathematical calculation to do the same conversion?
Sincerely





RE: Fixture Units to (gpm)
Mike Halloran
Pembroke Pines, FL, USA
RE: Fixture Units to (gpm)
Sounds like a straight proportionality problem. You should be able to figure it out from the table values that you have.
TTFN
RE: Fixture Units to (gpm)
"Drainage Fixture Units
A DFU is a measurement unit for potential water use for a given plumbing fixture or appliance, as provided for in the Building Officials & Code Administrators (BOCA) National Plumbing Code. "
A water closet of 1.6 GPF or less gets a DFU of 3.0 in Virginia Beach, where the DFU sum is computed as part of an inspection fee. A bathtub is 4.0 DFUs.
A water closet of 1.6 GPF gets a Water Supply Fixture Unit of 2.5 in Seattle, where they are used for sizing pipes. A bathtub is 10.0 WSFUs.
Apparently WSFUs are not the same as DFUs. It's not clear if they're the same everywhere, or how they are actually derived.
Maybe the cited code will provide a clue, but it's clear that there isn't going to be a simple correlation between FUs and gallons, because the FU is time- averaged and adjusted for duty cycle of each individual water sink or drainage source, and I'd bet there's been some political input toward encouraging use of low volume water closets, which are big water wasters, especially if there's a lot of fiber in your diet.
Mike Halloran
Pembroke Pines, FL, USA
RE: Fixture Units to (gpm)
charts from ashrae reprinted here:
http://ww
If you have a copy of ASHRAE Applications, it's in the service water heating section (48). There is a full description of how to use size appropriately but no relationships are given, just the charts.
As you can see, it all depends on the intended application. (ie. the frequency of use) You could curve fit approximate solutions to all of them but probably just easier to tabulate or read from the chart.
I2I
RE: Fixture Units to (gpm)
I2I
RE: Fixture Units to (gpm)
Many lessons learned
Sincerely
RE: Fixture Units to (gpm)
Using a spreadsheet to enter the table values (e.g. from ASPE data or code tables), I use the Indirect and Vlookup functions to locate the correct WSFU range to convert intermediate table values to GPM.