Plumbing fixture units for water systems

[mhagan4H7AL]

Does anyone know where the file location is that revit references for the water fixture unit chart E103.3(3)?. Attached is a screenshot of the statement under mechanical settings.

When utilizing the "predominantly flush valve" chart, anything under 5 fixtures automatically is assumed by revit to have a flow of 15GPM for anything under 5 water fixture units. This leads to oversized branch piping on several fixtures, etc. We would like to modify the file that revit references to include a conversion of fixture units and flow for the items with less than 5 fixture units so that revit sizes the piping accordingly. 

Any help on the file name, type of file and windows file path locations for this specific chart would be greatly appreciated.

Thank you!

[iainsavage]

Chart is in appendix E of the attached.

The 15 USgpm minimum is for "predominantly flush valves".

With predominantly flush tanks the minimum is 5 USgpm I think.

[iainsavage]

15gpm for flush valves, 3gpm for flush tanks:

[mhagan4H7AL]

Thanks for the reply.

That is correct, but there are 4 blank lines above the 5 fixture unit/15gpm line in the chart. When utilizing  the "predominantly flush valve" chart even when a fixture has a value of 1 fixture unit for example,  the chart that revit references still applies 15gpm, which grossly oversizes the piping. If we were sizing the piping manually it would not be an issue because we would just change the lines sizes as needed and manually. But when selecting an entire cold water system (which includes all the piping and branches to fixtures) and utilizing the "duct/pipe sizing" button, revit oversizes items with small fixture unit values. We are aware we could deselect all of the small branch lines, etc. before using the "duct/pipe sizing" button but we were trying to see if we could modify the file in revit to include a fixture unit valve and gpm on the 4 blank lines in the chart. In theory we would like to copy the top 4 lines of the "flush tanks" chart and apply it into the "flush valve" chart (wherever that file is located in windows explorer) so that revit recognizes something other than 15 gpm for items/totals of less than 5 fixture units.

[iainsavage]

The four blank lines indicate that the minimum flow is 15 gpm which I presume is based on US urinals with 1.25" Royal Sloan type flush valves on 1" pipe which discharge anything up to 3.5 gpm in a handful of seconds.

https://www.sloan.com/commercial-bathroom-products/flushometers/browse?level=product&product_fixture...