Showers

I would save yourself a letter template-induced headache and just use the 1.6gpm, unless using the 1.5 makes a huge difference, but I doubt it will.

I found a document from DOE that says a 1.6gpm spray valve is used for 22 seconds per plate. It also says, "The pre-rinse spray valve would be used an average of four hours per day, 365 days per year which is typical in Veteran’s Hospitals and federal prisons, and on military bases." The document is here if you want to use it: http://www1.eere.energy.gov/femp/pdfs/prerinsenozzle.pdf That's the best guidance I've found so far. But I'd still love to hear what others have done, or if anyone has recevied feedback from USGBC on this issue.

The link above is no longer valid, but the same information can be found here: http://www1.eere.energy.gov/femp/technologies/eep_low-flow_valves.html#table