Efficiency calculation

Hi Rashid - You cannot use whole building water meter data to satisfy the requirements of WEp1; you must do a calculation based on flush/flow rates. The documentation path for individual fixture flush/flow rates is the same in both LEED 2008 and LEED 2009, as follows: "For each fixture type that differs from UPC or IPC efficiency requirements (because of either lesser or greater water consumption rates), provide manufacturer cut sheets verifying flow rates for each fixture type, measured flow rates for a 20% representative sample of each fixture type, or evidence of the installation date of each fixture type for which worst-case default values were used."

Rashid, before you start conducting flow/flush rate testing of your building fixtures, you may want to spend a little time researching the fixtures to see if you can track down manufacturer information. Most plumbing fixtures and fittings will have manufacturer names stamped on them, and some will even include model numbers or flow/flush rates in terms of gallons per minute (gpm) or gallons per flush (gpf). Start by doing a building walkthrough and inspecting all of your fixtures. Organize them by fixture type and manufacturer and count up all of the installed fixtures. Look for manufacturer information on the fixture and carry a small mirror with you to make it easier to look at the back of flush handles or lavatory aerators. It may be much easier to try to contact manufacturers to acquire valid product information than to go through the process of testing a representative sample of 20% of your fixtures. If you're unable to track down manufacturer information, check back here to get assistance on conducting compliant flush/flow rate testing.