If the fixture upgrade will be done in house and will only consist of diaphragm replacement for installed flush valves, how can we authenticate the fixtures if there will be no copies of construction permits, substantial completion notices, contract excerpts, plumbing inspection reports, or commissioning reports? Can we use the purchase order for the parts as evidence?
Omar, Yes the purchase order and corresponding delivery ticket that ties the diaphragms to the number of units that you rebuilt in house will work well. Also you can provide a cut sheet of the diaphragm to prove flush rate by going on line to the diaphragm manufacturers website.