Our project is attempting to achieve an innovation credit for reducing process water usage. We have taken CIR ID1.1 Ruling dated 8/31/04 as the basis for the credit, but would like to verify that we have correctly interpreted the prescribed calculation methodology. The project is a residential housing unit on a university campus, that includes a laundry facility as part of the project design. The following is the approach we have taken: We have used the WE Credit 3 letter template to measure the regulated water usage. The regulated building fixtures that were input include toilets, urinals, lavatories, and showers. We then added process water fixtures - washing machines and drinking fountains -to the letter template to measure the process and regulated building loads combined. The baseline case was established as required for WE Credit 3, using Energy Policy Act minimums for base building fixtures. The water use data that was used for the baseline washing machines was taken for a conventional commercial washer from the same manufacturer as the design-case horizontal axis model. For the design case calculations, we used the specified base building fixtures, exactly as used in WE Credit 3, and the specified horizontal washers and conventional drinking fountains. 1) The first method we used was to calculate the savings exactly as described in the previous CIR. In that ruling it is stated that to achieve this credit "The project must demonstrate a process water savings that is equal to or greater than 10% of the regulated water usage as calculated in WEc3". The following are our results: Design regulated water usage = 852,549 gal 10% of design regulated water usage = 85,255 gal Process water savings = 1,072,006 gal Therefore , process water savings are greater than 10% of the regulated water usage. 2) the second method was to calculate the saving of only the process water on the project. The following were our results: Baseline process water = 2,062,798 gal Design process water = 990,792 gal (51.97% savings) Please confirm which of these calculation methodologies meets credit requirements. If neither is correct, please describe the methodology to be used.
Your proposed methods are not consistent with the method envisioned by the 8/31/2004 Credit Ruling. This ruling instructs practitioners to calculate the discrete process load savings, on an annual volume basis, compared to a baseline process load usage. The process water savings are then compared to the annual volume of water used in the Design Case in the WE credit 3 calculator to verify that the process water savings represent at least 10% of the base building water use. Using the data you\'ve provided, you comply for an innovation point. However, from your description, it appears you may also be missing certain fixtures. There are two water fixtures that are common in residential projects that are not listed in your description that you should verify. First, kitchen sinks, if present, must be included in the WE credit 3 calculation. Second, dishwashers, if present, must be included in your process water calculation.