Some products help us use other products or materials more efficiently. For example, drywall clips allow the elimination of corner studs, engineered stair stringers reduce lumber waste, and concrete pigments and polishing systems can turn concrete slabs into attractive finished floors. We also recognize some products, like vacuum plumbing systems, which use less material than their conventional counterparts. Many products with this attribute are fairly unique, so we bring a skeptical eye to manufacturer claims, but not a specific standard.
AcornVac Vacuum Plumbing System
All toilets and most showerheads today meet the federal water-efficiency standards, but not all of these products perform satisfactorily. With toilets and showerheads, we include products that meet or exceed WaterSense standards, which includes performance requirements—although we go beyond WaterSense where there are issues not adequately addressed by the program. We also look for other products that conserve potable water, such as rainwater catchment and graywater recovery and reuse systems.
AcornVac vacuum plumbing systems use small-diameter piping and a vacuum to pull water from toilets, showers, sinks, refrigeration condensate, and other sources through to a central vacuum-generating station where the waste can be stored or sent to the sewer system. AcornVac is appropriate for healthcare, hospitality, institutional, and other commercial applications looking for water savings and low-impact waste treatment, or where site or building conditions make standard plumbing difficult to install. Fewer materials are needed because the pipes are smaller and no vent piping is necessary, and there is more design flexibility because waste flow is not limited by gravity. The toilets in these systems use 0.5 gpf, but flush performance has not been tested by the MaP (Maximum Performance) protocol; these are included in GreenSpec as part of the system because of their ultra-low water use.
Toilets represent a significant portion of the potable water consumption in most commercial buildings, so the possibilities for savings in both new installations and replacements are huge. There have been improvements to the tank-type gravity system, and commercial water-pressure-based blow-out toilets as well as pressure- and vacuum-assisted flushing systems have been developed that offer superior performance in commercial applications. Commercial toilets include flushometer toilets.
All commercial toilets sold in the United States must meet the 1.6 gallon per flush federal standard.
The EPA WaterSense High Efficiency Toilet (HET) specification sets a higher bar, and although WaterSense is directed at residential toilets, it is frequently used for commercial toilets, as well, and encompasses the following aspects of performance:
- Flush volume – no more than 1.28 gallons per flush
- Flushing performance – minimum 350 grams per the Maximum Performance (MaP) test
- Fill valve – pilot valve type or equivalent performance
- Tank capacity – maximum holding volumes for tanks (with quantities determined by tank and flush type)
- Product marking – labeling and installation instructions that uphold the above criteria
Dual-flush toilets comply with WaterSense by making two flushes available: one for solid wastes and a lower-volume flush for liquids and paper. For dual-flush toilets, WaterSense accounts for water savings by averaging the high and low volume flush levels: two reduced flushes and one full flush cannot average more than 1.28 gallons per flush.
Note that commercial toilets may have different flushometer options. Dual-flush flushometer valves offer similar performance for standard commercial blow-out toilets, and many flushometers include sensors that improve sanitation by triggering the flush.
GreenSpec lists commercial toilets that meet WaterSense criteria for flushing volume and are able to flush 500 grams per the MaP test, exceeding WaterSense criteria. GreenSpec users, however, should be aware of the limitations of the WaterSense criteria. MaP Test results many times higher than the 350 g minimum are possible but may come at the expense of other bowl-clearing aspects of performance, such as:
- Floating or dissolved media clearance
- Rim clearing
- Water spot
- Back wall clearance
To the extent possible, GreenSpec considers these other aspects of performance qualitatively (as GreenSpec users should as well) because no other publicly available standards are available.
Also, be aware that in certain buildings—especially existing buildings—long horizontal drainline runs or low slopes may result in clogging with the lowest-flow toilets, due to inability to carry wastes.
WEc1: Water Use Reduction
WEc2: Innovative Wastewater Technologies
WEc3: Water Use Reduction
WEc3.1-3.2: Water Use Reduction
WEp1: Water Use Reduction—20% Reduction
WEp1: Minimum Indoor Plumbing Fixture and Fitting Efficiency
WEp1: Water Use Reduction
Ratings and Commentary