- ELECTRICIAN »
- Senior Director of Facilities »
- Facilities Director »
- Construction engineer, U.S. Dept. of State »
- Sr. Building Systems Engineer »
How Do Waterless Urinals Work?
OTHER PARTS OF THIS ARTICLEPt. 1: Modifying Faucet Aerators and Checking for Leaks to Save WaterPt. 2: This PagePt. 3: Tips for Maintaining Restrooms with Waterless UrinalsPt. 4: Assessing Odor with Waterless UrinalsPt. 5: Waterless Urinals Require Custodial and Maintenance TrainingPt. 6: Local Codes Differ on Waterless Urinals
Typically, the bodies of waterless urinals are constructed of vitreous china or porcelain, similar to standard flush urinals. Most waterless units use a liquid sealer and rely on a density differential between the sealant and the liquid waste. The sealant is less dense than water or urine, which pass through the sealant. The sealant creates a barrier between the liquid waste and the urinal bowl.
Liquid-seal urinals feature two different designs: cartridge and integrated drain trap.
The cartridge design uses various types of disposable cartridge inserts that fit into the custom-designed urinal base. The cartridge might simply slide into the base, or it might require a special tool for insertion and removal.
The cartridge typically contains a ½ liter of water and is topped with a liquid sealant. This cartridge collects sediment and directs the flow of liquid waste to the drain while blocking odors.
The integrated-trap design does not use a cartridge. Instead, it uses a liquid sealant that separates the waste from the urinal bowl through a fixed basin trap or a trap built into the urinal body.
Yet another type of waterless urinal does not require a liquid seal to operate. This urinal uses a flexible silicone diaphragm or elastomeric, expanding check valve. Typically housed in a removable cartridge, the diaphragm or check valve allows liquid waste to pass through and then seals, preventing sewer gases from entering the restroom.