Many factors such as available space, cost, flushing action, and aesthetics need to be considered to provide a urinal that meets the client’s needs.
by Siddharth Bhat, PE, CPD, GPD, LEED AP
In this edition in the series of articles I plan to publish on basic guidance for selecting plumbing fixtures, the next stop is selecting a urinal. In this article I will dive a bit into why urinals were invented and how they have improved toilet functionality from a male point of view.
One of the major design intents when designing a restroom is to reduce toilet usage time and toilet wait time. Initially, male restrooms had water closets for urination purposes too. Research has shown that since water closets are enclosed with a door, they provide more privacy to the user, and users who have more privacy while using a fixture tend to use the fixture for a longer time than when privacy is limited. Urinals have limited privacy as compared to a water closet, so they have helped reduce fixture usage and wait times in male restrooms. Similar research is being done on the female side too, but the major issue is that women need more privacy than men. Efforts are being made to see how this requirement can be taken into account while also reducing the amount of time needed to use a fixture.
Another important benefit of having urinals is reduced water consumption. Per the Energy Policy Act (EPAct) of 1992, a water closet typically uses 1.6 gallons per flush (gpf), while the urinal uses 1 gpf per flush—so the urinal effectively uses less water than a water closet would use for the same function. (Note that this issue can be eliminated by the use of dual-flush toilets.)
Urinals can be selected based on a number of parameters, some of which are discussed below.
The major urinal types available in the market are blowout, siphon jet, washdown, and waterless. These types are segregated based on the flushing principle used for the elimination of waste.
In a blowout type of urinal, the bowl has small holes through which jets of water are directed to the trap. These jets of water take the contents of the bowl along with them, and everything is flushed out of the bowl. Siphon-jet urinals tend to use siphonic action to take the contents out of the bowl. The major advantage of these urinals is that they also can remove solid matter out of the bowl, such as wrappers and tissue. This is one of the main reasons they are found extensively in commercial applications where there may be a high amount of usage. However, these urinals can be very noisy.
In washdown urinals, water flows from the top spreader bar down to the trap along the back body of the bowl. These urinals do not have the same amount of cleaning action that siphon-jet or blowout urinals have, but they are very quiet. Also, in the flushing action, the water flow is more laminar as compared to siphon-jet or blowout urinals, which may be appealing to some clients, so the aesthetics of the space play a major role in selecting washdown urinals.
Flush Valve Type
Flush valves can be differentiated by the location of installation. They can be exposed or concealed. Like the name suggests, with a concealed flush valve, the entire assembly is concealed, with only the flushometer button/sensor exposed. Some owners may prefer this due to aesthetic reasons. Some facilities such as correctional, behavioral, and healthcare may request the concealed type to prevent valves from being used for harming oneself.
The plumbing designer would need to verify the urinal fixture connection based on the location of the flush valve. For a concealed type of flush valve, you may need to specify a rear connection, while for an exposed flush valve you may need to provide a top connection.
Flush valves can be further divided as manual or sensor operated. Sensor-operated flush valves are more hygienic since users are not required to touch the flush valve for it to operate. Due to the Covid-19 pandemic, a lot of owners are opting for sensor-type flush valves to promote cleaner restroom conditions. Sensor-type valves may be hardwired or battery powered. The battery-powered valves can eliminate additional costs for electrical connections during building construction; however, using battery-powered sensors means that staff has to replace the batteries from time to time. In response to this concern, manufacturers have been increasing battery life to last for three to five years before replacement is required.
Type of Urinal
Some manufacturers provide different styles of urinals such as standard, small, and designer. Small-size urinals may be deployed in restrooms where space is a concern. Designer-style urinals come in different shapes and styles to match the aesthetic requirements of the client. It may be a good idea to provide clients with cut sheets of these urinals for approval in case the aesthetics of the fixture are of a concern.
One of the important items to consider for urinals is the flush volume. Per the EPAct of 1992, the maximum allowable flush volume is 1 gpf. In case the designer wants to be more conservative with water flow without going too low, you can opt for a 0.5-gpf flush volume.
When designing a green building such as a LEED-certified building where additional water conservation provides points, you may opt for a flush volume of 0.125 gpf. These urinals effectively use eight times less water than what is specified by the code. Also, waterless urinals (0 gpf) are available to provide maximum water savings.
Codes and Regulations
Many manufacturers provide data based on various codes and regulations that allow the designer to make the desired selection. Some of these include the American with Disabilities Act (ADA), BREEAM, California Energy Commission, CalGreen, EPD, Green Globes, HPD, LEED, WaterSense, etc.
Among these, the most common ones used in the United States are ADA, LEED, and WaterSense.
It is always important to select the right urinal that serves the needs of the client. Many factors such as available space, cost of the urinal, flushing action, aesthetics, ease of cleaning, etc., need to be considered when providing a selection. The designer needs to discuss these options with the client to ensure a design compatible with the owner’s intent.
About the Author
Siddharth Bhat, PE, CPD, GPD, LEED AP, is a Mechanical and Plumbing Engineer at DLZ Corporation with specialization in correctional facility design.
The opinions expressed in this article are those of the author and not the American Society of Plumbing Engineers.