Low Water Pressure in Urinals...Please Help

When we built our house 10 years ago, my old man decided to put urinals in our bathrooms. We have 2 bathrooms w/ one urinal in each. Being a do-it-yourself kind of guy, he decided to do all the work himself. Although the bowl toilets, sinks, and showers have good water pressure, the urinals don't. The only way we can use them is if we hold the lever down to flush it the whole time we stand there "doing our buisness." If anybody has any suggestions as to what might make these work better, please let me know...

To make them work right, you will need to repipe the house out to the meter.

The first urinal needs to be piped as a 20 fixture unit device, the second urnial needs to be counted as 15 making a total of 35 fixture units for just those two items. Chapter 610.10

Using table 6-5, it would seem that you needed at least a 1" meter and 1-1/4" main line pipe for these to work.
http://www.iapmo.org/common/ROP2004/upc04rop/preprint/ch6.pdf

I'm guessing that you have a 3/4" meter and a 1" main line. Not big enough to make a urinal work.

Sizing for plumbing, works in reverse, you count up the needed fixture units and work backwards toward the meter. Those two urnials by themselves are 35 fixture units. That's the same as a three bath home.

Most standard two bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, two 1.6 tank toilet, two lavatories, one shower, one tub/shower combo, and two hose bibs would be counted as 23.5 fixture units.
So if I add this up right, you need to be sized for 58.5 fixture units.
https://terrylove.com/watersize.htm

In commerical use, allowances are made for these devices and larger pipes and meters are installed.
Homes have proven to be a poor place for these.


Just off the top of my head, if repiping is out of the question, you may try an expansion tank near the urninals for a little added volume of usable water flow.

When I dd the plumbing at my church, back to back bathrooms, eight toilets in the womans, four on the other side with two urnials, I ran a 2" pipe right down the middle with a 2" cap on the far end and continued out to the street to a 2" meter. Off of the two inch I ran my supplies.
Even though it's on the top of a hill with very little head pressure, you would never know it.

Every fixture is by Toto including the urnials and flushometer valves. Most of the toilets are one-piece Ultramax's and a few two-piece ADA Drakes.

Thank you, I will look into the expansion tank. Anybody have a link for one? Our home is an earth sheltered home made out of cement, and repiping would require knocking down walls in our case. Thank you for the help, -Jesse

Basically, the expansion tank has an air bladder in it. If you made the output line big enough, it could push that stored water out to provide the required volume, and then be refilled by the supply line. Only problem would be if you tried to flush it again before it was refilled. I'm not sure what say a 5-gallon one costs, but you can get one at the big box stores. Given the relatively low volume flush of a urinal, that should work fine. My unprofessional opinion. Just make sure you use a big enough outlet pipe on the thing.

urinal

What kind of urinals and what kind of valves. A urinal is typically a low volume water user, i.e. 3/4 to 1 gpf, and almost any pressure will operate it, unless it is a blowout urinal. If your valves are Chicago, Central, or similar inline valves then the problem could be the slow closing mechanisms are shot, and they do not work all that well when they are new either.