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Multiple shower control valves?

Nearly-Complete

Nearly-Complete

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Joined
Feb 8, 2019
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27
Location
California
Does the plumbing code allow multiple valves in a shower?

Builder wants to circumvent Calgreen by placing multiple shower heads on separate control valves. I agree that the wording of Calgreen would allow this (see below). Does the plumbing code allow multiple valves for a single shower? My boss says it is allowed, and that the phrase in 408.3 (see below) is referring to the fact that you can’t have separate hot & cold valves.

2019 CA Green:
4.303.1.3.2 Multiple showerheads serving one shower

When a shower is served by more than one showerhead, the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons per minute at 80 psi, or the shower shall be designed to allow only one shower outlet to be in operation at a time.

2019 CA Plumbing
408.3 Individual Shower and Tub-Shower Combination Control Valves Showers and tub-shower combinations shall be provided with individual control valves of the pressure balance, thermostatic, or combination pressure balance/thermostatic mixing valve type that provide scald and thermal shock protection for the rated flow rate of the installed showerhead. These valves shall be installed at the point of use and comply with ASSE 1016/ASME A112.1016/CSA B125.16 or ASME A112.18.1/CSA B125.1.
 
Nearly-Complete said:
Does the plumbing code allow multiple valves in a shower?

Builder wants to circumvent Calgreen by placing multiple shower heads on separate control valves. I agree that the wording of Calgreen would allow this (see below). Does the plumbing code allow multiple valves for a single shower? My boss says it is allowed, and that the phrase in 408.3 (see below) is referring to the fact that you can’t have separate hot & cold valves.

2019 CA Green:
4.303.1.3.2 Multiple showerheads serving one shower

When a shower is served by more than one showerhead, the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons per minute at 80 psi, or the shower shall be designed to allow only one shower outlet to be in operation at a time.

2019 CA Plumbing
408.3 Individual Shower and Tub-Shower Combination Control Valves Showers and tub-shower combinations shall be provided with individual control valves of the pressure balance, thermostatic, or combination pressure balance/thermostatic mixing valve type that provide scald and thermal shock protection for the rated flow rate of the installed showerhead. These valves shall be installed at the point of use and comply with ASSE 1016/ASME A112.1016/CSA B125.16 or ASME A112.18.1/CSA B125.1.
Click to expand...
How can you circumvent the code when "...the shower shall be designed to allow only one shower outlet to be in operation at a time...."
It does not say One outlet per valve. ONE is ONE. And that one shall be 1.8 GPM.
 
Wait till you get a final, then you can illegality do what you want.
As long as you don't get caught.
 
I have approved a shower with three heads with three separate valves. The heads were at different heights. One for dad, one for mom, one for the kids. Technically the total gpm of the combined heads is not allowed to exceed the gpm for a shower.....but that wouldn't work.
 
mark handler said:
How can you circumvent the code when "...the shower shall be designed to allow only one shower outlet to be in operation at a time...."
It does not say One outlet per valve. ONE is ONE. And that one shall be 1.8 GPM.
Click to expand...

There is an OR there: 1.8 gpm for all the heads on one valve “OR the shower shall be designed to allow only one shower outlet to be in operation at a time.” They are complying with the first half of the OR statement, so I cannot force them to also comply with the second half.
 
ICE said:
I have approved a shower with three heads with three separate valves. The heads were at different heights. One for dad, one for mom, one for the kids. Technically the total gpm of the combined heads is not allowed to exceed the gpm for a shower.....but that wouldn't work.
Click to expand...

Did you basically trust them not to crank all three valves at once? In this situation, they are freely admitting they want to use the multiple valves/heads at the same time.
 
Nearly-Complete said:
Did you basically trust them not to crank all three valves at once? In this situation, they are freely admitting they want to use the multiple valves/heads at the same time.
Click to expand...

I believed the owner. The spacing of the heads made it obvious that he was telling the truth.
 
You can, per code, have multiple heads as long as the combined total is 1.8 GPM.
It does not say 1.8 GMP, per valve.
1.8 total.

You are asking code officials to tell you how to circumvent the state law.
IMPO, the only way is to Wait till you get a final, then illegality do what you want.
 
mark handler said:
You can, per code, have multiple heads as long as the combined total is 1.8 GPM.
It does not say 1.8 GMP, per valve.
1.8 total.

You are asking code officials to tell you how to circumvent the state law.
IMPO, the only way is to Wait till you get a final, then illegality do what you want.
Click to expand...

nononono... I’m a plan reviewer trying to enforce the requirement. The applicant is trying to get around the 1.8 gpm requirement.

The way Calgreen is written, “...the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons per minute at 80 psi...” does tie it to per valve.

That’s why I am asking if the plumbing code limits the shower to one valve. Otherwise I do not have a leg to stand on if I deny the application. My boss is on the applicant’s side on this issue, so I need something very solid or I will have to let it go.
 
I found the commentary to the 2016 Calgreen, and it does allow the specified flow rate to be applied to each valve when multiple valves are installed in the shower:

“The maximum flow rate provisions apply to the total amount of water flow resulting from each valve supplying the individual shower enclosure regard- less of the number of attached showerheads (or similar fixture outlets or sprays). For example, if only one valve supplies a shower enclosure or shower area , the maximum water flow, regardless of the number of shower- heads and other outlets, is 2.0 gpm at 80 psi. If two (or more) separate valves provide water to separate showerheads and other outlets, the maximum flow rate for each valve would be 2.0 gpm at 80 psi. If the operation of two or more showerheads and body sprays controlled by a single valve results in more than 2.0 gpm at 80 psi total water flow, then only one showerhead may operate at one time with a maximum flow rate of not more than 2.0 gpm.”
Page 37 in https://codes.iccsafe.org/content/get-pdf/2504/Guideto2016CalGreenResidential.pdf
 
3-19-20. When reading 2019 CPC and 2019 CGC, the wording seems clear as to each head maximum is 1.8 gpm. If 4 shower heads are on a single valve, not more than 1.8 gpm can be allowed. You could adjust the output in any configuration as long as the 1.8 gpm is not exceeded. However, if you had 10 single valves, then you could have 1.8 times 10 or 18 gpm discharging into the drain. You may ask, what about the drainage if there were 18 gpm flowing in the shower receptor? Great observation, but then you would need to decide is it an intermittent or continuous flow? I would determine it is intermittent and the Table 702.2(2) notes 15-30 gpm as 4 DFU's. Then using Table 702.2(1), the maximum dfu's for a 2" trap and arm is, yes you guessed it, 2"! So the minimum by Table 702.1 would be sufficient.
 
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