# Mixing Valves



## pigskin plumber (Oct 2, 2011)

Hey just curious if there are municipalities, that don't require a mixing valve with a hwt in homes? 

Cheers


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## marc76075 (Nov 24, 2010)

I don't have my code book in front of me, but I'm pretty sure Florida code doesn't require one.


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## ZL700 (Dec 8, 2009)

Canada enacted that requirement into code 2004-2005 to help prevent scalding and bacteria growth. So in Canada where you live, I'm sure it's a requirement all over.


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## track3 (Dec 31, 2011)

ZL700 said:


> Canada enacted that requirement into code 2004-2005 to help prevent scalding and bacteria growth.


I'm sure some ambulance chasing lawyers had something to do with it as well. 

So you go through all the work of setting the temp controls right and the homeowner has no clue how to change them, so of course they go to the water heater and turn it up to the max.

So, you go through all of that work, kids are still getting burned but it's the homeowners fault, and the water heater isn't going to last as long.

sounds like a little job security with less liability for me.


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## smoldrn (Oct 4, 2010)

I know that SC doesn't require one. Plus all our tub/shower valves are temperature balanced, probably like that everywhere.

As far as bacteria growth, I believe that Legionnaire's Disease is caused by the water in the tank not being hot enough,(I could be wrong).


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## ZL700 (Dec 8, 2009)

track3 said:


> I'm sure some ambulance chasing lawyers had something to do with it as well.
> 
> So you go through all the work of setting the temp controls right and the homeowner has no clue how to change them, so of course they go to the water heater and turn it up to the max.
> 
> ...


Thats why they use thermostatic mixing valves that top out at 120 degrees, failing to cold.
Actually water heaters will last longer at higher temp storage limiting chances of condensing when larger amounts of water is drawn.


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## ZL700 (Dec 8, 2009)

smoldrn said:


> I know that SC doesn't require one. Plus all our tub/shower valves are temperature balanced, probably like that everywhere.
> 
> As far as bacteria growth, I believe that Legionnaire's Disease is caused by the water in the tank not being hot enough,(I could be wrong).


 



At 151° F ​Legionella die within 2 minutes

At 140° F ​Legionella die within 32 minutes

At 135° F 
Legionella die within 2 hours

At 131° F 
Legionella die within 5 to 6 hours

Above 122° F 
Legionella can survive but do not multiply

95 to 115° F 
Ideal Legionella bacteria growth range

68 to 122° F 
Legionella bacteria growth range

Below 68° F 
Legionella can survive but are dormant


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## MarkToo (Dec 17, 2011)

ZL700 said:


> Canada enacted that requirement into code 2004-2005 to help prevent scalding and bacteria growth. So in Canada where you live, I'm sure it's a requirement all over.



Prior to this for a very short period, they were requiring us to set the HWT to 120F max. I was doing production housing at the time and flatly refused to comply.

They insisted on threat of not passing final inspections - thus no occupancy. Not good when you're closing a half-dozen houses a week. I had the builder losing it on me and the inspector unwilling to budge.

A call to the chief building inspector with an explanation as to what the problem was made it go away rather quickly once the liability issue was explained.

Just shows that bureaucrats that haven't got a clue shouldn't be making policy for anything.


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## Widdershins (Feb 5, 2011)

They're required on all tubs, tub/shower combinations and bidets up here on the Northern part of the Left Coast.

I usually mount them inside of a wall box inside the vanity and then pull the tempered line to the tub or bidet location.

The code requires integral checks, so I go with the Caleffi 521342A.

If the house has more than 2 tubs or tub/shower combinations I'll just install a single tempering valve on the H/W Tank.


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## OldSchool (Jan 30, 2010)

smoldrn said:


> I know that SC doesn't require one. Plus all our tub/shower valves are temperature balanced, probably like that everywhere.
> 
> As far as bacteria growth, I believe that Legionnaire's Disease is caused by the water in the tank not being hot enough,(I could be wrong).


That excalty right .... we already had pressure balance faucets up here... and the whole idea of the mixing valve on the HWT was increase HWT temperature to kill the bacteria.

Therefore making the water temperature unsafe .... every tank has to have a limited max water temperature output of 120 deg....

Lots of Pissed customers ... after that... you can't have a really hot shower any more


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## plbgbiz (Aug 27, 2010)

OldSchool said:


> ....Lots of Pissed customers ... after that... you can't have a really hot shower any more


Of course every statistic from the government should be scrutinized but this is not the first time I've heard this. Partial quote from the U.S. Consumer Product Safety Commission's website>> http://www.cpsc.gov/cpscpub/pubs/5098.html

_"Each year, approximately 3,800 injuries and 34 deaths occur in the home due to scalding from excessively hot tap water. The majority of these accidents involve the elderly and children under the age of five. The U.S. Consumer Product Safety Commission (CPSC) urges all users to lower their water heaters to 120 degrees Fahrenheit. In addition to preventing accidents, this decrease in temperature will conserve energy and save money.

Most adults will suffer third-degree burns if exposed to 150 degree water for two seconds. Burns will also occur with a six-second exposure to 140 degree water or with a thirty second exposure to 130 degree water. *Even if the temperature is 120 degrees, a five minute exposure could result in third-degree burns.*..."_

I don't understand how any normal human can stand a straight 120deg shower for any appreciable length of time.


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## plumber666 (Sep 19, 2010)

Excuzey moi, but I've never heard of this code business regarding mixing valves. Can you refer to the section that requires them, the last code I owned was '06, but if I get a second at work I'd like to check this out in the new one. Just sayin, but it sounds like BS to me.


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## OldSchool (Jan 30, 2010)

It not under our plumbing code.... it has been mandated through the ministry of housing in ontario.... so far as I know it is a provincial thing....

The whole thing was established through the federal government through the ministry of health.... as we all know the province has to accept and adopt these standards....

So it may not be law in all provinces.... it is however law in Ontario


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## smoldrn (Oct 4, 2010)

Here, I think it was part of Al Gore's water conservation act of '92. They figured that if you put your hand under scalding water, that you'd be too stupid to remove it, & get burned.
Just trying to protect the public from their own stupidity. I actually had a customer years ago who insisted I put a 2 handle tub valve in so that her kids could tell which side was hot. Duh uh.
Had to put a mixing valve at the wh.


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## ZL700 (Dec 8, 2009)

Canadian Plumbing Code –Maximum Hot Water Temperature
The Canadian commission on Building and Fire Codes has issued an Interim change to the 2005 National Plumbing Code on Water temperature control.​

_2.2.10.7 Water Temperature Control_
_1) Except as provided in Sentences (2), all valves supplying fixed-location showerheads shall be individual pressure-balanced or thermostatic-mixing valves conforming to ASME A112.18.1/CSA B125.1,“Plumbing supply fittings.”_
_2) Individual pressure-balanced or thermostatic-mixing valves shall not be required for showers having a single tempered water supply that is controlled by a master thermostatic-mixing valve conforming to CSA B125.3, “Plumbing fittings.”_
_3) All mixing valves supplying showerheads shall be of the pressure-balanced, thermostatic, __or combination pressure-balanced/thermostatic type capable of_
_a) maintaining a water outlet temperature that does not exceed 49°C, and_
_b) limiting thermal shock.._
_4) The temperature of water discharging into a bathtub shall not exceed 49°C._​
_Intent: Hot water delivered to fixtures at too high a temperature will result in scald burn injuries._
_2.6.1.12. Service Water Heater_​ 
_1) Thermostat controls for electric storage type service water heaters shall be set to a temperature of 60_*°*_C._
_Intent: Hot water stored at too low a temperature may lead to the proliferation of legionella bacteria._​ 

_Province of Ontario_​ 
_Since January 2005 and, still is in effect._​



_The Ontario Building Code was amended in September 2004 to specify that_
_“The maximum hot water temperature supplied to fixtures in residential occupancies shall not exceed 49 degrees_


_Celsius or 120 degrees Fahrenheit.”_

_This requirement exempts dishwashers and clothes washers._
_Options for compliance include:_​
_1) Installation of a mixing valve at the water heater to lower the temperature to 49_​​*°*_C__2) Installation of a mixing valve / pressure balance valve at each outlet._​



_According to the Ministry a replacement of a domestic water heater is a material alteration and necessitates __compliance with the new article. As well if a faucet is replaced the temperature at that faucet is required to be a __maximum of 49_​​
*°*_C and if a system is extended, only those faucets installed at the extended portion of the system __are required to meet code._​

​​​​​​​​​​​​​​​​​​
​


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## plumber666 (Sep 19, 2010)

This all makes me think of the story my mother told me about one Christmas many years ago. I was fascinated by a candle and so I reached out and touched the flame. I cried like hell, and never did it again, lesson learned. I was 5 months old.
Love when stuff like this becomes legislated. Had mother been smarter, she'd have sued the Ohio Candle Company and now all candles would be equipped with flame guards.


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