Thread: Tempering Valve

In which situations tempering valve required per code ?

In a shower? bath? or it needs to be installed in water heater?

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What is the adopted code in WA? Many of the codes now require a device to limit water temperatures at lavatories, tubs and showers (at around 120 degrees F. if memory serves).

This is what I am looking to help with - is here a code which regulate where it can and should be installed?
Anyone can help?

Originally Posted by Robert Gaspy

In which situations tempering valve required per code ?

In a shower? bath? or it needs to be installed in water heater?

Who's the manufacture?
WATTS, Honeywellwell, B&S.
NPC: Table of Revisions — National Plumbing Code 2005.
I try to take a pic at the tag.

Article 2.2.10.7. was replaced with the following text:
2.2.10.7. Water Temperature Control(See Appendix A.)
2.2.10.7.1) Except as provided in Sentence (2), all valves supplying fixed-location shower heads shall be individualpressure-balanced or thermostatic-mixing valves conforming to ASME A112.18.1/CSA B125.1, “PlumbingSupply Fittings.”2) Individual pressure-balanced or thermostatic-mixing valves shall not be required for showers having asingle tempered water supply that is controlled by a master thermostatic-mixing valve conforming to CSAB125.3, “Plumbing Fittings.”3) All mixing valves supplying shower heads shall be of the pressure-balanced, thermostatic, or combinationpressure-balanced/thermostatic type capable ofa) maintaining a water outlet temperature that does not exceed 49C, andb) limiting thermal shock.4) The temperature of water discharging into a bathtub shall not exceed 49C

Hope that helps.
Bob should be along...

From the 2009 IRC
P2708.3 Shower control valves. Individual shower and
tub/shower combination valves shall be equipped with control
valves of the pressure-balance, thermostatic-mixing or combination
pressure-balance/thermostatic-mixing valve types with
a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a
maximum of 120°F (49°C). In-line thermostatic valves shall
not be used for compliance with this section.

P2802.2 Temperature control. Where a combination water
heater-space heating system requires water for space heating at
temperatures exceeding 140°F (60°C), a master thermostatic
mixing valve complying with ASSE 1017 shall be installed to
temper the water to a temperature of 140°F (60°C) or less for
domestic uses.

In my home I have Delta brand valves at lavatories, tubs and at showers. Temperature limiting is one of the features of the brand & type.

Thank you very much for your explanation.

However, I am still confused.
To my understanding - all electric water heatters have temperature control. So, water temperature can not be higher then the standart in water heaters - which is 120 F.
So , do we need to make sure that every shower and a soaking bath has additional thermostatic valves?
Also, I recently saw free standing bath tab - claw bath. It has 2 lines - hot and cold coming to the bath tab. it has 2 handles - one for hot water and another for cold water. It is difficul for me to even imaging - where it could be possible to instal that tampering valve . It will destroy all view and image .
Could anyone advise,please ?

Originally Posted by Alton Darty

From the 2009 IRC
P2708.3 Shower control valves. Individual shower and
tub/shower combination valves shall be equipped with control
valves of the pressure-balance, thermostatic-mixing or combination
pressure-balance/thermostatic-mixing valve types with
a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a
maximum of 120°F (49°C). In-line thermostatic valves shall
not be used for compliance with this section.

P2802.2 Temperature control. Where a combination water
heater-space heating system requires water for space heating at
temperatures exceeding 140°F (60°C), a master thermostatic
mixing valve complying with ASSE 1017 shall be installed to
temper the water to a temperature of 140°F (60°C) or less for
domestic uses.

In my home I have Delta brand valves at lavatories, tubs and at showers. Temperature limiting is one of the features of the brand & type.

Water heaters should be set at 140 degrees to prevent bacterial formation and growth. Temperatures above 120 degrees can cause burns in a very short time. Tempering valves are needed so that both needs are met.
A tub with hot & cold valves allows one to adjust the water temps to a safe level. Imagine a shower valve without a tempering feature and a water heater set to 140 degrees, now have someone flush a toilet and think about what occurs to the water temperature produced at the water stream.
Also thermostats on electric water heaters often go to 150 degrees...

top-and-bottom-thermostat.jpg
Individual shower and tub/shower combination valves shall be equipped with control valves of the pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve types with a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a maximum of 120°F (49°C). In-line thermostatic valves shall not be used for compliance with this section.

Emphasis added

Originally Posted by Robert Gaspy

Thank you very much for your explanation.

However, I am still confused.
To my understanding - all electric water heatters have temperature control. So, water temperature can not be higher then the standart in water heaters - which is 120 F.
So , do we need to make sure that every shower and a soaking bath has additional thermostatic valves?
Also, I recently saw free standing bath tab - claw bath. It has 2 lines - hot and cold coming to the bath tab. it has 2 handles - one for hot water and another for cold water. It is difficul for me to even imaging - where it could be possible to instal that tampering valve . It will destroy all view and image .
Could anyone advise,please ?

Would it be the same if tempering valve is installed on the hot line which is coming out of water heater?

Originally Posted by Alton Darty

Water heaters should be set at 140 degrees to prevent bacterial formation and growth. Temperatures above 120 degrees can cause burns in a very short time. Tempering valves are needed so that both needs are met.
A tub with hot & cold valves allows one to adjust the water temps to a safe level. Imagine a shower valve without a tempering feature and a water heater set to 140 degrees, now have someone flush a toilet and think about what occurs to the water temperature produced at the water stream.
Also thermostats on electric water heaters often go to 150 degrees...

top-and-bottom-thermostat.jpg
Individual shower and tub/shower combination valves shall be equipped with control valves of the pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve types with a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a maximum of 120°F (49°C). In-line thermostatic valves shall not be used for compliance with this section.

Emphasis added

Robert
Water heaters are often used to supply hot water to in floor heating or heating coils at air handlers, to dish washers, clothes washers and other equipment besides providing hot water for domestic use. Unless the hot water piping was designed to separate hot water to heating systems and water to tubs/showers and lavatories placing a tempering valve at the water heater could be an issue.

I have no idea what plumbing code your area uses, or when the residence was constructed and what code may have been in use at that time. The info I provided was from some of the most recent code, and is what has been adopted in my area. As far as "what if" or "how to" the code is not an instruction or design manual.

Most tub/shower valves are not visible/accessible during a home inspection, if water temps at tub/shower valves or lavatories is above 120 degrees there is an issue which bears mention in the report. We don't have to verify that a tempering valve is in place, or that it is in the proper location, only that the water temps are higher than what is recommended and that the issue will need to be addressed.

Individual shower and tub/shower combination valves shall be equipped with control valves of the pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve types with a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a maximum of 120°F (49°C).In-line thermostatic valves shall not be used for compliance with this section.

Emphasis added

Excellent answer! Thank you
Can some one help me to find out what is the code for tempering valve in this area - Clark county WA? House is brand new.

Originally Posted by Alton Darty

Robert
Water heaters are often used to supply hot water to in floor heating or heating coils at air handlers, to dish washers, clothes washers and other equipment besides providing hot water for domestic use. Unless the hot water piping was designed to separate hot water to heating systems and water to tubs/showers and lavatories placing a tempering valve at the water heater could be an issue.

I have no idea what plumbing code your area uses, or when the residence was constructed and what code may have been in use at that time. The info I provided was from some of the most recent code, and is what has been adopted in my area. As far as "what if" or "how to" the code is not an instruction or design manual.

Most tub/shower valves are not visible/accessible during a home inspection, if water temps at tub/shower valves or lavatories is above 120 degrees there is an issue which bears mention in the report. We don't have to verify that a tempering valve is in place, or that it is in the proper location, only that the water temps are higher than what is recommended and that the issue will need to be addressed.

Individual shower and tub/shower combination valves shall be equipped with control valves of the pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve types with a high limit stop in accordance with ASSE 1016 or CSA B125.
The high limit stop shall be set to limit water temperature to a maximum of 120°F (49°C).In-line thermostatic valves shall not be used for compliance with this section.

Emphasis added

Robert
If the output temps at tub/shower is over 120 degrees F this is a safety issue and should be included in the inspection report as such. Report this as a safety issue and not a code compliance problem and people will listen. Find a good .PDF file from a burn center or a web page link such as The Burn Foundation - www.burnfoundation.org - Scald Burns to include in your report to help buyers find more info. A buyer insisting that a safety issue be fixed will go a lot further that an inspector pointing out a code issue.

Most states with a home inspection licensing requirement tend to strongly discourage inspectors from quoting codes. Even though code plays an important role in our inspection activities licensing boards take a very dim view of our quoting codes or code sections.

If this is for your own knowledge it would appear that the State of Washington has adopted the 2015 UPC as the plumbing standard, but some municipalities may not. Check with the local building or permitting office to find out.

From what I recall the requirement for tempering the water temps at tubs/showers has existed in the UPC since around 1994 or 1997.

Free acces to the 2015 UPC is available at 2015 UPC 2nd Print

Sections 408.3 and 409.4 (pages 67 and 68) deal with tempering valves at whirlpools, tubs, and tub/shower.

Used to be that you could order labels showing the information below from A. O. Smith ... they would send you the labels free of charge, as many as you wanted - I am not sure if they still do that or not.

This image was taken from an A. O. Smith water heater installation instructions, but the stickers were also good to have ('back then' I would put a sticker on the water heater, then put this information in my digital report report too when I started doing computer reports in 1994, and at some point I stopped putting the stickers on the water heaters).

NOTE that is based on ADULT SKIN, not that of children, which makes it even more important.

Thank you Alton,excellent explanation!!!

Originally Posted by Alton Darty

Robert
If the output temps at tub/shower is over 120 degrees F this is a safety issue and should be included in the inspection report as such. Report this as a safety issue and not a code compliance problem and people will listen. Find a good .PDF file from a burn center or a web page link such as The Burn Foundation - www.burnfoundation.org - Scald Burns to include in your report to help buyers find more info. A buyer insisting that a safety issue be fixed will go a lot further that an inspector pointing out a code issue.

Most states with a home inspection licensing requirement tend to strongly discourage inspectors from quoting codes. Even though code plays an important role in our inspection activities licensing boards take a very dim view of our quoting codes or code sections.

If this is for your own knowledge it would appear that the State of Washington has adopted the 2015 UPC as the plumbing standard, but some municipalities may not. Check with the local building or permitting office to find out.

From what I recall the requirement for tempering the water temps at tubs/showers has existed in the UPC since around 1994 or 1997.

Free acces to the 2015 UPC is available at 2015 UPC 2nd Print

Sections 408.3 and 409.4 (pages 67 and 68) deal with tempering valves at whirlpools, tubs, and tub/shower.