A White Paper
Developed by the ASSE International Scald Awareness Task Group
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ASSE International
18927 Hickory Creek Drive, Suite 220, Mokena, Illinois 60448
(708) 995-3019 | www.asse-plumbing.org
Guidelines for
Temperature Control Devices in
Domestic Hot Water Systems
2 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7
Section 8
3
5
6
6
7
8
9
10
11
12
13
14
16
17
18
Executive Summary
Purpose
Applications
Shower and Tub/Shower Combination Valves
Hot Water Distribution Systems
Individual Supply Fittings – TAFR Valves
In-Line Pressure Balancing Devices for Individual Fixtures
Tempered Water Through a Single Supply Pipe
Temperature Control Devices with Downstream Mixing Permitted
Mixing Valves for Plumbed Emergency Equipment
Devices Listed to Multiple Standards
Questions & Answers
Definitions
Matrix
Task Group Members
CONTENTS
TABLE
OF
3Guidelines for Temperature Control Devices in Domestic Hot Water Systems
The ASSE International Scald Awareness Task Group was formed to educate and give guidance to the
general public and plumbing industry on potential scalding hazards associated with domestic hot water at
the point of use.
Hot water from the tap accounts for more than 25 percent of all scald burns in children. The elderly and
the physically impaired are at increased risk of scald burns also. The attempt to prevent these scald injuries
was the driving force that brought about the invention of temperature control devices.
Each device covered by an ASSE product performance standard has specific applications as to where they
are intended to be used. However, over the past few years, ASSE International has been receiving calls
from inspectors, installers, and others asking if certain types of devices are approved to be used in certain
installations. The Authority Having Jurisdiction (AHJ) has the final approval of all installations, but one
must be aware of the manufacturer’s installation requirements, which may exceed the prevailing code.
There also appears to be a misunderstanding of the use of devices listed to multiple standards. For these
reasons, the ASSE Board of Directors thought it was best to write a white paper to serve as a reference
tool for adding clarity to where the devices should be installed.
The Task Group’s assignment was to develop a white paper that clearly explains where each temperature
control device, within ASSE’s portfolio of product performance standards, should be used, and create an
understandable reference tool that everyone in the plumbing industry can use.
THE ASSE PRODUCT PERFORMANCE STANDARDS FOR THESE DEVICES ARE:
ASSE 1016-2011/ASME A112.1016-2011/CSA B125.16-11, Performance Requirements for Automatic
Compensating Valves for Individual Showers and Tub/Shower Combinations
ASSE 1017-2009, Performance Requirements for Temperature Actuated Mixing Valves for Hot Water
Distribution Systems
ASSE 1062-2006, Performance Requirements for Temperature Actuated Flow Reduction (TAFR) Valves for
Individual Fixture Fittings
ASSE 1066-1997, Performance Requirements for Individual Pressure Balancing In-Line Valves for Individual
Fixture Fittings
ASSE 1069-2005, Performance Requirements for Automatic Temperature Control Mixing Valves
ASSE 1070-2015/ASME A112.1070-2015/CSA B125.70-15, Performance Requirements for Water
Temperature Limiting Devices
ASSE 1071-2012, Performance Requirements for Temperature Actuated Mixing Valves for Plumbed
Emergency Equipment
EXECUTIVE SUMMARY
SECTION
1
CONTENTS
4 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
This paper is the fourth in a series of white papers produced by the ASSE International Scald Awareness
Task Group. Each of the previous papers delve into a particular circumstance relating to the prevention of
scald injuries.
• Scald Hazards Associated with Low-Flow Showerheads: A White Paper
• Understanding Potential Water Heater Scald Hazards: A White Paper
• Adjustment of Automatic Compensating Valves to Prevent Potential Scald Hazards: A White Paper
These previous papers, along with this current paper, are available as downloads online at
www.asse-plumbing.org.
5Guidelines for Temperature Control Devices in Domestic Hot Water Systems
The primary purpose of this paper is to provide a simple-to-use and understandable reference guide that
everyone in the plumbing industry (plumbers, installers, maintenance personal, specifiers, inspectors,
engineers, educators, trainers, and code officials) can use in determining which device is correct for a
particular installation.
In some applications, installing the wrong device or installing the device in the wrong location can lead
to potentially serious scalding situations – it can be the same as if no temperature control device was
installed, thus exposing the end user to potentially scalding hot water temperatures. Furthermore, installing
the wrong device can lead to a false sense of security by the ultimate user. Therefore, it is extremely
important to make sure that the proper device is installed in the proper location.
We hope the information in this paper will be a useful reference for determining the proper use and
application of temperature control devices.
Upon completion of this paper, work began to develop a pocket-sized guide for the industry to use as
a simple reference, rather than going through the standards to determine the proper applications of the
various devices. A copy of this matrix can be found in Section 7 of this paper.
PURPOSE
SECTION
2
6 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Shower and Tub/Shower Combination Valves
• Shower valves shall be automatic temperature and/or pressure compensating valves intended to be
installed at an individual shower or tub/shower combination.
• These valves must comply with ASSE 1016-2011/ASME A112.1016-2011/CSA B125.16-11,
Performance Requirements for Automatic Compensating Valves for Individual Showers and
Tub/Shower Combinations.
• The user has access to flow and/or final temperature controls. No further mixing occurs downstream of
the device.
• These devices are intended to control the water temperature to wall- or ceiling-mounted:
a. Hand-held showers;
b. Shower heads;
c. Body sprays, either in individual shower or tub/shower combination fittings; and
d. Tub spouts, when part of tub/shower combination fittings.
• There are three different types shower valves that meet this standard:
a. Pressure balancing
b. Thermostatic (mechanical and electronic)
c. Combination pressure balancing and thermostatic
• The showerhead flow rate must not be less than the manufacturer’s published minimum flow rate for
the valve (device).
• The temperature limit stop must be set at the time of installation, and may need to be periodically
adjusted for variations in water temperatures.
• These devices provide both scald and thermal shock protection.
APPLICATIONS
SECTION
3
7Guidelines for Temperature Control Devices in Domestic Hot Water Systems
APPLICATIONS
Hot Water Distribution Systems
• Temperature actuated mixing valves for hot water distribution systems are used for controlling in-line
water temperatures in domestic hot water systems.
• These valves must comply with ASSE 1017-2009, Performance Requirements for Temperature
Actuated Mixing Valves for Hot Water Distribution Systems.
• When used, these devices shall be installed at or near the outlet of the hot water source ONLY.
• These valves are designed to provide a relatively uniform water temperature to the hot water
distribution system.
• As a side benefit, these valves allow the water to be stored at a higher temperature, extending the
amount of hot water available, and also reducing the chance of legionella (ASHRAE Guideline 12).
• These valves are NOT intended for point of use applications.
• Valves must be sized to match the flow requirements of the system:
Flow Rate Allowable Temperature
Fluctuation
0-5 GPM ±3° F
5-40 GPM ±5° F
Over 40 GPM ±7° F
• Further mixing downstream is allowed to provide final temperature control to protect against scalding.
• These devices used alone do not provide thermal shock protection or adequate scald protection.
• Installation note: to prohibit the cross-flow of hot or cold water through the valve, supplementary check
valves are recommended for devices that do not include integral check valves.
8 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Individual Supply Fittings – TAFR Valves
• Temperature actuated, flow reduction (TAFR) valves, when used, shall be installed on the discharge
outlet of the fixture fitting or integrated into fixture fittings.
• These valves must comply with ASSE 1062-2006, Performance Requirements for Temperature
Actuated Flow Reduction (TAFR) Valves for Individual Fixture Fittings.
• Intended for use in-line with, or integrated into, individual plumbing supply fittings such as shower
heads, bathtubs, whirlpool bathtubs, utility sink faucets, kitchen sinks, and lavatory faucets.
• Designed to automatically reduce flow to a trickle within five seconds of outlet temperatures greater
than a preset actuation temperature not to exceed 120° F (48.9° C).
• During the five (5) second response period, the bather may be exposed to temperatures in excess of
the set point of the device.
• After actuation, the device shall reset and open automatically at a predetermined lower temperature, or
with the use of a manual reset mechanism.
• These devices can be used on existing fixtures to provide scald protection – typically, where no other
form of scald protection is provided.
• TAFR valves are not intended to be installed in place of devices complying with ASSE 1016, ASSE
1017, ASSE 1066, ASSE 1069, or ASSE 1070.
• These devices provide scald protection ONLY, and DO NOT provide thermal shock protection.
CAUTION:
These valves automatically reduce discharge flow to a trickle if water temperature exceeds a preset limit.
This trickle can be as much as 0.25 GPM (0.95 L/m). When this device is installed on a bathtub spout and
the outlet temperature exceeds the preset limit, and if the bathtub drain is closed, the bathtub could fill
with extremely hot water from this allowable trickle.
CAUTION:
Some ultra-low-flow showerheads may still have a full spray pattern when the flow through this TAFR
device is reduced.
9Guidelines for Temperature Control Devices in Domestic Hot Water Systems
In-Line Pressure Balancing Devices for Individual Fixtures
• Automatic pressure balancing in-line valves are used to equalize incoming hot and cold water line
pressures. This minimizes mixed water temperature variations due to pressure fluctuations when used
in conjunction with a mixing valve or two handle valve set.
• These valves must comply with ASSE 1066-1997, Performance Requirements for Individual Pressure
Balancing In-Line Valves for Individual Fixture Fittings.
• They are not designed to limit the maximum outlet temperature at the point-of-use.
• These devices provide thermal shock protection for pressure disturbances ONLY, and
DO NOT provide scald protection if the incoming hot or cold water temperature changes.
10 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Tempered Water Through a Single Supply Pipe
• Automatic temperature control mixing valves shall be installed and set to supply only tempered water
to the end user, and automatically compensate for pressure and/or temperature variations in water
distribution systems.
• These valves must comply with ASSE 1069-2005, Performance Requirements for Automatic
Temperature Control Mixing Valves.
• These devices have the capability to significantly reduce the outlet flow in the event of a cold water
distribution system failure.
• The device is equipped with an adjustable means to limit the setting of the device towards the hot
position. The temperature limit stop must be set at the time of installation, and may be adjusted by the
building owner or representative.
• The device is designed to be the final temperature control.
• Intended to control the water temperature to individual or multiple fixtures.
• NOT intended for individual showers or tub/showers.
• Intended to be installed where the end user does NOT have access to the temperature adjustment
means.
• Designed to supply only tempered water to the end user.
• No further mixing downstream of the device.
• Typically installed for gang (multiple) showers and sitz baths.
• These devices provide scald protection and thermal shock protection.
11Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Temperature Control Devices with Downstream Mixing Permitted
• Water temperature limiting devices are intended to limit the hot or tempered water temperature supplied
to fittings for fixtures such as sinks, lavatories, bidets, or bathtubs to reduce the risk of scalding.
• These devices must comply with ASSE 1070-2015/ASME A112.1070-2015/CSA B125.70-15,
Performance Requirements for Water Temperature Limiting Devices.
• These devices are intended to supply tempered water to plumbing fixture fittings, or be integral with
plumbing fixture fittings supplying tempered water.
• These devices shall have:
a. Fixed (non-adjustable) temperature setting; or
b. Temperature setting that can be:
i. Adjusted and locked in position; or
ii. Adjusted with the use of a tool to protect against adjustment by the user.
• Further mixing downstream is allowed.
• These devices have an integral water temperature limiting capability. The user control allows the outlet
temperature to be adjusted up to a maximum temperature of 120° F (49° C).
• These devices provide scald protection ONLY, and DO NOT provide thermal shock protection.
12 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
Mixing Valves for Plumbed Emergency Equipment
• Temperature actuated mixing valves are intended to be used as a component that can provide tepid
water for emergency eye wash, eye wash/shower, drench showers, and combination units that comply
with the requirements of ANSI Z358.1.
• These valves must comply with ASSE 1071-2012, Performance Requirements for Temperature
Actuated Mixing Valves for Plumbed Emergency Equipment.
• These valves, by themselves, do not meet the requirements of ANSI Z358.1.
• These valves consist of a hot water inlet, a cold water inlet, a mixed water outlet, a temperature
controlling element, and a means for adjusting the mixed water outlet temperature while in service.
• These valves also have a means to limit the maximum outlet temperature under normal operating
conditions.
• Provisions shall be made so that the temperature cannot be inadvertently adjusted.
• These valves shall include a means of preventing cross-flow.
• Ideally, these devices are intended to be installed as close as possible to the plumbed emergency
equipment.
• These valves provide scald protection ONLY, and DO NOT provide thermal shock protection.
• These valves provide cold water bypass flow in the event of a hot water failure.
NOTE:
Emergency plumbed equipment must be flushed frequently, per industry standards, to minimize
stagnant water.
13Guidelines for Temperature Control Devices in Domestic Hot Water Systems
DEVICES LISTED TO
MULTIPLE STANDARDS
SECTION
4
There are many devices in the marketplace that are listed to multiple standards (e.g. ASSE 1017, ASSE
1069, and/or ASSE 1070). Devices listed to multiple standards are approved for each particular application
in accordance with the listing relevant to its use. While these devices listed to multiple standards are
designed to be installed in more than one application, a single device should not be installed to control the
entire temperature of the distribution system while simultaneously serving the needs of a fixture(s).
When a device listed to multiple standards is installed at the point of source or supply (at or about the
water heater) as a temperature control device for a potable water distribution system, it is considered to be
an ASSE 1017 device. It does NOT negate the requirement of an ASSE 1016, ASSE 1069, or ASSE 1070
type device, where required, to control the water temperature at the point of use.
Dual listed devices should be installed in accordance with one of the listed standards. When installed in
a particular location, the device should not be used to satisfy the requirements of multiple listings. Each
device should be installed within the scope and application of one of its respective standards.
14 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
QUESTIONS & ANSWERS
SECTION
5
In this section, we will introduce some hypothetical situations where the choice of the proper temperature
control device may not be absolutely clear. We will suggest a device and explain the rationale for the choice
– there may be other solutions available.
1. A high school wants to add a shower room with four metered showers.
Consistent with conservation requirements, they want to provide 105° F
water to the metering valves. What device can be used?
One solution is to install a device listed to ASSE 1069, in accordance with the manufacturer’s
installation instructions, with a single pipe system to all of the showers with a metering or on/off
control at each shower.
2. A plumber has a customer who has small children and wants to protect
the hot water to their bath tub. Since there is no access to the two hand
valve supply pipes, he wants to install a device at the water heater to limit
hot water to 110° F. What can he use to provide anti-scald protection?
One solution is to install a tub/shower combination valve listed to ASSE 1016 at the bath tub with the
limit stop set to 110° F.
Another solution would be to install a device listed to ASSE 1070 on the hot water supply to the bath
tub with the temperature limit set to 110° F.
Another solution is to install a device listed to ASSE 1062 on the bath tub spout.
* Installing a device listed to ASSE 1017 at the water heater will not provide adequate scald protection.
3. A hospital has several sitz baths located in individual cubicles. Can these
be supplied from a single, central ASSE 1070 control valve supply xture?
Yes. If the sitz bath has final adjustment capabilities of the water temperature at the point of use, the
proper device is one listed to ASSE 1070.
If the sitz bath uses only tempered water, the proper device is one listed to ASSE 1069.
15Guidelines for Temperature Control Devices in Domestic Hot Water Systems
QUESTIONS & ANSWERS
4. A doctor wants to have access to temperature adjustment at a scrub
sink he uses. Can a wall mounted 1016 valve be used to provide this
requirement?
No. A device listed to ASSE 1070 is to be used on surgical scrub sinks.
5. A plumber wants to install a device listed to multiple standards at the
water heater and set the limit stop to 110° F to not only control the
temperature of the water distribution system, but also to avoid the
potential of scalds at the downstream xtures. Is this a correct installation?
No. A device listed to multiple standards when installed to regulate the building’s distribution system
temperature should not be considered an ASSE 1069 or ASSE 1070 safety device. Mixing valves,
whether listed to ASSE 1017 or multiple-listed to ASSE 1017, ASSE 1069 or ASSE 1070, installed at
a water heater to regulate distribution temperature serve as ASSE 1017 point of source applications
ONLY. In this situation, the device will not be able to provide the required scald protection since the
device in this application only provides temperature control. Further point of use temperature control
devices must be installed as required.
16 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
DEFINITIONS
SECTION
6
Hot Water Source
Point at which hot water is generated.
Point of use
The final outlet of the water system just prior to discharge to atmosphere. (ASSE International
Plumbing Dictionary, 6th Edition)
Scalding
Hot water exposure for a time period long enough to cause a thermal injury. Scald burn injuries
can increase in severity at higher hot water temperatures or with longer exposures to a given
hot water temperature. (Scald Hazards Associated with Low-Flow Showerheads: A White Paper.
ASSE International, March 2012)
Thermal Shock
A significant sudden change in temperature from hot to cold or cold to hot, or hot to hotter that
causes a bather to violently react, which can lead to a slip and fall injury. (Scald Hazards Associated
with Low-Flow Showerheads: A White Paper. ASSE International, March 2012)
WATER
Cold Water
Water at temperatures of 40° F to 70° F (4° C to 21° C). (ASSE International Plumbing Dictionary,
6th Edition)
Hot Water
Water at a temperature of not less than 120° F (49° C). (ASSE International Plumbing Dictionary,
6th Edition)
Tempered water
A mixture of cold and hot water to produce warm water suitable for use. (ASSE International Plumbing
Dictionary, 6th Edition)
Tepid Water
A mixture of water, 60° F to 100° F, primarily used with emergency equipment. (ANSI Z358.1)
17Guidelines for Temperature Control Devices in Domestic Hot Water Systems
DEFINITIONS MATRIX
SECTION
7
STANDARD
NUMBER
SCALD
PROTECTION
THERMAL
SHOCK
PROTECTION
DOWNSTREAM
MIXING
ALLOWED
INSTALLED
AT
FINAL
TEMP
ADJUSTMENT
APPLICATION
ASSE 1016 YES YES NO
Point of use
YES Individual shower or
combination tub/shower valves *
ASSE 1017 NO NO YES At, or near, source NO Temperature control for hot
water distribution systems
ONLY. Additional downstream
safety devices required.
ASSE 1062 YES NO NO Point of use NO Temperature actuated ow
reduction device. These valves
are intended for use in-line with,
or are integrated into, individual
plumbing supply ttings such
as showerheads, bath, utility
faucets, sink and lavatory
faucets.
ASSE 1066 NO YES YES Ahead of the
control valve(s)
NO In-line ahead of individual
terminal ttings such as shower
ttings, bath, utility, sink or
lavatory faucets.
ASSE 1069 YES YES NO Where the bather
has no access to
the temperature
adjustment means
YES Single-pipe gang showers, sitz
baths
ASSE 1070 YES NO YES Near, or integral to,
plumbing xture
ttings
NO Controls and limits outlet water
temperature to ttings such
as sinks, lavatories, bidets or
bathtubs.
ASSE 1071 YES NO NO At the “plumbed
emergency
equipment”
Yes As part of “plumbed emergency
equipment” systems that
comply with ANSI Z358.1
*Refer to Model Codes - UPC-408.3 or IPC – 424.3 or IRC- P2708.3 or NSPC-1015.6
18 Guidelines for Temperature Control Devices in Domestic Hot Water Systems
TASK GROUP MEMBERS
SECTION
8
ASSE International expresses its sincerest gratitude to all of the members of this Scald Awareness Task
Group for their dedication and contributions to this project.
A total of 21 industry professionals contributed both time and expertise to the development of this
paper. The group is comprised of manufacturers, engineers, industry association members, master
plumbers, general interest individuals, inspectors, building officials, and labor representatives. Some of
the participants requested that their name and/or company name/affiliation not be mentioned in the paper.
Richard J. Prospal, FASSE ASSE International Past President, FASSE
Chairperson Prospal Consulting Services, Inc., Master Plumber
John Bertrand Moen Incorporated, Manager – Compliance
Laura Biggie Los Angeles Department of Building and Safety
David Dertz Village of Olympia Fields, Illinois State Certified Plumbing Inspector
Richard (Dick) Emmerson, FASSE Retired
Matthew Fratantonio Watts Water Technology, Engineering Manager – Thermostatics
Rob Furioso Symmons Inc., Product Compliance Administration
Ron George Plumb-Tech Design & Consulting Services, LLC, President
Steven Gregory Vernet SAS, Manager
Roger Griffith Griffith Engineering & Consulting, Inc., President
Wayne Harrison Wayne Harrison Consulting
Donald M. Jones NJ DCA Bureau of Code Services, Construction Code Inspector
Tim Kilbane Symmons, Inc., National Sales Manager Emeritus
John Koeller Koeller and Company, MaP Testing
Mannan Mohammed Reliance Worldwide Corporation (Canada), Inc., Engineering Manager
Shabbir Rawalpindiwala Kohler Co., Manager – Codes and Standards
Edward Saltzberg Edward Saltzberg & Associates
Michael Savage City of Rio Rancho, NM, Chief Building Official
Frederick Schilling Florida Building Commission, Commissioner, Master Plumber
Chris Shiver Chris Shiver, PE, LLC
Matt Sigler Plumbing Manufacturers International (PMI), Technical Director
Billy Smith American Society of Plumbing Engineers (ASPE),
Executive Director/CEO
TASK GROUP MEMBERS
ASSE International
18927 Hickory Creek Drive, Suite 220, Mokena, Illinois 60448
(708) 995-3019 | www.asse-plumbing.org
®
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