They say time flies when you are having fun, and I sometimes find it hard to believe that I am rapidly approaching the 40-year mark in my engineering career. I have spent the majority of that time in manufacturing in the PVF field. I have traveled around the globe, met remarkable people, and made enduring friendships. In October 2023, I had the opportunity to change directions when I joined IAPMO as the director of Standards Development. I have volunteered for decades in several standards development organizations, but always had an affinity for ASSE, where I have served on the Code and Product Standards Committees, Seal Control Board and Board of Directors as the manufacturers’ representative. I like standards because they level the playing field and set minimum product performance and professional qualification requirements.
A few weeks ago, ASSE / IAPMO’s senior graphic designer, Ben Ryan, asked if I would consider being a regular contributor to this magazine and I jumped at the opportunity. My Cite the Standard column will review a standard or related group of standards, give some background on their development, and show where they might be used. I hope you enjoy my column and welcome your feedback, particularly regarding which standards you would like me to address in the future. Here we go!
Sometimes it is easy to take for granted the many conveniences our modern lifestyles provide. Want a cold beverage? Grab one from the refrigerator. Need to warm up your lunch? Heat it in less than a minute in the microwave. Want to go to the gym? Mine is a 10-minute walk from my home. Want to wash up after your workout? Jump into a shower and adjust the water temperature until it’s just right. Aaah!
The ability to have water delivered on demand at a comfortable temperature and without a concern of scalding is a surprisingly new experience. In the past, water heaters were installed with an often alarmingly high pre-set temperature, and it was up to the user to adjust the water temperature at a fixture as needed. Cold water demand elsewhere in the localized plumbing system (the flushing of toilets or activation of a lawn sprinkler system, for example) could result in a blast of unmixed hot water at the fixture. While it is an easy task to quickly remove one’s hands from a faucet’s flow, getting out of the way of a shower stream is more difficult. The very young and old are particularly susceptible to scalding. Scalding is time and temperature dependent, but water exposures at temperatures as low as 120˚F can result in burns.
Thermal shock, the rapid and unexpected change in water temperature and/or pressure, is another concern. Thermal shock is the leading cause of bathers’ slip-andfall injuries.
Frederick Leonard, founder of Leonard Valve Company, is credited with inventing the first thermostatic mixing valve in 1911 after experiencing a scald from a hot towel placed on his face at a barber shop. Leonard’s valve utilized a thermostat formed of strips of two metals with different coefficients of thermal expansion. This type of thermostat would remain the primary technology used for mixing valves used in plumbing applications for the next 60 years.
The world of innovation is rife with examples of inventions in one field leading to advances in another. The aforementioned microwave was initially a military radar component. Play-Doh was sold as a wall cleaner until children discovered it was fun to mash into shapes. Pyrex glass was first used in the construction of high temperature railroad lanterns before being adapted into cookware. We find the same cross-pollination in the plumbing world. In 1934, Sergius Vernet realized he could use the thermal expansion properties of wax to make an element that could very precisely control the flow of coolant to an automotive radiator. Remarkably it was not until the 1970s that the wax thermostat element was adopted for plumbing applications, but today it is the most prevalent thermostat type used in our industry. ASSE publishes five distinct mixing valve standards:
ASSE 1016 AUTOMATIC COMPENSATING VALVES FOR INDIVIDUAL SHOWERS AND TUB/SHOWER COMBINATIONS (FIRST PUBLISHED IN 1973)
This standard covers automatic compensating valves offered in three types (P = pressure balancing, T = thermostatic and T/P = combination) that have hot- and cold-water inlet connections and a mixed water outlet where a selected mixed outlet temperature is maintained. These devices are installed at the point of use, where the user has access to flow or final temperature controls, and where no further downstream mixing occurs. The shower control valves covered by this standard will, in cases of changes to the incoming water supply pressure or temperature, reduce the risk of scalding and thermal shock.
ASSE 1017 TEMPERATURE ACTUATED MIXING VALVES FOR HOT WATER DISTRIBUTION SYSTEMS (FIRST PUBLISHED IN 1976)
This standard covers temperature actuated master mixing valves for hot water distribution systems that consist of hot- and cold-water inlet connections, a mixed water outlet, a thermal element or thermostatic sensor and a means for adjusting the mixed water outlet temperature. These devices are installed at the hot water source and are not intended for point‐of‐use temperature limiting, control or end use applications. These devices can be either mechanically actuated or electronically controlled and must be supplemented by a point‐of‐use device or in‐line device designed to control the final temperature.
ASSE 1069 AUTOMATIC TEMPERATURE CONTROL MIXING VALVES (FIRST PUBLISHED IN 1996)
This standard covers devices intended to control the water temperature to individual or multiple fixtures to reduce the risk of scalding and thermal shock. These devices are intended to be installed where the bather has no access to the temperature adjustment means, and where no further mixing occurs downstream of the device. These devices are designed to supply only tempered water to the end user, and automatically compensate for pressure and/or temperature variations in water distribution systems. These devices have the capability to significantly reduce the outlet flow in the event of a cold-water distribution system failure and are equipped with an adjustable means to limit the setting of the device towards the hot position.
ASSE 1070 WATER TEMPERATURE LIMITING DEVICES (FIRST PUBLISHED IN 2004)
This standard covers water temperature limiting devices intended to limit the hot or tempered water temperature supplied to fittings for fixtures such as sinks, bidets, lavatories, and bathtubs to reduce the risk of scalding. These devices are not designed to address thermal shock; they are intended to supply tempered water to plumbing fixture fittings or be integral with plumbing fixture fittings supplying tempered water. These devices are equipped with an adjustable and lockable means to limit the setting of the device toward the hot position.
ASSE 1071 TEMPERATURE ACTUATED MIXING VALVES FOR PLUMBED EMERGENCY EQUIPMENT
(FIRST PUBLISHED IN 2008)
This standard covers devices consisting of hot- and cold-water inlet connections, a mixed water outlet connection, a temperature controlling element, and a means for adjusting the mixed water outlet temperature while in service. The devices also have a means to limit the maximum outlet temperature under normal operating conditions. These devices — including eyewash, eye/face wash, drench showers, and combination units — are intended to be installed in systems that comply with ANSI Z358.1, Standard for Emergency Eyewash and Shower Equipment.
ASSE 1066 INDIVIDUAL PRESSURE BALANCING IN-LINE VALVES FOR INDIVIDUAL FIXTURE FITTINGS (FIRST PUBLISHED IN 1993)
This standard covers automatic pressure balancing in-line valves for individual fixture fittings, which are used to equalize incoming hot- and cold-water line pressures for the purpose of minimizing mixed water temperature variations due to pressure fluctuations when used in conjunction with a mixing valve or two-handle valve set. They are not designed to limit the maximum outlet temperature at the point of use. These devices are intended for use with individual plumbing fixture fittings used with showers, bathtubs, utility sinks, and shampoo sinks. These devices have a hot- and coldwater inlet and outlets, and equalize incoming hot- and cold-water line pressures for the purpose of minimizing mixed water temperature variations due to pressure fluctuations from the supply side. These devices have the capability to significantly reduce the outlet flow in the event of a cold- or hot-water supply failure.
In summary, the five ASSE mixing valve standards are for specific applications – 1016 for showers and tub/ shower combinations, 1017 for master mixing at the hot water source, 1069 for gang applications where no mixing occurs by the user, 1070 for lavatories and sinks, and 1071 for safety applications. Some mixing valves are certified to more than one of the subject standards. It is imperative the right device be used in the appropriate application. If in doubt, contact the manufacturer for additional information.
